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Date: Fri, 24 Aug 2012 14:12:58 -0700 From: Suresh Siddha <suresh.b.siddha@...el.com> To: hpa@...or.com, mingo@...nel.org, torvalds@...ux-foundation.org, andreas.herrmann3@....com, bp@...64.org, robert.richter@....com Cc: linux-kernel@...r.kernel.org, Suresh Siddha <suresh.b.siddha@...el.com> Subject: [PATCH 2/6] x86, fpu: remove unnecessary user_fpu_end() in save_xstate_sig() Few lines below we do drop_fpu() which is more safer. Remove the unnecessary user_fpu_end() in save_xstate_sig(), which allows the drop_fpu() to ignore any pending exceptions from the user-space and drop the current fpu. Signed-off-by: Suresh Siddha <suresh.b.siddha@...el.com> --- arch/x86/include/asm/fpu-internal.h | 17 +++-------------- arch/x86/kernel/xsave.c | 1 - 2 files changed, 3 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h index fe95ad0..fac39e9 100644 --- a/arch/x86/include/asm/fpu-internal.h +++ b/arch/x86/include/asm/fpu-internal.h @@ -412,22 +412,11 @@ static inline void __drop_fpu(struct task_struct *tsk) } /* - * The actual user_fpu_begin/end() functions - * need to be preemption-safe. + * Need to be preemption-safe. * - * NOTE! user_fpu_end() must be used only after you - * have saved the FP state, and user_fpu_begin() must - * be used only immediately before restoring it. - * These functions do not do any save/restore on - * their own. + * NOTE! user_fpu_begin() must be used only immediately before restoring + * it. This function does not do any save/restore on their own. */ -static inline void user_fpu_end(void) -{ - preempt_disable(); - __thread_fpu_end(current); - preempt_enable(); -} - static inline void user_fpu_begin(void) { preempt_disable(); diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c index 6cfc7d9..f0bb844 100644 --- a/arch/x86/kernel/xsave.c +++ b/arch/x86/kernel/xsave.c @@ -254,7 +254,6 @@ int save_xstate_sig(void __user *buf, void __user *buf_fx, int size) /* Update the thread's fxstate to save the fsave header. */ if (ia32_fxstate) fpu_fxsave(&tsk->thread.fpu); - user_fpu_end(); } else { sanitize_i387_state(tsk); if (__copy_to_user(buf_fx, xsave, xstate_size)) -- 1.7.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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