x86/fpu: Open code PF_USED_MATH usages

PF_USED_MATH is used directly, but also in a handful of helper inlines.

To ease the elimination of PF_USED_MATH, convert all inline helpers
to open-coded PF_USED_MATH usage.

Reviewed-by: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

7 files changed, 22 insertions, 19 deletions

diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c
index 4bafd5b05aca..bffb2c49ceb6 100644
--- a/arch/x86/ia32/ia32_signal.c
+++ b/arch/x86/ia32/ia32_signal.c
@@ -321,7 +321,7 @@ 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 (used_math()) {
+        if (current->flags & PF_USED_MATH) {
                 unsigned long fx_aligned, math_size;
 
                 sp = 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 44516ad6c890..2cac49e3b4bd 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -375,7 +375,8 @@ static inline void drop_fpu(struct task_struct *tsk)
                 __thread_fpu_end(fpu);
         }
 
-        clear_stopped_child_used_math(tsk);
+        tsk->flags &= ~PF_USED_MATH;
+
         preempt_enable();
 }
 
@@ -423,7 +424,7 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta
          * If the task has used the math, pre-load the FPU on xsave processors
          * or if the past 5 consecutive context-switches used math.
          */
-        fpu.preload = tsk_used_math(new) &&
+        fpu.preload = (new->flags & PF_USED_MATH) &&
                       (use_eager_fpu() || new->thread.fpu.counter > 5);
 
         if (old_fpu->has_fpu) {
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index cf49cd574d32..90f624d68b26 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -242,7 +242,7 @@ int fpu__copy(struct task_struct *dst, struct task_struct *src)
 
         task_disable_lazy_fpu_restore(dst);
 
-        if (tsk_used_math(src)) {
+        if (src->flags & PF_USED_MATH) {
                 int err = fpstate_alloc(&dst->thread.fpu);
 
                 if (err)
@@ -331,7 +331,7 @@ void fpu__restore(void)
         struct task_struct *tsk = current;
         struct fpu *fpu = &tsk->thread.fpu;
 
-        if (!tsk_used_math(tsk)) {
+        if (!(tsk->flags & PF_USED_MATH)) {
                 local_irq_enable();
                 /*
                  * does a slab alloc which can sleep
@@ -361,12 +361,14 @@ EXPORT_SYMBOL_GPL(fpu__restore);
 
 void fpu__flush_thread(struct task_struct *tsk)
 {
+        WARN_ON(tsk != current);
+
         if (!use_eager_fpu()) {
                 /* FPU state will be reallocated lazily at the first use. */
                 drop_fpu(tsk);
                 fpstate_free(&tsk->thread.fpu);
         } else {
-                if (!tsk_used_math(tsk)) {
+                if (!(tsk->flags & PF_USED_MATH)) {
                         /* kthread execs. TODO: cleanup this horror. */
                 if (WARN_ON(fpstate_alloc_init(tsk)))
                                 force_sig(SIGKILL, tsk);
@@ -383,12 +385,12 @@ void fpu__flush_thread(struct task_struct *tsk)
  */
 int fpregs_active(struct task_struct *target, const struct user_regset *regset)
 {
-        return tsk_used_math(target) ? regset->n : 0;
+        return (target->flags & PF_USED_MATH) ? regset->n : 0;
 }
 
 int xfpregs_active(struct task_struct *target, const struct user_regset *regset)
 {
-        return (cpu_has_fxsr && tsk_used_math(target)) ? regset->n : 0;
+        return (cpu_has_fxsr && (target->flags & PF_USED_MATH)) ? regset->n : 0;
 }
 
 int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
@@ -719,7 +721,7 @@ int dump_fpu(struct pt_regs *regs, struct user_i387_struct *fpu)
         struct task_struct *tsk = current;
         int fpvalid;
 
-        fpvalid = !!used_math();
+        fpvalid = !!(tsk->flags & PF_USED_MATH);
         if (fpvalid)
                 fpvalid = !fpregs_get(tsk, NULL,
                                       0, sizeof(struct user_i387_ia32_struct),
diff --git a/arch/x86/kernel/fpu/xsave.c b/arch/x86/kernel/fpu/xsave.c
index 61696c5005eb..8cd127049c9b 100644
--- a/arch/x86/kernel/fpu/xsave.c
+++ b/arch/x86/kernel/fpu/xsave.c
@@ -349,7 +349,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
         if (!access_ok(VERIFY_READ, buf, size))
                 return -EACCES;
 
-        if (!used_math() && fpstate_alloc_init(tsk))
+        if (!(tsk->flags & PF_USED_MATH) && fpstate_alloc_init(tsk))
                 return -1;
 
         if (!static_cpu_has(X86_FEATURE_FPU))
@@ -384,12 +384,12 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
                 int err = 0;
 
                 /*
-                 * Drop the current fpu which clears used_math(). This ensures
+                 * Drop the current fpu which clears PF_USED_MATH. 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
-                 * set_used_math() is again set.
+                 * PF_USED_MATH is again set.
                  */
                 drop_fpu(tsk);
 
@@ -401,7 +401,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
                         sanitize_restored_xstate(tsk, &env, xstate_bv, fx_only);
                 }
 
-                set_used_math();
+                tsk->flags |= PF_USED_MATH;
                 if (use_eager_fpu()) {
                         preempt_disable();
                         fpu__restore();
@@ -685,7 +685,7 @@ void xsave_init(void)
  */
 void __init_refok eager_fpu_init(void)
 {
-        WARN_ON(used_math());
+        WARN_ON(current->flags & PF_USED_MATH);
         current_thread_info()->status = 0;
 
         if (eagerfpu == ENABLE)
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 35f867aa597e..8e2529ebb8c6 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -217,7 +217,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
                 }
         }
 
-        if (used_math()) {
+        if (current->flags & PF_USED_MATH) {
                 sp = alloc_mathframe(sp, config_enabled(CONFIG_X86_32),
                                      &buf_fx, &math_size);
                 *fpstate = (void __user *)sp;
@@ -233,7 +233,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size,
                 return (void __user *)-1L;
 
         /* save i387 and extended state */
-        if (used_math() &&
+        if ((current->flags & PF_USED_MATH) &&
             save_xstate_sig(*fpstate, (void __user *)buf_fx, math_size) < 0)
                 return (void __user *)-1L;
 
@@ -664,7 +664,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
                 /*
                  * Ensure the signal handler starts with the new fpu state.
                  */
-                if (used_math())
+                if (current->flags & PF_USED_MATH)
                         fpu_reset_state(current);
         }
         signal_setup_done(failed, ksig, stepping);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index be276e0fe0ff..0635a1fd43ba 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6600,7 +6600,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         int r;
         sigset_t sigsaved;
 
-        if (!tsk_used_math(current) && fpstate_alloc_init(current))
+        if (!(current->flags & PF_USED_MATH) && fpstate_alloc_init(current))
                 return -ENOMEM;
 
         if (vcpu->sigset_active)
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index c9ff09a02385..bf628804d67c 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -148,7 +148,7 @@ void math_emulate(struct math_emu_info *info)
         unsigned long code_limit = 0;   /* Initialized to stop compiler warnings */
         struct desc_struct code_descriptor;
 
-        if (!used_math()) {
+        if (!(current->flags & PF_USED_MATH)) {
                 if (fpstate_alloc_init(current)) {
                         do_group_exit(SIGKILL);
                         return;