[tip:x86/fpu] x86/fpu: Remove struct fpu::fpregs_active

From: tip-bot for Ingo Molnar
Date: Tue Sep 26 2017 - 04:36:09 EST

Commit-ID: 99dc26bda233ee722bbd370bddf20beece3ffb93
Gitweb: http://git.kernel.org/tip/99dc26bda233ee722bbd370bddf20beece3ffb93
Author: Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Sat, 23 Sep 2017 15:00:03 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 24 Sep 2017 13:04:34 +0200

x86/fpu: Remove struct fpu::fpregs_active

The previous changes paved the way for the removal of the
fpu::fpregs_active state flag - we now only have the
fpu::fpstate_active and fpu::last_cpu fields left.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Eric Biggers <ebiggers3@xxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Yu-cheng Yu <yu-cheng.yu@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20170923130016.21448-21-mingo@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/fpu/internal.h | 5 -----
arch/x86/include/asm/fpu/types.h | 23 -----------------------
arch/x86/include/asm/trace/fpu.h | 5 +----
arch/x86/kernel/fpu/core.c | 9 ---------
arch/x86/kernel/fpu/signal.c | 2 --
5 files changed, 1 insertion(+), 43 deletions(-)

diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h
index 42a6016..629e7abc 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -526,14 +526,12 @@ static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu)
*/
static inline void fpregs_deactivate(struct fpu *fpu)
{
- fpu->fpregs_active = 0;
this_cpu_write(fpu_fpregs_owner_ctx, NULL);
trace_x86_fpu_regs_deactivated(fpu);
}

static inline void fpregs_activate(struct fpu *fpu)
{
- fpu->fpregs_active = 1;
this_cpu_write(fpu_fpregs_owner_ctx, fpu);
trace_x86_fpu_regs_activated(fpu);
}
@@ -552,8 +550,6 @@ static inline void fpregs_activate(struct fpu *fpu)
static inline void
switch_fpu_prepare(struct fpu *old_fpu, int cpu)
{
- WARN_ON_FPU(old_fpu->fpregs_active != old_fpu->fpstate_active);
-
if (old_fpu->fpstate_active) {
if (!copy_fpregs_to_fpstate(old_fpu))
old_fpu->last_cpu = -1;
@@ -561,7 +557,6 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu)
old_fpu->last_cpu = cpu;

/* But leave fpu_fpregs_owner_ctx! */
- old_fpu->fpregs_active = 0;
trace_x86_fpu_regs_deactivated(old_fpu);
} else
old_fpu->last_cpu = -1;
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h
index 3c80f5b..0c314a3 100644
--- a/arch/x86/include/asm/fpu/types.h
+++ b/arch/x86/include/asm/fpu/types.h
@@ -299,29 +299,6 @@ struct fpu {
unsigned char fpstate_active;

/*
- * @fpregs_active:
- *
- * This flag determines whether a given context is actively
- * loaded into the FPU's registers and that those registers
- * represent the task's current FPU state.
- *
- * Note the interaction with fpstate_active:
- *
- * # task does not use the FPU:
- * fpstate_active == 0
- *
- * # task uses the FPU and regs are active:
- * fpstate_active == 1 && fpregs_active == 1
- *
- * # the regs are inactive but still match fpstate:
- * fpstate_active == 1 && fpregs_active == 0 && fpregs_owner == fpu
- *
- * The third state is what we use for the lazy restore optimization
- * on lazy-switching CPUs.
- */
- unsigned char fpregs_active;
-
- /*
* @state:
*
* In-memory copy of all FPU registers that we save/restore
diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h
index 342e597..da565aa 100644
--- a/arch/x86/include/asm/trace/fpu.h
+++ b/arch/x86/include/asm/trace/fpu.h
@@ -12,7 +12,6 @@ DECLARE_EVENT_CLASS(x86_fpu,

TP_STRUCT__entry(
__field(struct fpu *, fpu)
- __field(bool, fpregs_active)
__field(bool, fpstate_active)
__field(u64, xfeatures)
__field(u64, xcomp_bv)
@@ -20,16 +19,14 @@ DECLARE_EVENT_CLASS(x86_fpu,

TP_fast_assign(
__entry->fpu = fpu;
- __entry->fpregs_active = fpu->fpregs_active;
__entry->fpstate_active = fpu->fpstate_active;
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 fpregs_active: %d fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
+ TP_printk("x86/fpu: %p fpstate_active: %d xfeatures: %llx xcomp_bv: %llx",
__entry->fpu,
- __entry->fpregs_active,
__entry->fpstate_active,
__entry->xfeatures,
__entry->xcomp_bv
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 01a47e9..93103a9 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -147,8 +147,6 @@ void fpu__save(struct fpu *fpu)
WARN_ON_FPU(fpu != &current->thread.fpu);

preempt_disable();
- WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
-
trace_x86_fpu_before_save(fpu);
if (fpu->fpstate_active) {
if (!copy_fpregs_to_fpstate(fpu)) {
@@ -191,7 +189,6 @@ EXPORT_SYMBOL_GPL(fpstate_init);

int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu)
{
- dst_fpu->fpregs_active = 0;
dst_fpu->last_cpu = -1;

if (!src_fpu->fpstate_active || !static_cpu_has(X86_FEATURE_FPU))
@@ -264,7 +261,6 @@ EXPORT_SYMBOL_GPL(fpu__activate_curr);
*/
void fpu__activate_fpstate_read(struct fpu *fpu)
{
- WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
/*
* If fpregs are active (in the current CPU), then
* copy them to the fpstate:
@@ -365,7 +361,6 @@ void fpu__current_fpstate_write_end(void)
{
struct fpu *fpu = &current->thread.fpu;

- WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
/*
* 'fpu' now has an updated copy of the state, but the
* registers may still be out of date. Update them with
@@ -419,8 +414,6 @@ void fpu__drop(struct fpu *fpu)
preempt_disable();

if (fpu == &current->thread.fpu) {
- WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
-
if (fpu->fpstate_active) {
/* Ignore delayed exceptions from user space */
asm volatile("1: fwait\n"
@@ -428,8 +421,6 @@ void fpu__drop(struct fpu *fpu)
_ASM_EXTABLE(1b, 2b));
fpregs_deactivate(fpu);
}
- } else {
- WARN_ON_FPU(fpu->fpregs_active);
}

fpu->fpstate_active = 0;
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index a88083b..629106e 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -171,8 +171,6 @@ 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;

- WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
-
if (fpu->fpstate_active || using_compacted_format()) {
/* Save the live register state to the user directly. */
if (copy_fpregs_to_sigframe(buf_fx))