[PATCH 29/33] x86/fpu: Rename fpu::fpstate_active to fpu::initialized

From: Ingo Molnar
Date: Sat Sep 23 2017 - 09:02:49 EST

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: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Eric Biggers <ebiggers3@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/ia32/ia32_signal.c | 2 +-
arch/x86/include/asm/fpu/internal.h | 4 ++--
arch/x86/include/asm/fpu/types.h | 6 +++---
arch/x86/include/asm/trace/fpu.h | 8 ++++----
arch/x86/kernel/fpu/core.c | 24 ++++++++++++------------
arch/x86/kernel/fpu/init.c | 2 +-
arch/x86/kernel/fpu/regset.c | 6 +++---
arch/x86/kernel/fpu/signal.c | 8 ++++----
arch/x86/kernel/fpu/xstate.c | 2 +-
arch/x86/kernel/signal.c | 6 +++---
arch/x86/mm/pkeys.c | 2 +-
11 files changed, 35 insertions(+), 35 deletions(-)

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index e0bb46c02857..0e2a5edbce00 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -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);
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 508e4181c4af..b26ae05da18a 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -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))
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 71db45ca8870..a1520575d86b 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -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:
diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h
index da565aae9fd2..39f7a27bef13 100644
--- a/arch/x86/include/asm/trace/fpu.h
+++ b/arch/x86/include/asm/trace/fpu.h
@@ -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
)
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index c248ce5ceff4..d770f9a6d4e1 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -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);
@@ -261,13 +261,13 @@ void fpu__activate_fpstate_read(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 current and for stopped child tasks: */
- fpu->fpstate_active = 1;
+ fpu->initialized = 1;
}
}

@@ -292,7 +292,7 @@ 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 {
@@ -301,7 +301,7 @@ 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;
}
}

@@ -343,7 +343,7 @@ 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"
@@ -352,7 +352,7 @@ void fpu__drop(struct fpu *fpu)
}
}

- fpu->fpstate_active = 0;
+ fpu->initialized = 0;

trace_x86_fpu_dropped(fpu);

diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c
index d5d44c452624..7affb7e3d9a5 100644
--- a/arch/x86/kernel/fpu/init.c
+++ b/arch/x86/kernel/fpu/init.c
@@ -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);
}

/*
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index 0467e536b0a2..5c2a051baeac 100644
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -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;
@@ -373,7 +373,7 @@ 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),
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 5b5d75e3b2a4..34c9a85eb5ba 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -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;
@@ -318,12 +318,12 @@ 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);

@@ -343,7 +343,7 @@ 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();
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index d5150163a0df..7ebd1a0811b6 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -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
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index e04442345fc0..4e188fda5961 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -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);
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index 4d24269c071f..d7bc0eea20a5 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -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;
--
2.11.0