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Commit e9625917 authored by Suresh Siddha's avatar Suresh Siddha Committed by H. Peter Anvin
Browse files

x86, fpu: drop_fpu() before restoring new state from sigframe 



No need to save the state with unlazy_fpu(), that is about to get overwritten
by the state from the signal frame. Instead use drop_fpu() and continue
to restore the new state.

Also fold the stop_fpu_preload() into drop_fpu().

Signed-off-by: default avatarSuresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-2-git-send-email-suresh.b.siddha@intel.com


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 72a671ce

arch/x86/include/asm/fpu-internal.h

+1 −6
Original line number Diff line number Diff line
@@ -448,17 +448,12 @@ static inline void save_init_fpu(struct task_struct *tsk) 
	preempt_enable();

}



static inline void stop_fpu_preload(struct task_struct *tsk)

{

	tsk->fpu_counter = 0;

}



static inline void drop_fpu(struct task_struct *tsk)

{

	/*

	 * Forget coprocessor state..

	 */

	stop_fpu_preload(tsk);

	tsk->fpu_counter = 0;

	preempt_disable();

	__drop_fpu(tsk);

	preempt_enable();

arch/x86/kernel/xsave.c

+3 −5
Original line number Diff line number Diff line
@@ -382,16 +382,14 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size) 
		struct xsave_struct *xsave = &tsk->thread.fpu.state->xsave;

		struct user_i387_ia32_struct env;



		stop_fpu_preload(tsk);

		unlazy_fpu(tsk);

		drop_fpu(tsk);



		if (__copy_from_user(xsave, buf_fx, state_size) ||

		    __copy_from_user(&env, buf, sizeof(env))) {

			drop_fpu(tsk);

		    __copy_from_user(&env, buf, sizeof(env)))

			return -1;

		}



		sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);

		set_used_math();

	} else {

		/*

		 * For 64-bit frames and 32-bit fsave frames, restore the user