Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758065AbdLVJn0 (ORCPT ); Fri, 22 Dec 2017 04:43:26 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38498 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932477AbdLVJBp (ORCPT ); Fri, 22 Dec 2017 04:01:45 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andy Lutomirski , Juergen Gross , Boris Ostrovsky , Borislav Petkov , Brian Gerst , Dave Hansen , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.14 049/159] x86/xen/64, x86/entry/64: Clean up SP code in cpu_initialize_context() Date: Fri, 22 Dec 2017 09:45:34 +0100 Message-Id: <20171222084626.417723914@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171222084623.668990192@linuxfoundation.org> References: <20171222084623.668990192@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3025 Lines: 89 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski commit f16b3da1dc936c0f8121741d0a1731bf242f2f56 upstream. I'm removing thread_struct::sp0, and Xen's usage of it is slightly dubious and unnecessary. Use appropriate helpers instead. While we're at at, reorder the code slightly to make it more obvious what's going on. Signed-off-by: Andy Lutomirski Reviewed-by: Juergen Gross Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/d5b9a3da2b47c68325bd2bbe8f82d9554dee0d0f.1509609304.git.luto@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/xen/smp_pv.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) --- a/arch/x86/xen/smp_pv.c +++ b/arch/x86/xen/smp_pv.c @@ -14,6 +14,7 @@ * single-threaded. */ #include +#include #include #include #include @@ -294,12 +295,19 @@ cpu_initialize_context(unsigned int cpu, #endif memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt)); + /* + * Bring up the CPU in cpu_bringup_and_idle() with the stack + * pointing just below where pt_regs would be if it were a normal + * kernel entry. + */ ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; ctxt->flags = VGCF_IN_KERNEL; ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ ctxt->user_regs.ds = __USER_DS; ctxt->user_regs.es = __USER_DS; ctxt->user_regs.ss = __KERNEL_DS; + ctxt->user_regs.cs = __KERNEL_CS; + ctxt->user_regs.esp = (unsigned long)task_pt_regs(idle); xen_copy_trap_info(ctxt->trap_ctxt); @@ -314,8 +322,13 @@ cpu_initialize_context(unsigned int cpu, ctxt->gdt_frames[0] = gdt_mfn; ctxt->gdt_ents = GDT_ENTRIES; + /* + * Set SS:SP that Xen will use when entering guest kernel mode + * from guest user mode. Subsequent calls to load_sp0() can + * change this value. + */ ctxt->kernel_ss = __KERNEL_DS; - ctxt->kernel_sp = idle->thread.sp0; + ctxt->kernel_sp = task_top_of_stack(idle); #ifdef CONFIG_X86_32 ctxt->event_callback_cs = __KERNEL_CS; @@ -327,10 +340,8 @@ cpu_initialize_context(unsigned int cpu, (unsigned long)xen_hypervisor_callback; ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback; - ctxt->user_regs.cs = __KERNEL_CS; per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir); - ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs); ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir)); if (HYPERVISOR_vcpu_op(VCPUOP_initialise, xen_vcpu_nr(cpu), ctxt)) BUG();