Merge branch 'for-rmk/prefetch' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable

2013-10-23 23:38:28 +01:00 · 2013-10-23 23:38:28 +01:00 · bdbf0a4cf2
parent 901e7e34f8 d779c07dd7
commit bdbf0a4cf2
6 changed files with 56 additions and 23 deletions
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@ -12,6 +12,7 @@
 #define __ASM_ARM_ATOMIC_H

 #include <linux/compiler.h>
+#include <linux/prefetch.h>
 #include <linux/types.h>
 #include <linux/irqflags.h>
 #include <asm/barrier.h>
@ -41,6 +42,7 @@ static inline void atomic_add(int i, atomic_t *v)
 	unsigned long tmp;
 	int result;

+	prefetchw(&v->counter);
 	__asm__ __volatile__("@ atomic_add\n"
 "1:	ldrex	%0, [%3]\n"
 "	add	%0, %0, %4\n"
@ -79,6 +81,7 @@ static inline void atomic_sub(int i, atomic_t *v)
 	unsigned long tmp;
 	int result;

+	prefetchw(&v->counter);
 	__asm__ __volatile__("@ atomic_sub\n"
 "1:	ldrex	%0, [%3]\n"
 "	sub	%0, %0, %4\n"
@ -138,6 +141,7 @@ static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
 {
 	unsigned long tmp, tmp2;

+	prefetchw(addr);
 	__asm__ __volatile__("@ atomic_clear_mask\n"
 "1:	ldrex	%0, [%3]\n"
 "	bic	%0, %0, %4\n"
@ -283,6 +287,7 @@ static inline void atomic64_set(atomic64_t *v, u64 i)
 {
 	u64 tmp;

+	prefetchw(&v->counter);
 	__asm__ __volatile__("@ atomic64_set\n"
 "1:	ldrexd	%0, %H0, [%2]\n"
 "	strexd	%0, %3, %H3, [%2]\n"
@ -299,6 +304,7 @@ static inline void atomic64_add(u64 i, atomic64_t *v)
 	u64 result;
 	unsigned long tmp;

+	prefetchw(&v->counter);
 	__asm__ __volatile__("@ atomic64_add\n"
 "1:	ldrexd	%0, %H0, [%3]\n"
 "	adds	%0, %0, %4\n"
@ -339,6 +345,7 @@ static inline void atomic64_sub(u64 i, atomic64_t *v)
 	u64 result;
 	unsigned long tmp;

+	prefetchw(&v->counter);
 	__asm__ __volatile__("@ atomic64_sub\n"
 "1:	ldrexd	%0, %H0, [%3]\n"
 "	subs	%0, %0, %4\n"
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@ -22,6 +22,7 @@
 #include <asm/hw_breakpoint.h>
 #include <asm/ptrace.h>
 #include <asm/types.h>
+#include <asm/unified.h>

 #ifdef __KERNEL__
 #define STACK_TOP	((current->personality & ADDR_LIMIT_32BIT) ? \
@ -87,6 +88,17 @@ unsigned long get_wchan(struct task_struct *p);
 #define KSTK_EIP(tsk)	task_pt_regs(tsk)->ARM_pc
 #define KSTK_ESP(tsk)	task_pt_regs(tsk)->ARM_sp

+#ifdef CONFIG_SMP
+#define __ALT_SMP_ASM(smp, up)						\
+	"9998:	" smp "\n"						\
+	"	.pushsection \".alt.smp.init\", \"a\"\n"		\
+	"	.long	9998b\n"					\
+	"	" up "\n"						\
+	"	.popsection\n"
+#else
+#define __ALT_SMP_ASM(smp, up)	up
+#endif
+
 /*
 * Prefetching support - only ARMv5.
 */
@ -97,17 +109,22 @@ static inline void prefetch(const void *ptr)
 {
 	__asm__ __volatile__(
 		"pld\t%a0"
-		:
-		: "p" (ptr)
-		: "cc");
+		:: "p" (ptr));
 }

+#if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
 #define ARCH_HAS_PREFETCHW
-#define prefetchw(ptr)	prefetch(ptr)
-
-#define ARCH_HAS_SPINLOCK_PREFETCH
-#define spin_lock_prefetch(x) do { } while (0)
-
+static inline void prefetchw(const void *ptr)
+{
+	__asm__ __volatile__(
+		".arch_extension	mp\n"
+		__ALT_SMP_ASM(
+			WASM(pldw)		"\t%a0",
+			WASM(pld)		"\t%a0"
+		)
+		:: "p" (ptr));
+}
+#endif
 #endif

 #define HAVE_ARCH_PICK_MMAP_LAYOUT
--- a/arch/arm/include/asm/spinlock.h
+++ b/arch/arm/include/asm/spinlock.h
@ -5,21 +5,13 @@
 #error SMP not supported on pre-ARMv6 CPUs
 #endif

-#include <asm/processor.h>
+#include <linux/prefetch.h>

 /*
 * sev and wfe are ARMv6K extensions.  Uniprocessor ARMv6 may not have the K
 * extensions, so when running on UP, we have to patch these instructions away.
 */
-#define ALT_SMP(smp, up)					\
-	"9998:	" smp "\n"					\
-	"	.pushsection \".alt.smp.init\", \"a\"\n"	\
-	"	.long	9998b\n"				\
-	"	" up "\n"					\
-	"	.popsection\n"
-
 #ifdef CONFIG_THUMB2_KERNEL
-#define SEV		ALT_SMP("sev.w", "nop.w")
 /*
 * For Thumb-2, special care is needed to ensure that the conditional WFE
 * instruction really does assemble to exactly 4 bytes (as required by
@ -31,17 +23,18 @@
 * the assembler won't change IT instructions which are explicitly present
 * in the input.
 */
-#define WFE(cond)	ALT_SMP(		\
+#define WFE(cond)	__ALT_SMP_ASM(		\
 	"it " cond "\n\t"			\
 	"wfe" cond ".n",			\
 						\
 	"nop.w"					\
 )
 #else
-#define SEV		ALT_SMP("sev", "nop")
-#define WFE(cond)	ALT_SMP("wfe" cond, "nop")
+#define WFE(cond)	__ALT_SMP_ASM("wfe" cond, "nop")
 #endif

+#define SEV		__ALT_SMP_ASM(WASM(sev), WASM(nop))
+
 static inline void dsb_sev(void)
 {
 #if __LINUX_ARM_ARCH__ >= 7
@ -77,6 +70,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock)
 	u32 newval;
 	arch_spinlock_t lockval;

+	prefetchw(&lock->slock);
 	__asm__ __volatile__(
 "1:	ldrex	%0, [%3]\n"
 "	add	%1, %0, %4\n"
@ -100,6 +94,7 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock)
 	unsigned long contended, res;
 	u32 slock;

+	prefetchw(&lock->slock);
 	do {
 		__asm__ __volatile__(
 		"	ldrex	%0, [%3]\n"
@ -152,6 +147,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw)
 {
 	unsigned long tmp;

+	prefetchw(&rw->lock);
 	__asm__ __volatile__(
 "1:	ldrex	%0, [%1]\n"
 "	teq	%0, #0\n"
@ -170,6 +166,7 @@ static inline int arch_write_trylock(arch_rwlock_t *rw)
 {
 	unsigned long contended, res;

+	prefetchw(&rw->lock);
 	do {
 		__asm__ __volatile__(
 		"	ldrex	%0, [%2]\n"
@ -203,7 +200,7 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
 }

 /* write_can_lock - would write_trylock() succeed? */
-#define arch_write_can_lock(x)		((x)->lock == 0)
+#define arch_write_can_lock(x)		(ACCESS_ONCE((x)->lock) == 0)

 /*
 * Read locks are a bit more hairy:
@ -221,6 +218,7 @@ static inline void arch_read_lock(arch_rwlock_t *rw)
 {
 	unsigned long tmp, tmp2;

+	prefetchw(&rw->lock);
 	__asm__ __volatile__(
 "1:	ldrex	%0, [%2]\n"
 "	adds	%0, %0, #1\n"
@ -241,6 +239,7 @@ static inline void arch_read_unlock(arch_rwlock_t *rw)

 	smp_mb();

+	prefetchw(&rw->lock);
 	__asm__ __volatile__(
 "1:	ldrex	%0, [%2]\n"
 "	sub	%0, %0, #1\n"
@ -259,6 +258,7 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 {
 	unsigned long contended, res;

+	prefetchw(&rw->lock);
 	do {
 		__asm__ __volatile__(
 		"	ldrex	%0, [%2]\n"
@ -280,7 +280,7 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
 }

 /* read_can_lock - would read_trylock() succeed? */
-#define arch_read_can_lock(x)		((x)->lock < 0x80000000)
+#define arch_read_can_lock(x)		(ACCESS_ONCE((x)->lock) < 0x80000000)

 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
--- a/arch/arm/include/asm/spinlock_types.h
+++ b/arch/arm/include/asm/spinlock_types.h
@ -25,7 +25,7 @@ typedef struct {
 #define __ARCH_SPIN_LOCK_UNLOCKED	{ { 0 } }

 typedef struct {
-	volatile unsigned int lock;
+	u32 lock;
 } arch_rwlock_t;

 #define __ARCH_RW_LOCK_UNLOCKED		{ 0 }
--- a/arch/arm/include/asm/unified.h
+++ b/arch/arm/include/asm/unified.h
@ -38,6 +38,8 @@
 #ifdef __ASSEMBLY__
 #define W(instr)	instr.w
 #define BSYM(sym)	sym + 1
+#else
+#define WASM(instr)	#instr ".w"
 #endif

 #else	/* !CONFIG_THUMB2_KERNEL */
@ -50,6 +52,8 @@
 #ifdef __ASSEMBLY__
 #define W(instr)	instr
 #define BSYM(sym)	sym
+#else
+#define WASM(instr)	#instr
 #endif

 #endif	/* CONFIG_THUMB2_KERNEL */
--- a/arch/arm/lib/bitops.h
+++ b/arch/arm/lib/bitops.h
@ -10,6 +10,11 @@ UNWIND(	.fnstart	)
 	and	r3, r0, #31		@ Get bit offset
 	mov	r0, r0, lsr #5
 	add	r1, r1, r0, lsl #2	@ Get word offset
+#if __LINUX_ARM_ARCH__ >= 7
+	.arch_extension	mp
+	ALT_SMP(W(pldw)	[r1])
+	ALT_UP(W(nop))
+#endif
 	mov	r3, r2, lsl r3
 1:	ldrex	r2, [r1]
 	\instr	r2, r2, r3