--- arch/x86/include/asm/rwsem.h
+++ arch/x86/include/asm/rwsem.h
@@ -41,6 +41,7 @@
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/lockdep.h>
+#include <asm/asm.h>
struct rwsem_waiter;
@@ -55,17 +56,28 @@ extern asmregparm struct rw_semaphore *
/*
* the semaphore definition
+ *
+ * The bias values and the counter type limits the number of
+ * potential readers/writers to 32767 for 32 bits and 2147483647
+ * for 64 bits.
*/
-#define RWSEM_UNLOCKED_VALUE 0x00000000
-#define RWSEM_ACTIVE_BIAS 0x00000001
-#define RWSEM_ACTIVE_MASK 0x0000ffff
-#define RWSEM_WAITING_BIAS (-0x00010000)
+#ifdef CONFIG_X86_64
+# define RWSEM_ACTIVE_MASK 0xffffffffL
+#else
+# define RWSEM_ACTIVE_MASK 0x0000ffffL
+#endif
+
+#define RWSEM_UNLOCKED_VALUE 0x00000000L
+#define RWSEM_ACTIVE_BIAS 0x00000001L
+#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1)
#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
+typedef signed long rwsem_count_t;
+
struct rw_semaphore {
- signed long count;
+ rwsem_count_t count;
spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -105,7 +117,7 @@ do { \
static inline void __down_read(struct rw_semaphore *sem)
{
asm volatile("# beginning down_read\n\t"
- LOCK_PREFIX " incl (%%eax)\n\t"
+ LOCK_PREFIX _ASM_INC "(%1)\n\t"
/* adds 0x00000001, returns the old value */
" jns 1f\n"
" call call_rwsem_down_read_failed\n"
@@ -121,14 +133,14 @@ static inline void __down_read(struct rw
*/
static inline int __down_read_trylock(struct rw_semaphore *sem)
{
- __s32 result, tmp;
+ rwsem_count_t result, tmp;
asm volatile("# beginning __down_read_trylock\n\t"
- " movl %0,%1\n\t"
+ " mov %0,%1\n\t"
"1:\n\t"
- " movl %1,%2\n\t"
- " addl %3,%2\n\t"
+ " mov %1,%2\n\t"
+ " add %3,%2\n\t"
" jle 2f\n\t"
- LOCK_PREFIX " cmpxchgl %2,%0\n\t"
+ LOCK_PREFIX " cmpxchg %2,%0\n\t"
" jnz 1b\n\t"
"2:\n\t"
"# ending __down_read_trylock\n\t"
@@ -143,13 +155,13 @@ static inline int __down_read_trylock(st
*/
static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
{
- int tmp;
+ rwsem_count_t tmp;
tmp = RWSEM_ACTIVE_WRITE_BIAS;
asm volatile("# beginning down_write\n\t"
- LOCK_PREFIX " xadd %%edx,(%%eax)\n\t"
+ LOCK_PREFIX " xadd %1,(%2)\n\t"
/* subtract 0x0000ffff, returns the old value */
- " testl %%edx,%%edx\n\t"
+ " test %1,%1\n\t"
/* was the count 0 before? */
" jz 1f\n"
" call call_rwsem_down_write_failed\n"
@@ -170,9 +182,9 @@ static inline void __down_write(struct r
*/
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
- signed long ret = cmpxchg(&sem->count,
- RWSEM_UNLOCKED_VALUE,
- RWSEM_ACTIVE_WRITE_BIAS);
+ rwsem_count_t ret = cmpxchg(&sem->count,
+ RWSEM_UNLOCKED_VALUE,
+ RWSEM_ACTIVE_WRITE_BIAS);
if (ret == RWSEM_UNLOCKED_VALUE)
return 1;
return 0;
@@ -183,9 +195,9 @@ static inline int __down_write_trylock(s
*/
static inline void __up_read(struct rw_semaphore *sem)
{
- __s32 tmp = -RWSEM_ACTIVE_READ_BIAS;
+ rwsem_count_t tmp = -RWSEM_ACTIVE_READ_BIAS;
asm volatile("# beginning __up_read\n\t"
- LOCK_PREFIX " xadd %%edx,(%%eax)\n\t"
+ LOCK_PREFIX " xadd %1,(%2)\n\t"
/* subtracts 1, returns the old value */
" jns 1f\n\t"
" call call_rwsem_wake\n"
@@ -201,18 +213,18 @@ static inline void __up_read(struct rw_s
*/
static inline void __up_write(struct rw_semaphore *sem)
{
+ rwsem_count_t tmp;
asm volatile("# beginning __up_write\n\t"
- " movl %2,%%edx\n\t"
- LOCK_PREFIX " xaddl %%edx,(%%eax)\n\t"
+ LOCK_PREFIX " xadd %1,(%2)\n\t"
/* tries to transition
0xffff0001 -> 0x00000000 */
" jz 1f\n"
" call call_rwsem_wake\n"
"1:\n\t"
"# ending __up_write\n"
- : "+m" (sem->count)
- : "a" (sem), "i" (-RWSEM_ACTIVE_WRITE_BIAS)
- : "memory", "cc", "edx");
+ : "+m" (sem->count), "=d" (tmp)
+ : "a" (sem), "1" (-RWSEM_ACTIVE_WRITE_BIAS)
+ : "memory", "cc");
}
/*
@@ -221,33 +233,38 @@ static inline void __up_write(struct rw_
static inline void __downgrade_write(struct rw_semaphore *sem)
{
asm volatile("# beginning __downgrade_write\n\t"
- LOCK_PREFIX " addl %2,(%%eax)\n\t"
- /* transitions 0xZZZZ0001 -> 0xYYYY0001 */
+ LOCK_PREFIX _ASM_ADD "%2,(%1)\n\t"
+ /*
+ * transitions 0xZZZZ0001 -> 0xYYYY0001 (i386)
+ * 0xZZZZZZZZ00000001 -> 0xYYYYYYYY00000001 (x86_64)
+ */
" jns 1f\n\t"
" call call_rwsem_downgrade_wake\n"
"1:\n\t"
"# ending __downgrade_write\n"
: "+m" (sem->count)
- : "a" (sem), "i" (-RWSEM_WAITING_BIAS)
+ : "a" (sem), "er" (-RWSEM_WAITING_BIAS)
: "memory", "cc");
}
/*
* implement atomic add functionality
*/
-static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
+static inline void rwsem_atomic_add(rwsem_count_t delta,
+ struct rw_semaphore *sem)
{
- asm volatile(LOCK_PREFIX "addl %1,%0"
+ asm volatile(LOCK_PREFIX _ASM_ADD "%1,%0"
: "+m" (sem->count)
- : "ir" (delta));
+ : "er" (delta));
}
/*
* implement exchange and add functionality
*/
-static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
+static inline rwsem_count_t rwsem_atomic_update(rwsem_count_t delta,
+ struct rw_semaphore *sem)
{
- int tmp = delta;
+ rwsem_count_t tmp = delta;
asm volatile(LOCK_PREFIX "xadd %0,%1"
: "+r" (tmp), "+m" (sem->count)
projects / ziggy471-frankenstein-kernel.git / blobdiff