path: root/arch
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authorJiri Slaby <jslaby@suse.cz>2015-03-05 09:13:31 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-26 15:01:00 +0100
commit99a9adcaf4b58031d8802c266b9166d558415c38 (patch)
treec53c991e2aeadb1c24963df2a5f03e697fa09518 /arch
parent16329d3d06836a47ac9bc66867b0bd09dfb76ad9 (diff)
x86/vdso: Fix the build on GCC5
commit e893286918d2cde3a94850d8f7101cd1039e0c62 upstream. On gcc5 the kernel does not link: ld: .eh_frame_hdr table[4] FDE at 0000000000000648 overlaps table[5] FDE at 0000000000000670. Because prior GCC versions always emitted NOPs on ALIGN directives, but gcc5 started omitting them. .LSTARTFDEDLSI1 says: /* HACK: The dwarf2 unwind routines will subtract 1 from the return address to get an address in the middle of the presumed call instruction. Since we didn't get here via a call, we need to include the nop before the real start to make up for it. */ .long .LSTART_sigreturn-1-. /* PC-relative start address */ But commit 69d0627a7f6e ("x86 vDSO: reorder vdso32 code") from 2.6.25 replaced .org __kernel_vsyscall+32,0x90 by ALIGN right before __kernel_sigreturn. Of course, ALIGN need not generate any NOP in there. Esp. gcc5 collapses vclock_gettime.o and int80.o together with no generated NOPs as "ALIGN". So fix this by adding to that point at least a single NOP and make the function ALIGN possibly with more NOPs then. Kudos for reporting and diagnosing should go to Richard. Reported-by: Richard Biener <rguenther@suse.de> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1425543211-12542-1-git-send-email-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/vdso/vdso32/sigreturn.S b/arch/x86/vdso/vdso32/sigreturn.S
index 31776d0efc8c..d7ec4e251c0a 100644
--- a/arch/x86/vdso/vdso32/sigreturn.S
+++ b/arch/x86/vdso/vdso32/sigreturn.S
@@ -17,6 +17,7 @@
.globl __kernel_sigreturn
.type __kernel_sigreturn,@function
+ nop /* this guy is needed for .LSTARTFDEDLSI1 below (watch for HACK) */