Messages in this thread Patch in this message | | | From | Andy Lutomirski <> | Subject | [RFC 14/17] x86/asm/64: Remove all remaining direct thread_struct::sp0 reads | Date | Wed, 6 Sep 2017 14:36:59 -0700 |
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The only remaining readers in context switch code or vm86(), and they all just want to update TSS.sp0 to match the current task. Replace them all with a new helper update_sp0().
Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/include/asm/switch_to.h | 6 ++++++ arch/x86/kernel/process_32.c | 2 +- arch/x86/kernel/process_64.c | 2 +- arch/x86/kernel/vm86_32.c | 4 ++-- 4 files changed, 10 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index f3fa19925ae1..d9bb491ba45c 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -83,4 +83,10 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread) } #endif +/* This is used when switching tasks or entering/exiting vm86 mode. */ +static inline void update_sp0(struct task_struct *task) +{ + load_sp0(task->thread.sp0); +} + #endif /* _ASM_X86_SWITCH_TO_H */ diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index e06a98e3a772..aab973504ca5 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -286,7 +286,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) * Reload esp0 and cpu_current_top_of_stack. This changes * current_thread_info(). */ - load_sp0(next->sp0); + update_sp0(next); refresh_sysenter_cs(next); /* in case prev or next is vm86 */ this_cpu_write(cpu_current_top_of_stack, (unsigned long)task_stack_page(next_p) + diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 06c4393b19b3..c33f8ad297bb 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -437,7 +437,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) this_cpu_write(current_task, next_p); /* Reload sp0. */ - load_sp0(next->sp0); + update_sp0(next_p); /* * Now maybe reload the debug registers and handle I/O bitmaps diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c index 3b98b7771f15..33dc5d3b9a4a 100644 --- a/arch/x86/kernel/vm86_32.c +++ b/arch/x86/kernel/vm86_32.c @@ -147,7 +147,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval) tsk->thread.sp0 = vm86->saved_sp0; tsk->thread.sysenter_cs = __KERNEL_CS; - load_sp0(tsk->thread.sp0); + update_sp0(tsk); refresh_sysenter_cs(&tsk->thread); vm86->saved_sp0 = 0; put_cpu(); @@ -371,7 +371,7 @@ static long do_sys_vm86(struct vm86plus_struct __user *user_vm86, bool plus) refresh_sysenter_cs(&tsk->thread); } - load_sp0(tsk->thread.sp0); + update_sp0(tsk); put_cpu(); if (vm86->flags & VM86_SCREEN_BITMAP) -- 2.13.5
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