[PATCH] i386: more vsyscall documentation

Document a limitation of vsyscall-sysenter, since patches to fix it have
been rejected.
Signed-off-by: NChuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

arch/i386/kernel/vsyscall-sysenter.S

@@ -21,6 +21,9 @@
  * instruction clobbers %esp, the user's %esp won't even survive entry
  * into the kernel. We store %esp in %ebp. Code in entry.S must fetch
  * arg6 from the stack.
+ *
+ * You can not use this vsyscall for the clone() syscall because the
+ * three dwords on the parent stack do not get copied to the child.
  */
 	.text
 	.globl __kernel_vsyscall