linux-kernel - [PATCH 001/208] x86/fpu: Rename unlazy_fpu() to fpu_

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Date:	Tue,  5 May 2015 18:19:53 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	linux-kernel@...r.kernel.org
Cc:	Andy Lutomirski <luto@...capital.net>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Fenghua Yu <fenghua.yu@...el.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Oleg Nesterov <oleg@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 001/208] x86/fpu: Rename unlazy_fpu() to fpu__save()

This function is a misnomer on two levels:

1) it doesn't really manipulate TS on modern CPUs anymore, its
   primary purpose is to save FPU state, used:

      - when executing fork()/clone(): to copy current FPU state
        to the child's FPU state.

      - when handling math exceptions: to generate the math error
        si_code in the signal frame.

2) even on legacy CPUs it doesn't actually 'unlazy', if then
   it lazies the FPU state: as a side effect of the old FNSAVE
   instruction which clears (destroys) FPU state it's necessary
   to set CR0::TS.

So rename it to fpu__save() to better reflect its purpose.

Reviewed-by: Borislav Petkov <bp@...en8.de>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/include/asm/fpu-internal.h | 2 +-
 arch/x86/include/asm/i387.h         | 2 +-
 arch/x86/kernel/i387.c              | 6 +++---
 arch/x86/kernel/traps.c             | 2 +-
 4 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index da5e96756570..49db0440b0ed 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -602,7 +602,7 @@ static inline void fpu_copy(struct task_struct *dst, struct task_struct *src)
 		struct fpu *dfpu = &dst->thread.fpu;
 		struct fpu *sfpu = &src->thread.fpu;
 
-		unlazy_fpu(src);
+		fpu__save(src);
 		memcpy(dfpu->state, sfpu->state, xstate_size);
 	}
 }
diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 6eb6fcb83f63..d4419da9b210 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -101,7 +101,7 @@ static inline int user_has_fpu(void)
 	return current->thread.fpu.has_fpu;
 }
 
-extern void unlazy_fpu(struct task_struct *tsk);
+extern void fpu__save(struct task_struct *tsk);
 
 #endif /* __ASSEMBLY__ */
 
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 009183276bb7..ec1a744eb853 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -117,7 +117,7 @@ void __kernel_fpu_end(void)
 }
 EXPORT_SYMBOL(__kernel_fpu_end);
 
-void unlazy_fpu(struct task_struct *tsk)
+void fpu__save(struct task_struct *tsk)
 {
 	preempt_disable();
 	if (__thread_has_fpu(tsk)) {
@@ -130,7 +130,7 @@ void unlazy_fpu(struct task_struct *tsk)
 	}
 	preempt_enable();
 }
-EXPORT_SYMBOL(unlazy_fpu);
+EXPORT_SYMBOL(fpu__save);
 
 unsigned int mxcsr_feature_mask __read_mostly = 0xffffffffu;
 unsigned int xstate_size;
@@ -251,7 +251,7 @@ int init_fpu(struct task_struct *tsk)
 
 	if (tsk_used_math(tsk)) {
 		if (cpu_has_fpu && tsk == current)
-			unlazy_fpu(tsk);
+			fpu__save(tsk);
 		task_disable_lazy_fpu_restore(tsk);
 		return 0;
 	}
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 324ab5247687..12f29f9907cd 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -731,7 +731,7 @@ static void math_error(struct pt_regs *regs, int error_code, int trapnr)
 	/*
 	 * Save the info for the exception handler and clear the error.
 	 */
-	unlazy_fpu(task);
+	fpu__save(task);
 	task->thread.trap_nr = trapnr;
 	task->thread.error_code = error_code;
 	info.si_signo = SIGFPE;
-- 
2.1.0

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