[PATCH][GIT PULL] recordmcount: Fix handling of elf64 big-endian objects

[PATCH][GIT PULL] recordmcount: Fix handling of elf64 big-endian objects

[Steven Rostedt]

Ingo,

Please pull the latest tip/perf/urgent tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/perf/urgent

Head SHA1: 2e885057b7f75035f0b85e02f737891482815a81


David Daney (1):
      recordmcount: Fix handling of elf64 big-endian objects

----
 scripts/recordmcount.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---------------------------
commit 2e885057b7f75035f0b85e02f737891482815a81
Author: David Daney <david.daney@cavium.com>
Date:   Mon Dec 19 17:42:42 2011 -0800

    recordmcount: Fix handling of elf64 big-endian objects.
    
    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.
    
    Link: http://lkml.kernel.org/r/1324345362-12230-1-git-send-email-ddaney.cavm@gmail.com
    
    Cc: stable@kernel.org # 3.0+
    Signed-off-by: David Daney <david.daney@cavium.com>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

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;
 }

Re: [PATCH][GIT PULL] recordmcount: Fix handling of elf64 big-endian objects

[Ingo Molnar]

* Steven Rostedt <rostedt@goodmis.org> wrote:

> 
> Ingo,
> 
> Please pull the latest tip/perf/urgent tree, which can be found at:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
> tip/perf/urgent
> 
> Head SHA1: 2e885057b7f75035f0b85e02f737891482815a81
> 
> 
> David Daney (1):
>       recordmcount: Fix handling of elf64 big-endian objects
> 
> ----
>  scripts/recordmcount.h |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

Pulled, thanks Steve!

	Ingo