Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754325AbbGQQ5g (ORCPT ); Fri, 17 Jul 2015 12:57:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:51361 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754215AbbGQQ5d (ORCPT ); Fri, 17 Jul 2015 12:57:33 -0400 From: Josh Poimboeuf To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: Michal Marek , Peter Zijlstra , Andy Lutomirski , Borislav Petkov , Linus Torvalds , Andi Kleen , Pedro Alves , x86@kernel.org, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 06/21] x86/paravirt: Add stack frame dependency to PVOP inline asm calls Date: Fri, 17 Jul 2015 11:47:22 -0500 Message-Id: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2936 Lines: 78 If a PVOP call macro is inlined at the beginning of a function, gcc can insert the call instruction before setting up a stack frame, which breaks frame pointer convention if CONFIG_FRAME_POINTER is enabled and can result in a bad stack trace. Force a stack frame to be created by listing the stack pointer as an output operand for the PVOP inline asm statements. Signed-off-by: Josh Poimboeuf --- arch/x86/include/asm/paravirt_types.h | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index ce029e4..1812294 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -497,8 +497,9 @@ int paravirt_disable_iospace(void); * makes sure the incoming and outgoing types are always correct. */ #ifdef CONFIG_X86_32 -#define PVOP_VCALL_ARGS \ - unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx +#define PVOP_VCALL_ARGS \ + unsigned long __eax = __eax, __edx = __edx, __ecx = __ecx; \ + register void *__sp asm("esp") #define PVOP_CALL_ARGS PVOP_VCALL_ARGS #define PVOP_CALL_ARG1(x) "a" ((unsigned long)(x)) @@ -516,9 +517,10 @@ int paravirt_disable_iospace(void); #define VEXTRA_CLOBBERS #else /* CONFIG_X86_64 */ /* [re]ax isn't an arg, but the return val */ -#define PVOP_VCALL_ARGS \ - unsigned long __edi = __edi, __esi = __esi, \ - __edx = __edx, __ecx = __ecx, __eax = __eax +#define PVOP_VCALL_ARGS \ + unsigned long __edi = __edi, __esi = __esi, \ + __edx = __edx, __ecx = __ecx, __eax = __eax; \ + register void *__sp asm("rsp") #define PVOP_CALL_ARGS PVOP_VCALL_ARGS #define PVOP_CALL_ARG1(x) "D" ((unsigned long)(x)) @@ -557,7 +559,7 @@ int paravirt_disable_iospace(void); asm volatile(pre \ paravirt_alt(PARAVIRT_CALL) \ post \ - : call_clbr \ + : "+r" (__sp), call_clbr \ : paravirt_type(op), \ paravirt_clobber(clbr), \ ##__VA_ARGS__ \ @@ -567,7 +569,7 @@ int paravirt_disable_iospace(void); asm volatile(pre \ paravirt_alt(PARAVIRT_CALL) \ post \ - : call_clbr \ + : "+r" (__sp), call_clbr \ : paravirt_type(op), \ paravirt_clobber(clbr), \ ##__VA_ARGS__ \ @@ -594,7 +596,7 @@ int paravirt_disable_iospace(void); asm volatile(pre \ paravirt_alt(PARAVIRT_CALL) \ post \ - : call_clbr \ + : "+r" (__sp), call_clbr \ : paravirt_type(op), \ paravirt_clobber(clbr), \ ##__VA_ARGS__ \ -- 2.1.0 -- 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/