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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 | #ifndef _ASM_GENERIC_FUTEX_H
#define _ASM_GENERIC_FUTEX_H
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
#ifndef CONFIG_SMP
/*
* The following implementation only for uniprocessor machines.
* It relies on preempt_disable() ensuring mutual exclusion.
*
*/
/**
* futex_atomic_op_inuser() - Atomic arithmetic operation with constant
* argument and comparison of the previous
* futex value with another constant.
*
* @encoded_op: encoded operation to execute
* @uaddr: pointer to user space address
*
* Return:
* 0 - On success
* <0 - On error
*/
static inline int
futex_atomic_op_inuser(int encoded_op, u32 __user *uaddr)
{
int op = (encoded_op >> 28) & 7;
int cmp = (encoded_op >> 24) & 15;
int oparg = (encoded_op << 8) >> 20;
int cmparg = (encoded_op << 20) >> 20;
int oldval, ret;
u32 tmp;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
preempt_disable();
pagefault_disable();
ret = -EFAULT;
if (unlikely(get_user(oldval, uaddr) != 0))
goto out_pagefault_enable;
ret = 0;
tmp = oldval;
switch (op) {
case FUTEX_OP_SET:
tmp = oparg;
break;
case FUTEX_OP_ADD:
tmp += oparg;
break;
case FUTEX_OP_OR:
tmp |= oparg;
break;
case FUTEX_OP_ANDN:
tmp &= ~oparg;
break;
case FUTEX_OP_XOR:
tmp ^= oparg;
break;
default:
ret = -ENOSYS;
}
if (ret == 0 && unlikely(put_user(tmp, uaddr) != 0))
ret = -EFAULT;
out_pagefault_enable:
pagefault_enable();
preempt_enable();
if (ret == 0) {
switch (cmp) {
case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
default: ret = -ENOSYS;
}
}
return ret;
}
/**
* futex_atomic_cmpxchg_inatomic() - Compare and exchange the content of the
* uaddr with newval if the current value is
* oldval.
* @uval: pointer to store content of @uaddr
* @uaddr: pointer to user space address
* @oldval: old value
* @newval: new value to store to @uaddr
*
* Return:
* 0 - On success
* <0 - On error
*/
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
u32 val;
preempt_disable();
if (unlikely(get_user(val, uaddr) != 0)) {
preempt_enable();
return -EFAULT;
}
if (val == oldval && unlikely(put_user(newval, uaddr) != 0)) {
preempt_enable();
return -EFAULT;
}
*uval = val;
preempt_enable();
return 0;
}
#else
static inline int
futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
{
int op = (encoded_op >> 28) & 7;
int cmp = (encoded_op >> 24) & 15;
int oparg = (encoded_op << 8) >> 20;
int cmparg = (encoded_op << 20) >> 20;
int oldval = 0, ret;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
oparg = 1 << oparg;
if (! access_ok (VERIFY_WRITE, uaddr, sizeof(u32)))
return -EFAULT;
pagefault_disable();
switch (op) {
case FUTEX_OP_SET:
case FUTEX_OP_ADD:
case FUTEX_OP_OR:
case FUTEX_OP_ANDN:
case FUTEX_OP_XOR:
default:
ret = -ENOSYS;
}
pagefault_enable();
if (!ret) {
switch (cmp) {
case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
default: ret = -ENOSYS;
}
}
return ret;
}
static inline int
futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
u32 oldval, u32 newval)
{
return -ENOSYS;
}
#endif /* CONFIG_SMP */
#endif
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