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x86/fpu: Merge fpu__reset() and fpu__clear() 

With recent cleanups and fixes the fpu__reset() and fpu__clear()
functions have become almost identical in functionality: the only
difference is that fpu__reset() assumed that the fpstate
was already active in the eagerfpu case, while fpu__clear()
activated it if it was inactive.

This distinction almost never matters, the only case where such
fpstate activation happens if if the init thread (PID 1) gets exec()-ed
for the first time.

So keep fpu__clear() and change all fpu__reset() uses to
fpu__clear() to simpify the logic.

( In a later patch we'll further simplify fpu__clear() by making
  sure that all contexts it is called on are already active. )

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
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: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2015-04-30 07:12:46 +02:00
parent 82c0e45eb5
commit fbce778246
4 changed files with 10 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/x86/include/asm/fpu/internal.h
View File

@ -56,7 +56,6 @@ extern void fpu__restore(void);
extern int fpu__restore_sig(void __user *buf, int ia32_frame);
extern void fpu__drop(struct fpu *fpu);
extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);
extern void fpu__reset(struct fpu *fpu);
extern void fpu__clear(struct fpu *fpu);
extern void fpu__init_check_bugs(void);
@ -490,7 +489,7 @@ static inline void switch_fpu_finish(struct fpu *new_fpu, fpu_switch_t fpu_switc
{
if (fpu_switch.preload) {
if (unlikely(copy_fpstate_to_fpregs(new_fpu)))
fpu__reset(new_fpu);
fpu__clear(new_fpu);
}
}

21
arch/x86/kernel/fpu/core.c
View File

@ -116,7 +116,7 @@ void __kernel_fpu_end(void)
if (fpu->fpregs_active) {
if (WARN_ON(copy_fpstate_to_fpregs(fpu)))
fpu__reset(fpu);
fpu__clear(fpu);
} else {
__fpregs_deactivate_hw();
}
@ -339,7 +339,7 @@ void fpu__restore(void)
kernel_fpu_disable();
fpregs_activate(fpu);
if (unlikely(copy_fpstate_to_fpregs(fpu))) {
fpu__reset(fpu);
fpu__clear(fpu);
force_sig_info(SIGSEGV, SEND_SIG_PRIV, tsk);
} else {
tsk->thread.fpu.counter++;
@ -376,19 +376,10 @@ void fpu__drop(struct fpu *fpu)
}
/*
* Reset the FPU state back to init state:
*/
void fpu__reset(struct fpu *fpu)
{
if (!use_eager_fpu())
fpu__drop(fpu);
else
restore_init_xstate();
}
/*
* Called by sys_execve() to clear the FPU fpregs, so that FPU state
* of the previous binary does not leak over into the exec()ed binary:
* Clear the FPU state back to init state.
*
* Called by sys_execve(), by the signal handler code and by various
* error paths.
*/
void fpu__clear(struct fpu *fpu)
{

4
arch/x86/kernel/fpu/xstate.c
View File

@ -401,7 +401,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
config_enabled(CONFIG_IA32_EMULATION));
if (!buf) {
fpu__reset(fpu);
fpu__clear(fpu);
return 0;
}
@ -474,7 +474,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
*/
user_fpu_begin();
if (restore_user_xstate(buf_fx, xfeatures, fx_only)) {
fpu__reset(fpu);
fpu__clear(fpu);
return -1;
}
}

2
arch/x86/kernel/signal.c
View File

@ -667,7 +667,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
* Ensure the signal handler starts with the new fpu state.
*/
if (fpu->fpstate_active)
fpu__reset(fpu);
fpu__clear(fpu);
}
signal_setup_done(failed, ksig, stepping);
}