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

5 files changed, 51 insertions, 23 deletions

diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index da1c77d39327..55ffc3b850f4 100644
--- 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"
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 413f3876341c..c3d5fc124a05 100644
--- 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
diff --git a/arch/arm/include/asm/spinlock.h b/arch/arm/include/asm/spinlock.h
index 4f2c28060c9a..499900781d59 100644
--- 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)
diff --git a/arch/arm/include/asm/spinlock_types.h b/arch/arm/include/asm/spinlock_types.h
index b262d2f8b478..47663fcb10ad 100644
--- 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 }
diff --git a/arch/arm/include/asm/unified.h b/arch/arm/include/asm/unified.h
index f5989f46b4d2..b88beaba6b4a 100644
--- 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 */