Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / kernel / futex_compat.c

diff --git a/kernel/kernel/futex_compat.c b/kernel/kernel/futex_compat.c
new file mode 100644 (file)
index 0000000..55c8c93
--- /dev/null
+++ b/kernel/kernel/futex_compat.c
@@ -0,0 +1,201 @@
+/*
+ * linux/kernel/futex_compat.c
+ *
+ * Futex compatibililty routines.
+ *
+ * Copyright 2006, Red Hat, Inc., Ingo Molnar
+ */
+
+#include <linux/linkage.h>
+#include <linux/compat.h>
+#include <linux/nsproxy.h>
+#include <linux/futex.h>
+#include <linux/ptrace.h>
+#include <linux/syscalls.h>
+
+#include <asm/uaccess.h>
+
+
+/*
+ * Fetch a robust-list pointer. Bit 0 signals PI futexes:
+ */
+static inline int
+fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
+                  compat_uptr_t __user *head, unsigned int *pi)
+{
+       if (get_user(*uentry, head))
+               return -EFAULT;
+
+       *entry = compat_ptr((*uentry) & ~1);
+       *pi = (unsigned int)(*uentry) & 1;
+
+       return 0;
+}
+
+static void __user *futex_uaddr(struct robust_list __user *entry,
+                               compat_long_t futex_offset)
+{
+       compat_uptr_t base = ptr_to_compat(entry);
+       void __user *uaddr = compat_ptr(base + futex_offset);
+
+       return uaddr;
+}
+
+/*
+ * Walk curr->robust_list (very carefully, it's a userspace list!)
+ * and mark any locks found there dead, and notify any waiters.
+ *
+ * We silently return on any sign of list-walking problem.
+ */
+void compat_exit_robust_list(struct task_struct *curr)
+{
+       struct compat_robust_list_head __user *head = curr->compat_robust_list;
+       struct robust_list __user *entry, *next_entry, *pending;
+       unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+       unsigned int uninitialized_var(next_pi);
+       compat_uptr_t uentry, next_uentry, upending;
+       compat_long_t futex_offset;
+       int rc;
+
+       if (!futex_cmpxchg_enabled)
+               return;
+
+       /*
+        * Fetch the list head (which was registered earlier, via
+        * sys_set_robust_list()):
+        */
+       if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
+               return;
+       /*
+        * Fetch the relative futex offset:
+        */
+       if (get_user(futex_offset, &head->futex_offset))
+               return;
+       /*
+        * Fetch any possibly pending lock-add first, and handle it
+        * if it exists:
+        */
+       if (fetch_robust_entry(&upending, &pending,
+                              &head->list_op_pending, &pip))
+               return;
+
+       next_entry = NULL;      /* avoid warning with gcc */
+       while (entry != (struct robust_list __user *) &head->list) {
+               /*
+                * Fetch the next entry in the list before calling
+                * handle_futex_death:
+                */
+               rc = fetch_robust_entry(&next_uentry, &next_entry,
+                       (compat_uptr_t __user *)&entry->next, &next_pi);
+               /*
+                * A pending lock might already be on the list, so
+                * dont process it twice:
+                */
+               if (entry != pending) {
+                       void __user *uaddr = futex_uaddr(entry, futex_offset);
+
+                       if (handle_futex_death(uaddr, curr, pi))
+                               return;
+               }
+               if (rc)
+                       return;
+               uentry = next_uentry;
+               entry = next_entry;
+               pi = next_pi;
+               /*
+                * Avoid excessively long or circular lists:
+                */
+               if (!--limit)
+                       break;
+
+               cond_resched();
+       }
+       if (pending) {
+               void __user *uaddr = futex_uaddr(pending, futex_offset);
+
+               handle_futex_death(uaddr, curr, pip);
+       }
+}
+
+COMPAT_SYSCALL_DEFINE2(set_robust_list,
+               struct compat_robust_list_head __user *, head,
+               compat_size_t, len)
+{
+       if (!futex_cmpxchg_enabled)
+               return -ENOSYS;
+
+       if (unlikely(len != sizeof(*head)))
+               return -EINVAL;
+
+       current->compat_robust_list = head;
+
+       return 0;
+}
+
+COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
+                       compat_uptr_t __user *, head_ptr,
+                       compat_size_t __user *, len_ptr)
+{
+       struct compat_robust_list_head __user *head;
+       unsigned long ret;
+       struct task_struct *p;
+
+       if (!futex_cmpxchg_enabled)
+               return -ENOSYS;
+
+       rcu_read_lock();
+
+       ret = -ESRCH;
+       if (!pid)
+               p = current;
+       else {
+               p = find_task_by_vpid(pid);
+               if (!p)
+                       goto err_unlock;
+       }
+
+       ret = -EPERM;
+       if (!ptrace_may_access(p, PTRACE_MODE_READ))
+               goto err_unlock;
+
+       head = p->compat_robust_list;
+       rcu_read_unlock();
+
+       if (put_user(sizeof(*head), len_ptr))
+               return -EFAULT;
+       return put_user(ptr_to_compat(head), head_ptr);
+
+err_unlock:
+       rcu_read_unlock();
+
+       return ret;
+}
+
+COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
+               struct compat_timespec __user *, utime, u32 __user *, uaddr2,
+               u32, val3)
+{
+       struct timespec ts;
+       ktime_t t, *tp = NULL;
+       int val2 = 0;
+       int cmd = op & FUTEX_CMD_MASK;
+
+       if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
+                     cmd == FUTEX_WAIT_BITSET ||
+                     cmd == FUTEX_WAIT_REQUEUE_PI)) {
+               if (compat_get_timespec(&ts, utime))
+                       return -EFAULT;
+               if (!timespec_valid(&ts))
+                       return -EINVAL;
+
+               t = timespec_to_ktime(ts);
+               if (cmd == FUTEX_WAIT)
+                       t = ktime_add_safe(ktime_get(), t);
+               tp = &t;
+       }
+       if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
+           cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
+               val2 = (int) (unsigned long) utime;
+
+       return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
+}