From eb8cdec4a984fde123a91250dcc9e0bddf5eafdc Mon Sep 17 00:00:00 2001
From: Bernd Schmidt <bernds_cb1@t-online.de>
Date: Mon, 21 Sep 2009 17:03:57 -0700
Subject: nommu: add support for Memory Protection Units (MPU)

Some architectures (like the Blackfin arch) implement some of the
"simpler" features that one would expect out of a MMU such as memory
protection.

In our case, we actually get read/write/exec protection down to the page
boundary so processes can't stomp on each other let alone the kernel.

There is a performance decrease (which depends greatly on the workload)
however as the hardware/software interaction was not optimized at design
time.

Signed-off-by: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 kernel/module.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'kernel/module.c')

diff --git a/kernel/module.c b/kernel/module.c
index b6ee424245dd..e6bc4b28aa62 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -47,6 +47,7 @@
 #include <linux/rculist.h>
 #include <asm/uaccess.h>
 #include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
 #include <linux/license.h>
 #include <asm/sections.h>
 #include <linux/tracepoint.h>
@@ -1535,6 +1536,10 @@ static void free_module(struct module *mod)
 
 	/* Finally, free the core (containing the module structure) */
 	module_free(mod, mod->module_core);
+
+#ifdef CONFIG_MPU
+	update_protections(current->mm);
+#endif
 }
 
 void *__symbol_get(const char *symbol)
-- 
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