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-rw-r--r--kernel/futex.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index f50b434756c1..3d38eaf05492 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -876,6 +876,8 @@ static struct task_struct *futex_find_get_task(pid_t pid)
return p;
}
+#ifdef CONFIG_FUTEX_PI
+
/*
* This task is holding PI mutexes at exit time => bad.
* Kernel cleans up PI-state, but userspace is likely hosed.
@@ -933,6 +935,8 @@ void exit_pi_state_list(struct task_struct *curr)
raw_spin_unlock_irq(&curr->pi_lock);
}
+#endif
+
/*
* We need to check the following states:
*
@@ -1547,6 +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:
@@ -1800,6 +1843,15 @@ static int futex_requeue(u32 __user *uaddr1, unsigned int flags,
struct futex_q *this, *next;
DEFINE_WAKE_Q(wake_q);
+ /*
+ * When PI not supported: return -ENOSYS if requeue_pi is true,
+ * consequently the compiler knows requeue_pi is always false past
+ * this point which will optimize away all the conditional code
+ * further down.
+ */
+ if (!IS_ENABLED(CONFIG_FUTEX_PI) && requeue_pi)
+ return -ENOSYS;
+
if (requeue_pi) {
/*
* Requeue PI only works on two distinct uaddrs. This
@@ -2595,6 +2647,9 @@ static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
struct futex_q q = futex_q_init;
int res, ret;
+ if (!IS_ENABLED(CONFIG_FUTEX_PI))
+ return -ENOSYS;
+
if (refill_pi_state_cache())
return -ENOMEM;
@@ -2774,6 +2829,9 @@ static int futex_unlock_pi(u32 __user *uaddr, unsigned int flags)
struct futex_q *top_waiter;
int ret;
+ if (!IS_ENABLED(CONFIG_FUTEX_PI))
+ return -ENOSYS;
+
retry:
if (get_user(uval, uaddr))
return -EFAULT;
@@ -2984,6 +3042,9 @@ static int futex_wait_requeue_pi(u32 __user *uaddr, unsigned int flags,
struct futex_q q = futex_q_init;
int res, ret;
+ if (!IS_ENABLED(CONFIG_FUTEX_PI))
+ return -ENOSYS;
+
if (uaddr == uaddr2)
return -EINVAL;