Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933530AbbDUQXg (ORCPT ); Tue, 21 Apr 2015 12:23:36 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:57190 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755736AbbDUPdE (ORCPT ); Tue, 21 Apr 2015 11:33:04 -0400 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jiri Slaby , Borislav Petkov , "H. Peter Anvin" , Linus Torvalds , Thomas Gleixner , Ingo Molnar , Luis Henriques Subject: [PATCH 3.16.y-ckt 018/144] x86/vdso: Fix the build on GCC5 Date: Tue, 21 Apr 2015 16:30:03 +0100 Message-Id: <1429630329-21748-19-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> References: <1429630329-21748-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2532 Lines: 67 3.16.7-ckt10 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby 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 Signed-off-by: Jiri Slaby Acked-by: Andy Lutomirski Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1425543211-12542-1-git-send-email-jslaby@suse.cz Signed-off-by: Ingo Molnar Signed-off-by: Luis Henriques --- arch/x86/vdso/vdso32/sigreturn.S | 1 + 1 file changed, 1 insertion(+) 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 @@ .text .globl __kernel_sigreturn .type __kernel_sigreturn,@function + nop /* this guy is needed for .LSTARTFDEDLSI1 below (watch for HACK) */ ALIGN __kernel_sigreturn: .LSTART_sigreturn: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/