1 /* SPDX-License-Identifier: GPL-2.0-only */
3 * Copyright (C) 2012 ARM Ltd.
10 #include <linux/futex.h>
11 #include <linux/uaccess.h>
13 #include <asm/errno.h>
15 #define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */
17 #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \
19 unsigned int loops = FUTEX_MAX_LOOPS; \
23 " prfm pstl1strm, %2\n" \
26 "2: stlxr %w0, %w3, %2\n" \
28 " sub %w4, %w4, %w0\n" \
33 " .pushsection .fixup,\"ax\"\n" \
38 _ASM_EXTABLE(1b, 4b) \
39 _ASM_EXTABLE(2b, 4b) \
40 : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \
42 : "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN) \
48 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr)
50 int oldval = 0, ret, tmp;
51 u32 __user *uaddr = __uaccess_mask_ptr(_uaddr);
57 __futex_atomic_op("mov %w3, %w5",
58 ret, oldval, uaddr, tmp, oparg);
61 __futex_atomic_op("add %w3, %w1, %w5",
62 ret, oldval, uaddr, tmp, oparg);
65 __futex_atomic_op("orr %w3, %w1, %w5",
66 ret, oldval, uaddr, tmp, oparg);
69 __futex_atomic_op("and %w3, %w1, %w5",
70 ret, oldval, uaddr, tmp, ~oparg);
73 __futex_atomic_op("eor %w3, %w1, %w5",
74 ret, oldval, uaddr, tmp, oparg);
89 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr,
90 u32 oldval, u32 newval)
93 unsigned int loops = FUTEX_MAX_LOOPS;
97 if (!access_ok(_uaddr, sizeof(u32)))
100 uaddr = __uaccess_mask_ptr(_uaddr);
102 asm volatile("// futex_atomic_cmpxchg_inatomic\n"
103 " prfm pstl1strm, %2\n"
105 " sub %w3, %w1, %w5\n"
107 "2: stlxr %w3, %w6, %2\n"
109 " sub %w4, %w4, %w3\n"
115 " .pushsection .fixup,\"ax\"\n"
121 : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops)
122 : "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN)
132 #endif /* __KERNEL__ */
133 #endif /* __ASM_FUTEX_H */