From: Russell King Date: Tue, 29 Jul 2014 11:18:34 +0000 (+0100) Subject: ARM: idmap: add identity mapping usage note X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=c5cc87fa8ddf971682fc5dd112e2dfacb11f30cd;p=deliverable%2Flinux.git 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 Signed-off-by: Russell King --- 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 #include +/* + * 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);