From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751451AbbCUUoq (ORCPT ); Sat, 21 Mar 2015 16:44:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34781 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751147AbbCUUop (ORCPT ); Sat, 21 Mar 2015 16:44:45 -0400 From: Denys Vlasenko To: Andy Lutomirski Cc: Denys Vlasenko , Linus Torvalds , Steven Rostedt , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Oleg Nesterov , Frederic Weisbecker , Alexei Starovoitov , Will Drewry , Kees Cook , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] x86: stop using PER_CPU_VAR(kernel_stack) Date: Sat, 21 Mar 2015 21:44:37 +0100 Message-Id: <1426970678-600-1-git-send-email-dvlasenk@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instead of PER_CPU_VAR(kernel_stack), 64-bit code can use PER_CPU_VAR(cpu_tss + TSS_sp0). 32-bit code switches to PER_CPU_VAR(cpu_current_top_of_stack), which has the same value. Signed-off-by: Denys Vlasenko CC: Linus Torvalds CC: Steven Rostedt CC: Ingo Molnar CC: Borislav Petkov CC: "H. Peter Anvin" CC: Andy Lutomirski CC: Oleg Nesterov CC: Frederic Weisbecker CC: Alexei Starovoitov CC: Will Drewry CC: Kees Cook CC: x86@kernel.org CC: linux-kernel@vger.kernel.org --- Andy, this patchset goes on top of PUSH conversion patches arch/x86/ia32/ia32entry.S | 2 +- arch/x86/include/asm/thread_info.h | 8 +++++++- arch/x86/kernel/entry_64.S | 2 +- arch/x86/xen/xen-asm_64.S | 5 +++-- 4 files changed, 12 insertions(+), 5 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index acbff3f..0a791c5 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -317,7 +317,7 @@ ENTRY(ia32_cstar_target) SWAPGS_UNSAFE_STACK movl %esp,%r8d CFI_REGISTER rsp,r8 - movq PER_CPU_VAR(kernel_stack),%rsp + movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp /* * No need to follow this irqs on/off section: the syscall * disabled irqs and here we enable it straight after entry: diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 89b814e..5be18d1 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -201,9 +201,15 @@ static inline unsigned long current_stack_pointer(void) #else /* !__ASSEMBLY__ */ /* Load thread_info address into "reg" */ +#ifdef CONFIG_X86_32 #define GET_THREAD_INFO(reg) \ - _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \ + _ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \ _ASM_SUB $(THREAD_SIZE),reg ; +#else +#define GET_THREAD_INFO(reg) \ + _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \ + _ASM_SUB $(THREAD_SIZE),reg ; +#endif /* * ASM operand which evaluates to thread_info address diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 43e7333..e5b5283 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -220,7 +220,7 @@ ENTRY(system_call) GLOBAL(system_call_after_swapgs) movq %rsp,PER_CPU_VAR(rsp_scratch) - movq PER_CPU_VAR(kernel_stack),%rsp + movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp /* Construct struct pt_regs on stack */ pushq_cfi $__USER_DS /* pt_regs->ss */ diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S index 985fc3e..acc49e0 100644 --- a/arch/x86/xen/xen-asm_64.S +++ b/arch/x86/xen/xen-asm_64.S @@ -15,6 +15,7 @@ #include #include #include +#include #include @@ -69,7 +70,7 @@ ENTRY(xen_sysret64) * still with the kernel gs, so we can easily switch back */ movq %rsp, PER_CPU_VAR(rsp_scratch) - movq PER_CPU_VAR(kernel_stack), %rsp + movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp pushq $__USER_DS pushq PER_CPU_VAR(rsp_scratch) @@ -88,7 +89,7 @@ ENTRY(xen_sysret32) * still with the kernel gs, so we can easily switch back */ movq %rsp, PER_CPU_VAR(rsp_scratch) - movq PER_CPU_VAR(kernel_stack), %rsp + movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp pushq $__USER32_DS pushq PER_CPU_VAR(rsp_scratch) -- 1.8.1.4