diff options
Diffstat (limited to 'arch/arc/include/asm/futex.h')
| -rw-r--r-- | arch/arc/include/asm/futex.h | 72 |
1 files changed, 43 insertions, 29 deletions
diff --git a/arch/arc/include/asm/futex.h b/arch/arc/include/asm/futex.h index 70cfe16b742d..11e1b1f3acda 100644 --- a/arch/arc/include/asm/futex.h +++ b/arch/arc/include/asm/futex.h @@ -20,6 +20,7 @@ #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ \ + smp_mb(); \ __asm__ __volatile__( \ "1: llock %1, [%2] \n" \ insn "\n" \ @@ -30,7 +31,7 @@ " .section .fixup,\"ax\" \n" \ " .align 4 \n" \ "4: mov %0, %4 \n" \ - " b 3b \n" \ + " j 3b \n" \ " .previous \n" \ " .section __ex_table,\"a\" \n" \ " .align 4 \n" \ @@ -40,12 +41,14 @@ \ : "=&r" (ret), "=&r" (oldval) \ : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + smp_mb() \ #else /* !CONFIG_ARC_HAS_LLSC */ #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ \ + smp_mb(); \ __asm__ __volatile__( \ "1: ld %1, [%2] \n" \ insn "\n" \ @@ -55,7 +58,7 @@ " .section .fixup,\"ax\" \n" \ " .align 4 \n" \ "4: mov %0, %4 \n" \ - " b 3b \n" \ + " j 3b \n" \ " .previous \n" \ " .section __ex_table,\"a\" \n" \ " .align 4 \n" \ @@ -65,7 +68,8 @@ \ : "=&r" (ret), "=&r" (oldval) \ : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ - : "cc", "memory") + : "cc", "memory"); \ + smp_mb() \ #endif @@ -83,6 +87,9 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) return -EFAULT; +#ifndef CONFIG_ARC_HAS_LLSC + preempt_disable(); /* to guarantee atomic r-m-w of futex op */ +#endif pagefault_disable(); switch (op) { @@ -90,6 +97,7 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg); break; case FUTEX_OP_ADD: + /* oldval = *uaddr; *uaddr += oparg ; ret = *uaddr */ __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg); break; case FUTEX_OP_OR: @@ -106,6 +114,9 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) } pagefault_enable(); +#ifndef CONFIG_ARC_HAS_LLSC + preempt_enable(); +#endif if (!ret) { switch (cmp) { @@ -134,54 +145,57 @@ static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) return ret; } -/* Compare-xchg with pagefaults disabled. - * Notes: - * -Best-Effort: Exchg happens only if compare succeeds. - * If compare fails, returns; leaving retry/looping to upper layers - * -successful cmp-xchg: return orig value in @addr (same as cmp val) - * -Compare fails: return orig value in @addr - * -user access r/w fails: return -EFAULT +/* + * cmpxchg of futex (pagefaults disabled by caller) + * Return 0 for success, -EFAULT otherwise */ static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval, - u32 newval) +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 expval, + u32 newval) { - u32 val; + int ret = 0; + u32 existval; - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) return -EFAULT; - pagefault_disable(); +#ifndef CONFIG_ARC_HAS_LLSC + preempt_disable(); /* to guarantee atomic r-m-w of futex op */ +#endif + smp_mb(); __asm__ __volatile__( #ifdef CONFIG_ARC_HAS_LLSC - "1: llock %0, [%3] \n" - " brne %0, %1, 3f \n" - "2: scond %2, [%3] \n" + "1: llock %1, [%4] \n" + " brne %1, %2, 3f \n" + "2: scond %3, [%4] \n" " bnz 1b \n" #else - "1: ld %0, [%3] \n" - " brne %0, %1, 3f \n" - "2: st %2, [%3] \n" + "1: ld %1, [%4] \n" + " brne %1, %2, 3f \n" + "2: st %3, [%4] \n" #endif "3: \n" " .section .fixup,\"ax\" \n" - "4: mov %0, %4 \n" - " b 3b \n" + "4: mov %0, %5 \n" + " j 3b \n" " .previous \n" " .section __ex_table,\"a\" \n" " .align 4 \n" " .word 1b, 4b \n" " .word 2b, 4b \n" " .previous\n" - : "=&r"(val) - : "r"(oldval), "r"(newval), "r"(uaddr), "ir"(-EFAULT) + : "+&r"(ret), "=&r"(existval) + : "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT) : "cc", "memory"); - pagefault_enable(); + smp_mb(); - *uval = val; - return val; +#ifndef CONFIG_ARC_HAS_LLSC + preempt_enable(); +#endif + *uval = existval; + return ret; } #endif |
