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