#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" \
" .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"
" it eq @ explicit IT needed for the 2b label\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 */
