Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933762AbaDIODr (ORCPT ); Wed, 9 Apr 2014 10:03:47 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:22906 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933448AbaDIODo (ORCPT ); Wed, 9 Apr 2014 10:03:44 -0400 From: Boris Ostrovsky To: konrad.wilk@oracle.com, david.vrabel@citrix.com Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, srostedt@redhat.com, boris.ostrovsky@oracle.com Subject: [PATCH] x86/xen: Fix 32-bit PV guests's usage of kernel_stack Date: Wed, 9 Apr 2014 10:06:41 -0400 Message-Id: <1397052401-20220-1-git-send-email-boris.ostrovsky@oracle.com> X-Mailer: git-send-email 1.8.1.4 X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit 198d208df4371734ac4728f69cb585c284d20a15 made 32-bit kernels use kernel_stack to point to thread_info. That change missed a couple of updates needed by Xen's PV guests: 1. kernel_stack needs to be initialized for secondary CPUs 2. GET_THREAD_INFO() now uses %fs register which may not be the kernel's version when executing xen_iret() Signed-off-by: Boris Ostrovsky --- arch/x86/xen/smp.c | 3 ++- arch/x86/xen/xen-asm_32.S | 4 ++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index a18eadd..7005974 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -441,10 +441,11 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle) irq_ctx_init(cpu); #else clear_tsk_thread_flag(idle, TIF_FORK); +#endif per_cpu(kernel_stack, cpu) = (unsigned long)task_stack_page(idle) - KERNEL_STACK_OFFSET + THREAD_SIZE; -#endif + xen_setup_runstate_info(cpu); xen_setup_timer(cpu); xen_init_lock_cpu(cpu); diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S index 33ca6e4..d433637 100644 --- a/arch/x86/xen/xen-asm_32.S +++ b/arch/x86/xen/xen-asm_32.S @@ -88,7 +88,11 @@ ENTRY(xen_iret) * avoid having to reload %fs */ #ifdef CONFIG_SMP + pushw %fs + movl $(__KERNEL_PERCPU), %eax + movl %eax, %fs GET_THREAD_INFO(%eax) + popw %fs movl %ss:TI_cpu(%eax), %eax movl %ss:__per_cpu_offset(,%eax,4), %eax mov %ss:xen_vcpu(%eax), %eax -- 1.7.10.4 -- 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/