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Commit 34b2cd5b authored by Ingo Molnar's avatar Ingo Molnar Committed by Thomas Gleixner
Browse files

x86: PEBS cleanup 



Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 573da422

arch/x86/kernel/process_64.c

+17 −12
Original line number Diff line number Diff line
@@ -500,7 +500,6 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, 
{

	struct thread_struct *prev, *next;

	unsigned long debugctl;

	unsigned long ds_prev = 0, ds_next = 0;



	prev = &prev_p->thread,

	next = &next_p->thread;
@@ -508,18 +507,24 @@ static inline void __switch_to_xtra(struct task_struct *prev_p, 
	debugctl = prev->debugctlmsr;



#ifdef CONFIG_X86_DS

	{

		unsigned long ds_prev = 0, ds_next = 0;



		if (prev->ds_ctx)

			ds_prev = (unsigned long)prev->ds_ctx->ds;

		if (next->ds_ctx)

			ds_next = (unsigned long)next->ds_ctx->ds;



		if (ds_next != ds_prev) {

		/* we clear debugctl to make sure DS

		 * is not in use when we change it */

			/*

			 * We clear debugctl to make sure DS

			 * is not in use when we change it:

			 */

			debugctl = 0;

			update_debugctlmsr(0);

			wrmsrl(MSR_IA32_DS_AREA, ds_next);

		}

	}

#endif /* CONFIG_X86_DS */



	if (next->debugctlmsr != debugctl)