X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fcompat.c;h=c9e2ec0b34a8cc38cda604273618a22c8d2d928c;hb=ed2e5581d2702743460349e494f3ab8c4b0f28d8;hp=e167efce8423e2cdaf2709412c36cc3ae642c90f;hpb=92629195314d8adefabeb78b13d681ad1c01e778;p=pandora-kernel.git

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);