[MODERATED] [PATCH v6 30/43] MDSv6

[Andi Kleen <andi@firstfloor.org>]

From: Andi Kleen <ak@linux.intel.com>
Subject:  mds sweep: Clear cpu for tty input

Schedule a clear cpu when input data is passed to the tty
layer in a interrupt. We consider tty data sensitive.
This avoids patching lots of serial drivers.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 drivers/tty/tty_buffer.c | 5 ++++-
 include/linux/tty_flip.h | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 77070c2d1240..71f6dd698968 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -17,6 +17,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/ratelimit.h>
+#include <linux/clearcpu.h>
 
 
 #define MIN_TTYB_SIZE	256
@@ -328,6 +329,7 @@ int tty_insert_flip_string_fixed_flag(struct tty_port *port,
 		/* There is a small chance that we need to split the data over
 		   several buffers. If this is the case we must loop */
 	} while (unlikely(size > copied));
+	lazy_clear_cpu_interrupt();
 	return copied;
 }
 EXPORT_SYMBOL(tty_insert_flip_string_fixed_flag);
@@ -363,6 +365,7 @@ int tty_insert_flip_string_flags(struct tty_port *port,
 		/* There is a small chance that we need to split the data over
 		   several buffers. If this is the case we must loop */
 	} while (unlikely(size > copied));
+	lazy_clear_cpu_interrupt();
 	return copied;
 }
 EXPORT_SYMBOL(tty_insert_flip_string_flags);
@@ -388,7 +391,7 @@ int __tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag)
 	if (~tb->flags & TTYB_NORMAL)
 		*flag_buf_ptr(tb, tb->used) = flag;
 	*char_buf_ptr(tb, tb->used++) = ch;
-
+	lazy_clear_cpu_interrupt();
 	return 1;
 }
 EXPORT_SYMBOL(__tty_insert_flip_char);
diff --git a/include/linux/tty_flip.h b/include/linux/tty_flip.h
index 767f62086bd9..41ae39e339b9 100644
--- a/include/linux/tty_flip.h
+++ b/include/linux/tty_flip.h
@@ -2,6 +2,8 @@
 #ifndef _LINUX_TTY_FLIP_H
 #define _LINUX_TTY_FLIP_H
 
+#include <linux/clearcpu.h>
+
 extern int tty_buffer_set_limit(struct tty_port *port, int limit);
 extern int tty_buffer_space_avail(struct tty_port *port);
 extern int tty_buffer_request_room(struct tty_port *port, size_t size);
@@ -21,6 +23,8 @@ static inline int tty_insert_flip_char(struct tty_port *port,
 	struct tty_buffer *tb = port->buf.tail;
 	int change;
 
+	lazy_clear_cpu_interrupt();
+
 	change = (tb->flags & TTYB_NORMAL) && (flag != TTY_NORMAL);
 	if (!change && tb->used < tb->size) {
 		if (~tb->flags & TTYB_NORMAL)
-- 
2.17.2