+ /* Update SP now because the page fault handler refuses to extend
+ * the stack if the faulting address is too far below the current
+ * SP, which frame now certainly is. If there's an error, the original
+ * value is restored on the way out.
+ * When writing the sigcontext to the stack, we have to write the
+ * original value, so that's passed to copy_sc_to_user, which does
+ * the right thing with it.
+ */
+ PT_REGS_SP(regs) = (unsigned long) frame;
+