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180 lines
4.3 KiB
180 lines
4.3 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#ifndef _ASM_ARM_FUTEX_H |
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#define _ASM_ARM_FUTEX_H |
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#ifdef __KERNEL__ |
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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_atomic_ex_table(err_reg) \ |
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"3:\n" \ |
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" .pushsection __ex_table,\"a\"\n" \ |
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" .align 3\n" \ |
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" .long 1b, 4f, 2b, 4f\n" \ |
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" .popsection\n" \ |
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" .pushsection .text.fixup,\"ax\"\n" \ |
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" .align 2\n" \ |
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"4: mov %0, " err_reg "\n" \ |
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" b 3b\n" \ |
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" .popsection" |
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#ifdef CONFIG_SMP |
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#define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ |
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({ \ |
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unsigned int __ua_flags; \ |
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smp_mb(); \ |
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prefetchw(uaddr); \ |
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__ua_flags = uaccess_save_and_enable(); \ |
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__asm__ __volatile__( \ |
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"1: ldrex %1, [%3]\n" \ |
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" " insn "\n" \ |
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"2: strex %2, %0, [%3]\n" \ |
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" teq %2, #0\n" \ |
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" bne 1b\n" \ |
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" mov %0, #0\n" \ |
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__futex_atomic_ex_table("%5") \ |
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: "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ |
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: "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ |
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: "cc", "memory"); \ |
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uaccess_restore(__ua_flags); \ |
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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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unsigned int __ua_flags; |
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int ret; |
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u32 val; |
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if (!access_ok(uaddr, sizeof(u32))) |
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return -EFAULT; |
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smp_mb(); |
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/* Prefetching cannot fault */ |
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prefetchw(uaddr); |
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__ua_flags = uaccess_save_and_enable(); |
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__asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" |
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"1: ldrex %1, [%4]\n" |
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" teq %1, %2\n" |
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" ite eq @ explicit IT needed for the 2b label\n" |
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"2: strexeq %0, %3, [%4]\n" |
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" movne %0, #0\n" |
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" teq %0, #0\n" |
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" bne 1b\n" |
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__futex_atomic_ex_table("%5") |
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: "=&r" (ret), "=&r" (val) |
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: "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) |
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: "cc", "memory"); |
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uaccess_restore(__ua_flags); |
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smp_mb(); |
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*uval = val; |
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return ret; |
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} |
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#else /* !SMP, we can work around lack of atomic ops by disabling preemption */ |
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#include <linux/preempt.h> |
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#include <asm/domain.h> |
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#define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \ |
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({ \ |
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unsigned int __ua_flags = uaccess_save_and_enable(); \ |
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__asm__ __volatile__( \ |
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"1: " TUSER(ldr) " %1, [%3]\n" \ |
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" " insn "\n" \ |
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"2: " TUSER(str) " %0, [%3]\n" \ |
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" mov %0, #0\n" \ |
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__futex_atomic_ex_table("%5") \ |
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: "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \ |
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: "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \ |
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: "cc", "memory"); \ |
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uaccess_restore(__ua_flags); \ |
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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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unsigned int __ua_flags; |
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int ret = 0; |
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u32 val; |
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if (!access_ok(uaddr, sizeof(u32))) |
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return -EFAULT; |
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preempt_disable(); |
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__ua_flags = uaccess_save_and_enable(); |
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__asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n" |
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" .syntax unified\n" |
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"1: " TUSER(ldr) " %1, [%4]\n" |
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" teq %1, %2\n" |
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" it eq @ explicit IT needed for the 2b label\n" |
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"2: " TUSERCOND(str, eq) " %3, [%4]\n" |
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__futex_atomic_ex_table("%5") |
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: "+r" (ret), "=&r" (val) |
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: "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT) |
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: "cc", "memory"); |
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uaccess_restore(__ua_flags); |
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*uval = val; |
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preempt_enable(); |
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return ret; |
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} |
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#endif /* !SMP */ |
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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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if (!access_ok(uaddr, sizeof(u32))) |
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return -EFAULT; |
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#ifndef CONFIG_SMP |
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preempt_disable(); |
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#endif |
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switch (op) { |
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case FUTEX_OP_SET: |
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__futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg); |
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break; |
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case FUTEX_OP_ADD: |
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__futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg); |
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break; |
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case FUTEX_OP_OR: |
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__futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg); |
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break; |
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case FUTEX_OP_ANDN: |
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__futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg); |
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break; |
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case FUTEX_OP_XOR: |
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__futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, 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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#ifndef CONFIG_SMP |
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preempt_enable(); |
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#endif |
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/* |
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* Store unconditionally. If ret != 0 the extra store is the least |
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* of the worries but GCC cannot figure out that __futex_atomic_op() |
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* is either setting ret to -EFAULT or storing the old value in |
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* oldval which results in a uninitialized warning at the call site. |
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*/ |
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*oval = oldval; |
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return ret; |
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} |
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#endif /* __KERNEL__ */ |
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#endif /* _ASM_ARM_FUTEX_H */
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