From 5c49574ffd7ac07eae8c3b065d19e6ebc7e4760f Mon Sep 17 00:00:00 2001
From: Al Viro <viro@zeniv.linux.org.uk>
Date: Sun, 18 Nov 2012 15:29:16 -0500
Subject: [PATCH] new helper: restore_altstack()
to be used by rt_sigreturn instances
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
include/linux/signal.h | 2 ++
kernel/signal.c | 7 +++++++
2 files changed, 9 insertions(+)
diff --git a/include/linux/signal.h b/include/linux/signal.h
index e19a011b43b76..5969522136fee 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -385,4 +385,6 @@ int unhandled_signal(struct task_struct *tsk, int sig);
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 e75e4bd2839bb..887f2fefe207e 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3103,6 +3103,13 @@ do_sigaltstack (const stack_t __user *uss, stack_t __user *uoss, unsigned long s
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
/**
--
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