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Commit b433dce0 authored by Suzuki K. Poulose's avatar Suzuki K. Poulose Committed by Catalin Marinas
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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 <will.deacon@arm.com>
Signed-off-by: default avatarSuzuki K. Poulose <suzuki.poulose@arm.com>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 87d1587b

arch/arm64/include/asm/kernel-pgtable.h

+26 −11
Original line number Diff line number Diff line
@@ -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

arch/arm64/mm/mmu.c

+33 −41
Original line number Diff line number Diff line
@@ -32,6 +32,7 @@ 


#include <asm/cputype.h>

#include <asm/fixmap.h>

#include <asm/kernel-pgtable.h>

#include <asm/sections.h>

#include <asm/setup.h>

#include <asm/sizes.h>
@@ -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

		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.

		 * When 64K pages are enabled, the pte page table for the

		 * first PGDIR_SIZE is already present in swapper_pg_dir.

			 * 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, PMD_SIZE);

				start = ALIGN(start, SECTION_SIZE);

			if (end < limit) {

			limit = end & PMD_MASK;

				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);