diff options
Diffstat (limited to 'kernel/futex.c')
| -rw-r--r-- | kernel/futex.c | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c index 0939255fc750..3d38eaf05492 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -1551,6 +1551,45 @@ out: return ret; } +static int futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr) +{ + unsigned int op = (encoded_op & 0x70000000) >> 28; + unsigned int cmp = (encoded_op & 0x0f000000) >> 24; + int oparg = sign_extend32((encoded_op & 0x00fff000) >> 12, 12); + int cmparg = sign_extend32(encoded_op & 0x00000fff, 12); + int oldval, ret; + + if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) { + if (oparg < 0 || oparg > 31) + return -EINVAL; + oparg = 1 << oparg; + } + + if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + return -EFAULT; + + ret = arch_futex_atomic_op_inuser(op, oparg, &oldval, uaddr); + if (ret) + return ret; + + switch (cmp) { + case FUTEX_OP_CMP_EQ: + return oldval == cmparg; + case FUTEX_OP_CMP_NE: + return oldval != cmparg; + case FUTEX_OP_CMP_LT: + return oldval < cmparg; + case FUTEX_OP_CMP_GE: + return oldval >= cmparg; + case FUTEX_OP_CMP_LE: + return oldval <= cmparg; + case FUTEX_OP_CMP_GT: + return oldval > cmparg; + default: + return -ENOSYS; + } +} + /* * Wake up all waiters hashed on the physical page that is mapped * to this virtual address: |