futex.h

  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_HEXAGON_FUTEX_H
  3#define _ASM_HEXAGON_FUTEX_H
  4
  5#ifdef __KERNEL__
  6
  7#include <linux/futex.h>
  8#include <linux/uaccess.h>
  9#include <asm/errno.h>
 10
 11/* XXX TODO-- need to add sync barriers! */
 12
 13#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
 14	__asm__ __volatile( \
 15	"1: %0 = memw_locked(%3);\n" \
 16	    /* For example: %1 = %4 */ \
 17	    insn \
 18	"2: memw_locked(%3,p2) = %1;\n" \
 19	"   if (!p2) jump 1b;\n" \
 20	"   %1 = #0;\n" \
 21	"3:\n" \
 22	".section .fixup,\"ax\"\n" \
 23	"4: %1 = #%5;\n" \
 24	"   jump ##3b\n" \
 25	".previous\n" \
 26	".section __ex_table,\"a\"\n" \
 27	".long 1b,4b,2b,4b\n" \
 28	".previous\n" \
 29	: "=&r" (oldval), "=&r" (ret), "+m" (*uaddr) \
 30	: "r" (uaddr), "r" (oparg), "i" (-EFAULT) \
 31	: "p2", "memory")
 32
 33
 34static inline int
 35arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
 36{
 37	int oldval = 0, ret;
 38
 39	if (!access_ok(uaddr, sizeof(u32)))
 40		return -EFAULT;
 41
 42	switch (op) {
 43	case FUTEX_OP_SET:
 44		__futex_atomic_op("%1 = %4\n", ret, oldval, uaddr, oparg);
 45		break;
 46	case FUTEX_OP_ADD:
 47		__futex_atomic_op("%1 = add(%0,%4)\n", ret, oldval, uaddr,
 48				  oparg);
 49		break;
 50	case FUTEX_OP_OR:
 51		__futex_atomic_op("%1 = or(%0,%4)\n", ret, oldval, uaddr,
 52				  oparg);
 53		break;
 54	case FUTEX_OP_ANDN:
 55		__futex_atomic_op("%1 = not(%4); %1 = and(%0,%1)\n", ret,
 56				  oldval, uaddr, oparg);
 57		break;
 58	case FUTEX_OP_XOR:
 59		__futex_atomic_op("%1 = xor(%0,%4)\n", ret, oldval, uaddr,
 60				  oparg);
 61		break;
 62	default:
 63		ret = -ENOSYS;
 64	}
 65
 66	if (!ret)
 67		*oval = oldval;
 68
 69	return ret;
 70}
 71
 72static inline int
 73futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, u32 oldval,
 74			      u32 newval)
 75{
 76	int prev;
 77	int ret;
 78
 79	if (!access_ok(uaddr, sizeof(u32)))
 80		return -EFAULT;
 81
 82	__asm__ __volatile__ (
 83	"1: %1 = memw_locked(%3)\n"
 84	"   {\n"
 85	"      p2 = cmp.eq(%1,%4)\n"
 86	"      if (!p2.new) jump:NT 3f\n"
 87	"   }\n"
 88	"2: memw_locked(%3,p2) = %5\n"
 89	"   if (!p2) jump 1b\n"
 90	"3:\n"
 91	".section .fixup,\"ax\"\n"
 92	"4: %0 = #%6\n"
 93	"   jump ##3b\n"
 94	".previous\n"
 95	".section __ex_table,\"a\"\n"
 96	".long 1b,4b,2b,4b\n"
 97	".previous\n"
 98	: "+r" (ret), "=&r" (prev), "+m" (*uaddr)
 99	: "r" (uaddr), "r" (oldval), "r" (newval), "i"(-EFAULT)
100	: "p2", "memory");
101
102	*uval = prev;
103	return ret;
104}
105
106#endif /* __KERNEL__ */
107#endif /* _ASM_HEXAGON_FUTEX_H */