new helper: restore_altstack()
to be used by rt_sigreturn instances
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/signal.h b/include/linux/signal.h
index e19a011..5969522 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -385,4 +385,6 @@
void signals_init(void);
+int restore_altstack(const stack_t __user *);
+
#endif /* _LINUX_SIGNAL_H */
diff --git a/kernel/signal.c b/kernel/signal.c
index e75e4bd..887f2fe 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3103,6 +3103,13 @@
return error;
}
+int restore_altstack(const stack_t __user *uss)
+{
+ int err = do_sigaltstack(uss, NULL, current_user_stack_pointer());
+ /* squash all but EFAULT for now */
+ return err == -EFAULT ? err : 0;
+}
+
#ifdef __ARCH_WANT_SYS_SIGPENDING
/**