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32 results

pgtable.h

Blame
    • Hugh Dickins's avatar
      fd8cfd30
      arch: fix has_transparent_hugepage() · fd8cfd30
      Hugh Dickins authored
      
      I've just discovered that the useful-sounding has_transparent_hugepage()
      is actually an architecture-dependent minefield: on some arches it only
      builds if CONFIG_TRANSPARENT_HUGEPAGE=y, on others it's also there when
      not, but on some of those (arm and arm64) it then gives the wrong
      answer; and on mips alone it's marked __init, which would crash if
      called later (but so far it has not been called later).
      
      Straighten this out: make it available to all configs, with a sensible
      default in asm-generic/pgtable.h, removing its definitions from those
      arches (arc, arm, arm64, sparc, tile) which are served by the default,
      adding #define has_transparent_hugepage has_transparent_hugepage to
      those (mips, powerpc, s390, x86) which need to override the default at
      runtime, and removing the __init from mips (but maybe that kind of code
      should be avoided after init: set a static variable the first time it's
      called).
      
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Andres Lagar-Cavilla <andreslc@google.com>
      Cc: Yang Shi <yang.shi@linaro.org>
      Cc: Ning Qu <quning@gmail.com>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: Konstantin Khlebnikov <koct9i@gmail.com>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Acked-by: Vineet Gupta <vgupta@synopsys.com>		[arch/arc]
      Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[arch/s390]
      Acked-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fd8cfd30
      History
      arch: fix has_transparent_hugepage()
      Hugh Dickins authored
      
      I've just discovered that the useful-sounding has_transparent_hugepage()
      is actually an architecture-dependent minefield: on some arches it only
      builds if CONFIG_TRANSPARENT_HUGEPAGE=y, on others it's also there when
      not, but on some of those (arm and arm64) it then gives the wrong
      answer; and on mips alone it's marked __init, which would crash if
      called later (but so far it has not been called later).
      
      Straighten this out: make it available to all configs, with a sensible
      default in asm-generic/pgtable.h, removing its definitions from those
      arches (arc, arm, arm64, sparc, tile) which are served by the default,
      adding #define has_transparent_hugepage has_transparent_hugepage to
      those (mips, powerpc, s390, x86) which need to override the default at
      runtime, and removing the __init from mips (but maybe that kind of code
      should be avoided after init: set a static variable the first time it's
      called).
      
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Andres Lagar-Cavilla <andreslc@google.com>
      Cc: Yang Shi <yang.shi@linaro.org>
      Cc: Ning Qu <quning@gmail.com>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Cc: Konstantin Khlebnikov <koct9i@gmail.com>
      Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
      Acked-by: Vineet Gupta <vgupta@synopsys.com>		[arch/arc]
      Acked-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[arch/s390]
      Acked-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    init.c 18.52 KiB
    // SPDX-License-Identifier: GPL-2.0-only
    /*
     * Copyright (C) 2012 Regents of the University of California
     * Copyright (C) 2019 Western Digital Corporation or its affiliates.
     */
    
    #include <linux/init.h>
    #include <linux/mm.h>
    #include <linux/memblock.h>
    #include <linux/initrd.h>
    #include <linux/swap.h>
    #include <linux/sizes.h>
    #include <linux/of_fdt.h>
    #include <linux/libfdt.h>
    #include <linux/set_memory.h>
    
    #include <asm/fixmap.h>
    #include <asm/tlbflush.h>
    #include <asm/sections.h>
    #include <asm/soc.h>
    #include <asm/io.h>
    #include <asm/ptdump.h>
    
    #include "../kernel/head.h"
    
    unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
    							__page_aligned_bss;
    EXPORT_SYMBOL(empty_zero_page);
    
    extern char _start[];
    #define DTB_EARLY_BASE_VA      PGDIR_SIZE
    void *dtb_early_va __initdata;
    uintptr_t dtb_early_pa __initdata;
    
    struct pt_alloc_ops {
    	pte_t *(*get_pte_virt)(phys_addr_t pa);
    	phys_addr_t (*alloc_pte)(uintptr_t va);
    #ifndef __PAGETABLE_PMD_FOLDED
    	pmd_t *(*get_pmd_virt)(phys_addr_t pa);
    	phys_addr_t (*alloc_pmd)(uintptr_t va);
    #endif
    };
    
    static void __init zone_sizes_init(void)
    {
    	unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };
    
    #ifdef CONFIG_ZONE_DMA32
    	max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G,
    			(unsigned long) PFN_PHYS(max_low_pfn)));
    #endif
    	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
    
    	free_area_init(max_zone_pfns);
    }
    
    static void setup_zero_page(void)
    {
    	memset((void *)empty_zero_page, 0, PAGE_SIZE);
    }
    
    #if defined(CONFIG_MMU) && defined(CONFIG_DEBUG_VM)
    static inline void print_mlk(char *name, unsigned long b, unsigned long t)
    {
    	pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld kB)\n", name, b, t,
    		  (((t) - (b)) >> 10));
    }
    
    static inline void print_mlm(char *name, unsigned long b, unsigned long t)
    {
    	pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld MB)\n", name, b, t,
    		  (((t) - (b)) >> 20));
    }
    
    static void print_vm_layout(void)
    {
    	pr_notice("Virtual kernel memory layout:\n");
    	print_mlk("fixmap", (unsigned long)FIXADDR_START,
    		  (unsigned long)FIXADDR_TOP);
    	print_mlm("pci io", (unsigned long)PCI_IO_START,
    		  (unsigned long)PCI_IO_END);
    	print_mlm("vmemmap", (unsigned long)VMEMMAP_START,
    		  (unsigned long)VMEMMAP_END);
    	print_mlm("vmalloc", (unsigned long)VMALLOC_START,
    		  (unsigned long)VMALLOC_END);
    	print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
    		  (unsigned long)high_memory);
    }
    #else
    static void print_vm_layout(void) { }
    #endif /* CONFIG_DEBUG_VM */
    
    void __init mem_init(void)
    {
    #ifdef CONFIG_FLATMEM
    	BUG_ON(!mem_map);
    #endif /* CONFIG_FLATMEM */
    
    	high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
    	memblock_free_all();
    
    	mem_init_print_info(NULL);
    	print_vm_layout();
    }
    
    #ifdef CONFIG_BLK_DEV_INITRD
    static void __init setup_initrd(void)
    {
    	phys_addr_t start;
    	unsigned long size;
    
    	/* Ignore the virtul address computed during device tree parsing */
    	initrd_start = initrd_end = 0;
    
    	if (!phys_initrd_size)
    		return;
    	/*
    	 * Round the memory region to page boundaries as per free_initrd_mem()
    	 * This allows us to detect whether the pages overlapping the initrd
    	 * are in use, but more importantly, reserves the entire set of pages
    	 * as we don't want these pages allocated for other purposes.
    	 */
    	start = round_down(phys_initrd_start, PAGE_SIZE);
    	size = phys_initrd_size + (phys_initrd_start - start);
    	size = round_up(size, PAGE_SIZE);
    
    	if (!memblock_is_region_memory(start, size)) {
    		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
    		       (u64)start, size);
    		goto disable;
    	}
    
    	if (memblock_is_region_reserved(start, size)) {
    		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
    		       (u64)start, size);
    		goto disable;
    	}
    
    	memblock_reserve(start, size);
    	/* Now convert initrd to virtual addresses */
    	initrd_start = (unsigned long)__va(phys_initrd_start);
    	initrd_end = initrd_start + phys_initrd_size;
    	initrd_below_start_ok = 1;
    
    	pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
    		(void *)(initrd_start), size);
    	return;
    disable:
    	pr_cont(" - disabling initrd\n");
    	initrd_start = 0;
    	initrd_end = 0;
    }
    #endif /* CONFIG_BLK_DEV_INITRD */
    
    void __init setup_bootmem(void)
    {
    	phys_addr_t mem_start = 0;
    	phys_addr_t start, end = 0;
    	phys_addr_t vmlinux_end = __pa_symbol(&_end);
    	phys_addr_t vmlinux_start = __pa_symbol(&_start);
    	u64 i;
    
    	/* Find the memory region containing the kernel */
    	for_each_mem_range(i, &start, &end) {
    		phys_addr_t size = end - start;
    		if (!mem_start)
    			mem_start = start;
    		if (start <= vmlinux_start && vmlinux_end <= end)
    			BUG_ON(size == 0);
    	}
    
    	/*
    	 * The maximal physical memory size is -PAGE_OFFSET.
    	 * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
    	 * as it is unusable by kernel.
    	 */
    	memblock_enforce_memory_limit(mem_start - PAGE_OFFSET);
    
    	/* Reserve from the start of the kernel to the end of the kernel */
    	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);
    
    	max_pfn = PFN_DOWN(memblock_end_of_DRAM());
    	max_low_pfn = max_pfn;
    	set_max_mapnr(max_low_pfn);
    
    #ifdef CONFIG_BLK_DEV_INITRD
    	setup_initrd();
    #endif /* CONFIG_BLK_DEV_INITRD */
    
    	/*
    	 * Avoid using early_init_fdt_reserve_self() since __pa() does
    	 * not work for DTB pointers that are fixmap addresses
    	 */
    	memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));
    
    	early_init_fdt_scan_reserved_mem();
    	memblock_allow_resize();
    	memblock_dump_all();
    }
    
    #ifdef CONFIG_MMU
    static struct pt_alloc_ops pt_ops;
    
    unsigned long va_pa_offset;
    EXPORT_SYMBOL(va_pa_offset);
    unsigned long pfn_base;
    EXPORT_SYMBOL(pfn_base);
    
    pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
    pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
    pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;
    
    #define MAX_EARLY_MAPPING_SIZE	SZ_128M
    
    pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
    
    void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
    {
    	unsigned long addr = __fix_to_virt(idx);
    	pte_t *ptep;
    
    	BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
    
    	ptep = &fixmap_pte[pte_index(addr)];
    
    	if (pgprot_val(prot))
    		set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
    	else
    		pte_clear(&init_mm, addr, ptep);
    	local_flush_tlb_page(addr);
    }
    
    static inline pte_t *__init get_pte_virt_early(phys_addr_t pa)
    {
    	return (pte_t *)((uintptr_t)pa);
    }
    
    static inline pte_t *__init get_pte_virt_fixmap(phys_addr_t pa)
    {
    	clear_fixmap(FIX_PTE);
    	return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
    }
    
    static inline pte_t *get_pte_virt_late(phys_addr_t pa)
    {
    	return (pte_t *) __va(pa);
    }
    
    static inline phys_addr_t __init alloc_pte_early(uintptr_t va)
    {
    	/*
    	 * We only create PMD or PGD early mappings so we
    	 * should never reach here with MMU disabled.
    	 */
    	BUG();
    }
    
    static inline phys_addr_t __init alloc_pte_fixmap(uintptr_t va)
    {
    	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
    }
    
    static phys_addr_t alloc_pte_late(uintptr_t va)
    {
    	unsigned long vaddr;
    
    	vaddr = __get_free_page(GFP_KERNEL);
    	if (!vaddr || !pgtable_pte_page_ctor(virt_to_page(vaddr)))
    		BUG();
    	return __pa(vaddr);
    }
    
    static void __init create_pte_mapping(pte_t *ptep,
    				      uintptr_t va, phys_addr_t pa,
    				      phys_addr_t sz, pgprot_t prot)
    {
    	uintptr_t pte_idx = pte_index(va);
    
    	BUG_ON(sz != PAGE_SIZE);
    
    	if (pte_none(ptep[pte_idx]))
    		ptep[pte_idx] = pfn_pte(PFN_DOWN(pa), prot);
    }
    
    #ifndef __PAGETABLE_PMD_FOLDED
    
    pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
    pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
    
    #if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
    #define NUM_EARLY_PMDS		1UL
    #else
    #define NUM_EARLY_PMDS		(1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
    #endif
    pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
    pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
    
    static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
    {
    	/* Before MMU is enabled */
    	return (pmd_t *)((uintptr_t)pa);
    }
    
    static pmd_t *__init get_pmd_virt_fixmap(phys_addr_t pa)
    {
    	clear_fixmap(FIX_PMD);
    	return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
    }
    
    static pmd_t *get_pmd_virt_late(phys_addr_t pa)
    {
    	return (pmd_t *) __va(pa);
    }
    
    static phys_addr_t __init alloc_pmd_early(uintptr_t va)
    {
    	uintptr_t pmd_num;
    
    	pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
    	BUG_ON(pmd_num >= NUM_EARLY_PMDS);
    	return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
    }
    
    static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
    {
    	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
    }
    
    static phys_addr_t alloc_pmd_late(uintptr_t va)
    {
    	unsigned long vaddr;
    
    	vaddr = __get_free_page(GFP_KERNEL);
    	BUG_ON(!vaddr);
    	return __pa(vaddr);
    }
    
    static void __init create_pmd_mapping(pmd_t *pmdp,
    				      uintptr_t va, phys_addr_t pa,
    				      phys_addr_t sz, pgprot_t prot)
    {
    	pte_t *ptep;
    	phys_addr_t pte_phys;
    	uintptr_t pmd_idx = pmd_index(va);
    
    	if (sz == PMD_SIZE) {
    		if (pmd_none(pmdp[pmd_idx]))
    			pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pa), prot);
    		return;
    	}
    
    	if (pmd_none(pmdp[pmd_idx])) {
    		pte_phys = pt_ops.alloc_pte(va);
    		pmdp[pmd_idx] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
    		ptep = pt_ops.get_pte_virt(pte_phys);
    		memset(ptep, 0, PAGE_SIZE);
    	} else {
    		pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_idx]));
    		ptep = pt_ops.get_pte_virt(pte_phys);
    	}
    
    	create_pte_mapping(ptep, va, pa, sz, prot);
    }
    
    #define pgd_next_t		pmd_t
    #define alloc_pgd_next(__va)	pt_ops.alloc_pmd(__va)
    #define get_pgd_next_virt(__pa)	pt_ops.get_pmd_virt(__pa)
    #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
    	create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
    #define fixmap_pgd_next		fixmap_pmd
    #else
    #define pgd_next_t		pte_t
    #define alloc_pgd_next(__va)	pt_ops.alloc_pte(__va)
    #define get_pgd_next_virt(__pa)	pt_ops.get_pte_virt(__pa)
    #define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
    	create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
    #define fixmap_pgd_next		fixmap_pte
    #endif
    
    void __init create_pgd_mapping(pgd_t *pgdp,
    				      uintptr_t va, phys_addr_t pa,
    				      phys_addr_t sz, pgprot_t prot)
    {
    	pgd_next_t *nextp;
    	phys_addr_t next_phys;
    	uintptr_t pgd_idx = pgd_index(va);
    
    	if (sz == PGDIR_SIZE) {
    		if (pgd_val(pgdp[pgd_idx]) == 0)
    			pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(pa), prot);
    		return;
    	}
    
    	if (pgd_val(pgdp[pgd_idx]) == 0) {
    		next_phys = alloc_pgd_next(va);
    		pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
    		nextp = get_pgd_next_virt(next_phys);
    		memset(nextp, 0, PAGE_SIZE);
    	} else {
    		next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_idx]));
    		nextp = get_pgd_next_virt(next_phys);
    	}
    
    	create_pgd_next_mapping(nextp, va, pa, sz, prot);
    }
    
    static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
    {
    	/* Upgrade to PMD_SIZE mappings whenever possible */
    	if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
    		return PAGE_SIZE;
    
    	return PMD_SIZE;
    }
    
    /*
     * setup_vm() is called from head.S with MMU-off.
     *
     * Following requirements should be honoured for setup_vm() to work
     * correctly:
     * 1) It should use PC-relative addressing for accessing kernel symbols.
     *    To achieve this we always use GCC cmodel=medany.
     * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
     *    so disable compiler instrumentation when FTRACE is enabled.
     *
     * Currently, the above requirements are honoured by using custom CFLAGS
     * for init.o in mm/Makefile.
     */
    
    #ifndef __riscv_cmodel_medany
    #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
    #endif
    
    asmlinkage void __init setup_vm(uintptr_t dtb_pa)
    {
    	uintptr_t va, pa, end_va;
    	uintptr_t load_pa = (uintptr_t)(&_start);
    	uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
    	uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
    #ifndef __PAGETABLE_PMD_FOLDED
    	pmd_t fix_bmap_spmd, fix_bmap_epmd;
    #endif
    
    	va_pa_offset = PAGE_OFFSET - load_pa;
    	pfn_base = PFN_DOWN(load_pa);
    
    	/*
    	 * Enforce boot alignment requirements of RV32 and
    	 * RV64 by only allowing PMD or PGD mappings.
    	 */
    	BUG_ON(map_size == PAGE_SIZE);
    
    	/* Sanity check alignment and size */
    	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
    	BUG_ON((load_pa % map_size) != 0);
    	BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);
    
    	pt_ops.alloc_pte = alloc_pte_early;
    	pt_ops.get_pte_virt = get_pte_virt_early;
    #ifndef __PAGETABLE_PMD_FOLDED
    	pt_ops.alloc_pmd = alloc_pmd_early;
    	pt_ops.get_pmd_virt = get_pmd_virt_early;
    #endif
    	/* Setup early PGD for fixmap */
    	create_pgd_mapping(early_pg_dir, FIXADDR_START,
    			   (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);
    
    #ifndef __PAGETABLE_PMD_FOLDED
    	/* Setup fixmap PMD */
    	create_pmd_mapping(fixmap_pmd, FIXADDR_START,
    			   (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
    	/* Setup trampoline PGD and PMD */
    	create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
    			   (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
    	create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
    			   load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
    #else
    	/* Setup trampoline PGD */
    	create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
    			   load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
    #endif
    
    	/*
    	 * Setup early PGD covering entire kernel which will allows
    	 * us to reach paging_init(). We map all memory banks later
    	 * in setup_vm_final() below.
    	 */
    	end_va = PAGE_OFFSET + load_sz;
    	for (va = PAGE_OFFSET; va < end_va; va += map_size)
    		create_pgd_mapping(early_pg_dir, va,
    				   load_pa + (va - PAGE_OFFSET),
    				   map_size, PAGE_KERNEL_EXEC);
    
    #ifndef __PAGETABLE_PMD_FOLDED
    	/* Setup early PMD for DTB */
    	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
    			   (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);
    	/* Create two consecutive PMD mappings for FDT early scan */
    	pa = dtb_pa & ~(PMD_SIZE - 1);
    	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
    			   pa, PMD_SIZE, PAGE_KERNEL);
    	create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,
    			   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
    	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
    #else
    	/* Create two consecutive PGD mappings for FDT early scan */
    	pa = dtb_pa & ~(PGDIR_SIZE - 1);
    	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
    			   pa, PGDIR_SIZE, PAGE_KERNEL);
    	create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,
    			   pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
    	dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
    #endif
    	dtb_early_pa = dtb_pa;
    
    	/*
    	 * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
    	 * range can not span multiple pmds.
    	 */
    	BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
    		     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
    
    #ifndef __PAGETABLE_PMD_FOLDED
    	/*
    	 * Early ioremap fixmap is already created as it lies within first 2MB
    	 * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
    	 * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
    	 * the user if not.
    	 */
    	fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
    	fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
    	if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
    		WARN_ON(1);
    		pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
    			pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
    		pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
    			fix_to_virt(FIX_BTMAP_BEGIN));
    		pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
    			fix_to_virt(FIX_BTMAP_END));
    
    		pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
    		pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
    	}
    #endif
    }
    
    static void __init setup_vm_final(void)
    {
    	uintptr_t va, map_size;
    	phys_addr_t pa, start, end;
    	u64 i;
    
    	/**
    	 * MMU is enabled at this point. But page table setup is not complete yet.
    	 * fixmap page table alloc functions should be used at this point
    	 */
    	pt_ops.alloc_pte = alloc_pte_fixmap;
    	pt_ops.get_pte_virt = get_pte_virt_fixmap;
    #ifndef __PAGETABLE_PMD_FOLDED
    	pt_ops.alloc_pmd = alloc_pmd_fixmap;
    	pt_ops.get_pmd_virt = get_pmd_virt_fixmap;
    #endif
    	/* Setup swapper PGD for fixmap */
    	create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
    			   __pa_symbol(fixmap_pgd_next),
    			   PGDIR_SIZE, PAGE_TABLE);
    
    	/* Map all memory banks */
    	for_each_mem_range(i, &start, &end) {
    		if (start >= end)
    			break;
    		if (start <= __pa(PAGE_OFFSET) &&
    		    __pa(PAGE_OFFSET) < end)
    			start = __pa(PAGE_OFFSET);
    
    		map_size = best_map_size(start, end - start);
    		for (pa = start; pa < end; pa += map_size) {
    			va = (uintptr_t)__va(pa);
    			create_pgd_mapping(swapper_pg_dir, va, pa,
    					   map_size, PAGE_KERNEL_EXEC);
    		}
    	}
    
    	/* Clear fixmap PTE and PMD mappings */
    	clear_fixmap(FIX_PTE);
    	clear_fixmap(FIX_PMD);
    
    	/* Move to swapper page table */
    	csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | SATP_MODE);
    	local_flush_tlb_all();
    
    	/* generic page allocation functions must be used to setup page table */
    	pt_ops.alloc_pte = alloc_pte_late;
    	pt_ops.get_pte_virt = get_pte_virt_late;
    #ifndef __PAGETABLE_PMD_FOLDED
    	pt_ops.alloc_pmd = alloc_pmd_late;
    	pt_ops.get_pmd_virt = get_pmd_virt_late;
    #endif
    }
    #else
    asmlinkage void __init setup_vm(uintptr_t dtb_pa)
    {
    #ifdef CONFIG_BUILTIN_DTB
    	dtb_early_va = soc_lookup_builtin_dtb();
    	if (!dtb_early_va) {
    		/* Fallback to first available DTS */
    		dtb_early_va = (void *) __dtb_start;
    	}
    #else
    	dtb_early_va = (void *)dtb_pa;
    #endif
    	dtb_early_pa = dtb_pa;
    }
    
    static inline void setup_vm_final(void)
    {
    }
    #endif /* CONFIG_MMU */
    
    #ifdef CONFIG_STRICT_KERNEL_RWX
    void mark_rodata_ro(void)
    {
    	unsigned long text_start = (unsigned long)_text;
    	unsigned long text_end = (unsigned long)_etext;
    	unsigned long rodata_start = (unsigned long)__start_rodata;
    	unsigned long data_start = (unsigned long)_data;
    	unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));
    
    	set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
    	set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
    	set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
    	set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);
    
    	debug_checkwx();
    }
    #endif
    
    static void __init resource_init(void)
    {
    	struct memblock_region *region;
    
    	for_each_mem_region(region) {
    		struct resource *res;
    
    		res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
    		if (!res)
    			panic("%s: Failed to allocate %zu bytes\n", __func__,
    			      sizeof(struct resource));
    
    		if (memblock_is_nomap(region)) {
    			res->name = "reserved";
    			res->flags = IORESOURCE_MEM;
    		} else {
    			res->name = "System RAM";
    			res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
    		}
    		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
    		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
    
    		request_resource(&iomem_resource, res);
    	}
    }
    
    void __init paging_init(void)
    {
    	setup_vm_final();
    	sparse_init();
    	setup_zero_page();
    	zone_sizes_init();
    	resource_init();
    }
    
    #ifdef CONFIG_SPARSEMEM_VMEMMAP
    int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
    			       struct vmem_altmap *altmap)
    {
    	return vmemmap_populate_basepages(start, end, node, NULL);
    }
    #endif