/arch/powerpc/include/asm/futex.h

  1#ifndef _ASM_POWERPC_FUTEX_H
  2#define _ASM_POWERPC_FUTEX_H
  3
  4#ifdef __KERNEL__
  5
  6#include <linux/futex.h>
  7#include <linux/uaccess.h>
  8#include <asm/errno.h>
  9#include <asm/synch.h>
 10#include <asm/asm-compat.h>
 11
 12#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
 13  __asm__ __volatile ( \
 14	PPC_RELEASE_BARRIER \
 15"1:	lwarx	%0,0,%2\n" \
 16	insn \
 17	PPC405_ERR77(0, %2) \
 18"2:	stwcx.	%1,0,%2\n" \
 19	"bne-	1b\n" \
 20	"li	%1,0\n" \
 21"3:	.section .fixup,\"ax\"\n" \
 22"4:	li	%1,%3\n" \
 23	"b	3b\n" \
 24	".previous\n" \
 25	".section __ex_table,\"a\"\n" \
 26	".align 3\n" \
 27	PPC_LONG "1b,4b,2b,4b\n" \
 28	".previous" \
 29	: "=&r" (oldval), "=&r" (ret) \
 30	: "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
 31	: "cr0", "memory")
 32
 33static inline int futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
 34{
 35	int op = (encoded_op >> 28) & 7;
 36	int cmp = (encoded_op >> 24) & 15;
 37	int oparg = (encoded_op << 8) >> 20;
 38	int cmparg = (encoded_op << 20) >> 20;
 39	int oldval = 0, ret;
 40	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
 41		oparg = 1 << oparg;
 42
 43	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
 44		return -EFAULT;
 45
 46	pagefault_disable();
 47
 48	switch (op) {
 49	case FUTEX_OP_SET:
 50		__futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
 51		break;
 52	case FUTEX_OP_ADD:
 53		__futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
 54		break;
 55	case FUTEX_OP_OR:
 56		__futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
 57		break;
 58	case FUTEX_OP_ANDN:
 59		__futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
 60		break;
 61	case FUTEX_OP_XOR:
 62		__futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
 63		break;
 64	default:
 65		ret = -ENOSYS;
 66	}
 67
 68	pagefault_enable();
 69
 70	if (!ret) {
 71		switch (cmp) {
 72		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
 73		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
 74		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
 75		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
 76		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
 77		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
 78		default: ret = -ENOSYS;
 79		}
 80	}
 81	return ret;
 82}
 83
 84static inline int
 85futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
 86{
 87	int prev;
 88
 89	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
 90		return -EFAULT;
 91
 92        __asm__ __volatile__ (
 93        PPC_RELEASE_BARRIER
 94"1:     lwarx   %0,0,%2         # futex_atomic_cmpxchg_inatomic\n\
 95        cmpw    0,%0,%3\n\
 96        bne-    3f\n"
 97        PPC405_ERR77(0,%2)
 98"2:     stwcx.  %4,0,%2\n\
 99        bne-    1b\n"
100        PPC_ACQUIRE_BARRIER
101"3:	.section .fixup,\"ax\"\n\
1024:	li	%0,%5\n\
103	b	3b\n\
104	.previous\n\
105	.section __ex_table,\"a\"\n\
106	.align 3\n\
107	" PPC_LONG "1b,4b,2b,4b\n\
108	.previous" \
109        : "=&r" (prev), "+m" (*uaddr)
110        : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
111        : "cc", "memory");
112
113        return prev;
114}
115
116#endif /* __KERNEL__ */
117#endif /* _ASM_POWERPC_FUTEX_H */