Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753286AbbEEBa6 (ORCPT ); Mon, 4 May 2015 21:30:58 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51006 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752617AbbEEBXL (ORCPT ); Mon, 4 May 2015 21:23:11 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Jiri Slaby" , "Linus Torvalds" , "Ingo Molnar" , "H. Peter Anvin" , "Borislav Petkov" , "Andy Lutomirski" , "Richard Biener" , "Thomas Gleixner" Date: Tue, 05 May 2015 02:16:39 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 107/221] x86/vdso: Fix the build on GCC5 In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2392 Lines: 66 3.2.69-rc1 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: Ben Hutchings --- arch/x86/vdso/vdso32/sigreturn.S | 1 + 1 file changed, 1 insertion(+) --- 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/