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authorLinus Torvalds <torvalds@linux-foundation.org>2015-04-13 13:24:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-13 13:24:23 -0700
commit421ec9017f3a1f3f032d894c55c15870f3d474aa (patch)
tree06ee21cf5ecdf87c40b30502faa3e0d1145004dd /arch/x86/kernel/i387.c
parent64f004a2ab68691b5a2e3db4cb460fcd31b6abc6 (diff)
parent7fc253e277ecf1ea57c2d670bdbcda3dffd19453 (diff)
downloadop-kernel-dev-421ec9017f3a1f3f032d894c55c15870f3d474aa.zip
op-kernel-dev-421ec9017f3a1f3f032d894c55c15870f3d474aa.tar.gz
Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu changes from Ingo Molnar: "Various x86 FPU handling cleanups, refactorings and fixes (Borislav Petkov, Oleg Nesterov, Rik van Riel)" * 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits) x86/fpu: Kill eager_fpu_init_bp() x86/fpu: Don't allocate fpu->state for swapper/0 x86/fpu: Rename drop_init_fpu() to fpu_reset_state() x86/fpu: Fold __drop_fpu() into its sole user x86/fpu: Don't abuse drop_init_fpu() in flush_thread() x86/fpu: Use restore_init_xstate() instead of math_state_restore() on kthread exec x86/fpu: Introduce restore_init_xstate() x86/fpu: Document user_fpu_begin() x86/fpu: Factor out memset(xstate, 0) in fpu_finit() paths x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave x86/fpu: Don't abuse FPU in kernel threads if use_eager_fpu() x86/fpu: Always allow FPU in interrupt if use_eager_fpu() x86/fpu: __kernel_fpu_begin() should clear fpu_owner_task even if use_eager_fpu() x86/fpu: Also check fpu_lazy_restore() when use_eager_fpu() x86/fpu: Use task_disable_lazy_fpu_restore() helper x86/fpu: Use an explicit if/else in switch_fpu_prepare() x86/fpu: Introduce task_disable_lazy_fpu_restore() helper x86/fpu: Move lazy restore functions up a few lines x86/fpu: Change math_error() to use unlazy_fpu(), kill (now) unused save_init_fpu() x86/fpu: Don't do __thread_fpu_end() if use_eager_fpu() ...
Diffstat (limited to 'arch/x86/kernel/i387.c')
-rw-r--r--arch/x86/kernel/i387.c54
1 files changed, 26 insertions, 28 deletions
diff --git a/arch/x86/kernel/i387.c b/arch/x86/kernel/i387.c
index 29c740d..367f39d 100644
--- a/arch/x86/kernel/i387.c
+++ b/arch/x86/kernel/i387.c
@@ -42,8 +42,8 @@ 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)
{
@@ -51,7 +51,7 @@ 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);
@@ -94,9 +94,10 @@ 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);
@@ -107,7 +108,7 @@ void __kernel_fpu_end(void)
if (__thread_has_fpu(me)) {
if (WARN_ON(restore_fpu_checking(me)))
- drop_init_fpu(me);
+ fpu_reset_state(me);
} else if (!use_eager_fpu()) {
stts();
}
@@ -120,10 +121,13 @@ void unlazy_fpu(struct task_struct *tsk)
{
preempt_disable();
if (__thread_has_fpu(tsk)) {
- __save_init_fpu(tsk);
- __thread_fpu_end(tsk);
- } else
- tsk->thread.fpu_counter = 0;
+ if (use_eager_fpu()) {
+ __save_fpu(tsk);
+ } else {
+ __save_init_fpu(tsk);
+ __thread_fpu_end(tsk);
+ }
+ }
preempt_enable();
}
EXPORT_SYMBOL(unlazy_fpu);
@@ -221,11 +225,12 @@ void fpu_finit(struct fpu *fpu)
return;
}
+ memset(fpu->state, 0, xstate_size);
+
if (cpu_has_fxsr) {
fx_finit(&fpu->state->fxsave);
} else {
struct i387_fsave_struct *fp = &fpu->state->fsave;
- memset(fp, 0, xstate_size);
fp->cwd = 0xffff037fu;
fp->swd = 0xffff0000u;
fp->twd = 0xffffffffu;
@@ -247,7 +252,7 @@ int init_fpu(struct task_struct *tsk)
if (tsk_used_math(tsk)) {
if (cpu_has_fpu && tsk == current)
unlazy_fpu(tsk);
- tsk->thread.fpu.last_cpu = ~0;
+ task_disable_lazy_fpu_restore(tsk);
return 0;
}
@@ -336,6 +341,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
+ struct xsave_struct *xsave = &target->thread.fpu.state->xsave;
int ret;
if (!cpu_has_xsave)
@@ -350,14 +356,12 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
* memory layout in the thread struct, so that we can copy the entire
* xstateregs to the user using one user_regset_copyout().
*/
- memcpy(&target->thread.fpu.state->fxsave.sw_reserved,
- xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
-
+ memcpy(&xsave->i387.sw_reserved,
+ xstate_fx_sw_bytes, sizeof(xstate_fx_sw_bytes));
/*
* Copy the xstate memory layout.
*/
- ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf,
- &target->thread.fpu.state->xsave, 0, -1);
+ ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
return ret;
}
@@ -365,8 +369,8 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
+ struct xsave_struct *xsave = &target->thread.fpu.state->xsave;
int ret;
- struct xsave_hdr_struct *xsave_hdr;
if (!cpu_has_xsave)
return -ENODEV;
@@ -375,22 +379,16 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
if (ret)
return ret;
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
- &target->thread.fpu.state->xsave, 0, -1);
-
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
/*
* mxcsr reserved bits must be masked to zero for security reasons.
*/
- target->thread.fpu.state->fxsave.mxcsr &= mxcsr_feature_mask;
-
- xsave_hdr = &target->thread.fpu.state->xsave.xsave_hdr;
-
- xsave_hdr->xstate_bv &= pcntxt_mask;
+ xsave->i387.mxcsr &= mxcsr_feature_mask;
+ xsave->xsave_hdr.xstate_bv &= pcntxt_mask;
/*
* These bits must be zero.
*/
- memset(xsave_hdr->reserved, 0, 48);
-
+ memset(&xsave->xsave_hdr.reserved, 0, 48);
return ret;
}
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