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| /* SPDX-License-Identifier: GPL-2.0-only */
| /*
| * Copyright (C) 2012 ARM Ltd.
| */
| #ifndef __ASM_FUTEX_H
| #define __ASM_FUTEX_H
|
| #include <linux/futex.h>
| #include <linux/uaccess.h>
|
| #include <asm/errno.h>
|
| #define FUTEX_MAX_LOOPS 128 /* What's the largest number you can think of? */
|
| #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg) \
| do { \
| unsigned int loops = FUTEX_MAX_LOOPS; \
| \
| uaccess_enable_privileged(); \
| asm volatile( \
| " prfm pstl1strm, %2\n" \
| "1: ldxr %w1, %2\n" \
| insn "\n" \
| "2: stlxr %w0, %w3, %2\n" \
| " cbz %w0, 3f\n" \
| " sub %w4, %w4, %w0\n" \
| " cbnz %w4, 1b\n" \
| " mov %w0, %w7\n" \
| "3:\n" \
| " dmb ish\n" \
| " .pushsection .fixup,\"ax\"\n" \
| " .align 2\n" \
| "4: mov %w0, %w6\n" \
| " b 3b\n" \
| " .popsection\n" \
| _ASM_EXTABLE(1b, 4b) \
| _ASM_EXTABLE(2b, 4b) \
| : "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp), \
| "+r" (loops) \
| : "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN) \
| : "memory"); \
| uaccess_disable_privileged(); \
| } while (0)
|
| static inline int
| arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr)
| {
| int oldval = 0, ret, tmp;
| u32 __user *uaddr = __uaccess_mask_ptr(_uaddr);
|
| if (!access_ok(_uaddr, sizeof(u32)))
| return -EFAULT;
|
| switch (op) {
| case FUTEX_OP_SET:
| __futex_atomic_op("mov %w3, %w5",
| ret, oldval, uaddr, tmp, oparg);
| break;
| case FUTEX_OP_ADD:
| __futex_atomic_op("add %w3, %w1, %w5",
| ret, oldval, uaddr, tmp, oparg);
| break;
| case FUTEX_OP_OR:
| __futex_atomic_op("orr %w3, %w1, %w5",
| ret, oldval, uaddr, tmp, oparg);
| break;
| case FUTEX_OP_ANDN:
| __futex_atomic_op("and %w3, %w1, %w5",
| ret, oldval, uaddr, tmp, ~oparg);
| break;
| case FUTEX_OP_XOR:
| __futex_atomic_op("eor %w3, %w1, %w5",
| ret, oldval, uaddr, tmp, oparg);
| break;
| default:
| ret = -ENOSYS;
| }
|
| if (!ret)
| *oval = oldval;
|
| return ret;
| }
|
| static inline int
| futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr,
| u32 oldval, u32 newval)
| {
| int ret = 0;
| unsigned int loops = FUTEX_MAX_LOOPS;
| u32 val, tmp;
| u32 __user *uaddr;
|
| if (!access_ok(_uaddr, sizeof(u32)))
| return -EFAULT;
|
| uaddr = __uaccess_mask_ptr(_uaddr);
| uaccess_enable_privileged();
| asm volatile("// futex_atomic_cmpxchg_inatomic\n"
| " prfm pstl1strm, %2\n"
| "1: ldxr %w1, %2\n"
| " sub %w3, %w1, %w5\n"
| " cbnz %w3, 4f\n"
| "2: stlxr %w3, %w6, %2\n"
| " cbz %w3, 3f\n"
| " sub %w4, %w4, %w3\n"
| " cbnz %w4, 1b\n"
| " mov %w0, %w8\n"
| "3:\n"
| " dmb ish\n"
| "4:\n"
| " .pushsection .fixup,\"ax\"\n"
| "5: mov %w0, %w7\n"
| " b 4b\n"
| " .popsection\n"
| _ASM_EXTABLE(1b, 5b)
| _ASM_EXTABLE(2b, 5b)
| : "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops)
| : "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN)
| : "memory");
| uaccess_disable_privileged();
|
| if (!ret)
| *uval = val;
|
| return ret;
| }
|
| #endif /* __ASM_FUTEX_H */
|
|
