#ifndef _ASM_ARM_FUTEX_H #define _ASM_ARM_FUTEX_H #ifdef __KERNEL__ #ifdef CONFIG_SMP #include <asm-generic/futex.h> #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" \ " .pushsection __ex_table,\"a\"\n" \ " .align 3\n" \ " .long 1b, 4f, 2b, 4f\n" \ " .popsection\n" \ " .pushsection .fixup,\"ax\"\n" \ "4: mov %0, %4\n" \ " b 3b\n" \ " .popsection" \ : "=&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" " it eq @ explicit IT needed for the 2b label\n" "2: streqt %2, [%3]\n" "3:\n" " .pushsection __ex_table,\"a\"\n" " .align 3\n" " .long 1b, 4f, 2b, 4f\n" " .popsection\n" " .pushsection .fixup,\"ax\"\n" "4: mov %0, %4\n" " b 3b\n" " .popsection" : "=&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 */