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Diffstat (limited to 'arch/arc/include/asm/futex.h')
| -rw-r--r-- | arch/arc/include/asm/futex.h | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/arc/include/asm/futex.h b/arch/arc/include/asm/futex.h new file mode 100644 index 000000000..eb887dd13 --- /dev/null +++ b/arch/arc/include/asm/futex.h @@ -0,0 +1,171 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Vineetg: August 2010: From Android kernel work + */ + +#ifndef _ASM_FUTEX_H +#define _ASM_FUTEX_H + +#include <linux/futex.h> +#include <linux/preempt.h> +#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: 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" \ + " 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() \ + +#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 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, + u32 __user *uaddr) +{ + int oldval = 0, ret; + +#ifndef CONFIG_ARC_HAS_LLSC + preempt_disable(); /* to guarantee atomic r-m-w of futex op */ +#endif + pagefault_disable(); + + switch (op) { + case FUTEX_OP_SET: + __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: + __futex_atomic_op("or %0, %1, %3", ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_ANDN: + __futex_atomic_op("bic %0, %1, %3", ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_XOR: + __futex_atomic_op("xor %0, %1, %3", ret, oldval, uaddr, oparg); + break; + default: + ret = -ENOSYS; + } + + pagefault_enable(); +#ifndef CONFIG_ARC_HAS_LLSC + preempt_enable(); +#endif + + if (!ret) + *oval = oldval; + + return ret; +} + +/* + * 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 expval, + u32 newval) +{ + int ret = 0; + u32 existval; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + +#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 %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, %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"(ret), "=&r"(existval) + : "r"(expval), "r"(newval), "r"(uaddr), "ir"(-EFAULT) + : "cc", "memory"); + + smp_mb(); + +#ifndef CONFIG_ARC_HAS_LLSC + preempt_enable(); +#endif + *uval = existval; + return ret; +} + +#endif |