1 #ifndef _ASM_ARM_FUTEX_H
2 #define _ASM_ARM_FUTEX_H
6 #include <linux/futex.h>
7 #include <linux/uaccess.h>
10 #define __futex_atomic_ex_table(err_reg) \
12 " .pushsection __ex_table,\"a\"\n" \
14 " .long 1b, 4f, 2b, 4f\n" \
16 " .pushsection .text.fixup,\"ax\"\n" \
18 "4: mov %0, " err_reg "\n" \
24 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
26 unsigned int __ua_flags; \
29 __ua_flags = uaccess_save_and_enable(); \
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) \
41 uaccess_restore(__ua_flags); \
45 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
46 u32 oldval, u32 newval)
48 unsigned int __ua_flags;
52 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
56 /* Prefetching cannot fault */
58 __ua_flags = uaccess_save_and_enable();
59 __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
62 " ite eq @ explicit IT needed for the 2b label\n"
63 "2: strexeq %0, %3, [%4]\n"
67 __futex_atomic_ex_table("%5")
68 : "=&r" (ret), "=&r" (val)
69 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
71 uaccess_restore(__ua_flags);
78 #else /* !SMP, we can work around lack of atomic ops by disabling preemption */
80 #include <linux/preempt.h>
81 #include <asm/domain.h>
83 #define __futex_atomic_op(insn, ret, oldval, tmp, uaddr, oparg) \
85 unsigned int __ua_flags = uaccess_save_and_enable(); \
86 __asm__ __volatile__( \
87 "1: " TUSER(ldr) " %1, [%3]\n" \
89 "2: " TUSER(str) " %0, [%3]\n" \
91 __futex_atomic_ex_table("%5") \
92 : "=&r" (ret), "=&r" (oldval), "=&r" (tmp) \
93 : "r" (uaddr), "r" (oparg), "Ir" (-EFAULT) \
95 uaccess_restore(__ua_flags); \
99 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
100 u32 oldval, u32 newval)
102 unsigned int __ua_flags;
106 if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
110 __ua_flags = uaccess_save_and_enable();
111 __asm__ __volatile__("@futex_atomic_cmpxchg_inatomic\n"
112 "1: " TUSER(ldr) " %1, [%4]\n"
114 " it eq @ explicit IT needed for the 2b label\n"
115 "2: " TUSER(streq) " %3, [%4]\n"
116 __futex_atomic_ex_table("%5")
117 : "+r" (ret), "=&r" (val)
118 : "r" (oldval), "r" (newval), "r" (uaddr), "Ir" (-EFAULT)
120 uaccess_restore(__ua_flags);
131 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
133 int oldval = 0, ret, tmp;
142 __futex_atomic_op("mov %0, %4", ret, oldval, tmp, uaddr, oparg);
145 __futex_atomic_op("add %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
148 __futex_atomic_op("orr %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
151 __futex_atomic_op("and %0, %1, %4", ret, oldval, tmp, uaddr, ~oparg);
154 __futex_atomic_op("eor %0, %1, %4", ret, oldval, tmp, uaddr, oparg);
166 * Store unconditionally. If ret != 0 the extra store is the least
167 * of the worries but GCC cannot figure out that __futex_atomic_op()
168 * is either setting ret to -EFAULT or storing the old value in
169 * oldval which results in a uninitialized warning at the call site.
176 #endif /* __KERNEL__ */
177 #endif /* _ASM_ARM_FUTEX_H */