perf/urgent fixes:

- Fix obtaining the 'start' address for a kernel module on s390, where
   .text doesn't coincides with the start of the module as reported on
   /proc/modules (Song Shan Gong)
 
 - Use official ELF e_machine value for BPF objects generated via perf + LLVM
   when specifying BPF scriptlet in 'perf record/trace --event' (Wang Nan)
 
 Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-urgent-for-mingo-20160726' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

 - Fix obtaining the 'start' address for a kernel module on s390, where
   .text doesn't coincide with the start of the module as reported in
   /proc/modules (Song Shan Gong)

 - Use official ELF e_machine value for BPF objects generated via perf + LLVM
   when specifying BPF scriptlet in 'perf record/trace --event' (Wang Nan)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2016-07-27 11:01:06 +02:00
commit e4b3e0694b
5 changed files with 36 additions and 1 deletions

View File

@ -37,6 +37,10 @@
#include "libbpf.h"
#include "bpf.h"
#ifndef EM_BPF
#define EM_BPF 247
#endif
#define __printf(a, b) __attribute__((format(printf, a, b)))
__printf(1, 2)
@ -439,7 +443,8 @@ static int bpf_object__elf_init(struct bpf_object *obj)
}
ep = &obj->efile.ehdr;
if ((ep->e_type != ET_REL) || (ep->e_machine != 0)) {
/* Old LLVM set e_machine to EM_NONE */
if ((ep->e_type != ET_REL) || (ep->e_machine && (ep->e_machine != EM_BPF))) {
pr_warning("%s is not an eBPF object file\n",
obj->path);
err = -LIBBPF_ERRNO__FORMAT;

View File

@ -2,3 +2,5 @@ libperf-y += header.o
libperf-y += kvm-stat.o
libperf-$(CONFIG_DWARF) += dwarf-regs.o
libperf-y += machine.o

View File

@ -0,0 +1,19 @@
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include "util.h"
#include "machine.h"
#include "api/fs/fs.h"
int arch__fix_module_text_start(u64 *start, const char *name)
{
char path[PATH_MAX];
snprintf(path, PATH_MAX, "module/%.*s/sections/.text",
(int)strlen(name) - 2, name + 1);
if (sysfs__read_ull(path, (unsigned long long *)start) < 0)
return -1;
return 0;
}

View File

@ -1093,12 +1093,20 @@ static int machine__set_modules_path(struct machine *machine)
return map_groups__set_modules_path_dir(&machine->kmaps, modules_path, 0);
}
int __weak arch__fix_module_text_start(u64 *start __maybe_unused,
const char *name __maybe_unused)
{
return 0;
}
static int machine__create_module(void *arg, const char *name, u64 start)
{
struct machine *machine = arg;
struct map *map;
if (arch__fix_module_text_start(&start, name) < 0)
return -1;
map = machine__findnew_module_map(machine, start, name);
if (map == NULL)
return -1;

View File

@ -216,6 +216,7 @@ struct symbol *machine__find_kernel_function_by_name(struct machine *machine,
struct map *machine__findnew_module_map(struct machine *machine, u64 start,
const char *filename);
int arch__fix_module_text_start(u64 *start, const char *name);
int __machine__load_kallsyms(struct machine *machine, const char *filename,
enum map_type type, bool no_kcore, symbol_filter_t filter);