From e962591749dfd4df9fea2c530ed7a3cfed50e5aa Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Fri, 24 Aug 2012 14:12:57 -0700 Subject: [PATCH] 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: Suresh Siddha Link: http://lkml.kernel.org/r/1345842782-24175-2-git-send-email-suresh.b.siddha@intel.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/fpu-internal.h | 7 +------ arch/x86/kernel/xsave.c | 8 +++----- 2 files changed, 4 insertions(+), 11 deletions(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index 4fbb419..78169d1 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -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(); diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 0923d27..07ddc87 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -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 -- 2.7.4