diff options
Diffstat (limited to 'kernel/arch/arc/include/asm/futex.h')
| -rw-r--r-- | kernel/arch/arc/include/asm/futex.h | 104 |
1 files changed, 77 insertions, 27 deletions
diff --git a/kernel/arch/arc/include/asm/futex.h b/kernel/arch/arc/include/asm/futex.h index 05b5aaf5b..11e1b1f3a 100644 --- a/kernel/arch/arc/include/asm/futex.h +++ b/kernel/arch/arc/include/asm/futex.h @@ -16,18 +16,22 @@ #include <linux/uaccess.h> #include <asm/errno.h> +#ifdef CONFIG_ARC_HAS_LLSC + #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)\ \ + smp_mb(); \ __asm__ __volatile__( \ - "1: ld %1, [%2] \n" \ + "1: llock %1, [%2] \n" \ insn "\n" \ - "2: st %0, [%2] \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" \ + " j 3b \n" \ " .previous \n" \ " .section __ex_table,\"a\" \n" \ " .align 4 \n" \ @@ -37,7 +41,37 @@ \ : "=&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" \ + "2: st %0, [%2] \n" \ + " mov %0, 0 \n" \ + "3: \n" \ + " .section .fixup,\"ax\" \n" \ + " .align 4 \n" \ + "4: mov %0, %4 \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" (ret), "=&r" (oldval) \ + : "r" (uaddr), "r" (oparg), "ir" (-EFAULT) \ + : "cc", "memory"); \ + smp_mb() \ + +#endif static inline int futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr) { @@ -53,6 +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) { @@ -60,6 +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: @@ -76,6 +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) { @@ -104,48 +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(); - /* 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 %1, [%4] \n" + " brne %1, %2, 3f \n" + "2: scond %3, [%4] \n" + " bnz 1b \n" +#else + "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 |