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perf kcore_copy: Amend the offset of sections that remap kernel text 

x86 PTI entry trampolines all map to the same physical page. If that is
reflected in the program headers of /proc/kcore, then do the same for the
copy of kcore.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1526986485-6562-18-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2018-05-22 13:54:45 +03:00 committed by Arnaldo Carvalho de Melo
parent a1a3a0624e
commit 22916fdb9c
1 changed files with 51 additions and 2 deletions
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53
tools/perf/util/symbol-elf.c
View File

@ -1390,6 +1390,7 @@ struct phdr_data {
u64 addr;
u64 len;
struct list_head node;
struct phdr_data *remaps;
};
struct sym_data {
@ -1597,16 +1598,62 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
return 0;
}
static void kcore_copy__find_remaps(struct kcore_copy_info *kci)
{
struct phdr_data *p, *k = NULL;
u64 kend;
if (!kci->stext)
return;
/* Find phdr that corresponds to the kernel map (contains stext) */
kcore_copy__for_each_phdr(kci, p) {
u64 pend = p->addr + p->len - 1;
if (p->addr <= kci->stext && pend >= kci->stext) {
k = p;
break;
}
}
if (!k)
return;
kend = k->offset + k->len;
/* Find phdrs that remap the kernel */
kcore_copy__for_each_phdr(kci, p) {
u64 pend = p->offset + p->len;
if (p == k)
continue;
if (p->offset >= k->offset && pend <= kend)
p->remaps = k;
}
}
static void kcore_copy__layout(struct kcore_copy_info *kci)
{
struct phdr_data *p;
off_t rel = 0;
kcore_copy__find_remaps(kci);
kcore_copy__for_each_phdr(kci, p) {
p->rel = rel;
rel += p->len;
if (!p->remaps) {
p->rel = rel;
rel += p->len;
}
kci->phnum += 1;
}
kcore_copy__for_each_phdr(kci, p) {
struct phdr_data *k = p->remaps;
if (k)
p->rel = p->offset - k->offset + k->rel;
}
}
static int kcore_copy__calc_maps(struct kcore_copy_info *kci, const char *dir,
@ -1821,6 +1868,8 @@ int kcore_copy(const char *from_dir, const char *to_dir)
kcore_copy__for_each_phdr(&kci, p) {
off_t offs = p->rel + offset;
if (p->remaps)
continue;
if (copy_bytes(kcore.fd, p->offset, extract.fd, offs, p->len))
goto out_extract_close;
}