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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-07-29 12:18:34 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2014-08-02 15:20:26 +0100 |
| commit | c5cc87fa8ddf971682fc5dd112e2dfacb11f30cd (patch) | |
| tree | 58fbb35b4c2fe14941c7d8c21f2053cf46addbd7 | |
| parent | 811a2407a3cf7bbd027fbe92d73416f17485a3d8 (diff) | |
| download | lwn-c5cc87fa8ddf971682fc5dd112e2dfacb11f30cd.tar.gz lwn-c5cc87fa8ddf971682fc5dd112e2dfacb11f30cd.zip | |
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.c | 5 |
1 files changed, 5 insertions, 0 deletions
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); |