ARM: idmap: add identity mapping usage note (c5cc87fa) · Commits · 戴 / test

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 −0

Original line number	Original line	Diff line number	Diff line
	@@ -9,6 +9,11 @@
	#include <asm/sections.h>		#include <asm/sections.h>
	#include <asm/system_info.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;		pgd_t *idmap_pgd;
	phys_addr_t (*arch_virt_to_idmap) (unsigned long x);		phys_addr_t (*arch_virt_to_idmap) (unsigned long x);

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