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x86/fpu: Rename fpu::fpstate_active to fpu::initialized 

The x86 FPU code used to have a complex state machine where both the FPU
registers and the FPU state context could be 'active' (or inactive)
independently of each other - which enabled features like lazy FPU restore.

Much of this complexity is gone in the current code: now we basically can
have FPU-less tasks (kernel threads) that don't use (and save/restore) FPU
state at all, plus full FPU users that save/restore directly with no laziness
whatsoever.

But the fpu::fpstate_active still carries bits of the old complexity - meanwhile
this flag has become a simple flag that shows whether the FPU context saving
area in the thread struct is initialized and used, or not.

Rename it to fpu::initialized to express this simplicity in the name as well.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-30-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar 2017-09-26 09:43:36 +02:00
parent 685c930d6e
commit e4a81bfcaa
11 changed files with 35 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/ia32/ia32_signal.c
View File

@ -231,7 +231,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs,
ksig->ka.sa.sa_restorer)
sp = (unsigned long) ksig->ka.sa.sa_restorer;
if (fpu->fpstate_active) {
if (fpu->initialized) {
unsigned long fx_aligned, math_size;
sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size);

4
arch/x86/include/asm/fpu/internal.h
View File

@ -527,7 +527,7 @@ static inline void fpregs_activate(struct fpu *fpu)
static inline void
switch_fpu_prepare(struct fpu *old_fpu, int cpu)
{
if (old_fpu->fpstate_active) {
if (old_fpu->initialized) {
if (!copy_fpregs_to_fpstate(old_fpu))
old_fpu->last_cpu = -1;
else
@ -550,7 +550,7 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu)
static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu)
{
bool preload = static_cpu_has(X86_FEATURE_FPU) &&
new_fpu->fpstate_active;
new_fpu->initialized;
if (preload) {
if (!fpregs_state_valid(new_fpu, cpu))

6
arch/x86/include/asm/fpu/types.h
View File

@ -293,13 +293,13 @@ struct fpu {
unsigned int last_cpu;
/*
* @fpstate_active:
* @initialized:
*
* This flag indicates whether this context is active: if the task
* This flag indicates whether this context is initialized: if the task
* is not running then we can restore from this context, if the task
* is running then we should save into this context.
*/
unsigned char fpstate_active;
unsigned char initialized;
/*
* @state:

8
arch/x86/include/asm/trace/fpu.h
View File

@ -12,22 +12,22 @@ DECLARE_EVENT_CLASS(x86_fpu,
TP_STRUCT__entry(
__field(struct fpu *, fpu)
__field(bool, fpstate_active)
__field(bool, initialized)
__field(u64, xfeatures)
__field(u64, xcomp_bv)
),
TP_fast_assign(
__entry->fpu = fpu;
__entry->fpstate_active = fpu->fpstate_active;
__entry->initialized = fpu->initialized;
if (boot_cpu_has(X86_FEATURE_OSXSAVE)) {
__entry->xfeatures = fpu->state.xsave.header.xfeatures;
__entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv;
}
),
TP_printk("x86/fpu: %p fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
TP_printk("x86/fpu: %p initialized: %d xfeatures: %llx xcomp_bv: %llx",
__entry->fpu,
__entry->fpstate_active,
__entry->initialized,
__entry->xfeatures,
__entry->xcomp_bv
)

24
arch/x86/kernel/fpu/core.c
View File

@ -100,7 +100,7 @@ void __kernel_fpu_begin(void)
kernel_fpu_disable();
if (fpu->fpstate_active) {
if (fpu->initialized) {
/*
* Ignore return value -- we don't care if reg state
* is clobbered.
@ -116,7 +116,7 @@ void __kernel_fpu_end(void)
{
struct fpu *fpu = &current->thread.fpu;
if (fpu->fpstate_active)
if (fpu->initialized)
copy_kernel_to_fpregs(&fpu->state);
kernel_fpu_enable();
@ -148,7 +148,7 @@ void fpu__save(struct fpu *fpu)
preempt_disable();
trace_x86_fpu_before_save(fpu);
if (fpu->fpstate_active) {
if (fpu->initialized) {
if (!copy_fpregs_to_fpstate(fpu)) {
copy_kernel_to_fpregs(&fpu->state);
}
@ -191,7 +191,7 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
{
dst_fpu->last_cpu = -1;
if (!src_fpu->fpstate_active || !static_cpu_has(X86_FEATURE_FPU))
if (!src_fpu->initialized || !static_cpu_has(X86_FEATURE_FPU))
return 0;
WARN_ON_FPU(src_fpu != &current->thread.fpu);
@ -240,13 +240,13 @@ void fpu__activate_curr(struct fpu *fpu)
{
WARN_ON_FPU(fpu != &current->thread.fpu);
if (!fpu->fpstate_active) {
if (!fpu->initialized) {
fpstate_init(&fpu->state);
trace_x86_fpu_init_state(fpu);
trace_x86_fpu_activate_state(fpu);
/* Safe to do for the current task: */
fpu->fpstate_active = 1;
fpu->initialized = 1;
}
}
EXPORT_SYMBOL_GPL(fpu__activate_curr);
@ -271,13 +271,13 @@ void fpu__activate_fpstate_read(struct fpu *fpu)
if (fpu == &current->thread.fpu) {
fpu__save(fpu);
} else {
if (!fpu->fpstate_active) {
if (!fpu->initialized) {
fpstate_init(&fpu->state);
trace_x86_fpu_init_state(fpu);
trace_x86_fpu_activate_state(fpu);
/* Safe to do for current and for stopped child tasks: */
fpu->fpstate_active = 1;
fpu->initialized = 1;
}
}
}
@ -303,7 +303,7 @@ void fpu__activate_fpstate_write(struct fpu *fpu)
*/
WARN_ON_FPU(fpu == &current->thread.fpu);
if (fpu->fpstate_active) {
if (fpu->initialized) {
/* Invalidate any lazy state: */
__fpu_invalidate_fpregs_state(fpu);
} else {
@ -312,7 +312,7 @@ void fpu__activate_fpstate_write(struct fpu *fpu)
trace_x86_fpu_activate_state(fpu);
/* Safe to do for stopped child tasks: */
fpu->fpstate_active = 1;
fpu->initialized = 1;
}
}
@ -354,7 +354,7 @@ void fpu__drop(struct fpu *fpu)
preempt_disable();
if (fpu == &current->thread.fpu) {
if (fpu->fpstate_active) {
if (fpu->initialized) {
/* Ignore delayed exceptions from user space */
asm volatile("1: fwait\n"
"2:\n"
@ -363,7 +363,7 @@ void fpu__drop(struct fpu *fpu)
}
}
fpu->fpstate_active = 0;
fpu->initialized = 0;
trace_x86_fpu_dropped(fpu);

2
arch/x86/kernel/fpu/init.c
View File

@ -240,7 +240,7 @@ static void __init fpu__init_system_ctx_switch(void)
WARN_ON_FPU(!on_boot_cpu);
on_boot_cpu = 0;
WARN_ON_FPU(current->thread.fpu.fpstate_active);
WARN_ON_FPU(current->thread.fpu.initialized);
}
/*

6
arch/x86/kernel/fpu/regset.c
View File

@ -16,14 +16,14 @@ int regset_fpregs_active(struct task_struct *target, const struct user_regset *r
{
struct fpu *target_fpu = &target->thread.fpu;
return target_fpu->fpstate_active ? regset->n : 0;
return target_fpu->initialized ? regset->n : 0;
}
int regset_xregset_fpregs_active(struct task_struct *target, const struct user_regset *regset)
{
struct fpu *target_fpu = &target->thread.fpu;
if (boot_cpu_has(X86_FEATURE_FXSR) && target_fpu->fpstate_active)
if (boot_cpu_has(X86_FEATURE_FXSR) && target_fpu->initialized)
return regset->n;
else
return 0;
@ -380,7 +380,7 @@ int dump_fpu(struct pt_regs *regs, struct user_i387_struct *ufpu)
struct fpu *fpu = &tsk->thread.fpu;
int fpvalid;
fpvalid = fpu->fpstate_active;
fpvalid = fpu->initialized;
if (fpvalid)
fpvalid = !fpregs_get(tsk, NULL,
0, sizeof(struct user_i387_ia32_struct),

8
arch/x86/kernel/fpu/signal.c
View File

@ -171,7 +171,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
sizeof(struct user_i387_ia32_struct), NULL,
(struct _fpstate_32 __user *) buf) ? -1 : 1;
if (fpu->fpstate_active || using_compacted_format()) {
if (fpu->initialized || using_compacted_format()) {
/* Save the live register state to the user directly. */
if (copy_fpregs_to_sigframe(buf_fx))
return -1;
@ -315,12 +315,12 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
int err = 0;
/*
* Drop the current fpu which clears fpu->fpstate_active. This ensures
* Drop the current fpu which clears fpu->initialized. This ensures
* that any context-switch during the copy of the new state,
* avoids the intermediate state from getting restored/saved.
* Thus avoiding the new restored state from getting corrupted.
* We will be ready to restore/save the state only after
* fpu->fpstate_active is again set.
* fpu->initialized is again set.
*/
fpu__drop(fpu);
@ -342,7 +342,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
}
fpu->fpstate_active = 1;
fpu->initialized = 1;
preempt_disable();
fpu__restore(fpu);
preempt_enable();

2
arch/x86/kernel/fpu/xstate.c
View File

@ -867,7 +867,7 @@ const void *get_xsave_field_ptr(int xsave_state)
{
struct fpu *fpu = &current->thread.fpu;
if (!fpu->fpstate_active)
if (!fpu->initialized)
return NULL;
/*
* fpu__save() takes the CPU's xstate registers

6
arch/x86/kernel/signal.c
View File

@ -263,7 +263,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
sp = (unsigned long) ka->sa.sa_restorer;
}
if (fpu->fpstate_active) {
if (fpu->initialized) {
sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32),
&buf_fx, &math_size);
*fpstate = (void __user *)sp;
@ -279,7 +279,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
return (void __user *)-1L;
/* save i387 and extended state */
if (fpu->fpstate_active &&
if (fpu->initialized &&
copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0)
return (void __user *)-1L;
@ -755,7 +755,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
/*
* Ensure the signal handler starts with the new fpu state.
*/
if (fpu->fpstate_active)
if (fpu->initialized)
fpu__clear(fpu);
}
signal_setup_done(failed, ksig, stepping);

2
arch/x86/mm/pkeys.c
View File

@ -44,7 +44,7 @@ int __execute_only_pkey(struct mm_struct *mm)
*/
preempt_disable();
if (!need_to_set_mm_pkey &&
current->thread.fpu.fpstate_active &&
current->thread.fpu.initialized &&
!__pkru_allows_read(read_pkru(), execute_only_pkey)) {
preempt_enable();
return execute_only_pkey;