From: David Daney <ddaney.cavm@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, David Daney <david.daney@cavium.com>
Subject: [PATCH] recordmcount: Fix handling of elf64 big-endian objects.
Date: Mon, 19 Dec 2011 17:42:42 -0800 [thread overview]
Message-ID: <1324345362-12230-1-git-send-email-ddaney.cavm@gmail.com> (raw)
From: David Daney <david.daney@cavium.com>
In ELF64, the sh_flags field is 64-bits wide. recordmcount was
erroneously treating it as a 32-bit wide field. For little endian
objects this works because the flags of interest (SHF_EXECINSTR)
reside in the lower 32 bits of the word, and you get the same result
with either a 32-bit or 64-bit read. Big endian objects on the
other hand do not work at all with this error.
The fix: Correctly treat sh_flags as 64-bits wide in elf64 objects.
The symptom I observed was that my
__start_mcount_loc..__stop_mcount_loc was empty even though ftrace
function tracing was enabled.
Signed-off-by: David Daney <david.daney@cavium.com>
---
scripts/recordmcount.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index f40a6af6..54e35c1 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -462,7 +462,7 @@ __has_rel_mcount(Elf_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
succeed_file();
}
if (w(txthdr->sh_type) != SHT_PROGBITS ||
- !(w(txthdr->sh_flags) & SHF_EXECINSTR))
+ !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
return NULL;
return txtname;
}
--
1.7.2.3
next reply other threads:[~2011-12-20 1:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-20 1:42 David Daney [this message]
2011-12-20 3:09 ` Steven Rostedt
2012-01-06 20:42 ` David Daney
2012-01-06 21:47 ` Steven Rostedt
2012-01-06 23:09 ` Steven Rostedt
2012-01-06 23:15 ` David Daney
2012-01-06 23:24 ` Steven Rostedt
2012-01-08 11:51 ` [tip:perf/core] " tip-bot for David Daney
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