recordmcount: Fix handling of elf64 big-endian objects.

commit 2e885057b7f75035f0b85e02f737891482815a81 upstream.

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
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index f40a6af..54e35c1 100644 (file)
--- 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 ||
                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;
 }
                return NULL;
        return txtname;
 }