From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bastian Blank Subject: Re: [PATCH] xen: Disable stack protector for irq helper Date: Mon, 5 Oct 2009 03:35:17 +0200 Message-ID: <20091005013517.GA6081@wavehammer.waldi.eu.org> References: <20091004183013.GA26101@wavehammer.waldi.eu.org> <4AC92A65.40806@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <4AC92A65.40806@goop.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jeremy Fitzhardinge Cc: Xen-devel , Linux Kernel Mailing List , Ingo Molnar , the arch/x86 maintainers , Stable Kernel List-Id: xen-devel@lists.xenproject.org On Sun, Oct 04, 2009 at 04:06:13PM -0700, Jeremy Fitzhardinge wrote: > On 10/04/09 11:30, Bastian Blank wrote: > > The stack protector needs additional registers on x86_32, which are not > > saved in calls to the small paravirt interrupt handlers. This leads to > > early crashes as registers are overwritten and not saved by the caller > > as instructed. > Thanks for the patch, but I don't think its quite right. > PV_CALLEE_SAVE_REGS_THUNK() is responsible for generating a wrapper for > the functions to save/restore all the appropriate registers. If it is > failing to do so, then the correct fix is to update > PV_SAVE/RESTORE_ALL_CALLER_REGS. Well, I did not understand this part of the code, but you seem right. So lets try the following. I have not yet run tested it. Save all caller-saved registers on x86_32 for the paravirt callee saved registers. Signed-off-by: Bastian Blank diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index e19ffe3..e4272f3 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -793,8 +793,8 @@ static __always_inline void __raw_spin_unlock(struct raw_spinlock *lock) #define PV_RESTORE_REGS "popl %edx; popl %ecx;" /* save and restore all caller-save registers, except return value */ -#define PV_SAVE_ALL_CALLER_REGS "pushl %ecx;" -#define PV_RESTORE_ALL_CALLER_REGS "popl %ecx;" +#define PV_SAVE_ALL_CALLER_REGS PV_SAVE_REGS +#define PV_RESTORE_ALL_CALLER_REGS PV_RESTORE_REGS #define PV_FLAGS_ARG "0" #define PV_EXTRA_CLOBBERS -- In the strict scientific sense we all feed on death -- even vegetarians. -- Spock, "Wolf in the Fold", stardate 3615.4