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

Browse source 
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;
}