diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-10-12 12:49:27 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-10-12 12:49:27 +0200 |
commit | 1389ac4b976abdc0555280dfc1aa2c3abcc19641 (patch) | |
tree | 1ec51aa0b1e33201f6f4f3bebc657f9ec65f8539 /arch/arm/include/asm/futex.h | |
parent | 69e13ad56f9e2cd81c4f8bfd6267211c10c14c08 (diff) | |
parent | fd048088306656824958e7783ffcee27e241b361 (diff) |
Merge branch 'linus' into x86/signal
Conflicts:
arch/x86/kernel/signal_64.c
Diffstat (limited to 'arch/arm/include/asm/futex.h')
-rw-r--r-- | arch/arm/include/asm/futex.h | 124 |
1 files changed, 121 insertions, 3 deletions
diff --git a/arch/arm/include/asm/futex.h b/arch/arm/include/asm/futex.h index 6a332a9f099..9ee743b95de 100644 --- a/arch/arm/include/asm/futex.h +++ b/arch/arm/include/asm/futex.h @@ -1,6 +1,124 @@ -#ifndef _ASM_FUTEX_H -#define _ASM_FUTEX_H +#ifndef _ASM_ARM_FUTEX_H +#define _ASM_ARM_FUTEX_H + +#ifdef __KERNEL__ + +#ifdef CONFIG_SMP #include <asm-generic/futex.h> -#endif +#else /* !SMP, we can work around lack of atomic ops by disabling preemption */ + +#include <linux/futex.h> +#include <linux/preempt.h> +#include <linux/uaccess.h> +#include <asm/errno.h> + +#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \ + __asm__ __volatile__( \ + "1: ldrt %1, [%2]\n" \ + " " insn "\n" \ + "2: strt %0, [%2]\n" \ + " mov %0, #0\n" \ + "3:\n" \ + " .section __ex_table,\"a\"\n" \ + " .align 3\n" \ + " .long 1b, 4f, 2b, 4f\n" \ + " .previous\n" \ + " .section .fixup,\"ax\"\n" \ + "4: mov %0, %4\n" \ + " b 3b\n" \ + " .previous" \ + : "=&r" (ret), "=&r" (oldval) \ + : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ + : "cc", "memory") + +static inline int +futex_atomic_op_inuser (int encoded_op, int __user *uaddr) +{ + int op = (encoded_op >> 28) & 7; + int cmp = (encoded_op >> 24) & 15; + int oparg = (encoded_op << 8) >> 20; + int cmparg = (encoded_op << 20) >> 20; + int oldval = 0, ret; + + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) + oparg = 1 << oparg; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) + return -EFAULT; + + pagefault_disable(); /* implies preempt_disable() */ + + switch (op) { + case FUTEX_OP_SET: + __futex_atomic_op("mov %0, %3", ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_ADD: + __futex_atomic_op("add %0, %1, %3", ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_OR: + __futex_atomic_op("orr %0, %1, %3", ret, oldval, uaddr, oparg); + break; + case FUTEX_OP_ANDN: + __futex_atomic_op("and %0, %1, %3", ret, oldval, uaddr, ~oparg); + break; + case FUTEX_OP_XOR: + __futex_atomic_op("eor %0, %1, %3", ret, oldval, uaddr, oparg); + break; + default: + ret = -ENOSYS; + } + + pagefault_enable(); /* subsumes preempt_enable() */ + + if (!ret) { + switch (cmp) { + case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break; + case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break; + case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break; + case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break; + case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break; + case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break; + default: ret = -ENOSYS; + } + } + return ret; +} + +static inline int +futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval) +{ + int val; + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int))) + return -EFAULT; + + pagefault_disable(); /* implies preempt_disable() */ + + __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" + "1: ldrt %0, [%3]\n" + " teq %0, %1\n" + "2: streqt %2, [%3]\n" + "3:\n" + " .section __ex_table,\"a\"\n" + " .align 3\n" + " .long 1b, 4f, 2b, 4f\n" + " .previous\n" + " .section .fixup,\"ax\"\n" + "4: mov %0, %4\n" + " b 3b\n" + " .previous" + : "=&r" (val) + : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) + : "cc", "memory"); + + pagefault_enable(); /* subsumes preempt_enable() */ + + return val; +} + +#endif /* !SMP */ + +#endif /* __KERNEL__ */ +#endif /* _ASM_ARM_FUTEX_H */ |