[PATCH 069/208] x86/fpu: Rename fpu__flush_thread() to fpu__clear()

Ingo Molnar
2015-05-05T16:48:57Z

The primary purpose of this function is to clear the current task's
FPU before an exec(), to not leak information from the previous task,
and to allow the new task to start with freshly initialized FPU
registers.

Rename the function to reflect this primary purpose.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/i387.h | 2 +-
arch/x86/kernel/fpu/core.c | 4 ++--
arch/x86/kernel/process.c | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/i387.h b/arch/x86/include/asm/i387.h
index 38376cdf297c..b8f7d76ac066 100644
--- a/arch/x86/include/asm/i387.h
+++ b/arch/x86/include/asm/i387.h
@@ -20,7 +20,7 @@ struct user_i387_struct;

extern int fpstate_alloc_init(struct fpu *fpu);
extern void fpstate_init(struct fpu *fpu);
-extern void fpu__flush_thread(struct task_struct *tsk);
+extern void fpu__clear(struct task_struct *tsk);

extern int dump_fpu(struct pt_regs *, struct user_i387_struct *);
extern void fpu__restore(void);
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 7045eff05292..e24f477f9113 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -381,11 +381,11 @@ void fpu__restore(void)
}
EXPORT_SYMBOL_GPL(fpu__restore);

-void fpu__flush_thread(struct task_struct *tsk)
+void fpu__clear(struct task_struct *tsk)
{
struct fpu *fpu = &tsk->thread.fpu;

- WARN_ON(tsk != current);
+ WARN_ON_ONCE(tsk != current); /* Almost certainly an anomaly */

if (!use_eager_fpu()) {
/* FPU state will be reallocated lazily at the first use. */
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index f2cd1df00b40..04ac5901dbee 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -130,7 +130,7 @@ void flush_thread(void)
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));

- fpu__flush_thread(tsk);
+ fpu__clear(tsk);
}

static void hard_disable_TSC(void)
--
2.1.0