linux/arch/arm/include/asm/idmap.h
Will Deacon 4e8ee7de22 ARM: SMP: use idmap_pgd for mapping MMU enable during secondary booting
The ARM SMP booting code allocates a temporary set of page tables
containing an identity mapping of the kernel image and provides this
to secondary CPUs for initial booting.

In reality, we only need to include the __turn_mmu_on function in the
identity mapping since the rest of the kernel is executing from virtual
addresses after this point.

This patch adds __turn_mmu_on to the .idmap.text section, allowing the
SMP booting code to use the idmap_pgd directly and not have to populate
its own set of page table.

As a result of this patch, we can make the identity_mapping_add function
static (since it is only used within mm/idmap.c) and also remove the
identity_mapping_del function. The identity map population is moved to
an early initcall so that it is setup in time for secondary CPU bringup.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2011-12-06 14:04:15 +00:00

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C

#ifndef __ASM_IDMAP_H
#define __ASM_IDMAP_H
#include <linux/compiler.h>
#include <asm/pgtable.h>
/* Tag a function as requiring to be executed via an identity mapping. */
#define __idmap __section(.idmap.text) noinline notrace
extern pgd_t *idmap_pgd;
void setup_mm_for_reboot(void);
#endif /* __ASM_IDMAP_H */