// 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.
 * Copyright (C) 2020 FORTH-ICS/CARV
 *  Nick Kossifidis <mick@ics.forth.gr>
 */

#include <linux/init.h>
#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/initrd.h>
#include <linux/swap.h>
#include <linux/swiotlb.h>
#include <linux/sizes.h>
#include <linux/of_fdt.h>
#include <linux/of_reserved_mem.h>
#include <linux/libfdt.h>
#include <linux/set_memory.h>
#include <linux/dma-map-ops.h>
#include <linux/crash_dump.h>
#include <linux/hugetlb.h>
#ifdef CONFIG_RELOCATABLE
#include <linux/elf.h>
#endif
#include <linux/kfence.h>

#include <asm/fixmap.h>
#include <asm/io.h>
#include <asm/numa.h>
#include <asm/pgtable.h>
#include <asm/ptdump.h>
#include <asm/sections.h>
#include <asm/soc.h>
#include <asm/tlbflush.h>

#include "../kernel/head.h"

struct kernel_mapping kernel_map __ro_after_init;
EXPORT_SYMBOL(kernel_map);
#ifdef CONFIG_XIP_KERNEL
#define kernel_map	(*(struct kernel_mapping *)XIP_FIXUP(&kernel_map))
#endif

#ifdef CONFIG_64BIT
u64 satp_mode __ro_after_init = !IS_ENABLED(CONFIG_XIP_KERNEL) ? SATP_MODE_57 : SATP_MODE_39;
#else
u64 satp_mode __ro_after_init = SATP_MODE_32;
#endif
EXPORT_SYMBOL(satp_mode);

#ifdef CONFIG_64BIT
bool pgtable_l4_enabled = IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_XIP_KERNEL);
bool pgtable_l5_enabled = IS_ENABLED(CONFIG_64BIT) && !IS_ENABLED(CONFIG_XIP_KERNEL);
EXPORT_SYMBOL(pgtable_l4_enabled);
EXPORT_SYMBOL(pgtable_l5_enabled);
#endif

phys_addr_t phys_ram_base __ro_after_init;
EXPORT_SYMBOL(phys_ram_base);

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 __initdata;
uintptr_t _dtb_early_pa __initdata;

phys_addr_t dma32_phys_limit __initdata;

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(dma32_phys_limit);
#endif
	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;

	free_area_init(max_zone_pfns);
}

#if defined(CONFIG_MMU) && defined(CONFIG_DEBUG_VM)

#define LOG2_SZ_1K  ilog2(SZ_1K)
#define LOG2_SZ_1M  ilog2(SZ_1M)
#define LOG2_SZ_1G  ilog2(SZ_1G)
#define LOG2_SZ_1T  ilog2(SZ_1T)

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)) >> LOG2_SZ_1K));
}

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)) >> LOG2_SZ_1M));
}

static inline void print_mlg(char *name, unsigned long b, unsigned long t)
{
	pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld GB)\n", name, b, t,
		   (((t) - (b)) >> LOG2_SZ_1G));
}

#ifdef CONFIG_64BIT
static inline void print_mlt(char *name, unsigned long b, unsigned long t)
{
	pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld TB)\n", name, b, t,
		   (((t) - (b)) >> LOG2_SZ_1T));
}
#else
#define print_mlt(n, b, t) do {} while (0)
#endif

static inline void print_ml(char *name, unsigned long b, unsigned long t)
{
	unsigned long diff = t - b;

	if (IS_ENABLED(CONFIG_64BIT) && (diff >> LOG2_SZ_1T) >= 10)
		print_mlt(name, b, t);
	else if ((diff >> LOG2_SZ_1G) >= 10)
		print_mlg(name, b, t);
	else if ((diff >> LOG2_SZ_1M) >= 10)
		print_mlm(name, b, t);
	else
		print_mlk(name, b, t);
}

static void __init print_vm_layout(void)
{
	pr_notice("Virtual kernel memory layout:\n");
	print_ml("fixmap", (unsigned long)FIXADDR_START,
		(unsigned long)FIXADDR_TOP);
	print_ml("pci io", (unsigned long)PCI_IO_START,
		(unsigned long)PCI_IO_END);
	print_ml("vmemmap", (unsigned long)VMEMMAP_START,
		(unsigned long)VMEMMAP_END);
	print_ml("vmalloc", (unsigned long)VMALLOC_START,
		(unsigned long)VMALLOC_END);
#ifdef CONFIG_64BIT
	print_ml("modules", (unsigned long)MODULES_VADDR,
		(unsigned long)MODULES_END);
#endif
	print_ml("lowmem", (unsigned long)PAGE_OFFSET,
		(unsigned long)high_memory);
	if (IS_ENABLED(CONFIG_64BIT)) {
#ifdef CONFIG_KASAN
		print_ml("kasan", KASAN_SHADOW_START, KASAN_SHADOW_END);
#endif

		print_ml("kernel", (unsigned long)kernel_map.virt_addr,
			 (unsigned long)ADDRESS_SPACE_END);
	}
}
#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 */

	swiotlb_init(max_pfn > PFN_DOWN(dma32_phys_limit), SWIOTLB_VERBOSE);
	memblock_free_all();

	print_vm_layout();
}

/* Limit the memory size via mem. */
static phys_addr_t memory_limit;

static int __init early_mem(char *p)
{
	u64 size;

	if (!p)
		return 1;

	size = memparse(p, &p) & PAGE_MASK;
	memory_limit = min_t(u64, size, memory_limit);

	pr_notice("Memory limited to %lldMB\n", (u64)memory_limit >> 20);

	return 0;
}
early_param("mem", early_mem);

static void __init setup_bootmem(void)
{
	phys_addr_t vmlinux_end = __pa_symbol(&_end);
	phys_addr_t max_mapped_addr;
	phys_addr_t phys_ram_end, vmlinux_start;

	if (IS_ENABLED(CONFIG_XIP_KERNEL))
		vmlinux_start = __pa_symbol(&_sdata);
	else
		vmlinux_start = __pa_symbol(&_start);

	memblock_enforce_memory_limit(memory_limit);

	/*
	 * Make sure we align the reservation on PMD_SIZE since we will
	 * map the kernel in the linear mapping as read-only: we do not want
	 * any allocation to happen between _end and the next pmd aligned page.
	 */
	if (IS_ENABLED(CONFIG_64BIT) && IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
		vmlinux_end = (vmlinux_end + PMD_SIZE - 1) & PMD_MASK;
	/*
	 * Reserve from the start of the kernel to the end of the kernel
	 */
	memblock_reserve(vmlinux_start, vmlinux_end - vmlinux_start);

	phys_ram_end = memblock_end_of_DRAM();

	/*
	 * Make sure we align the start of the memory on a PMD boundary so that
	 * at worst, we map the linear mapping with PMD mappings.
	 */
	if (!IS_ENABLED(CONFIG_XIP_KERNEL))
		phys_ram_base = memblock_start_of_DRAM() & PMD_MASK;

	/*
	 * In 64-bit, any use of __va/__pa before this point is wrong as we
	 * did not know the start of DRAM before.
	 */
	if (IS_ENABLED(CONFIG_64BIT))
		kernel_map.va_pa_offset = PAGE_OFFSET - phys_ram_base;

	/*
	 * memblock allocator is not aware of the fact that last 4K bytes of
	 * the addressable memory can not be mapped because of IS_ERR_VALUE
	 * macro. Make sure that last 4k bytes are not usable by memblock
	 * if end of dram is equal to maximum addressable memory.  For 64-bit
	 * kernel, this problem can't happen here as the end of the virtual
	 * address space is occupied by the kernel mapping then this check must
	 * be done as soon as the kernel mapping base address is determined.
	 */
	if (!IS_ENABLED(CONFIG_64BIT)) {
		max_mapped_addr = __pa(~(ulong)0);
		if (max_mapped_addr == (phys_ram_end - 1))
			memblock_set_current_limit(max_mapped_addr - 4096);
	}

	min_low_pfn = PFN_UP(phys_ram_base);
	max_low_pfn = max_pfn = PFN_DOWN(phys_ram_end);
	high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));

	dma32_phys_limit = min(4UL * SZ_1G, (unsigned long)PFN_PHYS(max_low_pfn));
	set_max_mapnr(max_low_pfn - ARCH_PFN_OFFSET);

	reserve_initrd_mem();

	/*
	 * No allocation should be done before reserving the memory as defined
	 * in the device tree, otherwise the allocation could end up in a
	 * reserved region.
	 */
	early_init_fdt_scan_reserved_mem();

	/*
	 * If DTB is built in, no need to reserve its memblock.
	 * Otherwise, do reserve it but avoid using
	 * early_init_fdt_reserve_self() since __pa() does
	 * not work for DTB pointers that are fixmap addresses
	 */
	if (!IS_ENABLED(CONFIG_BUILTIN_DTB))
		memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));

	dma_contiguous_reserve(dma32_phys_limit);
	if (IS_ENABLED(CONFIG_64BIT))
		hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
}

#ifdef CONFIG_MMU
struct pt_alloc_ops pt_ops __initdata;

pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
pgd_t trampoline_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
static pte_t fixmap_pte[PTRS_PER_PTE] __page_aligned_bss;

pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);

#ifdef CONFIG_XIP_KERNEL
#define pt_ops			(*(struct pt_alloc_ops *)XIP_FIXUP(&pt_ops))
#define trampoline_pg_dir      ((pgd_t *)XIP_FIXUP(trampoline_pg_dir))
#define fixmap_pte             ((pte_t *)XIP_FIXUP(fixmap_pte))
#define early_pg_dir           ((pgd_t *)XIP_FIXUP(early_pg_dir))
#endif /* CONFIG_XIP_KERNEL */

static const pgprot_t protection_map[16] = {
	[VM_NONE]					= PAGE_NONE,
	[VM_READ]					= PAGE_READ,
	[VM_WRITE]					= PAGE_COPY,
	[VM_WRITE | VM_READ]				= PAGE_COPY,
	[VM_EXEC]					= PAGE_EXEC,
	[VM_EXEC | VM_READ]				= PAGE_READ_EXEC,
	[VM_EXEC | VM_WRITE]				= PAGE_COPY_EXEC,
	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY_EXEC,
	[VM_SHARED]					= PAGE_NONE,
	[VM_SHARED | VM_READ]				= PAGE_READ,
	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
	[VM_SHARED | VM_EXEC]				= PAGE_EXEC,
	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READ_EXEC,
	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED_EXEC,
	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED_EXEC
};
DECLARE_VM_GET_PAGE_PROT

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 *__init 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 __init alloc_pte_late(uintptr_t va)
{
	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);

	BUG_ON(!ptdesc || !pagetable_pte_ctor(ptdesc));
	return __pa((pte_t *)ptdesc_address(ptdesc));
}

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

static pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
static pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
static pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);

#ifdef CONFIG_XIP_KERNEL
#define trampoline_pmd ((pmd_t *)XIP_FIXUP(trampoline_pmd))
#define fixmap_pmd     ((pmd_t *)XIP_FIXUP(fixmap_pmd))
#define early_pmd      ((pmd_t *)XIP_FIXUP(early_pmd))
#endif /* CONFIG_XIP_KERNEL */

static p4d_t trampoline_p4d[PTRS_PER_P4D] __page_aligned_bss;
static p4d_t fixmap_p4d[PTRS_PER_P4D] __page_aligned_bss;
static p4d_t early_p4d[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);

#ifdef CONFIG_XIP_KERNEL
#define trampoline_p4d ((p4d_t *)XIP_FIXUP(trampoline_p4d))
#define fixmap_p4d     ((p4d_t *)XIP_FIXUP(fixmap_p4d))
#define early_p4d      ((p4d_t *)XIP_FIXUP(early_p4d))
#endif /* CONFIG_XIP_KERNEL */

static pud_t trampoline_pud[PTRS_PER_PUD] __page_aligned_bss;
static pud_t fixmap_pud[PTRS_PER_PUD] __page_aligned_bss;
static pud_t early_pud[PTRS_PER_PUD] __initdata __aligned(PAGE_SIZE);

#ifdef CONFIG_XIP_KERNEL
#define trampoline_pud ((pud_t *)XIP_FIXUP(trampoline_pud))
#define fixmap_pud     ((pud_t *)XIP_FIXUP(fixmap_pud))
#define early_pud      ((pud_t *)XIP_FIXUP(early_pud))
#endif /* CONFIG_XIP_KERNEL */

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 *__init get_pmd_virt_late(phys_addr_t pa)
{
	return (pmd_t *) __va(pa);
}

static phys_addr_t __init alloc_pmd_early(uintptr_t va)
{
	BUG_ON((va - kernel_map.virt_addr) >> PUD_SHIFT);

	return (uintptr_t)early_pmd;
}

static phys_addr_t __init alloc_pmd_fixmap(uintptr_t va)
{
	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
}

static phys_addr_t __init alloc_pmd_late(uintptr_t va)
{
	struct ptdesc *ptdesc = pagetable_alloc(GFP_KERNEL & ~__GFP_HIGHMEM, 0);

	BUG_ON(!ptdesc || !pagetable_pmd_ctor(ptdesc));
	return __pa((pmd_t *)ptdesc_address(ptdesc));
}

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);
}

static pud_t *__init get_pud_virt_early(phys_addr_t pa)
{
	return (pud_t *)((uintptr_t)pa);
}

static pud_t *__init get_pud_virt_fixmap(phys_addr_t pa)
{
	clear_fixmap(FIX_PUD);
	return (pud_t *)set_fixmap_offset(FIX_PUD, pa);
}

static pud_t *__init get_pud_virt_late(phys_addr_t pa)
{
	return (pud_t *)__va(pa);
}

static phys_addr_t __init alloc_pud_early(uintptr_t va)
{
	/* Only one PUD is available for early mapping */
	BUG_ON((va - kernel_map.virt_addr) >> PGDIR_SHIFT);

	return (uintptr_t)early_pud;
}

static phys_addr_t __init alloc_pud_fixmap(uintptr_t va)
{
	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
}

static phys_addr_t alloc_pud_late(uintptr_t va)
{
	unsigned long vaddr;

	vaddr = __get_free_page(GFP_KERNEL);
	BUG_ON(!vaddr);
	return __pa(vaddr);
}

static p4d_t *__init get_p4d_virt_early(phys_addr_t pa)
{
	return (p4d_t *)((uintptr_t)pa);
}

static p4d_t *__init get_p4d_virt_fixmap(phys_addr_t pa)
{
	clear_fixmap(FIX_P4D);
	return (p4d_t *)set_fixmap_offset(FIX_P4D, pa);
}

static p4d_t *__init get_p4d_virt_late(phys_addr_t pa)
{
	return (p4d_t *)__va(pa);
}

static phys_addr_t __init alloc_p4d_early(uintptr_t va)
{
	/* Only one P4D is available for early mapping */
	BUG_ON((va - kernel_map.virt_addr) >> PGDIR_SHIFT);

	return (uintptr_t)early_p4d;
}

static phys_addr_t __init alloc_p4d_fixmap(uintptr_t va)
{
	return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
}

static phys_addr_t alloc_p4d_late(uintptr_t va)
{
	unsigned long vaddr;

	vaddr = __get_free_page(GFP_KERNEL);
	BUG_ON(!vaddr);
	return __pa(vaddr);
}

static void __init create_pud_mapping(pud_t *pudp,
				      uintptr_t va, phys_addr_t pa,
				      phys_addr_t sz, pgprot_t prot)
{
	pmd_t *nextp;
	phys_addr_t next_phys;
	uintptr_t pud_index = pud_index(va);

	if (sz == PUD_SIZE) {
		if (pud_val(pudp[pud_index]) == 0)
			pudp[pud_index] = pfn_pud(PFN_DOWN(pa), prot);
		return;
	}

	if (pud_val(pudp[pud_index]) == 0) {
		next_phys = pt_ops.alloc_pmd(va);
		pudp[pud_index] = pfn_pud(PFN_DOWN(next_phys), PAGE_TABLE);
		nextp = pt_ops.get_pmd_virt(next_phys);
		memset(nextp, 0, PAGE_SIZE);
	} else {
		next_phys = PFN_PHYS(_pud_pfn(pudp[pud_index]));
		nextp = pt_ops.get_pmd_virt(next_phys);
	}

	create_pmd_mapping(nextp, va, pa, sz, prot);
}

static void __init create_p4d_mapping(p4d_t *p4dp,
				      uintptr_t va, phys_addr_t pa,
				      phys_addr_t sz, pgprot_t prot)
{
	pud_t *nextp;
	phys_addr_t next_phys;
	uintptr_t p4d_index = p4d_index(va);

	if (sz == P4D_SIZE) {
		if (p4d_val(p4dp[p4d_index]) == 0)
			p4dp[p4d_index] = pfn_p4d(PFN_DOWN(pa), prot);
		return;
	}

	if (p4d_val(p4dp[p4d_index]) == 0) {
		next_phys = pt_ops.alloc_pud(va);
		p4dp[p4d_index] = pfn_p4d(PFN_DOWN(next_phys), PAGE_TABLE);
		nextp = pt_ops.get_pud_virt(next_phys);
		memset(nextp, 0, PAGE_SIZE);
	} else {
		next_phys = PFN_PHYS(_p4d_pfn(p4dp[p4d_index]));
		nextp = pt_ops.get_pud_virt(next_phys);
	}

	create_pud_mapping(nextp, va, pa, sz, prot);
}

#define pgd_next_t		p4d_t
#define alloc_pgd_next(__va)	(pgtable_l5_enabled ?			\
		pt_ops.alloc_p4d(__va) : (pgtable_l4_enabled ?		\
		pt_ops.alloc_pud(__va) : pt_ops.alloc_pmd(__va)))
#define get_pgd_next_virt(__pa)	(pgtable_l5_enabled ?			\
		pt_ops.get_p4d_virt(__pa) : (pgd_next_t *)(pgtable_l4_enabled ?	\
		pt_ops.get_pud_virt(__pa) : (pud_t *)pt_ops.get_pmd_virt(__pa)))
#define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)	\
				(pgtable_l5_enabled ?			\
		create_p4d_mapping(__nextp, __va, __pa, __sz, __prot) : \
				(pgtable_l4_enabled ?			\
		create_pud_mapping((pud_t *)__nextp, __va, __pa, __sz, __prot) :	\
		create_pmd_mapping((pmd_t *)__nextp, __va, __pa, __sz, __prot)))
#define fixmap_pgd_next		(pgtable_l5_enabled ?			\
		(uintptr_t)fixmap_p4d : (pgtable_l4_enabled ?		\
		(uintptr_t)fixmap_pud : (uintptr_t)fixmap_pmd))
#define trampoline_pgd_next	(pgtable_l5_enabled ?			\
		(uintptr_t)trampoline_p4d : (pgtable_l4_enabled ?	\
		(uintptr_t)trampoline_pud : (uintptr_t)trampoline_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		((uintptr_t)fixmap_pte)
#define create_p4d_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
#define create_pud_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
#define create_pmd_mapping(__pmdp, __va, __pa, __sz, __prot) do {} while(0)
#endif /* __PAGETABLE_PMD_FOLDED */

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 pa, uintptr_t va,
				      phys_addr_t size)
{
	if (!(pa & (PGDIR_SIZE - 1)) && !(va & (PGDIR_SIZE - 1)) && size >= PGDIR_SIZE)
		return PGDIR_SIZE;

	if (!(pa & (P4D_SIZE - 1)) && !(va & (P4D_SIZE - 1)) && size >= P4D_SIZE)
		return P4D_SIZE;

	if (!(pa & (PUD_SIZE - 1)) && !(va & (PUD_SIZE - 1)) && size >= PUD_SIZE)
		return PUD_SIZE;

	if (!(pa & (PMD_SIZE - 1)) && !(va & (PMD_SIZE - 1)) && size >= PMD_SIZE)
		return PMD_SIZE;

	return PAGE_SIZE;
}

#ifdef CONFIG_XIP_KERNEL
#define phys_ram_base  (*(phys_addr_t *)XIP_FIXUP(&phys_ram_base))
extern char _xiprom[], _exiprom[], __data_loc;

/* called from head.S with MMU off */
asmlinkage void __init __copy_data(void)
{
	void *from = (void *)(&__data_loc);
	void *to = (void *)CONFIG_PHYS_RAM_BASE;
	size_t sz = (size_t)((uintptr_t)(&_end) - (uintptr_t)(&_sdata));

	memcpy(to, from, sz);
}
#endif

#ifdef CONFIG_STRICT_KERNEL_RWX
static __init pgprot_t pgprot_from_va(uintptr_t va)
{
	if (is_va_kernel_text(va))
		return PAGE_KERNEL_READ_EXEC;

	/*
	 * In 64-bit kernel, the kernel mapping is outside the linear mapping so
	 * we must protect its linear mapping alias from being executed and
	 * written.
	 * And rodata section is marked readonly in mark_rodata_ro.
	 */
	if (IS_ENABLED(CONFIG_64BIT) && is_va_kernel_lm_alias_text(va))
		return PAGE_KERNEL_READ;

	return PAGE_KERNEL;
}

void mark_rodata_ro(void)
{
	set_kernel_memory(__start_rodata, _data, set_memory_ro);
	if (IS_ENABLED(CONFIG_64BIT))
		set_kernel_memory(lm_alias(__start_rodata), lm_alias(_data),
				  set_memory_ro);

	debug_checkwx();
}
#else
static __init pgprot_t pgprot_from_va(uintptr_t va)
{
	if (IS_ENABLED(CONFIG_64BIT) && !is_kernel_mapping(va))
		return PAGE_KERNEL;

	return PAGE_KERNEL_EXEC;
}
#endif /* CONFIG_STRICT_KERNEL_RWX */

#if defined(CONFIG_64BIT) && !defined(CONFIG_XIP_KERNEL)
u64 __pi_set_satp_mode_from_cmdline(uintptr_t dtb_pa);

static void __init disable_pgtable_l5(void)
{
	pgtable_l5_enabled = false;
	kernel_map.page_offset = PAGE_OFFSET_L4;
	satp_mode = SATP_MODE_48;
}

static void __init disable_pgtable_l4(void)
{
	pgtable_l4_enabled = false;
	kernel_map.page_offset = PAGE_OFFSET_L3;
	satp_mode = SATP_MODE_39;
}

static int __init print_no4lvl(char *p)
{
	pr_info("Disabled 4-level and 5-level paging");
	return 0;
}
early_param("no4lvl", print_no4lvl);

static int __init print_no5lvl(char *p)
{
	pr_info("Disabled 5-level paging");
	return 0;
}
early_param("no5lvl", print_no5lvl);

/*
 * There is a simple way to determine if 4-level is supported by the
 * underlying hardware: establish 1:1 mapping in 4-level page table mode
 * then read SATP to see if the configuration was taken into account
 * meaning sv48 is supported.
 */
static __init void set_satp_mode(uintptr_t dtb_pa)
{
	u64 identity_satp, hw_satp;
	uintptr_t set_satp_mode_pmd = ((unsigned long)set_satp_mode) & PMD_MASK;
	u64 satp_mode_cmdline = __pi_set_satp_mode_from_cmdline(dtb_pa);

	if (satp_mode_cmdline == SATP_MODE_57) {
		disable_pgtable_l5();
	} else if (satp_mode_cmdline == SATP_MODE_48) {
		disable_pgtable_l5();
		disable_pgtable_l4();
		return;
	}

	create_p4d_mapping(early_p4d,
			set_satp_mode_pmd, (uintptr_t)early_pud,
			P4D_SIZE, PAGE_TABLE);
	create_pud_mapping(early_pud,
			   set_satp_mode_pmd, (uintptr_t)early_pmd,
			   PUD_SIZE, PAGE_TABLE);
	/* Handle the case where set_satp_mode straddles 2 PMDs */
	create_pmd_mapping(early_pmd,
			   set_satp_mode_pmd, set_satp_mode_pmd,
			   PMD_SIZE, PAGE_KERNEL_EXEC);
	create_pmd_mapping(early_pmd,
			   set_satp_mode_pmd + PMD_SIZE,
			   set_satp_mode_pmd + PMD_SIZE,
			   PMD_SIZE, PAGE_KERNEL_EXEC);
retry:
	create_pgd_mapping(early_pg_dir,
			   set_satp_mode_pmd,
			   pgtable_l5_enabled ?
				(uintptr_t)early_p4d : (uintptr_t)early_pud,
			   PGDIR_SIZE, PAGE_TABLE);

	identity_satp = PFN_DOWN((uintptr_t)&early_pg_dir) | satp_mode;

	local_flush_tlb_all();
	csr_write(CSR_SATP, identity_satp);
	hw_satp = csr_swap(CSR_SATP, 0ULL);
	local_flush_tlb_all();

	if (hw_satp != identity_satp) {
		if (pgtable_l5_enabled) {
			disable_pgtable_l5();
			memset(early_pg_dir, 0, PAGE_SIZE);
			goto retry;
		}
		disable_pgtable_l4();
	}

	memset(early_pg_dir, 0, PAGE_SIZE);
	memset(early_p4d, 0, PAGE_SIZE);
	memset(early_pud, 0, PAGE_SIZE);
	memset(early_pmd, 0, PAGE_SIZE);
}
#endif

/*
 * 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

#ifdef CONFIG_RELOCATABLE
extern unsigned long __rela_dyn_start, __rela_dyn_end;

static void __init relocate_kernel(void)
{
	Elf64_Rela *rela = (Elf64_Rela *)&__rela_dyn_start;
	/*
	 * This holds the offset between the linked virtual address and the
	 * relocated virtual address.
	 */
	uintptr_t reloc_offset = kernel_map.virt_addr - KERNEL_LINK_ADDR;
	/*
	 * This holds the offset between kernel linked virtual address and
	 * physical address.
	 */
	uintptr_t va_kernel_link_pa_offset = KERNEL_LINK_ADDR - kernel_map.phys_addr;

	for ( ; rela < (Elf64_Rela *)&__rela_dyn_end; rela++) {
		Elf64_Addr addr = (rela->r_offset - va_kernel_link_pa_offset);
		Elf64_Addr relocated_addr = rela->r_addend;

		if (rela->r_info != R_RISCV_RELATIVE)
			continue;

		/*
		 * Make sure to not relocate vdso symbols like rt_sigreturn
		 * which are linked from the address 0 in vmlinux since
		 * vdso symbol addresses are actually used as an offset from
		 * mm->context.vdso in VDSO_OFFSET macro.
		 */
		if (relocated_addr >= KERNEL_LINK_ADDR)
			relocated_addr += reloc_offset;

		*(Elf64_Addr *)addr = relocated_addr;
	}
}
#endif /* CONFIG_RELOCATABLE */

#ifdef CONFIG_XIP_KERNEL
static void __init create_kernel_page_table(pgd_t *pgdir,
					    __always_unused bool early)
{
	uintptr_t va, end_va;

	/* Map the flash resident part */
	end_va = kernel_map.virt_addr + kernel_map.xiprom_sz;
	for (va = kernel_map.virt_addr; va < end_va; va += PMD_SIZE)
		create_pgd_mapping(pgdir, va,
				   kernel_map.xiprom + (va - kernel_map.virt_addr),
				   PMD_SIZE, PAGE_KERNEL_EXEC);

	/* Map the data in RAM */
	end_va = kernel_map.virt_addr + XIP_OFFSET + kernel_map.size;
	for (va = kernel_map.virt_addr + XIP_OFFSET; va < end_va; va += PMD_SIZE)
		create_pgd_mapping(pgdir, va,
				   kernel_map.phys_addr + (va - (kernel_map.virt_addr + XIP_OFFSET)),
				   PMD_SIZE, PAGE_KERNEL);
}
#else
static void __init create_kernel_page_table(pgd_t *pgdir, bool early)
{
	uintptr_t va, end_va;

	end_va = kernel_map.virt_addr + kernel_map.size;
	for (va = kernel_map.virt_addr; va < end_va; va += PMD_SIZE)
		create_pgd_mapping(pgdir, va,
				   kernel_map.phys_addr + (va - kernel_map.virt_addr),
				   PMD_SIZE,
				   early ?
					PAGE_KERNEL_EXEC : pgprot_from_va(va));
}
#endif

/*
 * Setup a 4MB mapping that encompasses the device tree: for 64-bit kernel,
 * this means 2 PMD entries whereas for 32-bit kernel, this is only 1 PGDIR
 * entry.
 */
static void __init create_fdt_early_page_table(uintptr_t fix_fdt_va,
					       uintptr_t dtb_pa)
{
#ifndef CONFIG_BUILTIN_DTB
	uintptr_t pa = dtb_pa & ~(PMD_SIZE - 1);

	/* Make sure the fdt fixmap address is always aligned on PMD size */
	BUILD_BUG_ON(FIX_FDT % (PMD_SIZE / PAGE_SIZE));

	/* In 32-bit only, the fdt lies in its own PGD */
	if (!IS_ENABLED(CONFIG_64BIT)) {
		create_pgd_mapping(early_pg_dir, fix_fdt_va,
				   pa, MAX_FDT_SIZE, PAGE_KERNEL);
	} else {
		create_pmd_mapping(fixmap_pmd, fix_fdt_va,
				   pa, PMD_SIZE, PAGE_KERNEL);
		create_pmd_mapping(fixmap_pmd, fix_fdt_va + PMD_SIZE,
				   pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
	}

	dtb_early_va = (void *)fix_fdt_va + (dtb_pa & (PMD_SIZE - 1));
#else
	/*
	 * For 64-bit kernel, __va can't be used since it would return a linear
	 * mapping address whereas dtb_early_va will be used before
	 * setup_vm_final installs the linear mapping. For 32-bit kernel, as the
	 * kernel is mapped in the linear mapping, that makes no difference.
	 */
	dtb_early_va = kernel_mapping_pa_to_va(XIP_FIXUP(dtb_pa));
#endif

	dtb_early_pa = dtb_pa;
}

/*
 * MMU is not enabled, the page tables are allocated directly using
 * early_pmd/pud/p4d and the address returned is the physical one.
 */
static void __init pt_ops_set_early(void)
{
	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;
	pt_ops.alloc_pud = alloc_pud_early;
	pt_ops.get_pud_virt = get_pud_virt_early;
	pt_ops.alloc_p4d = alloc_p4d_early;
	pt_ops.get_p4d_virt = get_p4d_virt_early;
#endif
}

/*
 * MMU is enabled but page table setup is not complete yet.
 * fixmap page table alloc functions must be used as a means to temporarily
 * map the allocated physical pages since the linear mapping does not exist yet.
 *
 * Note that this is called with MMU disabled, hence kernel_mapping_pa_to_va,
 * but it will be used as described above.
 */
static void __init pt_ops_set_fixmap(void)
{
	pt_ops.alloc_pte = kernel_mapping_pa_to_va(alloc_pte_fixmap);
	pt_ops.get_pte_virt = kernel_mapping_pa_to_va(get_pte_virt_fixmap);
#ifndef __PAGETABLE_PMD_FOLDED
	pt_ops.alloc_pmd = kernel_mapping_pa_to_va(alloc_pmd_fixmap);
	pt_ops.get_pmd_virt = kernel_mapping_pa_to_va(get_pmd_virt_fixmap);
	pt_ops.alloc_pud = kernel_mapping_pa_to_va(alloc_pud_fixmap);
	pt_ops.get_pud_virt = kernel_mapping_pa_to_va(get_pud_virt_fixmap);
	pt_ops.alloc_p4d = kernel_mapping_pa_to_va(alloc_p4d_fixmap);
	pt_ops.get_p4d_virt = kernel_mapping_pa_to_va(get_p4d_virt_fixmap);
#endif
}

/*
 * MMU is enabled and page table setup is complete, so from now, we can use
 * generic page allocation functions to setup page table.
 */
static void __init pt_ops_set_late(void)
{
	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;
	pt_ops.alloc_pud = alloc_pud_late;
	pt_ops.get_pud_virt = get_pud_virt_late;
	pt_ops.alloc_p4d = alloc_p4d_late;
	pt_ops.get_p4d_virt = get_p4d_virt_late;
#endif
}

#ifdef CONFIG_RANDOMIZE_BASE
extern bool __init __pi_set_nokaslr_from_cmdline(uintptr_t dtb_pa);
extern u64 __init __pi_get_kaslr_seed(uintptr_t dtb_pa);

static int __init print_nokaslr(char *p)
{
	pr_info("Disabled KASLR");
	return 0;
}
early_param("nokaslr", print_nokaslr);

unsigned long kaslr_offset(void)
{
	return kernel_map.virt_offset;
}
#endif

asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
	pmd_t __maybe_unused fix_bmap_spmd, fix_bmap_epmd;

#ifdef CONFIG_RANDOMIZE_BASE
	if (!__pi_set_nokaslr_from_cmdline(dtb_pa)) {
		u64 kaslr_seed = __pi_get_kaslr_seed(dtb_pa);
		u32 kernel_size = (uintptr_t)(&_end) - (uintptr_t)(&_start);
		u32 nr_pos;

		/*
		 * Compute the number of positions available: we are limited
		 * by the early page table that only has one PUD and we must
		 * be aligned on PMD_SIZE.
		 */
		nr_pos = (PUD_SIZE - kernel_size) / PMD_SIZE;

		kernel_map.virt_offset = (kaslr_seed % nr_pos) * PMD_SIZE;
	}
#endif

	kernel_map.virt_addr = KERNEL_LINK_ADDR + kernel_map.virt_offset;
	kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL);

#ifdef CONFIG_XIP_KERNEL
	kernel_map.xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR;
	kernel_map.xiprom_sz = (uintptr_t)(&_exiprom) - (uintptr_t)(&_xiprom);

	phys_ram_base = CONFIG_PHYS_RAM_BASE;
	kernel_map.phys_addr = (uintptr_t)CONFIG_PHYS_RAM_BASE;
	kernel_map.size = (uintptr_t)(&_end) - (uintptr_t)(&_sdata);

	kernel_map.va_kernel_xip_pa_offset = kernel_map.virt_addr - kernel_map.xiprom;
#else
	kernel_map.phys_addr = (uintptr_t)(&_start);
	kernel_map.size = (uintptr_t)(&_end) - kernel_map.phys_addr;
#endif

#if defined(CONFIG_64BIT) && !defined(CONFIG_XIP_KERNEL)
	set_satp_mode(dtb_pa);
#endif

	/*
	 * In 64-bit, we defer the setup of va_pa_offset to setup_bootmem,
	 * where we have the system memory layout: this allows us to align
	 * the physical and virtual mappings and then make use of PUD/P4D/PGD
	 * for the linear mapping. This is only possible because the kernel
	 * mapping lies outside the linear mapping.
	 * In 32-bit however, as the kernel resides in the linear mapping,
	 * setup_vm_final can not change the mapping established here,
	 * otherwise the same kernel addresses would get mapped to different
	 * physical addresses (if the start of dram is different from the
	 * kernel physical address start).
	 */
	kernel_map.va_pa_offset = IS_ENABLED(CONFIG_64BIT) ?
				0UL : PAGE_OFFSET - kernel_map.phys_addr;
	kernel_map.va_kernel_pa_offset = kernel_map.virt_addr - kernel_map.phys_addr;

	/*
	 * The default maximal physical memory size is KERN_VIRT_SIZE for 32-bit
	 * kernel, whereas for 64-bit kernel, the end of the virtual address
	 * space is occupied by the modules/BPF/kernel mappings which reduces
	 * the available size of the linear mapping.
	 */
	memory_limit = KERN_VIRT_SIZE - (IS_ENABLED(CONFIG_64BIT) ? SZ_4G : 0);

	/* Sanity check alignment and size */
	BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
	BUG_ON((kernel_map.phys_addr % PMD_SIZE) != 0);

#ifdef CONFIG_64BIT
	/*
	 * The last 4K bytes of the addressable memory can not be mapped because
	 * of IS_ERR_VALUE macro.
	 */
	BUG_ON((kernel_map.virt_addr + kernel_map.size) > ADDRESS_SPACE_END - SZ_4K);
#endif

#ifdef CONFIG_RELOCATABLE
	/*
	 * Early page table uses only one PUD, which makes it possible
	 * to map PUD_SIZE aligned on PUD_SIZE: if the relocation offset
	 * makes the kernel cross over a PUD_SIZE boundary, raise a bug
	 * since a part of the kernel would not get mapped.
	 */
	BUG_ON(PUD_SIZE - (kernel_map.virt_addr & (PUD_SIZE - 1)) < kernel_map.size);
	relocate_kernel();
#endif

	apply_early_boot_alternatives();
	pt_ops_set_early();

	/* Setup early PGD for fixmap */
	create_pgd_mapping(early_pg_dir, FIXADDR_START,
			   fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);

#ifndef __PAGETABLE_PMD_FOLDED
	/* Setup fixmap P4D and PUD */
	if (pgtable_l5_enabled)
		create_p4d_mapping(fixmap_p4d, FIXADDR_START,
				   (uintptr_t)fixmap_pud, P4D_SIZE, PAGE_TABLE);
	/* Setup fixmap PUD and PMD */
	if (pgtable_l4_enabled)
		create_pud_mapping(fixmap_pud, FIXADDR_START,
				   (uintptr_t)fixmap_pmd, PUD_SIZE, PAGE_TABLE);
	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, kernel_map.virt_addr,
			   trampoline_pgd_next, PGDIR_SIZE, PAGE_TABLE);
	if (pgtable_l5_enabled)
		create_p4d_mapping(trampoline_p4d, kernel_map.virt_addr,
				   (uintptr_t)trampoline_pud, P4D_SIZE, PAGE_TABLE);
	if (pgtable_l4_enabled)
		create_pud_mapping(trampoline_pud, kernel_map.virt_addr,
				   (uintptr_t)trampoline_pmd, PUD_SIZE, PAGE_TABLE);
#ifdef CONFIG_XIP_KERNEL
	create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
			   kernel_map.xiprom, PMD_SIZE, PAGE_KERNEL_EXEC);
#else
	create_pmd_mapping(trampoline_pmd, kernel_map.virt_addr,
			   kernel_map.phys_addr, PMD_SIZE, PAGE_KERNEL_EXEC);
#endif
#else
	/* Setup trampoline PGD */
	create_pgd_mapping(trampoline_pg_dir, kernel_map.virt_addr,
			   kernel_map.phys_addr, PGDIR_SIZE, PAGE_KERNEL_EXEC);
#endif

	/*
	 * Setup early PGD covering entire kernel which will allow
	 * us to reach paging_init(). We map all memory banks later
	 * in setup_vm_final() below.
	 */
	create_kernel_page_table(early_pg_dir, true);

	/* Setup early mapping for FDT early scan */
	create_fdt_early_page_table(__fix_to_virt(FIX_FDT), dtb_pa);

	/*
	 * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
	 * range can not span multiple pmds.
	 */
	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

	pt_ops_set_fixmap();
}

static void __init create_linear_mapping_range(phys_addr_t start,
					       phys_addr_t end,
					       uintptr_t fixed_map_size)
{
	phys_addr_t pa;
	uintptr_t va, map_size;

	for (pa = start; pa < end; pa += map_size) {
		va = (uintptr_t)__va(pa);
		map_size = fixed_map_size ? fixed_map_size :
					    best_map_size(pa, va, end - pa);

		create_pgd_mapping(swapper_pg_dir, va, pa, map_size,
				   pgprot_from_va(va));
	}
}

static void __init create_linear_mapping_page_table(void)
{
	phys_addr_t start, end;
	phys_addr_t kfence_pool __maybe_unused;
	u64 i;

#ifdef CONFIG_STRICT_KERNEL_RWX
	phys_addr_t ktext_start = __pa_symbol(_start);
	phys_addr_t ktext_size = __init_data_begin - _start;
	phys_addr_t krodata_start = __pa_symbol(__start_rodata);
	phys_addr_t krodata_size = _data - __start_rodata;

	/* Isolate kernel text and rodata so they don't get mapped with a PUD */
	memblock_mark_nomap(ktext_start,  ktext_size);
	memblock_mark_nomap(krodata_start, krodata_size);
#endif

#ifdef CONFIG_KFENCE
	/*
	 *  kfence pool must be backed by PAGE_SIZE mappings, so allocate it
	 *  before we setup the linear mapping so that we avoid using hugepages
	 *  for this region.
	 */
	kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE);
	BUG_ON(!kfence_pool);

	memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE);
	__kfence_pool = __va(kfence_pool);
#endif

	/* Map all memory banks in the linear mapping */
	for_each_mem_range(i, &start, &end) {
		if (start >= end)
			break;
		if (start <= __pa(PAGE_OFFSET) &&
		    __pa(PAGE_OFFSET) < end)
			start = __pa(PAGE_OFFSET);
		if (end >= __pa(PAGE_OFFSET) + memory_limit)
			end = __pa(PAGE_OFFSET) + memory_limit;

		create_linear_mapping_range(start, end, 0);
	}

#ifdef CONFIG_STRICT_KERNEL_RWX
	create_linear_mapping_range(ktext_start, ktext_start + ktext_size, 0);
	create_linear_mapping_range(krodata_start,
				    krodata_start + krodata_size, 0);

	memblock_clear_nomap(ktext_start,  ktext_size);
	memblock_clear_nomap(krodata_start, krodata_size);
#endif

#ifdef CONFIG_KFENCE
	create_linear_mapping_range(kfence_pool,
				    kfence_pool + KFENCE_POOL_SIZE,
				    PAGE_SIZE);

	memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE);
#endif
}

static void __init setup_vm_final(void)
{
	/* Setup swapper PGD for fixmap */
#if !defined(CONFIG_64BIT)
	/*
	 * In 32-bit, the device tree lies in a pgd entry, so it must be copied
	 * directly in swapper_pg_dir in addition to the pgd entry that points
	 * to fixmap_pte.
	 */
	unsigned long idx = pgd_index(__fix_to_virt(FIX_FDT));

	set_pgd(&swapper_pg_dir[idx], early_pg_dir[idx]);
#endif
	create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
			   __pa_symbol(fixmap_pgd_next),
			   PGDIR_SIZE, PAGE_TABLE);

	/* Map the linear mapping */
	create_linear_mapping_page_table();

	/* Map the kernel */
	if (IS_ENABLED(CONFIG_64BIT))
		create_kernel_page_table(swapper_pg_dir, false);

#ifdef CONFIG_KASAN
	kasan_swapper_init();
#endif

	/* Clear fixmap PTE and PMD mappings */
	clear_fixmap(FIX_PTE);
	clear_fixmap(FIX_PMD);
	clear_fixmap(FIX_PUD);
	clear_fixmap(FIX_P4D);

	/* Move to swapper page table */
	csr_write(CSR_SATP, PFN_DOWN(__pa_symbol(swapper_pg_dir)) | satp_mode);
	local_flush_tlb_all();

	pt_ops_set_late();
}
#else
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
	dtb_early_va = (void *)dtb_pa;
	dtb_early_pa = dtb_pa;
}

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

/*
 * reserve_crashkernel() - reserves memory for crash kernel
 *
 * This function reserves memory area given in "crashkernel=" kernel command
 * line parameter. The memory reserved is used by dump capture kernel when
 * primary kernel is crashing.
 */
static void __init arch_reserve_crashkernel(void)
{
	unsigned long long low_size = 0;
	unsigned long long crash_base, crash_size;
	char *cmdline = boot_command_line;
	bool high = false;
	int ret;

	if (!IS_ENABLED(CONFIG_KEXEC_CORE))
		return;

	ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
				&crash_size, &crash_base,
				&low_size, &high);
	if (ret)
		return;

	reserve_crashkernel_generic(cmdline, crash_size, crash_base,
				    low_size, high);
}

void __init paging_init(void)
{
	setup_bootmem();
	setup_vm_final();

	/* Depend on that Linear Mapping is ready */
	memblock_allow_resize();
}

void __init misc_mem_init(void)
{
	early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT);
	arch_numa_init();
	sparse_init();
	zone_sizes_init();
	arch_reserve_crashkernel();
	memblock_dump_all();
}

#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

#if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
/*
 * Pre-allocates page-table pages for a specific area in the kernel
 * page-table. Only the level which needs to be synchronized between
 * all page-tables is allocated because the synchronization can be
 * expensive.
 */
static void __init preallocate_pgd_pages_range(unsigned long start, unsigned long end,
					       const char *area)
{
	unsigned long addr;
	const char *lvl;

	for (addr = start; addr < end && addr >= start; addr = ALIGN(addr + 1, PGDIR_SIZE)) {
		pgd_t *pgd = pgd_offset_k(addr);
		p4d_t *p4d;
		pud_t *pud;
		pmd_t *pmd;

		lvl = "p4d";
		p4d = p4d_alloc(&init_mm, pgd, addr);
		if (!p4d)
			goto failed;

		if (pgtable_l5_enabled)
			continue;

		lvl = "pud";
		pud = pud_alloc(&init_mm, p4d, addr);
		if (!pud)
			goto failed;

		if (pgtable_l4_enabled)
			continue;

		lvl = "pmd";
		pmd = pmd_alloc(&init_mm, pud, addr);
		if (!pmd)
			goto failed;
	}
	return;

failed:
	/*
	 * The pages have to be there now or they will be missing in
	 * process page-tables later.
	 */
	panic("Failed to pre-allocate %s pages for %s area\n", lvl, area);
}

void __init pgtable_cache_init(void)
{
	preallocate_pgd_pages_range(VMALLOC_START, VMALLOC_END, "vmalloc");
	if (IS_ENABLED(CONFIG_MODULES))
		preallocate_pgd_pages_range(MODULES_VADDR, MODULES_END, "bpf/modules");
}
#endif