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authorWill Deacon <will.deacon@arm.com>2011-11-23 12:26:25 +0000
committerWill Deacon <will.deacon@arm.com>2011-12-06 14:04:15 +0000
commit4e8ee7de227e3ab9a72040b448ad728c5428a042 (patch)
treeffaf8492fd359d3281a55ff6e751504e905cc27c /arch/arm/kernel/smp.c
parent72662e01088394577be4a3f14da94cf87bea2591 (diff)
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>
Diffstat (limited to 'arch/arm/kernel/smp.c')
-rw-r--r--arch/arm/kernel/smp.c31
1 files changed, 1 insertions, 30 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 8afadda37459..76ff28d87bf3 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -62,7 +62,6 @@ int __cpuinit __cpu_up(unsigned int cpu)
{
struct cpuinfo_arm *ci = &per_cpu(cpu_data, cpu);
struct task_struct *idle = ci->idle;
- pgd_t *pgd;
int ret;
/*
@@ -85,29 +84,11 @@ int __cpuinit __cpu_up(unsigned int cpu)
}
/*
- * Allocate initial page tables to allow the new CPU to
- * enable the MMU safely. This essentially means a set
- * of our "standard" page tables, with the addition of
- * a 1:1 mapping for the physical address of the kernel.
- */
- pgd = pgd_alloc(&init_mm);
- if (!pgd)
- return -ENOMEM;
-
- if (PHYS_OFFSET != PAGE_OFFSET) {
-#ifndef CONFIG_HOTPLUG_CPU
- identity_mapping_add(pgd, __pa(__init_begin), __pa(__init_end));
-#endif
- identity_mapping_add(pgd, __pa(_stext), __pa(_etext));
- identity_mapping_add(pgd, __pa(_sdata), __pa(_edata));
- }
-
- /*
* We need to tell the secondary core where to find
* its stack and the page tables.
*/
secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
- secondary_data.pgdir = virt_to_phys(pgd);
+ secondary_data.pgdir = virt_to_phys(idmap_pgd);
secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
__cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
@@ -143,16 +124,6 @@ int __cpuinit __cpu_up(unsigned int cpu)
secondary_data.stack = NULL;
secondary_data.pgdir = 0;
- if (PHYS_OFFSET != PAGE_OFFSET) {
-#ifndef CONFIG_HOTPLUG_CPU
- identity_mapping_del(pgd, __pa(__init_begin), __pa(__init_end));
-#endif
- identity_mapping_del(pgd, __pa(_stext), __pa(_etext));
- identity_mapping_del(pgd, __pa(_sdata), __pa(_edata));
- }
-
- pgd_free(&init_mm, pgd);
-
return ret;
}