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Commit 46f5a10a authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar
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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: default avatarAndy Lutomirski <luto@kernel.org>
Reviewed-by: default avatarBorislav 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: default avatarIngo Molnar <mingo@kernel.org>
parent 20bb8344

arch/x86/include/asm/switch_to.h

+6 −0
Original line number Diff line number Diff line
@@ -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 */

arch/x86/kernel/process_32.c

+1 −1
Original line number Diff line number Diff line
@@ -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) +

arch/x86/kernel/process_64.c

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/vm86_32.c

+2 −2
Original line number Diff line number Diff line
@@ -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)