Merge branch 'linux-linaro-lsk' into linux-linaro-lsk-androidlsk-android-14.06

12 files changed, 34 insertions, 288 deletions

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 635bba31a75f..dea35c100fd6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -118,9 +118,6 @@ config IOMMU_HELPER
 config FIX_EARLYCON_MEM
 	def_bool y
 
-config KERNEL_MODE_NEON
-	def_bool y
-
 source "init/Kconfig"
 
 source "kernel/Kconfig.freezer"
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 50f559f574fe..c43b4ac13008 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -37,21 +37,8 @@ struct fpsimd_state {
 			u32 fpcr;
 		};
 	};
-	/* the id of the last cpu to have restored this state */
-	unsigned int cpu;
 };
 
-/*
- * Struct for stacking the bottom 'n' FP/SIMD registers.
- */
-struct fpsimd_partial_state {
-	u32		fpsr;
-	u32		fpcr;
-	u32		num_regs;
-	__uint128_t	vregs[32];
-};
-
-
 #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
 /* Masks for extracting the FPSR and FPCR from the FPSCR */
 #define VFP_FPSCR_STAT_MASK	0xf800009f
@@ -71,16 +58,6 @@ extern void fpsimd_load_state(struct fpsimd_state *state);
 extern void fpsimd_thread_switch(struct task_struct *next);
 extern void fpsimd_flush_thread(void);
 
-extern void fpsimd_preserve_current_state(void);
-extern void fpsimd_restore_current_state(void);
-extern void fpsimd_update_current_state(struct fpsimd_state *state);
-
-extern void fpsimd_flush_task_state(struct task_struct *target);
-
-extern void fpsimd_save_partial_state(struct fpsimd_partial_state *state,
-				      u32 num_regs);
-extern void fpsimd_load_partial_state(struct fpsimd_partial_state *state);
-
 #endif
 
 #endif
diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h
index 768414d55e64..bbec599c96bd 100644
--- a/arch/arm64/include/asm/fpsimdmacros.h
+++ b/arch/arm64/include/asm/fpsimdmacros.h
@@ -62,38 +62,3 @@
 	ldr	w\tmpnr, [\state, #16 * 2 + 4]
 	msr	fpcr, x\tmpnr
 .endm
-
-.altmacro
-.macro fpsimd_save_partial state, numnr, tmpnr1, tmpnr2
-	mrs	x\tmpnr1, fpsr
-	str	w\numnr, [\state, #8]
-	mrs	x\tmpnr2, fpcr
-	stp	w\tmpnr1, w\tmpnr2, [\state]
-	adr	x\tmpnr1, 0f
-	add	\state, \state, x\numnr, lsl #4
-	sub	x\tmpnr1, x\tmpnr1, x\numnr, lsl #1
-	br	x\tmpnr1
-	.irp	qa, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0
-	.irp	qb, %(qa + 1)
-	stp	q\qa, q\qb, [\state, # -16 * \qa - 16]
-	.endr
-	.endr
-0:
-.endm
-
-.macro fpsimd_restore_partial state, tmpnr1, tmpnr2
-	ldp	w\tmpnr1, w\tmpnr2, [\state]
-	msr	fpsr, x\tmpnr1
-	msr	fpcr, x\tmpnr2
-	adr	x\tmpnr1, 0f
-	ldr	w\tmpnr2, [\state, #8]
-	add	\state, \state, x\tmpnr2, lsl #4
-	sub	x\tmpnr1, x\tmpnr1, x\tmpnr2, lsl #1
-	br	x\tmpnr1
-	.irp	qa, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0
-	.irp	qb, %(qa + 1)
-	ldp	q\qa, q\qb, [\state, # -16 * \qa - 16]
-	.endr
-	.endr
-0:
-.endm
diff --git a/arch/arm64/include/asm/neon.h b/arch/arm64/include/asm/neon.h
deleted file mode 100644
index 13ce4cc18e26..000000000000
--- a/arch/arm64/include/asm/neon.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * linux/arch/arm64/include/asm/neon.h
- *
- * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/types.h>
-
-#define cpu_has_neon()		(1)
-
-#define kernel_neon_begin()	kernel_neon_begin_partial(32)
-
-void kernel_neon_begin_partial(u32 num_regs);
-void kernel_neon_end(void);
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index c09cbf6ce34a..59f151f8241d 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -109,7 +109,6 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_SIGPENDING		0
 #define TIF_NEED_RESCHED	1
 #define TIF_NOTIFY_RESUME	2	/* callback before returning to user */
-#define TIF_FOREIGN_FPSTATE	3	/* CPU's FP state is not current's */
 #define TIF_SYSCALL_TRACE	8
 #define TIF_SYSCALL_AUDIT	9
 #define TIF_SYSCALL_TRACEPOINT	10
@@ -125,7 +124,6 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
-#define _TIF_FOREIGN_FPSTATE	(1 << TIF_FOREIGN_FPSTATE)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
 #define _TIF_SYSCALL_TRACEPOINT	(1 << TIF_SYSCALL_TRACEPOINT)
@@ -133,7 +131,7 @@ static inline struct thread_info *current_thread_info(void)
 #define _TIF_32BIT		(1 << TIF_32BIT)
 
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
-				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE)
+				 _TIF_NOTIFY_RESUME)
 
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S
index d358ccacfc00..6a27cd6dbfa6 100644
--- a/arch/arm64/kernel/entry-fpsimd.S
+++ b/arch/arm64/kernel/entry-fpsimd.S
@@ -41,27 +41,3 @@ ENTRY(fpsimd_load_state)
 	fpsimd_restore x0, 8
 	ret
 ENDPROC(fpsimd_load_state)
-
-#ifdef CONFIG_KERNEL_MODE_NEON
-
-/*
- * Save the bottom n FP registers.
- *
- * x0 - pointer to struct fpsimd_partial_state
- */
-ENTRY(fpsimd_save_partial_state)
-	fpsimd_save_partial x0, 1, 8, 9
-	ret
-ENDPROC(fpsimd_load_partial_state)
-
-/*
- * Load the bottom n FP registers.
- *
- * x0 - pointer to struct fpsimd_partial_state
- */
-ENTRY(fpsimd_load_partial_state)
-	fpsimd_restore_partial x0, 8, 9
-	ret
-ENDPROC(fpsimd_load_partial_state)
-
-#endif
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 1fe70fa6160c..fa789169f98b 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -591,7 +591,7 @@ fast_work_pending:
 	str	x0, [sp, #S_X0]			// returned x0
 work_pending:
 	tbnz	x1, #TIF_NEED_RESCHED, work_resched
-	/* TIF_SIGPENDING, TIF_NOTIFY_RESUME or TIF_FOREIGN_FPSTATE case */
+	/* TIF_SIGPENDING or TIF_NOTIFY_RESUME case */
 	ldr	x2, [sp, #S_PSTATE]
 	mov	x0, sp				// 'regs'
 	tst	x2, #PSR_MODE_MASK		// user mode regs?
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index ad8aebb1cdef..522df9c7f3a4 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -22,7 +22,6 @@
 #include <linux/init.h>
 #include <linux/sched.h>
 #include <linux/signal.h>
-#include <linux/hardirq.h>
 
 #include <asm/fpsimd.h>
 #include <asm/cputype.h>
@@ -35,60 +34,6 @@
 #define FPEXC_IDF	(1 << 7)
 
 /*
- * In order to reduce the number of times the FPSIMD state is needlessly saved
- * and restored, we need to keep track of two things:
- * (a) for each task, we need to remember which CPU was the last one to have
- *     the task's FPSIMD state loaded into its FPSIMD registers;
- * (b) for each CPU, we need to remember which task's userland FPSIMD state has
- *     been loaded into its FPSIMD registers most recently, or whether it has
- *     been used to perform kernel mode NEON in the meantime.
- *
- * For (a), we add a 'cpu' field to struct fpsimd_state, which gets updated to
- * the id of the current CPU everytime the state is loaded onto a CPU. For (b),
- * we add the per-cpu variable 'fpsimd_last_state' (below), which contains the
- * address of the userland FPSIMD state of the task that was loaded onto the CPU
- * the most recently, or NULL if kernel mode NEON has been performed after that.
- *
- * With this in place, we no longer have to restore the next FPSIMD state right
- * when switching between tasks. Instead, we can defer this check to userland
- * resume, at which time we verify whether the CPU's fpsimd_last_state and the
- * task's fpsimd_state.cpu are still mutually in sync. If this is the case, we
- * can omit the FPSIMD restore.
- *
- * As an optimization, we use the thread_info flag TIF_FOREIGN_FPSTATE to
- * indicate whether or not the userland FPSIMD state of the current task is
- * present in the registers. The flag is set unless the FPSIMD registers of this
- * CPU currently contain the most recent userland FPSIMD state of the current
- * task.
- *
- * For a certain task, the sequence may look something like this:
- * - the task gets scheduled in; if both the task's fpsimd_state.cpu field
- *   contains the id of the current CPU, and the CPU's fpsimd_last_state per-cpu
- *   variable points to the task's fpsimd_state, the TIF_FOREIGN_FPSTATE flag is
- *   cleared, otherwise it is set;
- *
- * - the task returns to userland; if TIF_FOREIGN_FPSTATE is set, the task's
- *   userland FPSIMD state is copied from memory to the registers, the task's
- *   fpsimd_state.cpu field is set to the id of the current CPU, the current
- *   CPU's fpsimd_last_state pointer is set to this task's fpsimd_state and the
- *   TIF_FOREIGN_FPSTATE flag is cleared;
- *
- * - the task executes an ordinary syscall; upon return to userland, the
- *   TIF_FOREIGN_FPSTATE flag will still be cleared, so no FPSIMD state is
- *   restored;
- *
- * - the task executes a syscall which executes some NEON instructions; this is
- *   preceded by a call to kernel_neon_begin(), which copies the task's FPSIMD
- *   register contents to memory, clears the fpsimd_last_state per-cpu variable
- *   and sets the TIF_FOREIGN_FPSTATE flag;
- *
- * - the task gets preempted after kernel_neon_end() is called; as we have not
- *   returned from the 2nd syscall yet, TIF_FOREIGN_FPSTATE is still set so
- *   whatever is in the FPSIMD registers is not saved to memory, but discarded.
- */
-static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
-
-/*
  * Trapped FP/ASIMD access.
  */
 void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
@@ -126,137 +71,43 @@ void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
 
 void fpsimd_thread_switch(struct task_struct *next)
 {
-	/*
-	 * Save the current FPSIMD state to memory, but only if whatever is in
-	 * the registers is in fact the most recent userland FPSIMD state of
-	 * 'current'.
-	 */
-	if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE))
+	/* check if not kernel threads */
+	if (current->mm)
 		fpsimd_save_state(&current->thread.fpsimd_state);
-
-	if (next->mm) {
-		/*
-		 * If we are switching to a task whose most recent userland
-		 * FPSIMD state is already in the registers of *this* cpu,
-		 * we can skip loading the state from memory. Otherwise, set
-		 * the TIF_FOREIGN_FPSTATE flag so the state will be loaded
-		 * upon the next return to userland.
-		 */
-		struct fpsimd_state *st = &next->thread.fpsimd_state;
-
-		if (__this_cpu_read(fpsimd_last_state) == st
-		    && st->cpu == smp_processor_id())
-			clear_ti_thread_flag(task_thread_info(next),
-					     TIF_FOREIGN_FPSTATE);
-		else
-			set_ti_thread_flag(task_thread_info(next),
-					   TIF_FOREIGN_FPSTATE);
-	}
+	if (next->mm)
+		fpsimd_load_state(&next->thread.fpsimd_state);
 }
 
 void fpsimd_flush_thread(void)
 {
-	memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
-	set_thread_flag(TIF_FOREIGN_FPSTATE);
-}
-
-/*
- * Save the userland FPSIMD state of 'current' to memory, but only if the state
- * currently held in the registers does in fact belong to 'current'
- */
-void fpsimd_preserve_current_state(void)
-{
-	preempt_disable();
-	if (!test_thread_flag(TIF_FOREIGN_FPSTATE))
-		fpsimd_save_state(&current->thread.fpsimd_state);
-	preempt_enable();
-}
-
-/*
- * Load the userland FPSIMD state of 'current' from memory, but only if the
- * FPSIMD state already held in the registers is /not/ the most recent FPSIMD
- * state of 'current'
- */
-void fpsimd_restore_current_state(void)
-{
-	preempt_disable();
-	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
-		struct fpsimd_state *st = &current->thread.fpsimd_state;
-
-		fpsimd_load_state(st);
-		this_cpu_write(fpsimd_last_state, st);
-		st->cpu = smp_processor_id();
-	}
-	preempt_enable();
-}
-
-/*
- * Load an updated userland FPSIMD state for 'current' from memory and set the
- * flag that indicates that the FPSIMD register contents are the most recent
- * FPSIMD state of 'current'
- */
-void fpsimd_update_current_state(struct fpsimd_state *state)
-{
 	preempt_disable();
-	fpsimd_load_state(state);
-	if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
-		struct fpsimd_state *st = &current->thread.fpsimd_state;
-
-		this_cpu_write(fpsimd_last_state, st);
-		st->cpu = smp_processor_id();
-	}
+	memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
+	fpsimd_load_state(&current->thread.fpsimd_state);
 	preempt_enable();
 }
 
-/*
- * Invalidate live CPU copies of task t's FPSIMD state
- */
-void fpsimd_flush_task_state(struct task_struct *t)
-{
-	t->thread.fpsimd_state.cpu = NR_CPUS;
-}
-
 #ifdef CONFIG_KERNEL_MODE_NEON
 
-static DEFINE_PER_CPU(struct fpsimd_partial_state, hardirq_fpsimdstate);
-static DEFINE_PER_CPU(struct fpsimd_partial_state, softirq_fpsimdstate);
-
 /*
  * Kernel-side NEON support functions
  */
-void kernel_neon_begin_partial(u32 num_regs)
+void kernel_neon_begin(void)
 {
-	if (in_interrupt()) {
-		struct fpsimd_partial_state *s = this_cpu_ptr(
-			in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate);
+	/* Avoid using the NEON in interrupt context */
+	BUG_ON(in_interrupt());
+	preempt_disable();
 
-		BUG_ON(num_regs > 32);
-		fpsimd_save_partial_state(s, roundup(num_regs, 2));
-	} else {
-		/*
-		 * Save the userland FPSIMD state if we have one and if we
-		 * haven't done so already. Clear fpsimd_last_state to indicate
-		 * that there is no longer userland FPSIMD state in the
-		 * registers.
-		 */
-		preempt_disable();
-		if (current->mm &&
-		    !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
-			fpsimd_save_state(&current->thread.fpsimd_state);
-		this_cpu_write(fpsimd_last_state, NULL);
-	}
+	if (current->mm)
+		fpsimd_save_state(&current->thread.fpsimd_state);
 }
-EXPORT_SYMBOL(kernel_neon_begin_partial);
+EXPORT_SYMBOL(kernel_neon_begin);
 
 void kernel_neon_end(void)
 {
-	if (in_interrupt()) {
-		struct fpsimd_partial_state *s = this_cpu_ptr(
-			in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate);
-		fpsimd_load_partial_state(s);
-	} else {
-		preempt_enable();
-	}
+	if (current->mm)
+		fpsimd_load_state(&current->thread.fpsimd_state);
+
+	preempt_enable();
 }
 EXPORT_SYMBOL(kernel_neon_end);
 
@@ -268,12 +119,12 @@ static int fpsimd_cpu_pm_notifier(struct notifier_block *self,
 {
 	switch (cmd) {
 	case CPU_PM_ENTER:
-		if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE))
+		if (current->mm)
 			fpsimd_save_state(&current->thread.fpsimd_state);
 		break;
 	case CPU_PM_EXIT:
 		if (current->mm)
-			set_thread_flag(TIF_FOREIGN_FPSTATE);
+			fpsimd_load_state(&current->thread.fpsimd_state);
 		break;
 	case CPU_PM_ENTER_FAILED:
 	default:
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 15c91e25d045..3193bf35dbc8 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -215,7 +215,7 @@ void release_thread(struct task_struct *dead_task)
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
-	fpsimd_preserve_current_state();
+	fpsimd_save_state(&current->thread.fpsimd_state);
 	*dst = *src;
 	return 0;
 }
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 3e926b9c0641..0bf195533088 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -521,7 +521,6 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
 		return ret;
 
 	target->thread.fpsimd_state.user_fpsimd = newstate;
-	fpsimd_flush_task_state(target);
 	return ret;
 }
 
@@ -769,7 +768,6 @@ static int compat_vfp_set(struct task_struct *target,
 		uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
 	}
 
-	fpsimd_flush_task_state(target);
 	return ret;
 }
 
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index bbc1aad21ce6..e3cf09626245 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -51,7 +51,7 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
 	int err;
 
 	/* dump the hardware registers to the fpsimd_state structure */
-	fpsimd_preserve_current_state();
+	fpsimd_save_state(fpsimd);
 
 	/* copy the FP and status/control registers */
 	err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
@@ -86,8 +86,11 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
 	__get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
 
 	/* load the hardware registers from the fpsimd_state structure */
-	if (!err)
-		fpsimd_update_current_state(&fpsimd);
+	if (!err) {
+		preempt_disable();
+		fpsimd_load_state(&fpsimd);
+		preempt_enable();
+	}
 
 	return err ? -EFAULT : 0;
 }
@@ -420,8 +423,4 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
 		clear_thread_flag(TIF_NOTIFY_RESUME);
 		tracehook_notify_resume(regs);
 	}
-
-	if (thread_flags & _TIF_FOREIGN_FPSTATE)
-		fpsimd_restore_current_state();
-
 }
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 02de43260332..e51bbe79f5b5 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -219,7 +219,7 @@ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
 	 * Note that this also saves V16-31, which aren't visible
 	 * in AArch32.
 	 */
-	fpsimd_preserve_current_state();
+	fpsimd_save_state(fpsimd);
 
 	/* Place structure header on the stack */
 	__put_user_error(magic, &frame->magic, err);
@@ -282,8 +282,11 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
 	 * We don't need to touch the exception register, so
 	 * reload the hardware state.
 	 */
-	if (!err)
-		fpsimd_update_current_state(&fpsimd);
+	if (!err) {
+		preempt_disable();
+		fpsimd_load_state(&fpsimd);
+		preempt_enable();
+	}
 
 	return err ? -EFAULT : 0;
 }