From c5cc87fa8ddf971682fc5dd112e2dfacb11f30cd Mon Sep 17 00:00:00 2001
From: Russell King
Date: Tue, 29 Jul 2014 12:18:34 +0100
Subject: ARM: idmap: add identity mapping usage note

Add a note about the usage of the identity mapping; we do not support
accesses outside of the identity map region and kernel image while a
CPU is using the identity map.  This is because the identity mapping
may overwrite vmalloc space, IO mappings, the vectors pages, etc.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/mm/idmap.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'arch')

diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index d7a0ee898d24..c447ec70e868 100644
--- a/arch/arm/mm/idmap.c
+++ b/arch/arm/mm/idmap.c
@@ -9,6 +9,11 @@
 #include <asm/sections.h>
 #include <asm/system_info.h>
 
+/*
+ * Note: accesses outside of the kernel image and the identity map area
+ * are not supported on any CPU using the idmap tables as its current
+ * page tables.
+ */
 pgd_t *idmap_pgd;
 phys_addr_t (*arch_virt_to_idmap) (unsigned long x);
 
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