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x86/entry/64: Remove all remaining direct thread_struct::sp0 reads 

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>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/2d231687f4ff288c9d9e98d7861b7df374246ac3.1509609304.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski 2017-11-02 00:59:14 -07:00 committed by Ingo Molnar
parent 20bb83443e
commit 46f5a10a72
4 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/x86/include/asm/switch_to.h
View File

@ -84,4 +84,10 @@ 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 */

2
arch/x86/kernel/process_32.c
View File

@ -287,7 +287,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
* current_thread_info(). Refresh the SYSENTER configuration in
* case prev or next is vm86.
*/
load_sp0(next->sp0);
update_sp0(next_p);
refresh_sysenter_cs(next);
this_cpu_write(cpu_current_top_of_stack,
(unsigned long)task_stack_page(next_p) +

2
arch/x86/kernel/process_64.c
View File

@ -465,7 +465,7 @@ __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

4
arch/x86/kernel/vm86_32.c
View File

@ -148,7 +148,7 @@ void save_v86_state(struct kernel_vm86_regs *regs, int retval)
preempt_disable();
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;
preempt_enable();
@ -373,7 +373,7 @@ 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);
preempt_enable();
if (vm86->flags & VM86_SCREEN_BITMAP)