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Three more cleanups/improvements to the FPU handling code. (Oleg Nesterov) 

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Merge tag 'tip_x86_fpu' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/fpu

Pull x86/fpu updates from Borislav Petkov:

 "Three more cleanups/improvements to the FPU handling code. (Oleg Nesterov)"

Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2015-03-03 12:12:15 +01:00
parent f353e61230 110d7f7513
commit ae486033b9
3 changed files with 14 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
arch/x86/kernel/i387.c
View File

@ -41,8 +41,8 @@ void kernel_fpu_enable(void)
* be set (so that the clts/stts pair does nothing that is
* visible in the interrupted kernel thread).
*
* Except for the eagerfpu case when we return 1 unless we've already
* been eager and saved the state in kernel_fpu_begin().
* Except for the eagerfpu case when we return true; in the likely case
* the thread has FPU but we are not going to set/clear TS.
*/
static inline bool interrupted_kernel_fpu_idle(void)
{
@ -50,7 +50,7 @@ static inline bool interrupted_kernel_fpu_idle(void)
return false;
if (use_eager_fpu())
return __thread_has_fpu(current);
return true;
return !__thread_has_fpu(current) &&
(read_cr0() & X86_CR0_TS);
@ -93,9 +93,10 @@ void __kernel_fpu_begin(void)
if (__thread_has_fpu(me)) {
__save_init_fpu(me);
} else if (!use_eager_fpu()) {
} else {
this_cpu_write(fpu_owner_task, NULL);
clts();
if (!use_eager_fpu())
clts();
}
}
EXPORT_SYMBOL(__kernel_fpu_begin);

7
arch/x86/kernel/process.c
View File

@ -130,6 +130,7 @@ void flush_thread(void)
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
drop_init_fpu(tsk);
/*
* Free the FPU state for non xsave platforms. They get reallocated
@ -137,6 +138,12 @@ void flush_thread(void)
*/
if (!use_eager_fpu())
free_thread_xstate(tsk);
else if (!used_math()) {
/* kthread execs. TODO: cleanup this horror. */
if (WARN_ON(init_fpu(current)))
force_sig(SIGKILL, current);
math_state_restore();
}
}
static void hard_disable_TSC(void)

13
arch/x86/kernel/xsave.c
View File

@ -688,7 +688,7 @@ void eager_fpu_init(void)
{
static __refdata void (*boot_func)(void) = eager_fpu_init_bp;
clear_used_math();
WARN_ON(used_math());
current_thread_info()->status = 0;
if (eagerfpu == ENABLE)
@ -703,17 +703,6 @@ void eager_fpu_init(void)
boot_func();
boot_func = NULL;
}
/*
* This is same as math_state_restore(). But use_xsave() is
* not yet patched to use math_state_restore().
*/
init_fpu(current);
__thread_fpu_begin(current);
if (cpu_has_xsave)
xrstor_state(init_xstate_buf, -1);
else
fxrstor_checking(&init_xstate_buf->i387);
}
/*