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authorDavid S. Miller <davem@davemloft.net>2010-10-06 19:39:31 -0700
committerDavid S. Miller <davem@davemloft.net>2010-10-06 19:39:31 -0700
commit69259abb64d4da77273bf59accfc9fa79e7165f4 (patch)
treebd043ab03a788b749c8d5ae4049d8defae9abf34 /kernel/compat.c
parentdd53df265b1ee7a1fbbc76bb62c3bec2383bbd44 (diff)
parent12e94471b2be5ef9b55b10004a3a2cd819490036 (diff)
downloadlinux-rt-69259abb64d4da77273bf59accfc9fa79e7165f4.tar.gz
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
Conflicts: drivers/net/pcmcia/pcnet_cs.c net/caif/caif_socket.c
Diffstat (limited to 'kernel/compat.c')
-rw-r--r--kernel/compat.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/kernel/compat.c b/kernel/compat.c
index e167efce8423..c9e2ec0b34a8 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -1126,3 +1126,24 @@ compat_sys_sysinfo(struct compat_sysinfo __user *info)
return 0;
}
+
+/*
+ * Allocate user-space memory for the duration of a single system call,
+ * in order to marshall parameters inside a compat thunk.
+ */
+void __user *compat_alloc_user_space(unsigned long len)
+{
+ void __user *ptr;
+
+ /* If len would occupy more than half of the entire compat space... */
+ if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
+ return NULL;
+
+ ptr = arch_compat_alloc_user_space(len);
+
+ if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
+ return NULL;
+
+ return ptr;
+}
+EXPORT_SYMBOL_GPL(compat_alloc_user_space);