1 #ifndef _ASM_ARM_FUTEX_H
2 #define _ASM_ARM_FUTEX_H
6 #if defined(CONFIG_CPU_USE_DOMAINS) && defined(CONFIG_SMP)
7 /* ARM doesn't provide unprivileged exclusive memory accessors */
8 #include <asm-generic/futex.h>
11 #include <linux/futex.h>
12 #include <linux/uaccess.h>
13 #include <asm/errno.h>
15 #define __futex_atomic_ex_table(err_reg) \
17 " .pushsection __ex_table,\"a\"\n" \
19 " .long 1b, 4f, 2b, 4f\n" \
21 " .pushsection .fixup,\"ax\"\n" \
22 "4: mov %0, " err_reg "\n" \
28 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
30 __asm__ __volatile__( \
31 "1: ldrex %1, [%3]\n" \
33 "2: strex %2, %0, [%3]\n" \
37 __futex_atomic_ex_table("%5") \
38 : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \
39 : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \
43 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
44 u32 oldval, u32 newval)
49 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
53 __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
56 " ite eq @ explicit IT needed for the 2b label\n"
57 "2: strexeq %0, %3, [%4]\n"
61 __futex_atomic_ex_table("%5")
62 : "=&r" (ret), "=&r" (val)
63 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
71 #else /* !SMP, we can work around lack of atomic ops by disabling preemption */
73 #include <linux/preempt.h>
74 #include <asm/domain.h>
76 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
77 __asm__ __volatile__( \
78 "1: " TUSER(ldr) " %1, [%3]\n" \
80 "2: " TUSER(str) " %0, [%3]\n" \
82 __futex_atomic_ex_table("%5") \
83 : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \
84 : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \
88 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
89 u32 oldval, u32 newval)
94 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
97 __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
98 "1: " TUSER(ldr) " %1, [%4]\n"
100 " it eq @ explicit IT needed for the 2b label\n"
101 "2: " TUSER(streq) " %3, [%4]\n"
102 __futex_atomic_ex_table("%5")
103 : "+r" (ret), "=&r" (val)
104 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
114 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
116 int op = (encoded_op >> 28) & 7;
117 int cmp = (encoded_op >> 24) & 15;
118 int oparg = (encoded_op << 8) >> 20;
119 int cmparg = (encoded_op << 20) >> 20;
120 int oldval = 0, ret, tmp;
122 if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
125 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
128 pagefault_disable(); /* implies preempt_disable() */
132 __futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg);
135 __futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
138 __futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
141 __futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg);
144 __futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
150 pagefault_enable(); /* subsumes preempt_enable() */
154 case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
155 case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
156 case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
157 case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
158 case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
159 case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
160 default: ret = -ENOSYS;
166 #endif /* !(CPU_USE_DOMAINS && SMP) */
167 #endif /* __KERNEL__ */
168 #endif /* _ASM_ARM_FUTEX_H */