115 lines
3.8 KiB
Diff
115 lines
3.8 KiB
Diff
From 252c6cff2b83c4cc969b64306956a5c8c130a50d Mon Sep 17 00:00:00 2001
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From: Denys Vlasenko <dvlasenk@redhat.com>
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Date: Fri, 24 Apr 2015 17:31:33 +0200
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Subject: [PATCH 2/9] x86/entry: Stop using PER_CPU_VAR(kernel_stack)
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PER_CPU_VAR(kernel_stack) is redundant:
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- On the 64-bit build, we can use PER_CPU_VAR(cpu_tss + TSS_sp0).
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- On the 32-bit build, we can use PER_CPU_VAR(cpu_current_top_of_stack).
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PER_CPU_VAR(kernel_stack) will be deleted by a separate change.
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Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: Alexei Starovoitov <ast@plumgrid.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>
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Cc: Andy Lutomirski <luto@amacapital.net>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Frederic Weisbecker <fweisbec@gmail.com>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Kees Cook <keescook@chromium.org>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Oleg Nesterov <oleg@redhat.com>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Steven Rostedt <rostedt@goodmis.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Cc: Will Drewry <wad@chromium.org>
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Link: http://lkml.kernel.org/r/1429889495-27850-1-git-send-email-dvlasenk@redhat.com
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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---
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arch/x86/ia32/ia32entry.S | 2 +-
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arch/x86/include/asm/thread_info.h | 8 +++++++-
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arch/x86/kernel/entry_64.S | 2 +-
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arch/x86/xen/xen-asm_64.S | 5 +++--
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4 files changed, 12 insertions(+), 5 deletions(-)
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diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S
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index 72bf268..e3c0f06 100644
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--- a/arch/x86/ia32/ia32entry.S
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+++ b/arch/x86/ia32/ia32entry.S
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@@ -356,7 +356,7 @@ ENTRY(ia32_cstar_target)
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SWAPGS_UNSAFE_STACK
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movl %esp,%r8d
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CFI_REGISTER rsp,r8
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- movq PER_CPU_VAR(kernel_stack),%rsp
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+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
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ENABLE_INTERRUPTS(CLBR_NONE)
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/* Zero-extending 32-bit regs, do not remove */
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diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
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index b4bdec3..d656a36 100644
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--- a/arch/x86/include/asm/thread_info.h
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+++ b/arch/x86/include/asm/thread_info.h
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@@ -198,9 +198,15 @@ static inline unsigned long current_stack_pointer(void)
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#else /* !__ASSEMBLY__ */
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/* Load thread_info address into "reg" */
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+#ifdef CONFIG_X86_32
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#define GET_THREAD_INFO(reg) \
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- _ASM_MOV PER_CPU_VAR(kernel_stack),reg ; \
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+ _ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
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_ASM_SUB $(THREAD_SIZE),reg ;
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+#else
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+#define GET_THREAD_INFO(reg) \
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+ _ASM_MOV PER_CPU_VAR(cpu_tss + TSS_sp0),reg ; \
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+ _ASM_SUB $(THREAD_SIZE),reg ;
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+#endif
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/*
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* ASM operand which evaluates to a 'thread_info' address of
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diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
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index b32f346..00cde3c 100644
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--- a/arch/x86/kernel/entry_64.S
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+++ b/arch/x86/kernel/entry_64.S
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@@ -216,7 +216,7 @@ ENTRY(system_call)
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GLOBAL(system_call_after_swapgs)
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movq %rsp,PER_CPU_VAR(rsp_scratch)
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- movq PER_CPU_VAR(kernel_stack),%rsp
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+ movq PER_CPU_VAR(cpu_tss + TSS_sp0),%rsp
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/* Construct struct pt_regs on stack */
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pushq_cfi $__USER_DS /* pt_regs->ss */
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diff --git a/arch/x86/xen/xen-asm_64.S b/arch/x86/xen/xen-asm_64.S
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index 985fc3e..acc49e0 100644
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--- a/arch/x86/xen/xen-asm_64.S
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+++ b/arch/x86/xen/xen-asm_64.S
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@@ -15,6 +15,7 @@
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#include <asm/percpu.h>
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#include <asm/processor-flags.h>
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#include <asm/segment.h>
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+#include <asm/asm-offsets.h>
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#include <xen/interface/xen.h>
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@@ -69,7 +70,7 @@ ENTRY(xen_sysret64)
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* still with the kernel gs, so we can easily switch back
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*/
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movq %rsp, PER_CPU_VAR(rsp_scratch)
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- movq PER_CPU_VAR(kernel_stack), %rsp
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+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
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pushq $__USER_DS
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pushq PER_CPU_VAR(rsp_scratch)
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@@ -88,7 +89,7 @@ ENTRY(xen_sysret32)
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* still with the kernel gs, so we can easily switch back
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*/
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movq %rsp, PER_CPU_VAR(rsp_scratch)
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- movq PER_CPU_VAR(kernel_stack), %rsp
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+ movq PER_CPU_VAR(cpu_tss + TSS_sp0), %rsp
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pushq $__USER32_DS
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pushq PER_CPU_VAR(rsp_scratch)
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--
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2.4.3
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