From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754058AbbIRN5T (ORCPT ); Fri, 18 Sep 2015 09:57:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46709 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753506AbbIRN5Q (ORCPT ); Fri, 18 Sep 2015 09:57:16 -0400 Date: Fri, 18 Sep 2015 08:57:05 -0500 From: Josh Poimboeuf To: Chris J Arges Cc: x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, mmarek@suse.cz, peterz@infradead.org, luto@kernel.org, bp@alien8.de, torvalds@linux-foundation.org, andi@firstfloor.org, palves@redhat.com, namhyung@gmail.com, bernd@petrovitsch.priv.at, akpm@linux-foundation.org, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, david.vrabel@citrix.com, jeremy@goop.org, chrisw@sous-sol.org, akataria@vmware.com, rusty@rustcorp.com.au, herbert@gondor.apana.org.au, davem@davemloft.net, pavel@ucw.cz, rjw@rjwysocki.net, len.brown@intel.com, matt.fleming@intel.com, David Hildenbrand , "Michael S. Tsirkin" Subject: Re: [PATCH 1/3] x86/uaccess: Add stack frame output operand in get_user inline asm Message-ID: <20150918135705.GH21027@treble.hsd1.ky.comcast.net> References: <1442528077-11118-1-git-send-email-chris.j.arges@canonical.com> <1442528077-11118-2-git-send-email-chris.j.arges@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1442528077-11118-2-git-send-email-chris.j.arges@canonical.com> User-Agent: Mutt/1.5.23.1-rc1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 17, 2015 at 05:14:35PM -0500, Chris J Arges wrote: > Numerous 'call without frame pointer save/setup' warnings are introduced by > stacktool because of functions using the get_user macro. Bad stack traces could > occur due to lack of or misplacement of stack frame setup code. > > This patch forces a stack frame to be created before the inline asm code if > CONFIG_FRAME_POINTER is enabled by listing the stack pointer as an output > operand for the get_user inline assembly statement. > > Signed-off-by: Chris J Arges Reviewed-by: Josh Poimboeuf > --- > arch/x86/include/asm/uaccess.h | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h > index a8df874..55b8db5 100644 > --- a/arch/x86/include/asm/uaccess.h > +++ b/arch/x86/include/asm/uaccess.h > @@ -176,10 +176,11 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) > ({ \ > int __ret_gu; \ > register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \ > + register void *__sp asm(_ASM_SP); \ > __chk_user_ptr(ptr); \ > might_fault(); \ > - asm volatile("call __get_user_%P3" \ > - : "=a" (__ret_gu), "=r" (__val_gu) \ > + asm volatile("call __get_user_%P4" \ > + : "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp) \ > : "0" (ptr), "i" (sizeof(*(ptr)))); \ > (x) = (__force __typeof__(*(ptr))) __val_gu; \ > __ret_gu; \ > -- > 1.9.1 >