1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (C) 2012 ARM Ltd.
8 #include <linux/futex.h>
9 #include <linux/uaccess.h>
11 #include <asm/errno.h>
13 #define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */
15 #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \
17 unsigned int loops = FUTEX_MAX_LOOPS; \
19 uaccess_enable_privileged(); \
21 " prfm pstl1strm, %2\n" \
24 "2: stlxr %w0, %w3, %2\n" \
26 " sub %w4, %w4, %w0\n" \
31 _ASM_EXTABLE_UACCESS_ERR(1b, 3b, %w0) \
32 _ASM_EXTABLE_UACCESS_ERR(2b, 3b, %w0) \
33 : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \
35 : "r" (oparg), "Ir" (-EAGAIN) \
37 uaccess_disable_privileged(); \
41 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr)
43 int oldval = 0, ret, tmp;
44 u32 __user *uaddr = __uaccess_mask_ptr(_uaddr);
46 if (!access_ok(_uaddr, sizeof(u32)))
51 __futex_atomic_op("mov %w3, %w5",
52 ret, oldval, uaddr, tmp, oparg);
55 __futex_atomic_op("add %w3, %w1, %w5",
56 ret, oldval, uaddr, tmp, oparg);
59 __futex_atomic_op("orr %w3, %w1, %w5",
60 ret, oldval, uaddr, tmp, oparg);
63 __futex_atomic_op("and %w3, %w1, %w5",
64 ret, oldval, uaddr, tmp, ~oparg);
67 __futex_atomic_op("eor %w3, %w1, %w5",
68 ret, oldval, uaddr, tmp, oparg);
81 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr,
82 u32 oldval, u32 newval)
85 unsigned int loops = FUTEX_MAX_LOOPS;
89 if (!access_ok(_uaddr, sizeof(u32)))
92 uaddr = __uaccess_mask_ptr(_uaddr);
93 uaccess_enable_privileged();
94 asm volatile("// futex_atomic_cmpxchg_inatomic\n"
95 " prfm pstl1strm, %2\n"
97 " sub %w3, %w1, %w5\n"
99 "2: stlxr %w3, %w6, %2\n"
101 " sub %w4, %w4, %w3\n"
107 _ASM_EXTABLE_UACCESS_ERR(1b, 4b, %w0)
108 _ASM_EXTABLE_UACCESS_ERR(2b, 4b, %w0)
109 : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops)
110 : "r" (oldval), "r" (newval), "Ir" (-EAGAIN)
112 uaccess_disable_privileged();
120 #endif /* __ASM_FUTEX_H */