diff options
Diffstat (limited to 'arch/arc/include/asm/futex.h')
| -rw-r--r-- | arch/arc/include/asm/futex.h | 58 |
1 files changed, 47 insertions, 11 deletions
diff --git a/arch/arc/include/asm/futex.h b/arch/arc/include/asm/futex.h index 4dc64ddeb..70cfe16b7 100644 --- a/arch/arc/include/asm/futex.h +++ b/arch/arc/include/asm/futex.h @@ -16,12 +16,40 @@ #include <linux/uaccess.h> #include <asm/errno.h> +#ifdef CONFIG_ARC_HAS_LLSC + +#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ + \ + __asm__ __volatile__( \ + "1: llock %1, [%2] \n" \ + insn "\n" \ + "2: scond %0, [%2] \n" \ + " bnz 1b \n" \ + " mov %0, 0 \n" \ + "3: \n" \ + " .section .fixup,\"ax\" \n" \ + " .align 4 \n" \ + "4: mov %0, %4 \n" \ + " b 3b \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " .align 4 \n" \ + " .word 1b, 4b \n" \ + " .word 2b, 4b \n" \ + " .previous \n" \ + \ + : "=&r" (ret), "=&r" (oldval) \ + : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ + : "cc", "memory") + +#else /* !CONFIG_ARC_HAS_LLSC */ + #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ \ __asm__ __volatile__( \ - "1: ld %1, [%2] \n" \ + "1: ld %1, [%2] \n" \ insn "\n" \ - "2: st %0, [%2] \n" \ + "2: st %0, [%2] \n" \ " mov %0, 0 \n" \ "3: \n" \ " .section .fixup,\"ax\" \n" \ @@ -39,6 +67,8 @@ : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ : "cc", "memory") +#endif + static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) { int op = (encoded_op >> 28) & 7; @@ -53,7 +83,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; - pagefault_disable(); /* implies preempt_disable() */ + pagefault_disable(); switch (op) { case FUTEX_OP_SET: @@ -75,7 +105,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) ret = -ENOSYS; } - pagefault_enable(); /* subsumes preempt_enable() */ + pagefault_enable(); if (!ret) { switch (cmp) { @@ -104,7 +134,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) return ret; } -/* Compare-xchg with preemption disabled. +/* Compare-xchg with pagefaults disabled. * Notes: * -Best-Effort: Exchg happens only if compare succeeds. * If compare fails, returns; leaving retry/looping to upper layers @@ -121,13 +151,19 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; - pagefault_disable(); /* implies preempt_disable() */ + pagefault_disable(); - /* TBD : can use llock/scond */ __asm__ __volatile__( - "1: ld %0, [%3] \n" - " brne %0, %1, 3f \n" - "2: st %2, [%3] \n" +#ifdef CONFIG_ARC_HAS_LLSC + "1: llock %0, [%3] \n" + " brne %0, %1, 3f \n" + "2: scond %2, [%3] \n" + " bnz 1b \n" +#else + "1: ld %0, [%3] \n" + " brne %0, %1, 3f \n" + "2: st %2, [%3] \n" +#endif "3: \n" " .section .fixup,\"ax\" \n" "4: mov %0, %4 \n" @@ -142,7 +178,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, : "r"(oldval), "r"(newval), "r"(uaddr), "ir"(-EFAULT) : "cc", "memory"); - pagefault_enable(); /* subsumes preempt_enable() */ + pagefault_enable(); *uval = val; return val; |