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-rw-r--r--arch/arm/include/asm/assembler.h13
-rw-r--r--arch/arm/include/asm/atomic.h61
-rw-r--r--arch/arm/include/asm/system.h176
3 files changed, 241 insertions, 9 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index 6116e4893c0..15f8a092b70 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -114,3 +114,16 @@
.align 3; \
.long 9999b,9001f; \
.previous
+
+/*
+ * SMP data memory barrier
+ */
+ .macro smp_dmb
+#ifdef CONFIG_SMP
+#if __LINUX_ARM_ARCH__ >= 7
+ dmb
+#elif __LINUX_ARM_ARCH__ == 6
+ mcr p15, 0, r0, c7, c10, 5 @ dmb
+#endif
+#endif
+ .endm
diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h
index ee99723b3a6..16b52f39798 100644
--- a/arch/arm/include/asm/atomic.h
+++ b/arch/arm/include/asm/atomic.h
@@ -44,11 +44,29 @@ static inline void atomic_set(atomic_t *v, int i)
: "cc");
}
+static inline void atomic_add(int i, atomic_t *v)
+{
+ unsigned long tmp;
+ int result;
+
+ __asm__ __volatile__("@ atomic_add\n"
+"1: ldrex %0, [%2]\n"
+" add %0, %0, %3\n"
+" strex %1, %0, [%2]\n"
+" teq %1, #0\n"
+" bne 1b"
+ : "=&r" (result), "=&r" (tmp)
+ : "r" (&v->counter), "Ir" (i)
+ : "cc");
+}
+
static inline int atomic_add_return(int i, atomic_t *v)
{
unsigned long tmp;
int result;
+ smp_mb();
+
__asm__ __volatile__("@ atomic_add_return\n"
"1: ldrex %0, [%2]\n"
" add %0, %0, %3\n"
@@ -59,14 +77,34 @@ static inline int atomic_add_return(int i, atomic_t *v)
: "r" (&v->counter), "Ir" (i)
: "cc");
+ smp_mb();
+
return result;
}
+static inline void atomic_sub(int i, atomic_t *v)
+{
+ unsigned long tmp;
+ int result;
+
+ __asm__ __volatile__("@ atomic_sub\n"
+"1: ldrex %0, [%2]\n"
+" sub %0, %0, %3\n"
+" strex %1, %0, [%2]\n"
+" teq %1, #0\n"
+" bne 1b"
+ : "=&r" (result), "=&r" (tmp)
+ : "r" (&v->counter), "Ir" (i)
+ : "cc");
+}
+
static inline int atomic_sub_return(int i, atomic_t *v)
{
unsigned long tmp;
int result;
+ smp_mb();
+
__asm__ __volatile__("@ atomic_sub_return\n"
"1: ldrex %0, [%2]\n"
" sub %0, %0, %3\n"
@@ -77,6 +115,8 @@ static inline int atomic_sub_return(int i, atomic_t *v)
: "r" (&v->counter), "Ir" (i)
: "cc");
+ smp_mb();
+
return result;
}
@@ -84,6 +124,8 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
{
unsigned long oldval, res;
+ smp_mb();
+
do {
__asm__ __volatile__("@ atomic_cmpxchg\n"
"ldrex %1, [%2]\n"
@@ -95,6 +137,8 @@ static inline int atomic_cmpxchg(atomic_t *ptr, int old, int new)
: "cc");
} while (res);
+ smp_mb();
+
return oldval;
}
@@ -135,6 +179,7 @@ static inline int atomic_add_return(int i, atomic_t *v)
return val;
}
+#define atomic_add(i, v) (void) atomic_add_return(i, v)
static inline int atomic_sub_return(int i, atomic_t *v)
{
@@ -148,6 +193,7 @@ static inline int atomic_sub_return(int i, atomic_t *v)
return val;
}
+#define atomic_sub(i, v) (void) atomic_sub_return(i, v)
static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
{
@@ -187,10 +233,8 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
}
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
-#define atomic_add(i, v) (void) atomic_add_return(i, v)
-#define atomic_inc(v) (void) atomic_add_return(1, v)
-#define atomic_sub(i, v) (void) atomic_sub_return(i, v)
-#define atomic_dec(v) (void) atomic_sub_return(1, v)
+#define atomic_inc(v) atomic_add(1, v)
+#define atomic_dec(v) atomic_sub(1, v)
#define atomic_inc_and_test(v) (atomic_add_return(1, v) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, v) == 0)
@@ -200,11 +244,10 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
#define atomic_add_negative(i,v) (atomic_add_return(i, v) < 0)
-/* Atomic operations are already serializing on ARM */
-#define smp_mb__before_atomic_dec() barrier()
-#define smp_mb__after_atomic_dec() barrier()
-#define smp_mb__before_atomic_inc() barrier()
-#define smp_mb__after_atomic_inc() barrier()
+#define smp_mb__before_atomic_dec() smp_mb()
+#define smp_mb__after_atomic_dec() smp_mb()
+#define smp_mb__before_atomic_inc() smp_mb()
+#define smp_mb__after_atomic_inc() smp_mb()
#include <asm-generic/atomic.h>
#endif
diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
index bd4dc8ed53d..d65b2f5bf41 100644
--- a/arch/arm/include/asm/system.h
+++ b/arch/arm/include/asm/system.h
@@ -248,6 +248,8 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
unsigned int tmp;
#endif
+ smp_mb();
+
switch (size) {
#if __LINUX_ARM_ARCH__ >= 6
case 1:
@@ -307,6 +309,7 @@ static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size
__bad_xchg(ptr, size), ret = 0;
break;
}
+ smp_mb();
return ret;
}
@@ -316,6 +319,12 @@ extern void enable_hlt(void);
#include <asm-generic/cmpxchg-local.h>
+#if __LINUX_ARM_ARCH__ < 6
+
+#ifdef CONFIG_SMP
+#error "SMP is not supported on this platform"
+#endif
+
/*
* cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
* them available.
@@ -329,6 +338,173 @@ extern void enable_hlt(void);
#include <asm-generic/cmpxchg.h>
#endif
+#else /* __LINUX_ARM_ARCH__ >= 6 */
+
+extern void __bad_cmpxchg(volatile void *ptr, int size);
+
+/*
+ * cmpxchg only support 32-bits operands on ARMv6.
+ */
+
+static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
+ unsigned long new, int size)
+{
+ unsigned long oldval, res;
+
+ switch (size) {
+#ifdef CONFIG_CPU_32v6K
+ case 1:
+ do {
+ asm volatile("@ __cmpxchg1\n"
+ " ldrexb %1, [%2]\n"
+ " mov %0, #0\n"
+ " teq %1, %3\n"
+ " strexbeq %0, %4, [%2]\n"
+ : "=&r" (res), "=&r" (oldval)
+ : "r" (ptr), "Ir" (old), "r" (new)
+ : "memory", "cc");
+ } while (res);
+ break;
+ case 2:
+ do {
+ asm volatile("@ __cmpxchg1\n"
+ " ldrexh %1, [%2]\n"
+ " mov %0, #0\n"
+ " teq %1, %3\n"
+ " strexheq %0, %4, [%2]\n"
+ : "=&r" (res), "=&r" (oldval)
+ : "r" (ptr), "Ir" (old), "r" (new)
+ : "memory", "cc");
+ } while (res);
+ break;
+#endif /* CONFIG_CPU_32v6K */
+ case 4:
+ do {
+ asm volatile("@ __cmpxchg4\n"
+ " ldrex %1, [%2]\n"
+ " mov %0, #0\n"
+ " teq %1, %3\n"
+ " strexeq %0, %4, [%2]\n"
+ : "=&r" (res), "=&r" (oldval)
+ : "r" (ptr), "Ir" (old), "r" (new)
+ : "memory", "cc");
+ } while (res);
+ break;
+ default:
+ __bad_cmpxchg(ptr, size);
+ oldval = 0;
+ }
+
+ return oldval;
+}
+
+static inline unsigned long __cmpxchg_mb(volatile void *ptr, unsigned long old,
+ unsigned long new, int size)
+{
+ unsigned long ret;
+
+ smp_mb();
+ ret = __cmpxchg(ptr, old, new, size);
+ smp_mb();
+
+ return ret;
+}
+
+#define cmpxchg(ptr,o,n) \
+ ((__typeof__(*(ptr)))__cmpxchg_mb((ptr), \
+ (unsigned long)(o), \
+ (unsigned long)(n), \
+ sizeof(*(ptr))))
+
+static inline unsigned long __cmpxchg_local(volatile void *ptr,
+ unsigned long old,
+ unsigned long new, int size)
+{
+ unsigned long ret;
+
+ switch (size) {
+#ifndef CONFIG_CPU_32v6K
+ case 1:
+ case 2:
+ ret = __cmpxchg_local_generic(ptr, old, new, size);
+ break;
+#endif /* !CONFIG_CPU_32v6K */
+ default:
+ ret = __cmpxchg(ptr, old, new, size);
+ }
+
+ return ret;
+}
+
+#define cmpxchg_local(ptr,o,n) \
+ ((__typeof__(*(ptr)))__cmpxchg_local((ptr), \
+ (unsigned long)(o), \
+ (unsigned long)(n), \
+ sizeof(*(ptr))))
+
+#ifdef CONFIG_CPU_32v6K
+
+/*
+ * Note : ARMv7-M (currently unsupported by Linux) does not support
+ * ldrexd/strexd. If ARMv7-M is ever supported by the Linux kernel, it should
+ * not be allowed to use __cmpxchg64.
+ */
+static inline unsigned long long __cmpxchg64(volatile void *ptr,
+ unsigned long long old,
+ unsigned long long new)
+{
+ register unsigned long long oldval asm("r0");
+ register unsigned long long __old asm("r2") = old;
+ register unsigned long long __new asm("r4") = new;
+ unsigned long res;
+
+ do {
+ asm volatile(
+ " @ __cmpxchg8\n"
+ " ldrexd %1, %H1, [%2]\n"
+ " mov %0, #0\n"
+ " teq %1, %3\n"
+ " teqeq %H1, %H3\n"
+ " strexdeq %0, %4, %H4, [%2]\n"
+ : "=&r" (res), "=&r" (oldval)
+ : "r" (ptr), "Ir" (__old), "r" (__new)
+ : "memory", "cc");
+ } while (res);
+
+ return oldval;
+}
+
+static inline unsigned long long __cmpxchg64_mb(volatile void *ptr,
+ unsigned long long old,
+ unsigned long long new)
+{
+ unsigned long long ret;
+
+ smp_mb();
+ ret = __cmpxchg64(ptr, old, new);
+ smp_mb();
+
+ return ret;
+}
+
+#define cmpxchg64(ptr,o,n) \
+ ((__typeof__(*(ptr)))__cmpxchg64_mb((ptr), \
+ (unsigned long long)(o), \
+ (unsigned long long)(n)))
+
+#define cmpxchg64_local(ptr,o,n) \
+ ((__typeof__(*(ptr)))__cmpxchg64((ptr), \
+ (unsigned long long)(o), \
+ (unsigned long long)(n)))
+
+#else /* !CONFIG_CPU_32v6K */
+
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
+
+#endif /* CONFIG_CPU_32v6K */
+
+#endif /* __LINUX_ARM_ARCH__ >= 6 */
+
#endif /* __ASSEMBLY__ */
#define arch_align_stack(x) (x)
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-22 10:57:43 +0000