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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_FUTEX_H
#define _ASM_X86_FUTEX_H
#ifdef __KERNEL__
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/asm.h>
#include <asm/errno.h>
#include <asm/processor.h>
#include <asm/smap.h>
#define unsafe_atomic_op1(insn, oval, uaddr, oparg, label) \
do { \
int oldval = 0, ret; \
asm volatile("1:\t" insn "\n" \
"2:\n" \
"\t.section .fixup,\"ax\"\n" \
"3:\tmov\t%3, %1\n" \
"\tjmp\t2b\n" \
"\t.previous\n" \
_ASM_EXTABLE_UA(1b, 3b) \
: "=r" (oldval), "=r" (ret), "+m" (*uaddr) \
: "i" (-EFAULT), "0" (oparg), "1" (0)); \
if (ret) \
goto label; \
*oval = oldval; \
} while(0)
#define unsafe_atomic_op2(insn, oval, uaddr, oparg, label) \
do { \
int oldval = 0, ret, tem; \
asm volatile("1:\tmovl %2, %0\n" \
"2:\tmovl\t%0, %3\n" \
"\t" insn "\n" \
"3:\t" LOCK_PREFIX "cmpxchgl %3, %2\n" \
"\tjnz\t2b\n" \
"4:\n" \
"\t.section .fixup,\"ax\"\n" \
"5:\tmov\t%5, %1\n" \
"\tjmp\t4b\n" \
"\t.previous\n" \
_ASM_EXTABLE_UA(1b, 5b) \
_ASM_EXTABLE_UA(3b, 5b) \
: "=&a" (oldval), "=&r" (ret), \
"+m" (*uaddr), "=&r" (tem) \
: "r" (oparg), "i" (-EFAULT), "1" (0)); \
if (ret) \
goto label; \
*oval = oldval; \
} while(0)
static __always_inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
u32 __user *uaddr)
{
if (!user_access_begin(uaddr, sizeof(u32)))
return -EFAULT;
switch (op) {
case FUTEX_OP_SET:
unsafe_atomic_op1("xchgl %0, %2", oval, uaddr, oparg, Efault);
break;
case FUTEX_OP_ADD:
unsafe_atomic_op1(LOCK_PREFIX "xaddl %0, %2", oval,
uaddr, oparg, Efault);
break;
case FUTEX_OP_OR:
unsafe_atomic_op2("orl %4, %3", oval, uaddr, oparg, Efault);
break;
case FUTEX_OP_ANDN:
unsafe_atomic_op2("andl %4, %3", oval, uaddr, ~oparg, Efault);
break;
case FUTEX_OP_XOR:
unsafe_atomic_op2("xorl %4, %3", oval, uaddr, oparg, Efault);
break;
default:
user_access_end();
return -ENOSYS;
}
user_access_end();
return 0;
Efault:
user_access_end();
return -EFAULT;
}
static inline int futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
int ret = 0;
if (!user_access_begin(uaddr, sizeof(u32)))
return -EFAULT;
asm volatile("\n"
"1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"
"2:\n"
"\t.section .fixup, \"ax\"\n"
"3:\tmov %3, %0\n"
"\tjmp 2b\n"
"\t.previous\n"
_ASM_EXTABLE_UA(1b, 3b)
: "+r" (ret), "=a" (oldval), "+m" (*uaddr)
: "i" (-EFAULT), "r" (newval), "1" (oldval)
: "memory"
);
user_access_end();
*uval = oldval;
return ret;
}
#endif
#endif /* _ASM_X86_FUTEX_H */
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