We want to simplify the FPU state machine by eliminating fpu->fpregs_active,
and we can do that because the two state flags (::fpregs_active and
::fpstate_active) are set essentially together.
The old lazy FPU switching code used to make a distinction - but there's
no lazy switching code anymore, we always switch in an 'eager' fashion.
Do this by first changing all substantial uses of fpu->fpregs_active
to fpu->fpstate_active and adding a few debug checks to double check
our assumption is correct.
Cc: Andy Lutomirski <l...@kernel.org>
Cc: Borislav Petkov <b...@alien8.de>
Cc: Dave Hansen <dave.han...@linux.intel.com>
Cc: Fenghua Yu <fenghua...@intel.com>
Cc: H. Peter Anvin <h...@zytor.com>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng...@intel.com>
Signed-off-by: Ingo Molnar <mi...@kernel.org>
---
arch/x86/include/asm/fpu/internal.h | 4 +++-
arch/x86/kernel/fpu/core.c | 16 ++++++++++------
arch/x86/kernel/fpu/signal.c | 4 +++-
arch/x86/mm/pkeys.c | 3 +--
4 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/fpu/internal.h
b/arch/x86/include/asm/fpu/internal.h
index b223c57dd5dc..7fa676f93ac1 100644
--- a/arch/x86/include/asm/fpu/internal.h
+++ b/arch/x86/include/asm/fpu/internal.h
@@ -556,7 +556,9 @@ static inline void fpregs_activate(struct fpu *fpu)
static inline void
switch_fpu_prepare(struct fpu *old_fpu, int cpu)
{
- if (old_fpu->fpregs_active) {
+ 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;
else
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 815dfba7781a..eab244622402 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->fpregs_active) {
+ if (fpu->fpstate_active) {
/*
* Ignore return value -- we don't care if reg state
* is clobbered.
@@ -116,7 +116,7 @@ void __kernel_fpu_end(void)
{
struct fpu *fpu = ¤t->thread.fpu;
- if (fpu->fpregs_active)
+ if (fpu->fpstate_active)
copy_kernel_to_fpregs(&fpu->state);
kernel_fpu_enable();
@@ -147,8 +147,10 @@ void fpu__save(struct fpu *fpu)
WARN_ON_FPU(fpu != ¤t->thread.fpu);
preempt_disable();
+ WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
+
trace_x86_fpu_before_save(fpu);
- if (fpu->fpregs_active) {
+ if (fpu->fpstate_active) {
if (!copy_fpregs_to_fpstate(fpu)) {
copy_kernel_to_fpregs(&fpu->state);
}
@@ -262,11 +264,12 @@ 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:
*/
- if (fpu->fpregs_active) {
+ if (fpu->fpstate_active) {
fpu__save(fpu);
} else {
if (!fpu->fpstate_active) {
@@ -362,12 +365,13 @@ void fpu__current_fpstate_write_end(void)
{
struct fpu *fpu = ¤t->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
* an XRSTOR if they are active.
*/
- if (fpu->fpregs_active)
+ if (fpu->fpstate_active)
copy_kernel_to_fpregs(&fpu->state);
/*
@@ -417,7 +421,7 @@ void fpu__drop(struct fpu *fpu)
if (fpu == ¤t->thread.fpu) {
WARN_ON_FPU(fpu->fpstate_active != fpu->fpregs_active);
- if (fpu->fpregs_active) {
+ if (fpu->fpstate_active) {
/* Ignore delayed exceptions from user space */
asm volatile("1: fwait\n"
"2:\n"
diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 684025654d0c..a88083ba7f8b 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -171,7 +171,9 @@ 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->fpregs_active || using_compacted_format()) {
+ 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))
return -1;
diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c
index e2c23472233e..4d24269c071f 100644
--- a/arch/x86/mm/pkeys.c
+++ b/arch/x86/mm/pkeys.c
@@ -18,7 +18,6 @@
#include <asm/cpufeature.h> /* boot_cpu_has, ... */
#include <asm/mmu_context.h> /* vma_pkey() */
-#include <asm/fpu/internal.h> /* fpregs_active() */
int __execute_only_pkey(struct mm_struct *mm)
{
@@ -45,7 +44,7 @@ int __execute_only_pkey(struct mm_struct *mm)
*/
preempt_disable();
if (!need_to_set_mm_pkey &&
- current->thread.fpu.fpregs_active &&
+ current->thread.fpu.fpstate_active &&
!__pkru_allows_read(read_pkru(), execute_only_pkey)) {
preempt_enable();
return execute_only_pkey;
--
2.11.0
