From: Remi Bernon <rbernon@codeweavers.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>
Cc: Remi Bernon <rbernon@codeweavers.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] perf symbol: Look for ImageBase in PE file to compute .text offset
Date: Thu, 9 Sep 2021 21:26:36 +0200 [thread overview]
Message-ID: <20210909192637.4139125-1-rbernon@codeweavers.com> (raw)
Instead of using the file offset in the debug file.
This fixes a regression from 00a3423492bc90be99e529a64f13fdd80a0e8c0a,
causing incorrect symbol resolution when debug file have been stripped
from non-debug sections (in which case its .text section is empty and
doesn't have any file position).
The debug files could also be created with a different file alignment,
and have different file positions from the mmap-ed binary, or have the
section reordered.
This instead looks for the file image base, using the corresponding bfd
*ABS* symbols. As PE symbols only have 4 bytes, it also needs to keep
.text section vma high bits.
Signed-off-by: Remi Bernon <rbernon@codeweavers.com>
---
Hi!
As I'm not updating it often I only recently realized that perf had a
regression when using stripped debug info files, and all symbols from
PE files are off. This should make things better.
Cheers,
tools/perf/util/symbol.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 77fc46ca07c0..0fc9a5410739 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1581,10 +1581,6 @@ int dso__load_bfd_symbols(struct dso *dso, const char *debugfile)
if (bfd_get_flavour(abfd) == bfd_target_elf_flavour)
goto out_close;
- section = bfd_get_section_by_name(abfd, ".text");
- if (section)
- dso->text_offset = section->vma - section->filepos;
-
symbols_size = bfd_get_symtab_upper_bound(abfd);
if (symbols_size == 0) {
bfd_close(abfd);
@@ -1602,6 +1598,22 @@ int dso__load_bfd_symbols(struct dso *dso, const char *debugfile)
if (symbols_count < 0)
goto out_free;
+ section = bfd_get_section_by_name(abfd, ".text");
+ if (section) {
+ for (i = 0; i < symbols_count; ++i) {
+ if (!strcmp(bfd_asymbol_name(symbols[i]), "__ImageBase") ||
+ !strcmp(bfd_asymbol_name(symbols[i]), "__image_base__"))
+ break;
+ }
+ if (i < symbols_count) {
+ /* PE symbols can only have 4 bytes, so use .text high bits */
+ dso->text_offset = section->vma - (u32)section->vma;
+ dso->text_offset += (u32)bfd_asymbol_value(symbols[i]);
+ } else {
+ dso->text_offset = section->vma - section->filepos;
+ }
+ }
+
qsort(symbols, symbols_count, sizeof(asymbol *), bfd_symbols__cmpvalue);
#ifdef bfd_get_section
--
2.33.0
next reply other threads:[~2021-09-09 19:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 19:26 Remi Bernon [this message]
2021-09-09 20:27 ` [PATCH] perf symbol: Look for ImageBase in PE file to compute .text offset Arnaldo Carvalho de Melo
2021-09-12 8:25 ` Rémi Bernon
2021-09-13 19:24 ` Arnaldo Carvalho de Melo
2021-09-13 20:37 ` Rémi Bernon
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