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x86, fpu: drop_fpu() before restoring new state from sigframe

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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 <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1345842782-24175-2-git-send-email-suresh.b.siddha@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Suresh Siddha 2012-08-24 14:12:57 -07:00 committed by H. Peter Anvin
parent 72a671ced6
commit e962591749
2 changed files with 4 additions and 11 deletions
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7
arch/x86/include/asm/fpu-internal.h
View File

@ -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();

8
arch/x86/kernel/xsave.c
View File

@ -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