linux/tools/perf/util/symbol-elf.c

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#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <inttypes.h>
#include "symbol.h"
#include "demangle-java.h"
perf symbols: Add Rust demangling Rust demangling is another step after bfd demangling. Add a diagnosis to identify mangled Rust symbols based on the hash that the Rust mangler appends as the last path component, as well as other characteristics. Add a demangler to reconstruct the original symbol. Committer notes: How I tested it: Enabled COPR on Fedora 24 and then installed the 'rust-binary' package, with it: $ cat src/main.rs fn main() { println!("Hello, world!"); } $ cat Cargo.toml [package] name = "hello_world" version = "0.0.1" authors = [ "Arnaldo Carvalho de Melo <acme@kernel.org>" ] $ perf record cargo bench Compiling hello_world v0.0.1 (file:///home/acme/projects/hello_world) Running target/release/hello_world-d4b9dab4b2a47d75 running 0 tests test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.096 MB perf.data (1457 samples) ] $ Before this patch: $ perf report --stdio --dsos librbml-e8edd0fd.so # dso: librbml-e8edd0fd.so # # Total Lost Samples: 0 # # Samples: 1K of event 'cycles:u' # Event count (approx.): 979599126 # # Overhead Command Symbol # ........ ....... ............................................................................................................. # 1.78% rustc [.] rbml::reader::maybe_get_doc::hb9d387df6024b15b 1.50% rustc [.] _$LT$reader..DocsIterator$LT$$u27$a$GT$$u20$as$u20$std..iter..Iterator$GT$::next::hd9af9e60d79a35c8 1.20% rustc [.] rbml::reader::doc_at::hc88107fba445af31 0.46% rustc [.] _$LT$reader..TaggedDocsIterator$LT$$u27$a$GT$$u20$as$u20$std..iter..Iterator$GT$::next::h0cb40e696e4bb489 0.35% rustc [.] rbml::reader::Decoder::_next_int::h66eef7825a398bc3 0.29% rustc [.] rbml::reader::Decoder::_next_sub::h8e5266005580b836 0.15% rustc [.] rbml::reader::get_doc::h094521c645459139 0.14% rustc [.] _$LT$reader..Decoder$LT$$u27$doc$GT$$u20$as$u20$serialize..Decoder$GT$::read_u32::h0acea2fff9669327 0.07% rustc [.] rbml::reader::Decoder::next_doc::h6714d469c9dfaf91 0.07% rustc [.] _ZN4rbml6reader10doc_as_u6417h930b740aa94f1d3aE@plt 0.06% rustc [.] _fini $ After: $ perf report --stdio --dsos librbml-e8edd0fd.so # dso: librbml-e8edd0fd.so # # Total Lost Samples: 0 # # Samples: 1K of event 'cycles:u' # Event count (approx.): 979599126 # # Overhead Command Symbol # ........ ....... ................................................................. # 1.78% rustc [.] rbml::reader::maybe_get_doc 1.50% rustc [.] <reader::DocsIterator<'a> as std::iter::Iterator>::next 1.20% rustc [.] rbml::reader::doc_at 0.46% rustc [.] <reader::TaggedDocsIterator<'a> as std::iter::Iterator>::next 0.35% rustc [.] rbml::reader::Decoder::_next_int 0.29% rustc [.] rbml::reader::Decoder::_next_sub 0.15% rustc [.] rbml::reader::get_doc 0.14% rustc [.] <reader::Decoder<'doc> as serialize::Decoder>::read_u32 0.07% rustc [.] rbml::reader::Decoder::next_doc 0.07% rustc [.] _ZN4rbml6reader10doc_as_u6417h930b740aa94f1d3aE@plt 0.06% rustc [.] _fini $ Signed-off-by: David Tolnay <dtolnay@gmail.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5780B7FA.3030602@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-09 15:20:00 +08:00
#include "demangle-rust.h"
#include "machine.h"
#include "vdso.h"
#include "debug.h"
#include "sane_ctype.h"
#include <symbol/kallsyms.h>
#ifndef EM_AARCH64
#define EM_AARCH64 183 /* ARM 64 bit */
#endif
typedef Elf64_Nhdr GElf_Nhdr;
#ifdef HAVE_CPLUS_DEMANGLE_SUPPORT
extern char *cplus_demangle(const char *, int);
static inline char *bfd_demangle(void __maybe_unused *v, const char *c, int i)
{
return cplus_demangle(c, i);
}
#else
#ifdef NO_DEMANGLE
static inline char *bfd_demangle(void __maybe_unused *v,
const char __maybe_unused *c,
int __maybe_unused i)
{
return NULL;
}
#else
#define PACKAGE 'perf'
#include <bfd.h>
#endif
#endif
#ifndef HAVE_ELF_GETPHDRNUM_SUPPORT
static int elf_getphdrnum(Elf *elf, size_t *dst)
{
GElf_Ehdr gehdr;
GElf_Ehdr *ehdr;
ehdr = gelf_getehdr(elf, &gehdr);
if (!ehdr)
return -1;
*dst = ehdr->e_phnum;
return 0;
}
#endif
#ifndef HAVE_ELF_GETSHDRSTRNDX_SUPPORT
static int elf_getshdrstrndx(Elf *elf __maybe_unused, size_t *dst __maybe_unused)
{
pr_err("%s: update your libelf to > 0.140, this one lacks elf_getshdrstrndx().\n", __func__);
return -1;
}
#endif
#ifndef NT_GNU_BUILD_ID
#define NT_GNU_BUILD_ID 3
#endif
/**
* elf_symtab__for_each_symbol - iterate thru all the symbols
*
* @syms: struct elf_symtab instance to iterate
* @idx: uint32_t idx
* @sym: GElf_Sym iterator
*/
#define elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) \
for (idx = 0, gelf_getsym(syms, idx, &sym);\
idx < nr_syms; \
idx++, gelf_getsym(syms, idx, &sym))
static inline uint8_t elf_sym__type(const GElf_Sym *sym)
{
return GELF_ST_TYPE(sym->st_info);
}
#ifndef STT_GNU_IFUNC
#define STT_GNU_IFUNC 10
#endif
static inline int elf_sym__is_function(const GElf_Sym *sym)
{
return (elf_sym__type(sym) == STT_FUNC ||
elf_sym__type(sym) == STT_GNU_IFUNC) &&
sym->st_name != 0 &&
sym->st_shndx != SHN_UNDEF;
}
static inline bool elf_sym__is_object(const GElf_Sym *sym)
{
return elf_sym__type(sym) == STT_OBJECT &&
sym->st_name != 0 &&
sym->st_shndx != SHN_UNDEF;
}
static inline int elf_sym__is_label(const GElf_Sym *sym)
{
return elf_sym__type(sym) == STT_NOTYPE &&
sym->st_name != 0 &&
sym->st_shndx != SHN_UNDEF &&
sym->st_shndx != SHN_ABS;
}
static bool elf_sym__is_a(GElf_Sym *sym, enum map_type type)
{
switch (type) {
case MAP__FUNCTION:
return elf_sym__is_function(sym);
case MAP__VARIABLE:
return elf_sym__is_object(sym);
default:
return false;
}
}
static inline const char *elf_sym__name(const GElf_Sym *sym,
const Elf_Data *symstrs)
{
return symstrs->d_buf + sym->st_name;
}
static inline const char *elf_sec__name(const GElf_Shdr *shdr,
const Elf_Data *secstrs)
{
return secstrs->d_buf + shdr->sh_name;
}
static inline int elf_sec__is_text(const GElf_Shdr *shdr,
const Elf_Data *secstrs)
{
return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;
}
static inline bool elf_sec__is_data(const GElf_Shdr *shdr,
const Elf_Data *secstrs)
{
return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;
}
static bool elf_sec__is_a(GElf_Shdr *shdr, Elf_Data *secstrs,
enum map_type type)
{
switch (type) {
case MAP__FUNCTION:
return elf_sec__is_text(shdr, secstrs);
case MAP__VARIABLE:
return elf_sec__is_data(shdr, secstrs);
default:
return false;
}
}
static size_t elf_addr_to_index(Elf *elf, GElf_Addr addr)
{
Elf_Scn *sec = NULL;
GElf_Shdr shdr;
size_t cnt = 1;
while ((sec = elf_nextscn(elf, sec)) != NULL) {
gelf_getshdr(sec, &shdr);
if ((addr >= shdr.sh_addr) &&
(addr < (shdr.sh_addr + shdr.sh_size)))
return cnt;
++cnt;
}
return -1;
}
Elf_Scn *elf_section_by_name(Elf *elf, GElf_Ehdr *ep,
GElf_Shdr *shp, const char *name, size_t *idx)
{
Elf_Scn *sec = NULL;
size_t cnt = 1;
/* Elf is corrupted/truncated, avoid calling elf_strptr. */
if (!elf_rawdata(elf_getscn(elf, ep->e_shstrndx), NULL))
return NULL;
while ((sec = elf_nextscn(elf, sec)) != NULL) {
char *str;
gelf_getshdr(sec, shp);
str = elf_strptr(elf, ep->e_shstrndx, shp->sh_name);
if (str && !strcmp(name, str)) {
if (idx)
*idx = cnt;
return sec;
}
++cnt;
}
return NULL;
}
static bool want_demangle(bool is_kernel_sym)
{
return is_kernel_sym ? symbol_conf.demangle_kernel : symbol_conf.demangle;
}
static char *demangle_sym(struct dso *dso, int kmodule, const char *elf_name)
{
int demangle_flags = verbose > 0 ? (DMGL_PARAMS | DMGL_ANSI) : DMGL_NO_OPTS;
char *demangled = NULL;
/*
* We need to figure out if the object was created from C++ sources
* DWARF DW_compile_unit has this, but we don't always have access
* to it...
*/
if (!want_demangle(dso->kernel || kmodule))
return demangled;
demangled = bfd_demangle(NULL, elf_name, demangle_flags);
if (demangled == NULL)
demangled = java_demangle_sym(elf_name, JAVA_DEMANGLE_NORET);
else if (rust_is_mangled(demangled))
/*
* Input to Rust demangling is the BFD-demangled
* name which it Rust-demangles in place.
*/
rust_demangle_sym(demangled);
return demangled;
}
#define elf_section__for_each_rel(reldata, pos, pos_mem, idx, nr_entries) \
for (idx = 0, pos = gelf_getrel(reldata, 0, &pos_mem); \
idx < nr_entries; \
++idx, pos = gelf_getrel(reldata, idx, &pos_mem))
#define elf_section__for_each_rela(reldata, pos, pos_mem, idx, nr_entries) \
for (idx = 0, pos = gelf_getrela(reldata, 0, &pos_mem); \
idx < nr_entries; \
++idx, pos = gelf_getrela(reldata, idx, &pos_mem))
/*
* We need to check if we have a .dynsym, so that we can handle the
* .plt, synthesizing its symbols, that aren't on the symtabs (be it
* .dynsym or .symtab).
* And always look at the original dso, not at debuginfo packages, that
* have the PLT data stripped out (shdr_rel_plt.sh_type == SHT_NOBITS).
*/
int dso__synthesize_plt_symbols(struct dso *dso, struct symsrc *ss, struct map *map)
{
uint32_t nr_rel_entries, idx;
GElf_Sym sym;
u64 plt_offset;
GElf_Shdr shdr_plt;
struct symbol *f;
GElf_Shdr shdr_rel_plt, shdr_dynsym;
Elf_Data *reldata, *syms, *symstrs;
Elf_Scn *scn_plt_rel, *scn_symstrs, *scn_dynsym;
size_t dynsym_idx;
GElf_Ehdr ehdr;
char sympltname[1024];
Elf *elf;
int nr = 0, symidx, err = 0;
perf symbols: Fix builds with NO_LIBELF set Build currently fails: $ make -C tools/perf O=/tmp/pbuild NO_LIBELF=1 util/symbol.c: In function ‘dso__load’: util/symbol.c:1128:27: error: ‘struct symsrc’ has no member named ‘dynsym’ CC /tmp/pbuild/util/pager.o make: *** [/tmp/pbuild/util/symbol.o] Error 1 make: *** Waiting for unfinished jobs.... Moving the dynsym reference to symbol-elf.c reveals that NO_LIBELF requires NO_LIBUNWIND: $ make -C tools/perf O=/tmp/pbuild NO_LIBELF=1 LINK /tmp/pbuild/perf /tmp/pbuild/libperf.a(unwind.o): In function `elf_section_offset': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:176: undefined reference to `elf_begin' /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:181: undefined reference to `gelf_getehdr' /tmp/pbuild/libperf.a(unwind.o): In function `elf_section_by_name': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:157: undefined reference to `elf_nextscn' /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:160: undefined reference to `gelf_getshdr' /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:161: undefined reference to `elf_strptr' /tmp/pbuild/libperf.a(unwind.o): In function `elf_section_offset': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:190: undefined reference to `elf_end' /tmp/pbuild/libperf.a(unwind.o): In function `read_unwind_spec': /opt/sw/ahern/perf.git/tools/perf/util/unwind.c:190: undefined reference to `elf_end' collect2: ld returned 1 exit status make: *** [/tmp/pbuild/perf] Error 1 make: Leaving directory `/opt/sw/ahern/perf.git/tools/perf' This patch fixes both. Reviewed-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/1345391234-71906-1-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-19 23:47:14 +08:00
if (!ss->dynsym)
return 0;
elf = ss->elf;
ehdr = ss->ehdr;
scn_dynsym = ss->dynsym;
shdr_dynsym = ss->dynshdr;
dynsym_idx = ss->dynsym_idx;
if (scn_dynsym == NULL)
goto out_elf_end;
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rela.plt", NULL);
if (scn_plt_rel == NULL) {
scn_plt_rel = elf_section_by_name(elf, &ehdr, &shdr_rel_plt,
".rel.plt", NULL);
if (scn_plt_rel == NULL)
goto out_elf_end;
}
err = -1;
if (shdr_rel_plt.sh_link != dynsym_idx)
goto out_elf_end;
if (elf_section_by_name(elf, &ehdr, &shdr_plt, ".plt", NULL) == NULL)
goto out_elf_end;
/*
* Fetch the relocation section to find the idxes to the GOT
* and the symbols in the .dynsym they refer to.
*/
reldata = elf_getdata(scn_plt_rel, NULL);
if (reldata == NULL)
goto out_elf_end;
syms = elf_getdata(scn_dynsym, NULL);
if (syms == NULL)
goto out_elf_end;
scn_symstrs = elf_getscn(elf, shdr_dynsym.sh_link);
if (scn_symstrs == NULL)
goto out_elf_end;
symstrs = elf_getdata(scn_symstrs, NULL);
if (symstrs == NULL)
goto out_elf_end;
if (symstrs->d_size == 0)
goto out_elf_end;
nr_rel_entries = shdr_rel_plt.sh_size / shdr_rel_plt.sh_entsize;
plt_offset = shdr_plt.sh_offset;
if (shdr_rel_plt.sh_type == SHT_RELA) {
GElf_Rela pos_mem, *pos;
elf_section__for_each_rela(reldata, pos, pos_mem, idx,
nr_rel_entries) {
const char *elf_name = NULL;
char *demangled = NULL;
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
elf_name = elf_sym__name(&sym, symstrs);
demangled = demangle_sym(dso, 0, elf_name);
if (demangled != NULL)
elf_name = demangled;
snprintf(sympltname, sizeof(sympltname),
"%s@plt", elf_name);
free(demangled);
f = symbol__new(plt_offset, shdr_plt.sh_entsize,
STB_GLOBAL, sympltname);
if (!f)
goto out_elf_end;
symbols__insert(&dso->symbols[map->type], f);
++nr;
}
} else if (shdr_rel_plt.sh_type == SHT_REL) {
GElf_Rel pos_mem, *pos;
elf_section__for_each_rel(reldata, pos, pos_mem, idx,
nr_rel_entries) {
const char *elf_name = NULL;
char *demangled = NULL;
symidx = GELF_R_SYM(pos->r_info);
plt_offset += shdr_plt.sh_entsize;
gelf_getsym(syms, symidx, &sym);
elf_name = elf_sym__name(&sym, symstrs);
demangled = demangle_sym(dso, 0, elf_name);
if (demangled != NULL)
elf_name = demangled;
snprintf(sympltname, sizeof(sympltname),
"%s@plt", elf_name);
free(demangled);
f = symbol__new(plt_offset, shdr_plt.sh_entsize,
STB_GLOBAL, sympltname);
if (!f)
goto out_elf_end;
symbols__insert(&dso->symbols[map->type], f);
++nr;
}
}
err = 0;
out_elf_end:
if (err == 0)
return nr;
pr_debug("%s: problems reading %s PLT info.\n",
__func__, dso->long_name);
return 0;
}
char *dso__demangle_sym(struct dso *dso, int kmodule, char *elf_name)
{
return demangle_sym(dso, kmodule, elf_name);
}
/*
* Align offset to 4 bytes as needed for note name and descriptor data.
*/
#define NOTE_ALIGN(n) (((n) + 3) & -4U)
static int elf_read_build_id(Elf *elf, void *bf, size_t size)
{
int err = -1;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf_Data *data;
Elf_Scn *sec;
Elf_Kind ek;
void *ptr;
if (size < BUILD_ID_SIZE)
goto out;
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
goto out;
if (gelf_getehdr(elf, &ehdr) == NULL) {
pr_err("%s: cannot get elf header.\n", __func__);
goto out;
}
/*
* Check following sections for notes:
* '.note.gnu.build-id'
* '.notes'
* '.note' (VDSO specific)
*/
do {
sec = elf_section_by_name(elf, &ehdr, &shdr,
".note.gnu.build-id", NULL);
if (sec)
break;
sec = elf_section_by_name(elf, &ehdr, &shdr,
".notes", NULL);
if (sec)
break;
sec = elf_section_by_name(elf, &ehdr, &shdr,
".note", NULL);
if (sec)
break;
return err;
} while (0);
data = elf_getdata(sec, NULL);
if (data == NULL)
goto out;
ptr = data->d_buf;
while (ptr < (data->d_buf + data->d_size)) {
GElf_Nhdr *nhdr = ptr;
size_t namesz = NOTE_ALIGN(nhdr->n_namesz),
descsz = NOTE_ALIGN(nhdr->n_descsz);
const char *name;
ptr += sizeof(*nhdr);
name = ptr;
ptr += namesz;
if (nhdr->n_type == NT_GNU_BUILD_ID &&
nhdr->n_namesz == sizeof("GNU")) {
if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
size_t sz = min(size, descsz);
memcpy(bf, ptr, sz);
memset(bf + sz, 0, size - sz);
err = descsz;
break;
}
}
ptr += descsz;
}
out:
return err;
}
int filename__read_build_id(const char *filename, void *bf, size_t size)
{
int fd, err = -1;
Elf *elf;
if (size < BUILD_ID_SIZE)
goto out;
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
goto out_close;
}
err = elf_read_build_id(elf, bf, size);
elf_end(elf);
out_close:
close(fd);
out:
return err;
}
int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
{
int fd, err = -1;
if (size < BUILD_ID_SIZE)
goto out;
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
while (1) {
char bf[BUFSIZ];
GElf_Nhdr nhdr;
size_t namesz, descsz;
if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
break;
namesz = NOTE_ALIGN(nhdr.n_namesz);
descsz = NOTE_ALIGN(nhdr.n_descsz);
if (nhdr.n_type == NT_GNU_BUILD_ID &&
nhdr.n_namesz == sizeof("GNU")) {
if (read(fd, bf, namesz) != (ssize_t)namesz)
break;
if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
size_t sz = min(descsz, size);
if (read(fd, build_id, sz) == (ssize_t)sz) {
memset(build_id + sz, 0, size - sz);
err = 0;
break;
}
} else if (read(fd, bf, descsz) != (ssize_t)descsz)
break;
} else {
int n = namesz + descsz;
if (n > (int)sizeof(bf)) {
n = sizeof(bf);
pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
__func__, filename, nhdr.n_namesz, nhdr.n_descsz);
}
if (read(fd, bf, n) != n)
break;
}
}
close(fd);
out:
return err;
}
int filename__read_debuglink(const char *filename, char *debuglink,
size_t size)
{
int fd, err = -1;
Elf *elf;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
Elf_Data *data;
Elf_Scn *sec;
Elf_Kind ek;
fd = open(filename, O_RDONLY);
if (fd < 0)
goto out;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug2("%s: cannot read %s ELF file.\n", __func__, filename);
goto out_close;
}
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
goto out_elf_end;
if (gelf_getehdr(elf, &ehdr) == NULL) {
pr_err("%s: cannot get elf header.\n", __func__);
goto out_elf_end;
}
sec = elf_section_by_name(elf, &ehdr, &shdr,
".gnu_debuglink", NULL);
if (sec == NULL)
goto out_elf_end;
data = elf_getdata(sec, NULL);
if (data == NULL)
goto out_elf_end;
/* the start of this section is a zero-terminated string */
strncpy(debuglink, data->d_buf, size);
err = 0;
out_elf_end:
elf_end(elf);
out_close:
close(fd);
out:
return err;
}
static int dso__swap_init(struct dso *dso, unsigned char eidata)
{
static unsigned int const endian = 1;
dso->needs_swap = DSO_SWAP__NO;
switch (eidata) {
case ELFDATA2LSB:
/* We are big endian, DSO is little endian. */
if (*(unsigned char const *)&endian != 1)
dso->needs_swap = DSO_SWAP__YES;
break;
case ELFDATA2MSB:
/* We are little endian, DSO is big endian. */
if (*(unsigned char const *)&endian != 0)
dso->needs_swap = DSO_SWAP__YES;
break;
default:
pr_err("unrecognized DSO data encoding %d\n", eidata);
return -EINVAL;
}
return 0;
}
static int decompress_kmodule(struct dso *dso, const char *name,
enum dso_binary_type type)
{
int fd = -1;
char tmpbuf[] = "/tmp/perf-kmod-XXXXXX";
struct kmod_path m;
if (type != DSO_BINARY_TYPE__SYSTEM_PATH_KMODULE_COMP &&
type != DSO_BINARY_TYPE__GUEST_KMODULE_COMP &&
type != DSO_BINARY_TYPE__BUILD_ID_CACHE)
return -1;
if (kmod_path__parse_ext(&m, dso->long_name) || !m.comp)
return -1;
fd = mkstemp(tmpbuf);
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (fd < 0) {
dso->load_errno = errno;
goto out;
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
}
if (!decompress_to_file(m.ext, name, fd)) {
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
dso->load_errno = DSO_LOAD_ERRNO__DECOMPRESSION_FAILURE;
close(fd);
fd = -1;
}
unlink(tmpbuf);
out:
free(m.ext);
return fd;
}
perf symbols: Use both runtime and debug images We keep both a 'runtime' elf image as well as a 'debug' elf image around and generate symbols by looking at both of these. This eliminates the need for the want_symtab/goto restart mechanism combined with iterating over and reopening the elf images a second time. Also give dso__synthsize_plt_symbols() the runtime image (which has dynsyms) instead of the symbol image (which may only have a symtab and no dynsyms). Previously if a debug image was found all runtime images were ignored. This fixes 2 issues: - Symbol resolution to failure on PowerPC systems with debug symbols installed, as the debug images lack a '.opd' section which contains function descriptors. - On all archs, plt synthesis failed when a debug image was loaded and that debug image lacks a dynsym section while a runtime image has a dynsym section. Assumptions: - If a .opd section exists, it is contained in the highest priority image with a dynsym section. - This generally implies that the debug image lacks a dynsym section (ie: it is marked as NO_BITS). Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com> Cc: David Hansen <dave@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Hellsley <matthltc@us.ibm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1344637382-22789-17-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-08-11 06:23:02 +08:00
bool symsrc__possibly_runtime(struct symsrc *ss)
{
return ss->dynsym || ss->opdsec;
}
bool symsrc__has_symtab(struct symsrc *ss)
{
return ss->symtab != NULL;
}
void symsrc__destroy(struct symsrc *ss)
{
zfree(&ss->name);
elf_end(ss->elf);
close(ss->fd);
}
bool __weak elf__needs_adjust_symbols(GElf_Ehdr ehdr)
{
return ehdr.e_type == ET_EXEC || ehdr.e_type == ET_REL;
}
int symsrc__init(struct symsrc *ss, struct dso *dso, const char *name,
enum dso_binary_type type)
{
int err = -1;
GElf_Ehdr ehdr;
Elf *elf;
int fd;
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (dso__needs_decompress(dso)) {
fd = decompress_kmodule(dso, name, type);
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (fd < 0)
return -1;
} else {
fd = open(name, O_RDONLY);
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (fd < 0) {
dso->load_errno = errno;
return -1;
}
}
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL) {
pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
goto out_close;
}
if (gelf_getehdr(elf, &ehdr) == NULL) {
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
dso->load_errno = DSO_LOAD_ERRNO__INVALID_ELF;
pr_debug("%s: cannot get elf header.\n", __func__);
goto out_elf_end;
}
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (dso__swap_init(dso, ehdr.e_ident[EI_DATA])) {
dso->load_errno = DSO_LOAD_ERRNO__INTERNAL_ERROR;
goto out_elf_end;
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
}
/* Always reject images with a mismatched build-id: */
if (dso->has_build_id && !symbol_conf.ignore_vmlinux_buildid) {
u8 build_id[BUILD_ID_SIZE];
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (elf_read_build_id(elf, build_id, BUILD_ID_SIZE) < 0) {
dso->load_errno = DSO_LOAD_ERRNO__CANNOT_READ_BUILDID;
goto out_elf_end;
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
}
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (!dso__build_id_equal(dso, build_id)) {
pr_debug("%s: build id mismatch for %s.\n", __func__, name);
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
dso->load_errno = DSO_LOAD_ERRNO__MISMATCHING_BUILDID;
goto out_elf_end;
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
}
}
ss->is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
ss->symtab = elf_section_by_name(elf, &ehdr, &ss->symshdr, ".symtab",
NULL);
if (ss->symshdr.sh_type != SHT_SYMTAB)
ss->symtab = NULL;
ss->dynsym_idx = 0;
ss->dynsym = elf_section_by_name(elf, &ehdr, &ss->dynshdr, ".dynsym",
&ss->dynsym_idx);
if (ss->dynshdr.sh_type != SHT_DYNSYM)
ss->dynsym = NULL;
ss->opdidx = 0;
ss->opdsec = elf_section_by_name(elf, &ehdr, &ss->opdshdr, ".opd",
&ss->opdidx);
if (ss->opdshdr.sh_type != SHT_PROGBITS)
ss->opdsec = NULL;
perf symbols: Adjust symbol for shared objects He Kuang reported a problem that perf fails to get correct symbol on Android platform in [1]. The problem can be reproduced on normal x86_64 platform. I will describe the reproducing steps in detail at the end of commit message. The reason of this problem is the missing of symbol adjustment for normal shared objects. In most of the cases skipping adjustment is okay. However, when '.text' section have different 'address' and 'offset' the result is wrong. I checked all shared objects in my working platform, only wine dll objects and debug objects (in .debug) have this problem. However, it is common on Android. For example: $ readelf -S ./libsurfaceflinger.so | grep \.text [10] .text PROGBITS 0000000000029030 00012030 This patch enables symbol adjustment for dynamic objects so the symbol address got from elfutils would be adjusted correctly. Now nearly all types of ELF files should adjust symbols. Makes ss->adjust_symbols default to true. Steps to reproduce the problem: $ cat ./Makefile PWD := $(shell pwd) LDFLAGS += "-Wl,-rpath=$(PWD)" CFLAGS += -g main: main.c libbuggy.so libbuggy.so: buggy.c gcc -g -shared -fPIC -Wl,-Ttext-segment=0x200000 $< -o $@ clean: rm -rf main libbuggy.so *.o $ cat ./buggy.c int fib(int x) { return (x == 0) ? 1 : (x == 1) ? 1 : fib(x - 1) + fib(x - 2); } $ cat ./main.c #include <stdio.h> extern int fib(int x); int main() { int i; for (i = 0; i < 40; i++) printf("%d\n", fib(i)); return 0; } $ make $ perf record ./main ... $ perf report --stdio # Overhead Command Shared Object Symbol # ........ ....... ................. ............................... # 14.97% main libbuggy.so [.] 0x000000000000066c 8.68% main libbuggy.so [.] 0x00000000000006aa 8.52% main libbuggy.so [.] fib@plt 7.95% main libbuggy.so [.] 0x0000000000000664 5.94% main libbuggy.so [.] 0x00000000000006a9 5.35% main libbuggy.so [.] 0x0000000000000678 ... The correct result should be (after this patch): # Overhead Command Shared Object Symbol # ........ ....... ................. ............................... # 91.47% main libbuggy.so [.] fib 8.52% main libbuggy.so [.] fib@plt 0.00% main [kernel.kallsyms] [k] kmem_cache_free [1] http://lkml.kernel.org/g/1452567507-54013-1-git-send-email-hekuang@huawei.com Signed-off-by: Wang Nan <wangnan0@huawei.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Cody P Schafer <dev@codyps.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kirill Smelkov <kirr@nexedi.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/1460024671-64774-3-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-04-07 18:24:31 +08:00
if (dso->kernel == DSO_TYPE_USER)
ss->adjust_symbols = true;
else
ss->adjust_symbols = elf__needs_adjust_symbols(ehdr);
ss->name = strdup(name);
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
if (!ss->name) {
dso->load_errno = errno;
goto out_elf_end;
perf symbols: Save DSO loading errno to better report errors Before, when some problem happened while trying to load the kernel symtab, 'perf top' would show: ┌─Warning:───────────────────────────┐ │The vmlinux file can't be used. │ │Kernel samples will not be resolved.│ │ │ │ │ │Press any key... │ └────────────────────────────────────┘ Now, it reports: # perf top --vmlinux /dev/null ┌─Warning:───────────────────────────────────────────┐ │The /tmp/passwd file can't be used: Invalid ELF file│ │Kernel samples will not be resolved. │ │ │ │ │ │Press any key... │ └────────────────────────────────────────────────────┘ This is possible because we now register the reason for not being able to load the symtab in the dso->load_errno member, and provide a dso__strerror_load() routine to format this error into a strerror like string with a short reason for the error while loading. That can be just forwarding the dso__strerror_load() call to strerror_r(), or, for a separate errno range providing a custom message. Reported-by: Ingo Molnar <mingo@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-u5rb5uq63xqhkfb8uv2lxd5u@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-03-24 22:49:02 +08:00
}
ss->elf = elf;
ss->fd = fd;
ss->ehdr = ehdr;
ss->type = type;
return 0;
out_elf_end:
elf_end(elf);
out_close:
close(fd);
return err;
}
/**
* ref_reloc_sym_not_found - has kernel relocation symbol been found.
* @kmap: kernel maps and relocation reference symbol
*
* This function returns %true if we are dealing with the kernel maps and the
* relocation reference symbol has not yet been found. Otherwise %false is
* returned.
*/
static bool ref_reloc_sym_not_found(struct kmap *kmap)
{
return kmap && kmap->ref_reloc_sym && kmap->ref_reloc_sym->name &&
!kmap->ref_reloc_sym->unrelocated_addr;
}
/**
* ref_reloc - kernel relocation offset.
* @kmap: kernel maps and relocation reference symbol
*
* This function returns the offset of kernel addresses as determined by using
* the relocation reference symbol i.e. if the kernel has not been relocated
* then the return value is zero.
*/
static u64 ref_reloc(struct kmap *kmap)
{
if (kmap && kmap->ref_reloc_sym &&
kmap->ref_reloc_sym->unrelocated_addr)
return kmap->ref_reloc_sym->addr -
kmap->ref_reloc_sym->unrelocated_addr;
return 0;
}
void __weak arch__sym_update(struct symbol *s __maybe_unused,
GElf_Sym *sym __maybe_unused) { }
int dso__load_sym(struct dso *dso, struct map *map, struct symsrc *syms_ss,
struct symsrc *runtime_ss, int kmodule)
{
struct kmap *kmap = dso->kernel ? map__kmap(map) : NULL;
struct map_groups *kmaps = kmap ? map__kmaps(map) : NULL;
struct map *curr_map = map;
struct dso *curr_dso = dso;
Elf_Data *symstrs, *secstrs;
uint32_t nr_syms;
int err = -1;
uint32_t idx;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
GElf_Shdr tshdr;
Elf_Data *syms, *opddata = NULL;
GElf_Sym sym;
Elf_Scn *sec, *sec_strndx;
Elf *elf;
int nr = 0;
bool remap_kernel = false, adjust_kernel_syms = false;
if (kmap && !kmaps)
return -1;
dso->symtab_type = syms_ss->type;
dso->is_64_bit = syms_ss->is_64_bit;
dso->rel = syms_ss->ehdr.e_type == ET_REL;
/*
* Modules may already have symbols from kallsyms, but those symbols
* have the wrong values for the dso maps, so remove them.
*/
if (kmodule && syms_ss->symtab)
symbols__delete(&dso->symbols[map->type]);
if (!syms_ss->symtab) {
/*
* If the vmlinux is stripped, fail so we will fall back
* to using kallsyms. The vmlinux runtime symbols aren't
* of much use.
*/
if (dso->kernel)
goto out_elf_end;
syms_ss->symtab = syms_ss->dynsym;
syms_ss->symshdr = syms_ss->dynshdr;
}
elf = syms_ss->elf;
ehdr = syms_ss->ehdr;
sec = syms_ss->symtab;
shdr = syms_ss->symshdr;
if (elf_section_by_name(runtime_ss->elf, &runtime_ss->ehdr, &tshdr,
".text", NULL))
dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
if (runtime_ss->opdsec)
opddata = elf_rawdata(runtime_ss->opdsec, NULL);
syms = elf_getdata(sec, NULL);
if (syms == NULL)
goto out_elf_end;
sec = elf_getscn(elf, shdr.sh_link);
if (sec == NULL)
goto out_elf_end;
symstrs = elf_getdata(sec, NULL);
if (symstrs == NULL)
goto out_elf_end;
sec_strndx = elf_getscn(runtime_ss->elf, runtime_ss->ehdr.e_shstrndx);
if (sec_strndx == NULL)
goto out_elf_end;
secstrs = elf_getdata(sec_strndx, NULL);
if (secstrs == NULL)
goto out_elf_end;
nr_syms = shdr.sh_size / shdr.sh_entsize;
memset(&sym, 0, sizeof(sym));
/*
* The kernel relocation symbol is needed in advance in order to adjust
* kernel maps correctly.
*/
if (ref_reloc_sym_not_found(kmap)) {
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
const char *elf_name = elf_sym__name(&sym, symstrs);
if (strcmp(elf_name, kmap->ref_reloc_sym->name))
continue;
kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
map->reloc = kmap->ref_reloc_sym->addr -
kmap->ref_reloc_sym->unrelocated_addr;
break;
}
}
/*
* Handle any relocation of vdso necessary because older kernels
* attempted to prelink vdso to its virtual address.
*/
if (dso__is_vdso(dso))
map->reloc = map->start - dso->text_offset;
dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
/*
* Initial kernel and module mappings do not map to the dso. For
* function mappings, flag the fixups.
*/
if (map->type == MAP__FUNCTION && (dso->kernel || kmodule)) {
remap_kernel = true;
adjust_kernel_syms = dso->adjust_symbols;
}
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
struct symbol *f;
const char *elf_name = elf_sym__name(&sym, symstrs);
char *demangled = NULL;
int is_label = elf_sym__is_label(&sym);
const char *section_name;
bool used_opd = false;
if (!is_label && !elf_sym__is_a(&sym, map->type))
continue;
/* Reject ARM ELF "mapping symbols": these aren't unique and
* don't identify functions, so will confuse the profile
* output: */
if (ehdr.e_machine == EM_ARM || ehdr.e_machine == EM_AARCH64) {
if (elf_name[0] == '$' && strchr("adtx", elf_name[1])
&& (elf_name[2] == '\0' || elf_name[2] == '.'))
continue;
}
if (runtime_ss->opdsec && sym.st_shndx == runtime_ss->opdidx) {
u32 offset = sym.st_value - syms_ss->opdshdr.sh_addr;
u64 *opd = opddata->d_buf + offset;
sym.st_value = DSO__SWAP(dso, u64, *opd);
sym.st_shndx = elf_addr_to_index(runtime_ss->elf,
sym.st_value);
used_opd = true;
}
/*
* When loading symbols in a data mapping, ABS symbols (which
* has a value of SHN_ABS in its st_shndx) failed at
* elf_getscn(). And it marks the loading as a failure so
* already loaded symbols cannot be fixed up.
*
* I'm not sure what should be done. Just ignore them for now.
* - Namhyung Kim
*/
if (sym.st_shndx == SHN_ABS)
continue;
sec = elf_getscn(runtime_ss->elf, sym.st_shndx);
if (!sec)
goto out_elf_end;
gelf_getshdr(sec, &shdr);
if (is_label && !elf_sec__is_a(&shdr, secstrs, map->type))
continue;
section_name = elf_sec__name(&shdr, secstrs);
/* On ARM, symbols for thumb functions have 1 added to
* the symbol address as a flag - remove it */
if ((ehdr.e_machine == EM_ARM) &&
(map->type == MAP__FUNCTION) &&
(sym.st_value & 1))
--sym.st_value;
if (dso->kernel || kmodule) {
char dso_name[PATH_MAX];
/* Adjust symbol to map to file offset */
if (adjust_kernel_syms)
sym.st_value -= shdr.sh_addr - shdr.sh_offset;
if (strcmp(section_name,
(curr_dso->short_name +
dso->short_name_len)) == 0)
goto new_symbol;
if (strcmp(section_name, ".text") == 0) {
/*
* The initial kernel mapping is based on
* kallsyms and identity maps. Overwrite it to
* map to the kernel dso.
*/
if (remap_kernel && dso->kernel) {
remap_kernel = false;
map->start = shdr.sh_addr +
ref_reloc(kmap);
map->end = map->start + shdr.sh_size;
map->pgoff = shdr.sh_offset;
map->map_ip = map__map_ip;
map->unmap_ip = map__unmap_ip;
/* Ensure maps are correctly ordered */
if (kmaps) {
map__get(map);
map_groups__remove(kmaps, map);
map_groups__insert(kmaps, map);
map__put(map);
}
}
/*
* The initial module mapping is based on
* /proc/modules mapped to offset zero.
* Overwrite it to map to the module dso.
*/
if (remap_kernel && kmodule) {
remap_kernel = false;
map->pgoff = shdr.sh_offset;
}
curr_map = map;
curr_dso = dso;
goto new_symbol;
}
if (!kmap)
goto new_symbol;
snprintf(dso_name, sizeof(dso_name),
"%s%s", dso->short_name, section_name);
curr_map = map_groups__find_by_name(kmaps, map->type, dso_name);
if (curr_map == NULL) {
u64 start = sym.st_value;
if (kmodule)
start += map->start + shdr.sh_offset;
curr_dso = dso__new(dso_name);
if (curr_dso == NULL)
goto out_elf_end;
curr_dso->kernel = dso->kernel;
curr_dso->long_name = dso->long_name;
curr_dso->long_name_len = dso->long_name_len;
curr_map = map__new2(start, curr_dso,
map->type);
perf symbols: Fix dso__load_sym to put dso Fix dso__load_sym to put dso because dsos__add already got it. Refcnt debugger explain the problem: ---- ==== [0] ==== Unreclaimed dso: 0x19dd200 Refcount +1 => 1 at ./perf(dso__new+0x1ff) [0x4a62df] ./perf(dso__load_sym+0xe89) [0x503509] ./perf(dso__load_vmlinux+0xbf) [0x4aa77f] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa8dc] ./perf() [0x50539a] ./perf(convert_perf_probe_events+0xd79) [0x50ad39] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount +1 => 2 at ./perf(dso__get+0x34) [0x4a65f4] ./perf(map__new2+0x76) [0x4be216] ./perf(dso__load_sym+0xee1) [0x503561] ./perf(dso__load_vmlinux+0xbf) [0x4aa77f] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa8dc] ./perf() [0x50539a] ./perf(convert_perf_probe_events+0xd79) [0x50ad39] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount +1 => 3 at ./perf(dsos__add+0xf3) [0x4a6bc3] ./perf(dso__load_sym+0xfc1) [0x503641] ./perf(dso__load_vmlinux+0xbf) [0x4aa77f] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa8dc] ./perf() [0x50539a] ./perf(convert_perf_probe_events+0xd79) [0x50ad39] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount -1 => 2 at ./perf(dso__put+0x2f) [0x4a664f] ./perf(map_groups__exit+0xb9) [0x4bee29] ./perf(machine__delete+0xb0) [0x4b93d0] ./perf(exit_probe_symbol_maps+0x28) [0x506718] ./perf() [0x45628a] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount -1 => 1 at ./perf(dso__put+0x2f) [0x4a664f] ./perf(machine__delete+0xfe) [0x4b941e] ./perf(exit_probe_symbol_maps+0x28) [0x506718] ./perf() [0x45628a] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] ---- So, in the dso__load_sym, dso is gotten 3 times, by dso__new, map__new2, and dsos__add. The last 2 is actually released by map_groups and machine__delete correspondingly. However, the first reference by dso__new, is never released. Committer note: Changed the place where the reference count is dropped to: Fix it by dropping it right after creating curr_map, since we know that either that operation failed and we need to drop the dso refcount or that it succeed and we have it referenced via curr_map->dso. Then only drop the curr_map refcount after we call dsos__add() to make sure we hold a reference to it via curr_map->dso. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20151209021118.10245.49869.stgit@localhost.localdomain Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-12-09 10:11:18 +08:00
dso__put(curr_dso);
if (curr_map == NULL) {
goto out_elf_end;
}
if (adjust_kernel_syms) {
curr_map->start = shdr.sh_addr +
ref_reloc(kmap);
curr_map->end = curr_map->start +
shdr.sh_size;
curr_map->pgoff = shdr.sh_offset;
} else {
curr_map->map_ip = identity__map_ip;
curr_map->unmap_ip = identity__map_ip;
}
curr_dso->symtab_type = dso->symtab_type;
map_groups__insert(kmaps, curr_map);
perf symbols: Fix dso__load_sym to put dso Fix dso__load_sym to put dso because dsos__add already got it. Refcnt debugger explain the problem: ---- ==== [0] ==== Unreclaimed dso: 0x19dd200 Refcount +1 => 1 at ./perf(dso__new+0x1ff) [0x4a62df] ./perf(dso__load_sym+0xe89) [0x503509] ./perf(dso__load_vmlinux+0xbf) [0x4aa77f] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa8dc] ./perf() [0x50539a] ./perf(convert_perf_probe_events+0xd79) [0x50ad39] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount +1 => 2 at ./perf(dso__get+0x34) [0x4a65f4] ./perf(map__new2+0x76) [0x4be216] ./perf(dso__load_sym+0xee1) [0x503561] ./perf(dso__load_vmlinux+0xbf) [0x4aa77f] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa8dc] ./perf() [0x50539a] ./perf(convert_perf_probe_events+0xd79) [0x50ad39] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount +1 => 3 at ./perf(dsos__add+0xf3) [0x4a6bc3] ./perf(dso__load_sym+0xfc1) [0x503641] ./perf(dso__load_vmlinux+0xbf) [0x4aa77f] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa8dc] ./perf() [0x50539a] ./perf(convert_perf_probe_events+0xd79) [0x50ad39] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount -1 => 2 at ./perf(dso__put+0x2f) [0x4a664f] ./perf(map_groups__exit+0xb9) [0x4bee29] ./perf(machine__delete+0xb0) [0x4b93d0] ./perf(exit_probe_symbol_maps+0x28) [0x506718] ./perf() [0x45628a] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] Refcount -1 => 1 at ./perf(dso__put+0x2f) [0x4a664f] ./perf(machine__delete+0xfe) [0x4b941e] ./perf(exit_probe_symbol_maps+0x28) [0x506718] ./perf() [0x45628a] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f74dd0efaf5] ./perf() [0x4220a9] ---- So, in the dso__load_sym, dso is gotten 3 times, by dso__new, map__new2, and dsos__add. The last 2 is actually released by map_groups and machine__delete correspondingly. However, the first reference by dso__new, is never released. Committer note: Changed the place where the reference count is dropped to: Fix it by dropping it right after creating curr_map, since we know that either that operation failed and we need to drop the dso refcount or that it succeed and we have it referenced via curr_map->dso. Then only drop the curr_map refcount after we call dsos__add() to make sure we hold a reference to it via curr_map->dso. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20151209021118.10245.49869.stgit@localhost.localdomain Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-12-09 10:11:18 +08:00
/*
* Add it before we drop the referece to curr_map,
* i.e. while we still are sure to have a reference
* to this DSO via curr_map->dso.
*/
dsos__add(&map->groups->machine->dsos, curr_dso);
perf tools: Fix to put new map after inserting to map_groups in dso__load_sym Fix dso__load_sym to put the map object which is already insterted to kmaps. Refcnt debugger shows ==== [0] ==== Unreclaimed map: 0x39113e0 Refcount +1 => 1 at ./perf(map__new2+0xb5) [0x4be155] ./perf(dso__load_sym+0xee1) [0x503461] ./perf(dso__load_vmlinux+0xbf) [0x4aa6df] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa83c] ./perf() [0x50528a] ./perf(convert_perf_probe_events+0xd79) [0x50ac29] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f152368baf5] ./perf() [0x4220a9] Refcount +1 => 2 at ./perf(maps__insert+0x9a) [0x4bfffa] ./perf(dso__load_sym+0xf89) [0x503509] ./perf(dso__load_vmlinux+0xbf) [0x4aa6df] ./perf(dso__load_vmlinux_path+0x8c) [0x4aa83c] ./perf() [0x50528a] ./perf(convert_perf_probe_events+0xd79) [0x50ac29] ./perf() [0x45600f] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f152368baf5] ./perf() [0x4220a9] Refcount -1 => 1 at ./perf(map_groups__exit+0x94) [0x4bed04] ./perf(machine__delete+0xb0) [0x4b9300] ./perf(exit_probe_symbol_maps+0x28) [0x506608] ./perf() [0x45628a] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f152368baf5] ./perf() [0x4220a9] This means that the dso__load_sym calls map__new2 and maps_insert, both of them bump the map refcount, but map_groups__exit will drop just one reference. Fix it by dropping the refcount after inserting it into kmaps. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20151118064026.30709.50038.stgit@localhost.localdomain Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-11-18 14:40:27 +08:00
/* kmaps already got it */
map__put(curr_map);
dso__set_loaded(curr_dso, map->type);
} else
curr_dso = curr_map->dso;
goto new_symbol;
}
if ((used_opd && runtime_ss->adjust_symbols)
|| (!used_opd && syms_ss->adjust_symbols)) {
pr_debug4("%s: adjusting symbol: st_value: %#" PRIx64 " "
"sh_addr: %#" PRIx64 " sh_offset: %#" PRIx64 "\n", __func__,
(u64)sym.st_value, (u64)shdr.sh_addr,
(u64)shdr.sh_offset);
sym.st_value -= shdr.sh_addr - shdr.sh_offset;
}
new_symbol:
demangled = demangle_sym(dso, kmodule, elf_name);
if (demangled != NULL)
elf_name = demangled;
perf symbols: Add Rust demangling Rust demangling is another step after bfd demangling. Add a diagnosis to identify mangled Rust symbols based on the hash that the Rust mangler appends as the last path component, as well as other characteristics. Add a demangler to reconstruct the original symbol. Committer notes: How I tested it: Enabled COPR on Fedora 24 and then installed the 'rust-binary' package, with it: $ cat src/main.rs fn main() { println!("Hello, world!"); } $ cat Cargo.toml [package] name = "hello_world" version = "0.0.1" authors = [ "Arnaldo Carvalho de Melo <acme@kernel.org>" ] $ perf record cargo bench Compiling hello_world v0.0.1 (file:///home/acme/projects/hello_world) Running target/release/hello_world-d4b9dab4b2a47d75 running 0 tests test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.096 MB perf.data (1457 samples) ] $ Before this patch: $ perf report --stdio --dsos librbml-e8edd0fd.so # dso: librbml-e8edd0fd.so # # Total Lost Samples: 0 # # Samples: 1K of event 'cycles:u' # Event count (approx.): 979599126 # # Overhead Command Symbol # ........ ....... ............................................................................................................. # 1.78% rustc [.] rbml::reader::maybe_get_doc::hb9d387df6024b15b 1.50% rustc [.] _$LT$reader..DocsIterator$LT$$u27$a$GT$$u20$as$u20$std..iter..Iterator$GT$::next::hd9af9e60d79a35c8 1.20% rustc [.] rbml::reader::doc_at::hc88107fba445af31 0.46% rustc [.] _$LT$reader..TaggedDocsIterator$LT$$u27$a$GT$$u20$as$u20$std..iter..Iterator$GT$::next::h0cb40e696e4bb489 0.35% rustc [.] rbml::reader::Decoder::_next_int::h66eef7825a398bc3 0.29% rustc [.] rbml::reader::Decoder::_next_sub::h8e5266005580b836 0.15% rustc [.] rbml::reader::get_doc::h094521c645459139 0.14% rustc [.] _$LT$reader..Decoder$LT$$u27$doc$GT$$u20$as$u20$serialize..Decoder$GT$::read_u32::h0acea2fff9669327 0.07% rustc [.] rbml::reader::Decoder::next_doc::h6714d469c9dfaf91 0.07% rustc [.] _ZN4rbml6reader10doc_as_u6417h930b740aa94f1d3aE@plt 0.06% rustc [.] _fini $ After: $ perf report --stdio --dsos librbml-e8edd0fd.so # dso: librbml-e8edd0fd.so # # Total Lost Samples: 0 # # Samples: 1K of event 'cycles:u' # Event count (approx.): 979599126 # # Overhead Command Symbol # ........ ....... ................................................................. # 1.78% rustc [.] rbml::reader::maybe_get_doc 1.50% rustc [.] <reader::DocsIterator<'a> as std::iter::Iterator>::next 1.20% rustc [.] rbml::reader::doc_at 0.46% rustc [.] <reader::TaggedDocsIterator<'a> as std::iter::Iterator>::next 0.35% rustc [.] rbml::reader::Decoder::_next_int 0.29% rustc [.] rbml::reader::Decoder::_next_sub 0.15% rustc [.] rbml::reader::get_doc 0.14% rustc [.] <reader::Decoder<'doc> as serialize::Decoder>::read_u32 0.07% rustc [.] rbml::reader::Decoder::next_doc 0.07% rustc [.] _ZN4rbml6reader10doc_as_u6417h930b740aa94f1d3aE@plt 0.06% rustc [.] _fini $ Signed-off-by: David Tolnay <dtolnay@gmail.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5780B7FA.3030602@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-09 15:20:00 +08:00
f = symbol__new(sym.st_value, sym.st_size,
GELF_ST_BIND(sym.st_info), elf_name);
free(demangled);
if (!f)
goto out_elf_end;
arch__sym_update(f, &sym);
__symbols__insert(&curr_dso->symbols[curr_map->type], f, dso->kernel);
nr++;
}
/*
* For misannotated, zeroed, ASM function sizes.
*/
if (nr > 0) {
symbols__fixup_end(&dso->symbols[map->type]);
symbols__fixup_duplicate(&dso->symbols[map->type]);
if (kmap) {
/*
* We need to fixup this here too because we create new
* maps here, for things like vsyscall sections.
*/
__map_groups__fixup_end(kmaps, map->type);
}
}
err = nr;
out_elf_end:
return err;
}
static int elf_read_maps(Elf *elf, bool exe, mapfn_t mapfn, void *data)
{
GElf_Phdr phdr;
size_t i, phdrnum;
int err;
u64 sz;
if (elf_getphdrnum(elf, &phdrnum))
return -1;
for (i = 0; i < phdrnum; i++) {
if (gelf_getphdr(elf, i, &phdr) == NULL)
return -1;
if (phdr.p_type != PT_LOAD)
continue;
if (exe) {
if (!(phdr.p_flags & PF_X))
continue;
} else {
if (!(phdr.p_flags & PF_R))
continue;
}
sz = min(phdr.p_memsz, phdr.p_filesz);
if (!sz)
continue;
err = mapfn(phdr.p_vaddr, sz, phdr.p_offset, data);
if (err)
return err;
}
return 0;
}
int file__read_maps(int fd, bool exe, mapfn_t mapfn, void *data,
bool *is_64_bit)
{
int err;
Elf *elf;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL)
return -1;
if (is_64_bit)
*is_64_bit = (gelf_getclass(elf) == ELFCLASS64);
err = elf_read_maps(elf, exe, mapfn, data);
elf_end(elf);
return err;
}
enum dso_type dso__type_fd(int fd)
{
enum dso_type dso_type = DSO__TYPE_UNKNOWN;
GElf_Ehdr ehdr;
Elf_Kind ek;
Elf *elf;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (elf == NULL)
goto out;
ek = elf_kind(elf);
if (ek != ELF_K_ELF)
goto out_end;
if (gelf_getclass(elf) == ELFCLASS64) {
dso_type = DSO__TYPE_64BIT;
goto out_end;
}
if (gelf_getehdr(elf, &ehdr) == NULL)
goto out_end;
if (ehdr.e_machine == EM_X86_64)
dso_type = DSO__TYPE_X32BIT;
else
dso_type = DSO__TYPE_32BIT;
out_end:
elf_end(elf);
out:
return dso_type;
}
static int copy_bytes(int from, off_t from_offs, int to, off_t to_offs, u64 len)
{
ssize_t r;
size_t n;
int err = -1;
char *buf = malloc(page_size);
if (buf == NULL)
return -1;
if (lseek(to, to_offs, SEEK_SET) != to_offs)
goto out;
if (lseek(from, from_offs, SEEK_SET) != from_offs)
goto out;
while (len) {
n = page_size;
if (len < n)
n = len;
/* Use read because mmap won't work on proc files */
r = read(from, buf, n);
if (r < 0)
goto out;
if (!r)
break;
n = r;
r = write(to, buf, n);
if (r < 0)
goto out;
if ((size_t)r != n)
goto out;
len -= n;
}
err = 0;
out:
free(buf);
return err;
}
struct kcore {
int fd;
int elfclass;
Elf *elf;
GElf_Ehdr ehdr;
};
static int kcore__open(struct kcore *kcore, const char *filename)
{
GElf_Ehdr *ehdr;
kcore->fd = open(filename, O_RDONLY);
if (kcore->fd == -1)
return -1;
kcore->elf = elf_begin(kcore->fd, ELF_C_READ, NULL);
if (!kcore->elf)
goto out_close;
kcore->elfclass = gelf_getclass(kcore->elf);
if (kcore->elfclass == ELFCLASSNONE)
goto out_end;
ehdr = gelf_getehdr(kcore->elf, &kcore->ehdr);
if (!ehdr)
goto out_end;
return 0;
out_end:
elf_end(kcore->elf);
out_close:
close(kcore->fd);
return -1;
}
static int kcore__init(struct kcore *kcore, char *filename, int elfclass,
bool temp)
{
kcore->elfclass = elfclass;
if (temp)
kcore->fd = mkstemp(filename);
else
kcore->fd = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0400);
if (kcore->fd == -1)
return -1;
kcore->elf = elf_begin(kcore->fd, ELF_C_WRITE, NULL);
if (!kcore->elf)
goto out_close;
if (!gelf_newehdr(kcore->elf, elfclass))
goto out_end;
memset(&kcore->ehdr, 0, sizeof(GElf_Ehdr));
return 0;
out_end:
elf_end(kcore->elf);
out_close:
close(kcore->fd);
unlink(filename);
return -1;
}
static void kcore__close(struct kcore *kcore)
{
elf_end(kcore->elf);
close(kcore->fd);
}
static int kcore__copy_hdr(struct kcore *from, struct kcore *to, size_t count)
{
GElf_Ehdr *ehdr = &to->ehdr;
GElf_Ehdr *kehdr = &from->ehdr;
memcpy(ehdr->e_ident, kehdr->e_ident, EI_NIDENT);
ehdr->e_type = kehdr->e_type;
ehdr->e_machine = kehdr->e_machine;
ehdr->e_version = kehdr->e_version;
ehdr->e_entry = 0;
ehdr->e_shoff = 0;
ehdr->e_flags = kehdr->e_flags;
ehdr->e_phnum = count;
ehdr->e_shentsize = 0;
ehdr->e_shnum = 0;
ehdr->e_shstrndx = 0;
if (from->elfclass == ELFCLASS32) {
ehdr->e_phoff = sizeof(Elf32_Ehdr);
ehdr->e_ehsize = sizeof(Elf32_Ehdr);
ehdr->e_phentsize = sizeof(Elf32_Phdr);
} else {
ehdr->e_phoff = sizeof(Elf64_Ehdr);
ehdr->e_ehsize = sizeof(Elf64_Ehdr);
ehdr->e_phentsize = sizeof(Elf64_Phdr);
}
if (!gelf_update_ehdr(to->elf, ehdr))
return -1;
if (!gelf_newphdr(to->elf, count))
return -1;
return 0;
}
static int kcore__add_phdr(struct kcore *kcore, int idx, off_t offset,
u64 addr, u64 len)
{
GElf_Phdr phdr = {
.p_type = PT_LOAD,
.p_flags = PF_R | PF_W | PF_X,
.p_offset = offset,
.p_vaddr = addr,
.p_paddr = 0,
.p_filesz = len,
.p_memsz = len,
.p_align = page_size,
};
if (!gelf_update_phdr(kcore->elf, idx, &phdr))
return -1;
return 0;
}
static off_t kcore__write(struct kcore *kcore)
{
return elf_update(kcore->elf, ELF_C_WRITE);
}
perf buildid-cache: Add ability to add kcore to the cache kcore can be used to view the running kernel object code. However, kcore changes as modules are loaded and unloaded, and when the kernel decides to modify its own code. Consequently it is useful to create a copy of kcore at a particular time. Unlike vmlinux, kcore is not unique for a given build-id. And in addition, the kallsyms and modules files are also needed. The tool therefore creates a directory: ~/.debug/[kernel.kcore]/<build-id>/<YYYYmmddHHMMSShh> which contains: kcore, kallsyms and modules. Note that the copied kcore contains only code sections. See the kcore_copy() function for how that is determined. The tool will not make additional copies of kcore if there is already one with the same modules at the same addresses. Currently, perf tools will not look for kcore in the cache. That is addressed in another patch. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/525BF849.5030405@intel.com [ renamed 'index' to 'idx' to avoid shadowing string.h symbol in f12, use at least one member initializer when initializing a struct to zeros, also to fix the build on f12 ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-10-14 21:57:29 +08:00
struct phdr_data {
off_t offset;
u64 addr;
u64 len;
};
struct kcore_copy_info {
u64 stext;
u64 etext;
u64 first_symbol;
u64 last_symbol;
u64 first_module;
u64 last_module_symbol;
struct phdr_data kernel_map;
struct phdr_data modules_map;
};
static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
u64 start)
{
struct kcore_copy_info *kci = arg;
if (!symbol_type__is_a(type, MAP__FUNCTION))
return 0;
if (strchr(name, '[')) {
if (start > kci->last_module_symbol)
kci->last_module_symbol = start;
return 0;
}
if (!kci->first_symbol || start < kci->first_symbol)
kci->first_symbol = start;
if (!kci->last_symbol || start > kci->last_symbol)
kci->last_symbol = start;
if (!strcmp(name, "_stext")) {
kci->stext = start;
return 0;
}
if (!strcmp(name, "_etext")) {
kci->etext = start;
return 0;
}
return 0;
}
static int kcore_copy__parse_kallsyms(struct kcore_copy_info *kci,
const char *dir)
{
char kallsyms_filename[PATH_MAX];
scnprintf(kallsyms_filename, PATH_MAX, "%s/kallsyms", dir);
if (symbol__restricted_filename(kallsyms_filename, "/proc/kallsyms"))
return -1;
if (kallsyms__parse(kallsyms_filename, kci,
kcore_copy__process_kallsyms) < 0)
return -1;
return 0;
}
static int kcore_copy__process_modules(void *arg,
const char *name __maybe_unused,
u64 start)
{
struct kcore_copy_info *kci = arg;
if (!kci->first_module || start < kci->first_module)
kci->first_module = start;
return 0;
}
static int kcore_copy__parse_modules(struct kcore_copy_info *kci,
const char *dir)
{
char modules_filename[PATH_MAX];
scnprintf(modules_filename, PATH_MAX, "%s/modules", dir);
if (symbol__restricted_filename(modules_filename, "/proc/modules"))
return -1;
if (modules__parse(modules_filename, kci,
kcore_copy__process_modules) < 0)
return -1;
return 0;
}
static void kcore_copy__map(struct phdr_data *p, u64 start, u64 end, u64 pgoff,
u64 s, u64 e)
{
if (p->addr || s < start || s >= end)
return;
p->addr = s;
p->offset = (s - start) + pgoff;
p->len = e < end ? e - s : end - s;
}
static int kcore_copy__read_map(u64 start, u64 len, u64 pgoff, void *data)
{
struct kcore_copy_info *kci = data;
u64 end = start + len;
kcore_copy__map(&kci->kernel_map, start, end, pgoff, kci->stext,
kci->etext);
kcore_copy__map(&kci->modules_map, start, end, pgoff, kci->first_module,
kci->last_module_symbol);
return 0;
}
static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
{
if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
return -1;
return 0;
}
static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
Elf *elf)
{
if (kcore_copy__parse_kallsyms(kci, dir))
return -1;
if (kcore_copy__parse_modules(kci, dir))
return -1;
if (kci->stext)
kci->stext = round_down(kci->stext, page_size);
else
kci->stext = round_down(kci->first_symbol, page_size);
if (kci->etext) {
kci->etext = round_up(kci->etext, page_size);
} else if (kci->last_symbol) {
kci->etext = round_up(kci->last_symbol, page_size);
kci->etext += page_size;
}
kci->first_module = round_down(kci->first_module, page_size);
if (kci->last_module_symbol) {
kci->last_module_symbol = round_up(kci->last_module_symbol,
page_size);
kci->last_module_symbol += page_size;
}
if (!kci->stext || !kci->etext)
return -1;
if (kci->first_module && !kci->last_module_symbol)
return -1;
return kcore_copy__read_maps(kci, elf);
}
static int kcore_copy__copy_file(const char *from_dir, const char *to_dir,
const char *name)
{
char from_filename[PATH_MAX];
char to_filename[PATH_MAX];
scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
return copyfile_mode(from_filename, to_filename, 0400);
}
static int kcore_copy__unlink(const char *dir, const char *name)
{
char filename[PATH_MAX];
scnprintf(filename, PATH_MAX, "%s/%s", dir, name);
return unlink(filename);
}
static int kcore_copy__compare_fds(int from, int to)
{
char *buf_from;
char *buf_to;
ssize_t ret;
size_t len;
int err = -1;
buf_from = malloc(page_size);
buf_to = malloc(page_size);
if (!buf_from || !buf_to)
goto out;
while (1) {
/* Use read because mmap won't work on proc files */
ret = read(from, buf_from, page_size);
if (ret < 0)
goto out;
if (!ret)
break;
len = ret;
if (readn(to, buf_to, len) != (int)len)
goto out;
if (memcmp(buf_from, buf_to, len))
goto out;
}
err = 0;
out:
free(buf_to);
free(buf_from);
return err;
}
static int kcore_copy__compare_files(const char *from_filename,
const char *to_filename)
{
int from, to, err = -1;
from = open(from_filename, O_RDONLY);
if (from < 0)
return -1;
to = open(to_filename, O_RDONLY);
if (to < 0)
goto out_close_from;
err = kcore_copy__compare_fds(from, to);
close(to);
out_close_from:
close(from);
return err;
}
static int kcore_copy__compare_file(const char *from_dir, const char *to_dir,
const char *name)
{
char from_filename[PATH_MAX];
char to_filename[PATH_MAX];
scnprintf(from_filename, PATH_MAX, "%s/%s", from_dir, name);
scnprintf(to_filename, PATH_MAX, "%s/%s", to_dir, name);
return kcore_copy__compare_files(from_filename, to_filename);
}
/**
* kcore_copy - copy kallsyms, modules and kcore from one directory to another.
* @from_dir: from directory
* @to_dir: to directory
*
* This function copies kallsyms, modules and kcore files from one directory to
* another. kallsyms and modules are copied entirely. Only code segments are
* copied from kcore. It is assumed that two segments suffice: one for the
* kernel proper and one for all the modules. The code segments are determined
* from kallsyms and modules files. The kernel map starts at _stext or the
* lowest function symbol, and ends at _etext or the highest function symbol.
* The module map starts at the lowest module address and ends at the highest
* module symbol. Start addresses are rounded down to the nearest page. End
* addresses are rounded up to the nearest page. An extra page is added to the
* highest kernel symbol and highest module symbol to, hopefully, encompass that
* symbol too. Because it contains only code sections, the resulting kcore is
* unusual. One significant peculiarity is that the mapping (start -> pgoff)
* is not the same for the kernel map and the modules map. That happens because
* the data is copied adjacently whereas the original kcore has gaps. Finally,
* kallsyms and modules files are compared with their copies to check that
* modules have not been loaded or unloaded while the copies were taking place.
*
* Return: %0 on success, %-1 on failure.
*/
int kcore_copy(const char *from_dir, const char *to_dir)
{
struct kcore kcore;
struct kcore extract;
size_t count = 2;
int idx = 0, err = -1;
off_t offset = page_size, sz, modules_offset = 0;
struct kcore_copy_info kci = { .stext = 0, };
char kcore_filename[PATH_MAX];
char extract_filename[PATH_MAX];
if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
return -1;
if (kcore_copy__copy_file(from_dir, to_dir, "modules"))
goto out_unlink_kallsyms;
scnprintf(kcore_filename, PATH_MAX, "%s/kcore", from_dir);
scnprintf(extract_filename, PATH_MAX, "%s/kcore", to_dir);
if (kcore__open(&kcore, kcore_filename))
goto out_unlink_modules;
if (kcore_copy__calc_maps(&kci, from_dir, kcore.elf))
goto out_kcore_close;
if (kcore__init(&extract, extract_filename, kcore.elfclass, false))
goto out_kcore_close;
if (!kci.modules_map.addr)
count -= 1;
if (kcore__copy_hdr(&kcore, &extract, count))
goto out_extract_close;
if (kcore__add_phdr(&extract, idx++, offset, kci.kernel_map.addr,
kci.kernel_map.len))
goto out_extract_close;
if (kci.modules_map.addr) {
modules_offset = offset + kci.kernel_map.len;
if (kcore__add_phdr(&extract, idx, modules_offset,
kci.modules_map.addr, kci.modules_map.len))
goto out_extract_close;
}
sz = kcore__write(&extract);
if (sz < 0 || sz > offset)
goto out_extract_close;
if (copy_bytes(kcore.fd, kci.kernel_map.offset, extract.fd, offset,
kci.kernel_map.len))
goto out_extract_close;
if (modules_offset && copy_bytes(kcore.fd, kci.modules_map.offset,
extract.fd, modules_offset,
kci.modules_map.len))
goto out_extract_close;
if (kcore_copy__compare_file(from_dir, to_dir, "modules"))
goto out_extract_close;
if (kcore_copy__compare_file(from_dir, to_dir, "kallsyms"))
goto out_extract_close;
err = 0;
out_extract_close:
kcore__close(&extract);
if (err)
unlink(extract_filename);
out_kcore_close:
kcore__close(&kcore);
out_unlink_modules:
if (err)
kcore_copy__unlink(to_dir, "modules");
out_unlink_kallsyms:
if (err)
kcore_copy__unlink(to_dir, "kallsyms");
return err;
}
int kcore_extract__create(struct kcore_extract *kce)
{
struct kcore kcore;
struct kcore extract;
size_t count = 1;
int idx = 0, err = -1;
off_t offset = page_size, sz;
if (kcore__open(&kcore, kce->kcore_filename))
return -1;
strcpy(kce->extract_filename, PERF_KCORE_EXTRACT);
if (kcore__init(&extract, kce->extract_filename, kcore.elfclass, true))
goto out_kcore_close;
if (kcore__copy_hdr(&kcore, &extract, count))
goto out_extract_close;
if (kcore__add_phdr(&extract, idx, offset, kce->addr, kce->len))
goto out_extract_close;
sz = kcore__write(&extract);
if (sz < 0 || sz > offset)
goto out_extract_close;
if (copy_bytes(kcore.fd, kce->offs, extract.fd, offset, kce->len))
goto out_extract_close;
err = 0;
out_extract_close:
kcore__close(&extract);
if (err)
unlink(kce->extract_filename);
out_kcore_close:
kcore__close(&kcore);
return err;
}
void kcore_extract__delete(struct kcore_extract *kce)
{
unlink(kce->extract_filename);
}
#ifdef HAVE_GELF_GETNOTE_SUPPORT
perf sdt: ELF support for SDT This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-01 16:03:46 +08:00
/**
* populate_sdt_note : Parse raw data and identify SDT note
* @elf: elf of the opened file
* @data: raw data of a section with description offset applied
* @len: note description size
* @type: type of the note
* @sdt_notes: List to add the SDT note
*
* Responsible for parsing the @data in section .note.stapsdt in @elf and
* if its an SDT note, it appends to @sdt_notes list.
*/
static int populate_sdt_note(Elf **elf, const char *data, size_t len,
struct list_head *sdt_notes)
{
const char *provider, *name, *args;
perf sdt: ELF support for SDT This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-01 16:03:46 +08:00
struct sdt_note *tmp = NULL;
GElf_Ehdr ehdr;
GElf_Addr base_off = 0;
GElf_Shdr shdr;
int ret = -EINVAL;
union {
Elf64_Addr a64[NR_ADDR];
Elf32_Addr a32[NR_ADDR];
} buf;
Elf_Data dst = {
.d_buf = &buf, .d_type = ELF_T_ADDR, .d_version = EV_CURRENT,
.d_size = gelf_fsize((*elf), ELF_T_ADDR, NR_ADDR, EV_CURRENT),
.d_off = 0, .d_align = 0
};
Elf_Data src = {
.d_buf = (void *) data, .d_type = ELF_T_ADDR,
.d_version = EV_CURRENT, .d_size = dst.d_size, .d_off = 0,
.d_align = 0
};
tmp = (struct sdt_note *)calloc(1, sizeof(struct sdt_note));
if (!tmp) {
ret = -ENOMEM;
goto out_err;
}
INIT_LIST_HEAD(&tmp->note_list);
if (len < dst.d_size + 3)
goto out_free_note;
/* Translation from file representation to memory representation */
if (gelf_xlatetom(*elf, &dst, &src,
elf_getident(*elf, NULL)[EI_DATA]) == NULL) {
pr_err("gelf_xlatetom : %s\n", elf_errmsg(-1));
goto out_free_note;
}
/* Populate the fields of sdt_note */
provider = data + dst.d_size;
name = (const char *)memchr(provider, '\0', data + len - provider);
if (name++ == NULL)
goto out_free_note;
tmp->provider = strdup(provider);
if (!tmp->provider) {
ret = -ENOMEM;
goto out_free_note;
}
tmp->name = strdup(name);
if (!tmp->name) {
ret = -ENOMEM;
goto out_free_prov;
}
args = memchr(name, '\0', data + len - name);
/*
* There is no argument if:
* - We reached the end of the note;
* - There is not enough room to hold a potential string;
* - The argument string is empty or just contains ':'.
*/
if (args == NULL || data + len - args < 2 ||
args[1] == ':' || args[1] == '\0')
tmp->args = NULL;
else {
tmp->args = strdup(++args);
if (!tmp->args) {
ret = -ENOMEM;
goto out_free_name;
}
}
perf sdt: ELF support for SDT This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-01 16:03:46 +08:00
if (gelf_getclass(*elf) == ELFCLASS32) {
memcpy(&tmp->addr, &buf, 3 * sizeof(Elf32_Addr));
tmp->bit32 = true;
} else {
memcpy(&tmp->addr, &buf, 3 * sizeof(Elf64_Addr));
tmp->bit32 = false;
}
if (!gelf_getehdr(*elf, &ehdr)) {
pr_debug("%s : cannot get elf header.\n", __func__);
ret = -EBADF;
goto out_free_args;
perf sdt: ELF support for SDT This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-01 16:03:46 +08:00
}
/* Adjust the prelink effect :
* Find out the .stapsdt.base section.
* This scn will help us to handle prelinking (if present).
* Compare the retrieved file offset of the base section with the
* base address in the description of the SDT note. If its different,
* then accordingly, adjust the note location.
*/
if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_BASE_SCN, NULL)) {
base_off = shdr.sh_offset;
if (base_off) {
if (tmp->bit32)
tmp->addr.a32[0] = tmp->addr.a32[0] + base_off -
tmp->addr.a32[1];
else
tmp->addr.a64[0] = tmp->addr.a64[0] + base_off -
tmp->addr.a64[1];
}
}
list_add_tail(&tmp->note_list, sdt_notes);
return 0;
out_free_args:
free(tmp->args);
perf sdt: ELF support for SDT This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-01 16:03:46 +08:00
out_free_name:
free(tmp->name);
out_free_prov:
free(tmp->provider);
out_free_note:
free(tmp);
out_err:
return ret;
}
/**
* construct_sdt_notes_list : constructs a list of SDT notes
* @elf : elf to look into
* @sdt_notes : empty list_head
*
* Scans the sections in 'elf' for the section
* .note.stapsdt. It, then calls populate_sdt_note to find
* out the SDT events and populates the 'sdt_notes'.
*/
static int construct_sdt_notes_list(Elf *elf, struct list_head *sdt_notes)
{
GElf_Ehdr ehdr;
Elf_Scn *scn = NULL;
Elf_Data *data;
GElf_Shdr shdr;
size_t shstrndx, next;
GElf_Nhdr nhdr;
size_t name_off, desc_off, offset;
int ret = 0;
if (gelf_getehdr(elf, &ehdr) == NULL) {
ret = -EBADF;
goto out_ret;
}
if (elf_getshdrstrndx(elf, &shstrndx) != 0) {
ret = -EBADF;
goto out_ret;
}
/* Look for the required section */
scn = elf_section_by_name(elf, &ehdr, &shdr, SDT_NOTE_SCN, NULL);
if (!scn) {
ret = -ENOENT;
goto out_ret;
}
if ((shdr.sh_type != SHT_NOTE) || (shdr.sh_flags & SHF_ALLOC)) {
ret = -ENOENT;
goto out_ret;
}
data = elf_getdata(scn, NULL);
/* Get the SDT notes */
for (offset = 0; (next = gelf_getnote(data, offset, &nhdr, &name_off,
&desc_off)) > 0; offset = next) {
if (nhdr.n_namesz == sizeof(SDT_NOTE_NAME) &&
!memcmp(data->d_buf + name_off, SDT_NOTE_NAME,
sizeof(SDT_NOTE_NAME))) {
/* Check the type of the note */
if (nhdr.n_type != SDT_NOTE_TYPE)
goto out_ret;
ret = populate_sdt_note(&elf, ((data->d_buf) + desc_off),
nhdr.n_descsz, sdt_notes);
if (ret < 0)
goto out_ret;
}
}
if (list_empty(sdt_notes))
ret = -ENOENT;
out_ret:
return ret;
}
/**
* get_sdt_note_list : Wrapper to construct a list of sdt notes
* @head : empty list_head
* @target : file to find SDT notes from
*
* This opens the file, initializes
* the ELF and then calls construct_sdt_notes_list.
*/
int get_sdt_note_list(struct list_head *head, const char *target)
{
Elf *elf;
int fd, ret;
fd = open(target, O_RDONLY);
if (fd < 0)
return -EBADF;
elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
if (!elf) {
ret = -EBADF;
goto out_close;
}
ret = construct_sdt_notes_list(elf, head);
elf_end(elf);
out_close:
close(fd);
return ret;
}
/**
* cleanup_sdt_note_list : free the sdt notes' list
* @sdt_notes: sdt notes' list
*
* Free up the SDT notes in @sdt_notes.
* Returns the number of SDT notes free'd.
*/
int cleanup_sdt_note_list(struct list_head *sdt_notes)
{
struct sdt_note *tmp, *pos;
int nr_free = 0;
list_for_each_entry_safe(pos, tmp, sdt_notes, note_list) {
list_del(&pos->note_list);
free(pos->name);
free(pos->provider);
free(pos);
nr_free++;
}
return nr_free;
}
/**
* sdt_notes__get_count: Counts the number of sdt events
* @start: list_head to sdt_notes list
*
* Returns the number of SDT notes in a list
*/
int sdt_notes__get_count(struct list_head *start)
{
struct sdt_note *sdt_ptr;
int count = 0;
list_for_each_entry(sdt_ptr, start, note_list)
count++;
return count;
}
#endif
perf sdt: ELF support for SDT This patch serves the initial support to identify and list SDT events in binaries. When programs containing SDT markers are compiled, gcc with the help of assembler directives identifies them and places them in the section ".note.stapsdt". To find these markers from the binaries, one needs to traverse through this section and parse the relevant details like the name, type and location of the marker. Also, the original location could be skewed due to the effect of prelinking. If that is the case, the locations need to be adjusted. The functions in this patch open a given ELF, find out the SDT section, parse the relevant details, adjust the location (if necessary) and populate them in a list. A typical note entry in ".note.stapsdt" section is as follows : |--nhdr.n_namesz--| ------------------------------------ | nhdr | "stapsdt" | ----- |----------------------------------| | | <location> <base_address> | | | <semaphore> | nhdr.n_descsize | "provider_name" "note_name" | | | <args> | ----- |----------------------------------| | nhdr | "stapsdt" | |... The above shows an excerpt from the section ".note.stapsdt". 'nhdr' is a structure which has the note name size (n_namesz), note description size (n_desc_sz) and note type (n_type). So, in order to parse the note note info, we need nhdr to tell us where to start from. As can be seen from <sys/sdt.h>, the name of the SDT notes given is "stapsdt". But this is not the identifier of the note. After that, we go to description of the note to find out its location, the address of the ".stapsdt.base" section and the semaphore address. Then, we find the provider name and the SDT marker name and then follow the arguments. Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/146736022628.27797.1201368329092908163.stgit@devbox Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-07-01 16:03:46 +08:00
void symbol__elf_init(void)
{
elf_version(EV_CURRENT);
}