From 4e8ee7de227e3ab9a72040b448ad728c5428a042 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 23 Nov 2011 12:26:25 +0000 Subject: 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 Signed-off-by: Will Deacon --- arch/arm/kernel/smp.c | 31 +------------------------------ 1 file changed, 1 insertion(+), 30 deletions(-) (limited to 'arch/arm/kernel/smp.c') diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 8afadda3745..76ff28d87bf 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; /* @@ -84,30 +83,12 @@ int __cpuinit __cpu_up(unsigned int cpu) init_idle(idle, 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; } -- cgit v1.2.3-18-g5258