arch/riscv/mm/init.c - linux/torvalds/linux - Git at Google

 // 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 <asm/fixmap.h>
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
 #include <asm/pgtable.h>
 #include <asm/io.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[];
 void *dtb_early_va;

 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_nodes(max_zone_pfns);
 }

 static void setup_zero_page(void)
 {
 	memset((void *)empty_zero_page, 0, PAGE_SIZE);
 }

 #ifdef 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)
 {
 	unsigned long size;

 	if (initrd_start >= initrd_end) {
 		pr_info("initrd not found or empty");
 		goto disable;
 	}
 	if (__pa_symbol(initrd_end) > PFN_PHYS(max_low_pfn)) {
 		pr_err("initrd extends beyond end of memory");
 		goto disable;
 	}

 	size = initrd_end - initrd_start;
 	memblock_reserve(__pa_symbol(initrd_start), 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 */

 static phys_addr_t dtb_early_pa __initdata;

 void __init setup_bootmem(void)
 {
 	struct memblock_region *reg;
 	phys_addr_t mem_size = 0;
 	phys_addr_t vmlinux_end = __pa_symbol(&_end);
 	phys_addr_t vmlinux_start = __pa_symbol(&_start);

 	/* Find the memory region containing the kernel */
 	for_each_memblock(memory, reg) {
 		phys_addr_t end = reg->base + reg->size;

 		if (reg->base <= vmlinux_end && vmlinux_end <= end) {
 			mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);

 			/*
 			 * Remove memblock from the end of usable area to the
 			 * end of region
 			 */
 			if (reg->base + mem_size < end)
 				memblock_remove(reg->base + mem_size,
 						end - reg->base - mem_size);
 		}
 	}
 	BUG_ON(mem_size == 0);

 	/* Reserve from the start of the kernel to the end of the kernel */
 	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);

 	set_max_mapnr(PFN_DOWN(mem_size));
 	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());

 #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();

 	for_each_memblock(memory, reg) {
 		unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
 		unsigned long end_pfn = memblock_region_memory_end_pfn(reg);

 		memblock_set_node(PFN_PHYS(start_pfn),
 				  PFN_PHYS(end_pfn - start_pfn),
 				  &memblock.memory, 0);
 	}
 }

 #ifdef CONFIG_MMU
 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;
 static bool mmu_enabled;

 #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 pte_t *__init get_pte_virt(phys_addr_t pa)
 {
 	if (mmu_enabled) {
 		clear_fixmap(FIX_PTE);
 		return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
 	} else {
 		return (pte_t *)((uintptr_t)pa);
 	}
 }

 static phys_addr_t __init alloc_pte(uintptr_t va)
 {
 	/*
 	 * We only create PMD or PGD early mappings so we
 	 * should never reach here with MMU disabled.
 	 */
 	BUG_ON(!mmu_enabled);

 	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
 }

 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_index = pte_index(va);

 	BUG_ON(sz != PAGE_SIZE);

 	if (pte_none(ptep[pte_index]))
 		ptep[pte_index] = 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);

 static pmd_t *__init get_pmd_virt(phys_addr_t pa)
 {
 	if (mmu_enabled) {
 		clear_fixmap(FIX_PMD);
 		return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
 	} else {
 		return (pmd_t *)((uintptr_t)pa);
 	}
 }

 static phys_addr_t __init alloc_pmd(uintptr_t va)
 {
 	uintptr_t pmd_num;

 	if (mmu_enabled)
 		return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);

 	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 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_index = pmd_index(va);

 	if (sz == PMD_SIZE) {
 		if (pmd_none(pmdp[pmd_index]))
 			pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pa), prot);
 		return;
 	}

 	if (pmd_none(pmdp[pmd_index])) {
 		pte_phys = alloc_pte(va);
 		pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
 		ptep = get_pte_virt(pte_phys);
 		memset(ptep, 0, PAGE_SIZE);
 	} else {
 		pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_index]));
 		ptep = get_pte_virt(pte_phys);
 	}

 	create_pte_mapping(ptep, va, pa, sz, prot);
 }

 #define pgd_next_t		pmd_t
 #define alloc_pgd_next(__va)	alloc_pmd(__va)
 #define get_pgd_next_virt(__pa)	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)	alloc_pte(__va)
 #define get_pgd_next_virt(__pa)	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

 static 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_index = pgd_index(va);

 	if (sz == PGDIR_SIZE) {
 		if (pgd_val(pgdp[pgd_index]) == 0)
 			pgdp[pgd_index] = pfn_pgd(PFN_DOWN(pa), prot);
 		return;
 	}

 	if (pgd_val(pgdp[pgd_index]) == 0) {
 		next_phys = alloc_pgd_next(va);
 		pgdp[pgd_index] = 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_index]));
 		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, 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);

 	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);

 	/* 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);

 	/* Create fixed mapping for early FDT parsing */
 	end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE;
 	for (va = __fix_to_virt(FIX_FDT); va < end_va; va += PAGE_SIZE)
 		create_pte_mapping(fixmap_pte, va,
 				   dtb_pa + (va - __fix_to_virt(FIX_FDT)),
 				   PAGE_SIZE, PAGE_KERNEL);

 	/* Save pointer to DTB for early FDT parsing */
 	dtb_early_va = (void *)fix_to_virt(FIX_FDT) + (dtb_pa & ~PAGE_MASK);
 	/* Save physical address for memblock reservation */
 	dtb_early_pa = dtb_pa;
 }

 static void __init setup_vm_final(void)
 {
 	uintptr_t va, map_size;
 	phys_addr_t pa, start, end;
 	struct memblock_region *reg;

 	/* Set mmu_enabled flag */
 	mmu_enabled = true;

 	/* 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_memblock(memory, reg) {
 		start = reg->base;
 		end = start + reg->size;

 		if (start >= end)
 			break;
 		if (memblock_is_nomap(reg))
 			continue;
 		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();
 }
 #else
 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 {
 	dtb_early_va = (void *)dtb_pa;
 }

 static inline void setup_vm_final(void)
 {
 }
 #endif /* CONFIG_MMU */

 void __init paging_init(void)
 {
 	setup_vm_final();
 	memblocks_present();
 	sparse_init();
 	setup_zero_page();
 	zone_sizes_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);
 }
 #endif
	// 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 <asm/fixmap.h>
	#include <asm/tlbflush.h>
	#include <asm/sections.h>
	#include <asm/pgtable.h>
	#include <asm/io.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[];
	void *dtb_early_va;

	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_nodes(max_zone_pfns);
	}

	static void setup_zero_page(void)
	{
	memset((void *)empty_zero_page, 0, PAGE_SIZE);
	}

	#ifdef 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)
	{
	unsigned long size;

	if (initrd_start >= initrd_end) {
	pr_info("initrd not found or empty");
	goto disable;
	}
	if (__pa_symbol(initrd_end) > PFN_PHYS(max_low_pfn)) {
	pr_err("initrd extends beyond end of memory");
	goto disable;
	}

	size = initrd_end - initrd_start;
	memblock_reserve(__pa_symbol(initrd_start), 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 */

	static phys_addr_t dtb_early_pa __initdata;

	void __init setup_bootmem(void)
	{
	struct memblock_region *reg;
	phys_addr_t mem_size = 0;
	phys_addr_t vmlinux_end = __pa_symbol(&_end);
	phys_addr_t vmlinux_start = __pa_symbol(&_start);

	/* Find the memory region containing the kernel */
	for_each_memblock(memory, reg) {
	phys_addr_t end = reg->base + reg->size;

	if (reg->base <= vmlinux_end && vmlinux_end <= end) {
	mem_size = min(reg->size, (phys_addr_t)-PAGE_OFFSET);

	/*
	* Remove memblock from the end of usable area to the
	* end of region
	*/
	if (reg->base + mem_size < end)
	memblock_remove(reg->base + mem_size,
	end - reg->base - mem_size);
	}
	}
	BUG_ON(mem_size == 0);

	/* Reserve from the start of the kernel to the end of the kernel */
	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);

	set_max_mapnr(PFN_DOWN(mem_size));
	max_low_pfn = PFN_DOWN(memblock_end_of_DRAM());

	#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();

	for_each_memblock(memory, reg) {
	unsigned long start_pfn = memblock_region_memory_base_pfn(reg);
	unsigned long end_pfn = memblock_region_memory_end_pfn(reg);

	memblock_set_node(PFN_PHYS(start_pfn),
	PFN_PHYS(end_pfn - start_pfn),
	&memblock.memory, 0);
	}
	}

	#ifdef CONFIG_MMU
	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;
	static bool mmu_enabled;

	#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 pte_t *__init get_pte_virt(phys_addr_t pa)
	{
	if (mmu_enabled) {
	clear_fixmap(FIX_PTE);
	return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
	} else {
	return (pte_t *)((uintptr_t)pa);
	}
	}

	static phys_addr_t __init alloc_pte(uintptr_t va)
	{
	/*
	* We only create PMD or PGD early mappings so we
	* should never reach here with MMU disabled.
	*/
	BUG_ON(!mmu_enabled);

	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
	}

	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_index = pte_index(va);

	BUG_ON(sz != PAGE_SIZE);

	if (pte_none(ptep[pte_index]))
	ptep[pte_index] = 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);

	static pmd_t *__init get_pmd_virt(phys_addr_t pa)
	{
	if (mmu_enabled) {
	clear_fixmap(FIX_PMD);
	return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
	} else {
	return (pmd_t *)((uintptr_t)pa);
	}
	}

	static phys_addr_t __init alloc_pmd(uintptr_t va)
	{
	uintptr_t pmd_num;

	if (mmu_enabled)
	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);

	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 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_index = pmd_index(va);

	if (sz == PMD_SIZE) {
	if (pmd_none(pmdp[pmd_index]))
	pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pa), prot);
	return;
	}

	if (pmd_none(pmdp[pmd_index])) {
	pte_phys = alloc_pte(va);
	pmdp[pmd_index] = pfn_pmd(PFN_DOWN(pte_phys), PAGE_TABLE);
	ptep = get_pte_virt(pte_phys);
	memset(ptep, 0, PAGE_SIZE);
	} else {
	pte_phys = PFN_PHYS(_pmd_pfn(pmdp[pmd_index]));
	ptep = get_pte_virt(pte_phys);
	}

	create_pte_mapping(ptep, va, pa, sz, prot);
	}

	#define pgd_next_t pmd_t
	#define alloc_pgd_next(__va) alloc_pmd(__va)
	#define get_pgd_next_virt(__pa) 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) alloc_pte(__va)
	#define get_pgd_next_virt(__pa) 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

	static 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_index = pgd_index(va);

	if (sz == PGDIR_SIZE) {
	if (pgd_val(pgdp[pgd_index]) == 0)
	pgdp[pgd_index] = pfn_pgd(PFN_DOWN(pa), prot);
	return;
	}

	if (pgd_val(pgdp[pgd_index]) == 0) {
	next_phys = alloc_pgd_next(va);
	pgdp[pgd_index] = 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_index]));
	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, 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);

	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);

	/* 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);

	/* Create fixed mapping for early FDT parsing */
	end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE;
	for (va = __fix_to_virt(FIX_FDT); va < end_va; va += PAGE_SIZE)
	create_pte_mapping(fixmap_pte, va,
	dtb_pa + (va - __fix_to_virt(FIX_FDT)),
	PAGE_SIZE, PAGE_KERNEL);

	/* Save pointer to DTB for early FDT parsing */
	dtb_early_va = (void *)fix_to_virt(FIX_FDT) + (dtb_pa & ~PAGE_MASK);
	/* Save physical address for memblock reservation */
	dtb_early_pa = dtb_pa;
	}

	static void __init setup_vm_final(void)
	{
	uintptr_t va, map_size;
	phys_addr_t pa, start, end;
	struct memblock_region *reg;

	/* Set mmu_enabled flag */
	mmu_enabled = true;

	/* 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_memblock(memory, reg) {
	start = reg->base;
	end = start + reg->size;

	if (start >= end)
	break;
	if (memblock_is_nomap(reg))
	continue;
	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();
	}
	#else
	asmlinkage void __init setup_vm(uintptr_t dtb_pa)
	{
	dtb_early_va = (void *)dtb_pa;
	}

	static inline void setup_vm_final(void)
	{
	}
	#endif /* CONFIG_MMU */

	void __init paging_init(void)
	{
	setup_vm_final();
	memblocks_present();
	sparse_init();
	setup_zero_page();
	zone_sizes_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);
	}
	#endif