include/asm/futex.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002
0003 #ifndef __ASM_CSKY_FUTEX_H
0004 #define __ASM_CSKY_FUTEX_H
0005
0006 #ifndef CONFIG_SMP
0007 #include <asm-generic/futex.h>
0008 #else
0009 #include <linux/atomic.h>
0010 #include <linux/futex.h>
0011 #include <linux/uaccess.h>
0012 #include <linux/errno.h>
0013
0014 #define __futex_atomic_op(insn, ret, oldval, uaddr, oparg)      \
0015 {                                   \
0016     u32 tmp;                            \
0017                                     \
0018     __atomic_pre_full_fence();                  \
0019                                     \
0020     __asm__ __volatile__ (                      \
0021     "1: ldex.w  %[ov], %[u]         \n"     \
0022     "   "insn"                  \n"     \
0023     "2: stex.w  %[t], %[u]          \n"     \
0024     "   bez %[t], 1b            \n"     \
0025     "   br  4f              \n"     \
0026     "3: mov %[r], %[e]          \n"     \
0027     "4:                     \n"     \
0028     "   .section __ex_table,\"a\"       \n"     \
0029     "   .balign 4               \n"     \
0030     "   .long   1b, 3b              \n"     \
0031     "   .long   2b, 3b              \n"     \
0032     "   .previous               \n"     \
0033     : [r] "+r" (ret), [ov] "=&r" (oldval),              \
0034       [u] "+m" (*uaddr), [t] "=&r" (tmp)                \
0035     : [op] "Jr" (oparg), [e] "jr" (-EFAULT)             \
0036     : "memory");                            \
0037                                     \
0038     __atomic_post_full_fence();                 \
0039 }
0040
0041 static inline int
0042 arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr)
0043 {
0044     int oldval = 0, ret = 0;
0045
0046     if (!access_ok(uaddr, sizeof(u32)))
0047         return -EFAULT;
0048
0049     switch (op) {
0050     case FUTEX_OP_SET:
0051         __futex_atomic_op("mov %[t], %[ov]",
0052                   ret, oldval, uaddr, oparg);
0053         break;
0054     case FUTEX_OP_ADD:
0055         __futex_atomic_op("add %[t], %[ov], %[op]",
0056                   ret, oldval, uaddr, oparg);
0057         break;
0058     case FUTEX_OP_OR:
0059         __futex_atomic_op("or %[t], %[ov], %[op]",
0060                   ret, oldval, uaddr, oparg);
0061         break;
0062     case FUTEX_OP_ANDN:
0063         __futex_atomic_op("and %[t], %[ov], %[op]",
0064                   ret, oldval, uaddr, ~oparg);
0065         break;
0066     case FUTEX_OP_XOR:
0067         __futex_atomic_op("xor %[t], %[ov], %[op]",
0068                   ret, oldval, uaddr, oparg);
0069         break;
0070     default:
0071         ret = -ENOSYS;
0072     }
0073
0074     if (!ret)
0075         *oval = oldval;
0076
0077     return ret;
0078 }
0079
0080
0081
0082 static inline int
0083 futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
0084                   u32 oldval, u32 newval)
0085 {
0086     int ret = 0;
0087     u32 val, tmp;
0088
0089     if (!access_ok(uaddr, sizeof(u32)))
0090         return -EFAULT;
0091
0092     __atomic_pre_full_fence();
0093
0094     __asm__ __volatile__ (
0095     "1: ldex.w  %[v], %[u]          \n"
0096     "   cmpne   %[v], %[ov]         \n"
0097     "   bt  4f              \n"
0098     "   mov %[t], %[nv]         \n"
0099     "2: stex.w  %[t], %[u]          \n"
0100     "   bez %[t], 1b            \n"
0101     "   br  4f              \n"
0102     "3: mov %[r], %[e]          \n"
0103     "4:                     \n"
0104     "   .section __ex_table,\"a\"       \n"
0105     "   .balign 4               \n"
0106     "   .long   1b, 3b              \n"
0107     "   .long   2b, 3b              \n"
0108     "   .previous               \n"
0109     : [r] "+r" (ret), [v] "=&r" (val), [u] "+m" (*uaddr),
0110       [t] "=&r" (tmp)
0111     : [ov] "Jr" (oldval), [nv] "Jr" (newval), [e] "Jr" (-EFAULT)
0112     : "memory");
0113
0114     __atomic_post_full_fence();
0115
0116     *uval = val;
0117     return ret;
0118 }
0119
0120 #endif /* CONFIG_SMP */
0121 #endif /* __ASM_CSKY_FUTEX_H */