Merge Linus master into drm-next

The merge is clean, but the arm build fails afterwards,
due to API changes in the regulator tree.

I've included the patch into the merge to fix the build.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 66 insertions, 64 deletions

diff --git a/arch/x86/include/asm/fpu-internal.h b/arch/x86/include/asm/fpu-internal.h
index 72ba21a8b5fc..da5e96756570 100644
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -67,6 +67,34 @@ extern void finit_soft_fpu(struct i387_soft_struct *soft);
 static inline void finit_soft_fpu(struct i387_soft_struct *soft) {}
 #endif
 
+/*
+ * Must be run with preemption disabled: this clears the fpu_owner_task,
+ * on this CPU.
+ *
+ * This will disable any lazy FPU state restore of the current FPU state,
+ * but if the current thread owns the FPU, it will still be saved by.
+ */
+static inline void __cpu_disable_lazy_restore(unsigned int cpu)
+{
+	per_cpu(fpu_owner_task, cpu) = NULL;
+}
+
+/*
+ * Used to indicate that the FPU state in memory is newer than the FPU
+ * state in registers, and the FPU state should be reloaded next time the
+ * task is run. Only safe on the current task, or non-running tasks.
+ */
+static inline void task_disable_lazy_fpu_restore(struct task_struct *tsk)
+{
+	tsk->thread.fpu.last_cpu = ~0;
+}
+
+static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu)
+{
+	return new == this_cpu_read_stable(fpu_owner_task) &&
+		cpu == new->thread.fpu.last_cpu;
+}
+
 static inline int is_ia32_compat_frame(void)
 {
 	return config_enabled(CONFIG_IA32_EMULATION) &&
@@ -107,7 +135,6 @@ static __always_inline __pure bool use_fxsr(void)
 
 static inline void fx_finit(struct i387_fxsave_struct *fx)
 {
-	memset(fx, 0, xstate_size);
 	fx->cwd = 0x37f;
 	fx->mxcsr = MXCSR_DEFAULT;
 }
@@ -351,8 +378,14 @@ static inline void __thread_fpu_begin(struct task_struct *tsk)
 	__thread_set_has_fpu(tsk);
 }
 
-static inline void __drop_fpu(struct task_struct *tsk)
+static inline void drop_fpu(struct task_struct *tsk)
 {
+	/*
+	 * Forget coprocessor state..
+	 */
+	preempt_disable();
+	tsk->thread.fpu_counter = 0;
+
 	if (__thread_has_fpu(tsk)) {
 		/* Ignore delayed exceptions from user space */
 		asm volatile("1: fwait\n"
@@ -360,30 +393,29 @@ static inline void __drop_fpu(struct task_struct *tsk)
 			     _ASM_EXTABLE(1b, 2b));
 		__thread_fpu_end(tsk);
 	}
-}
 
-static inline void drop_fpu(struct task_struct *tsk)
-{
-	/*
-	 * Forget coprocessor state..
-	 */
-	preempt_disable();
-	tsk->thread.fpu_counter = 0;
-	__drop_fpu(tsk);
 	clear_stopped_child_used_math(tsk);
 	preempt_enable();
 }
 
-static inline void drop_init_fpu(struct task_struct *tsk)
+static inline void restore_init_xstate(void)
+{
+	if (use_xsave())
+		xrstor_state(init_xstate_buf, -1);
+	else
+		fxrstor_checking(&init_xstate_buf->i387);
+}
+
+/*
+ * Reset the FPU state in the eager case and drop it in the lazy case (later use
+ * will reinit it).
+ */
+static inline void fpu_reset_state(struct task_struct *tsk)
 {
 	if (!use_eager_fpu())
 		drop_fpu(tsk);
-	else {
-		if (use_xsave())
-			xrstor_state(init_xstate_buf, -1);
-		else
-			fxrstor_checking(&init_xstate_buf->i387);
-	}
+	else
+		restore_init_xstate();
 }
 
 /*
@@ -400,24 +432,6 @@ static inline void drop_init_fpu(struct task_struct *tsk)
  */
 typedef struct { int preload; } fpu_switch_t;
 
-/*
- * Must be run with preemption disabled: this clears the fpu_owner_task,
- * on this CPU.
- *
- * This will disable any lazy FPU state restore of the current FPU state,
- * but if the current thread owns the FPU, it will still be saved by.
- */
-static inline void __cpu_disable_lazy_restore(unsigned int cpu)
-{
-	per_cpu(fpu_owner_task, cpu) = NULL;
-}
-
-static inline int fpu_lazy_restore(struct task_struct *new, unsigned int cpu)
-{
-	return new == this_cpu_read_stable(fpu_owner_task) &&
-		cpu == new->thread.fpu.last_cpu;
-}
-
 static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct task_struct *new, int cpu)
 {
 	fpu_switch_t fpu;
@@ -426,13 +440,17 @@ 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) && (use_eager_fpu() ||
-					     new->thread.fpu_counter > 5);
+	fpu.preload = tsk_used_math(new) &&
+		      (use_eager_fpu() || new->thread.fpu_counter > 5);
+
 	if (__thread_has_fpu(old)) {
 		if (!__save_init_fpu(old))
-			cpu = ~0;
-		old->thread.fpu.last_cpu = cpu;
-		old->thread.fpu.has_fpu = 0;	/* But leave fpu_owner_task! */
+			task_disable_lazy_fpu_restore(old);
+		else
+			old->thread.fpu.last_cpu = cpu;
+
+		/* But leave fpu_owner_task! */
+		old->thread.fpu.has_fpu = 0;
 
 		/* Don't change CR0.TS if we just switch! */
 		if (fpu.preload) {
@@ -443,10 +461,10 @@ static inline fpu_switch_t switch_fpu_prepare(struct task_struct *old, struct ta
 			stts();
 	} else {
 		old->thread.fpu_counter = 0;
-		old->thread.fpu.last_cpu = ~0;
+		task_disable_lazy_fpu_restore(old);
 		if (fpu.preload) {
 			new->thread.fpu_counter++;
-			if (!use_eager_fpu() && fpu_lazy_restore(new, cpu))
+			if (fpu_lazy_restore(new, cpu))
 				fpu.preload = 0;
 			else
 				prefetch(new->thread.fpu.state);
@@ -466,7 +484,7 @@ static inline void switch_fpu_finish(struct task_struct *new, fpu_switch_t fpu)
 {
 	if (fpu.preload) {
 		if (unlikely(restore_fpu_checking(new)))
-			drop_init_fpu(new);
+			fpu_reset_state(new);
 	}
 }
 
@@ -495,10 +513,12 @@ static inline int restore_xstate_sig(void __user *buf, int ia32_frame)
 }
 
 /*
- * Need to be preemption-safe.
+ * Needs to be preemption-safe.
  *
  * NOTE! user_fpu_begin() must be used only immediately before restoring
- * it. This function does not do any save/restore on their own.
+ * the save state. It does not do any saving/restoring on its own. In
+ * lazy FPU mode, it is just an optimization to avoid a #NM exception,
+ * the task can lose the FPU right after preempt_enable().
  */
 static inline void user_fpu_begin(void)
 {
@@ -520,24 +540,6 @@ static inline void __save_fpu(struct task_struct *tsk)
 }
 
 /*
- * These disable preemption on their own and are safe
- */
-static inline void save_init_fpu(struct task_struct *tsk)
-{
-	WARN_ON_ONCE(!__thread_has_fpu(tsk));
-
-	if (use_eager_fpu()) {
-		__save_fpu(tsk);
-		return;
-	}
-
-	preempt_disable();
-	__save_init_fpu(tsk);
-	__thread_fpu_end(tsk);
-	preempt_enable();
-}
-
-/*
  * i387 state interaction
  */
 static inline unsigned short get_fpu_cwd(struct task_struct *tsk)