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authorRussell King <rmk+kernel@arm.linux.org.uk>2014-07-29 12:18:34 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-08-02 15:20:26 +0100
commitc5cc87fa8ddf971682fc5dd112e2dfacb11f30cd (patch)
tree58fbb35b4c2fe14941c7d8c21f2053cf46addbd7
parent811a2407a3cf7bbd027fbe92d73416f17485a3d8 (diff)
downloadlinux-c5cc87fa8ddf971682fc5dd112e2dfacb11f30cd.tar.gz
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>
-rw-r--r--arch/arm/mm/idmap.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
index d7a0ee898d2..c447ec70e86 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);