From b433dce056d3814dc4b33e5a8a533d6401ffcfb0 Mon Sep 17 00:00:00 2001 From: "Suzuki K. Poulose" Date: Mon, 19 Oct 2015 14:19:28 +0100 Subject: [PATCH] arm64: Handle section maps for swapper/idmap We use section maps with 4K page size to create the swapper/idmaps. So far we have used !64K or 4K checks to handle the case where we use the section maps. This patch adds a new symbol, ARM64_SWAPPER_USES_SECTION_MAPS, to handle cases where we use section maps, instead of using the page size symbols. Cc: Will Deacon Signed-off-by: Suzuki K. Poulose Reviewed-by: Ard Biesheuvel Acked-by: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/kernel-pgtable.h | 37 +++++++++---- arch/arm64/mm/mmu.c | 74 +++++++++++-------------- 2 files changed, 59 insertions(+), 52 deletions(-) diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h index 3c92fa7bad2b..4e08faabd9e4 100644 --- a/arch/arm64/include/asm/kernel-pgtable.h +++ b/arch/arm64/include/asm/kernel-pgtable.h @@ -19,6 +19,19 @@ #ifndef __ASM_KERNEL_PGTABLE_H #define __ASM_KERNEL_PGTABLE_H + +/* + * The linear mapping and the start of memory are both 2M aligned (per + * the arm64 booting.txt requirements). Hence we can use section mapping + * with 4K (section size = 2M) but not with 16K (section size = 32M) or + * 64K (section size = 512M). + */ +#ifdef CONFIG_ARM64_4K_PAGES +#define ARM64_SWAPPER_USES_SECTION_MAPS 1 +#else +#define ARM64_SWAPPER_USES_SECTION_MAPS 0 +#endif + /* * The idmap and swapper page tables need some space reserved in the kernel * image. Both require pgd, pud (4 levels only) and pmd tables to (section) @@ -28,26 +41,28 @@ * could be increased on the fly if system RAM is out of reach for the default * VA range, so 3 pages are reserved in all cases. */ -#ifdef CONFIG_ARM64_64K_PAGES -#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) -#else +#if ARM64_SWAPPER_USES_SECTION_MAPS #define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1) +#else +#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS) #endif #define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE) #define IDMAP_DIR_SIZE (3 * PAGE_SIZE) /* Initial memory map size */ -#ifdef CONFIG_ARM64_64K_PAGES -#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT -#define SWAPPER_BLOCK_SIZE PAGE_SIZE -#define SWAPPER_TABLE_SHIFT PMD_SHIFT -#else +#if ARM64_SWAPPER_USES_SECTION_MAPS #define SWAPPER_BLOCK_SHIFT SECTION_SHIFT #define SWAPPER_BLOCK_SIZE SECTION_SIZE #define SWAPPER_TABLE_SHIFT PUD_SHIFT +#else +#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT +#define SWAPPER_BLOCK_SIZE PAGE_SIZE +#define SWAPPER_TABLE_SHIFT PMD_SHIFT #endif +/* The size of the initial kernel direct mapping */ +#define SWAPPER_INIT_MAP_SIZE (_AC(1, UL) << SWAPPER_TABLE_SHIFT) /* * Initial memory map attributes. @@ -55,10 +70,10 @@ #define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED) #define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S) -#ifdef CONFIG_ARM64_64K_PAGES -#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) -#else +#if ARM64_SWAPPER_USES_SECTION_MAPS #define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS) +#else +#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS) #endif diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index eed6d52f5e54..c2fa6b56613c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -32,6 +32,7 @@ #include #include +#include #include #include #include @@ -406,14 +407,11 @@ static void __init map_mem(void) * memory addressable from the initial direct kernel mapping. * * The initial direct kernel mapping, located at swapper_pg_dir, gives - * us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from - * PHYS_OFFSET (which must be aligned to 2MB as per - * Documentation/arm64/booting.txt). + * us PUD_SIZE (with SECTION maps) or PMD_SIZE (without SECTION maps, + * memory starting from PHYS_OFFSET (which must be aligned to 2MB as + * per Documentation/arm64/booting.txt). */ - if (IS_ENABLED(CONFIG_ARM64_64K_PAGES)) - limit = PHYS_OFFSET + PMD_SIZE; - else - limit = PHYS_OFFSET + PUD_SIZE; + limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE; memblock_set_current_limit(limit); /* map all the memory banks */ @@ -424,21 +422,24 @@ static void __init map_mem(void) if (start >= end) break; -#ifndef CONFIG_ARM64_64K_PAGES - /* - * For the first memory bank align the start address and - * current memblock limit to prevent create_mapping() from - * allocating pte page tables from unmapped memory. - * When 64K pages are enabled, the pte page table for the - * first PGDIR_SIZE is already present in swapper_pg_dir. - */ - if (start < limit) - start = ALIGN(start, PMD_SIZE); - if (end < limit) { - limit = end & PMD_MASK; - memblock_set_current_limit(limit); + if (ARM64_SWAPPER_USES_SECTION_MAPS) { + /* + * For the first memory bank align the start address and + * current memblock limit to prevent create_mapping() from + * allocating pte page tables from unmapped memory. With + * the section maps, if the first block doesn't end on section + * size boundary, create_mapping() will try to allocate a pte + * page, which may be returned from an unmapped area. + * When section maps are not used, the pte page table for the + * current limit is already present in swapper_pg_dir. + */ + if (start < limit) + start = ALIGN(start, SECTION_SIZE); + if (end < limit) { + limit = end & SECTION_MASK; + memblock_set_current_limit(limit); + } } -#endif __map_memblock(start, end); } @@ -551,12 +552,12 @@ int kern_addr_valid(unsigned long addr) return pfn_valid(pte_pfn(*pte)); } #ifdef CONFIG_SPARSEMEM_VMEMMAP -#ifdef CONFIG_ARM64_64K_PAGES +#if !ARM64_SWAPPER_USES_SECTION_MAPS int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) { return vmemmap_populate_basepages(start, end, node); } -#else /* !CONFIG_ARM64_64K_PAGES */ +#else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) { unsigned long addr = start; @@ -691,7 +692,7 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys) { const u64 dt_virt_base = __fix_to_virt(FIX_FDT); pgprot_t prot = PAGE_KERNEL | PTE_RDONLY; - int granularity, size, offset; + int size, offset; void *dt_virt; /* @@ -717,24 +718,15 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys) */ BUILD_BUG_ON(dt_virt_base % SZ_2M); - if (IS_ENABLED(CONFIG_ARM64_64K_PAGES)) { - BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> PMD_SHIFT != - __fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT); - - granularity = PAGE_SIZE; - } else { - BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> PUD_SHIFT != - __fix_to_virt(FIX_BTMAP_BEGIN) >> PUD_SHIFT); - - granularity = PMD_SIZE; - } + BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != + __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); - offset = dt_phys % granularity; + offset = dt_phys % SWAPPER_BLOCK_SIZE; dt_virt = (void *)dt_virt_base + offset; /* map the first chunk so we can read the size from the header */ - create_mapping(round_down(dt_phys, granularity), dt_virt_base, - granularity, prot); + create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, + SWAPPER_BLOCK_SIZE, prot); if (fdt_check_header(dt_virt) != 0) return NULL; @@ -743,9 +735,9 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys) if (size > MAX_FDT_SIZE) return NULL; - if (offset + size > granularity) - create_mapping(round_down(dt_phys, granularity), dt_virt_base, - round_up(offset + size, granularity), prot); + if (offset + size > SWAPPER_BLOCK_SIZE) + create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, + round_up(offset + size, SWAPPER_BLOCK_SIZE), prot); memblock_reserve(dt_phys, size); -- 2.39.5