drm/panthor: Don't add write fences to the shared BOs

[drm/drm-misc.git] / arch / riscv / mm / init.c

// 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 <linux/execmem.h>

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

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

u64 new_vmalloc[NR_CPUS / sizeof(u64) + 1];

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 __ro_after_init = !IS_ENABLED(CONFIG_XIP_KERNEL);
bool pgtable_l5_enabled __ro_after_init = !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)
{
        bool swiotlb = max_pfn > PFN_DOWN(dma32_phys_limit);
#ifdef CONFIG_FLATMEM
        BUG_ON(!mem_map);
#endif /* CONFIG_FLATMEM */

        if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) && !swiotlb &&
            dma_cache_alignment != 1) {
                /*
                 * If no bouncing needed for ZONE_DMA, allocate 1MB swiotlb
                 * buffer per 1GB of RAM for kmalloc() bouncing on
                 * non-coherent platforms.
                 */
                unsigned long size =
                        DIV_ROUND_UP(memblock_phys_mem_size(), 1024);
                swiotlb_adjust_size(min(swiotlb_size_or_default(), size));
                swiotlb = true;
        }

        swiotlb_init(swiotlb, SWIOTLB_VERBOSE);
        memblock_free_all();

        print_vm_layout();
}

/* Limit the memory size via mem. */
static phys_addr_t memory_limit;
#ifdef CONFIG_XIP_KERNEL
#define memory_limit    (*(phys_addr_t *)XIP_FIXUP(&memory_limit))
#endif /* CONFIG_XIP_KERNEL */

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);

        /*
         * 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) && IS_ENABLED(CONFIG_MMU))
                kernel_map.va_pa_offset = PAGE_OFFSET - phys_ram_base;

        /*
         * The size of the linear page mapping may restrict the amount of
         * usable RAM.
         */
        if (IS_ENABLED(CONFIG_64BIT) && IS_ENABLED(CONFIG_MMU)) {
                max_mapped_addr = __pa(PAGE_OFFSET) + KERN_VIRT_SIZE;
                memblock_cap_memory_range(phys_ram_base,
                                          max_mapped_addr - phys_ram_base);
        }

        /*
         * Reserve physical address space that would be mapped to virtual
         * addresses greater than (void *)(-PAGE_SIZE) because:
         *  - This memory would overlap with ERR_PTR
         *  - This memory belongs to high memory, which is not supported
         *
         * This is not applicable to 64-bit kernel, because virtual addresses
         * after (void *)(-PAGE_SIZE) are not linearly mapped: they are
         * occupied by kernel mapping. Also it is unrealistic for high memory
         * to exist on 64-bit platforms.
         */
        if (!IS_ENABLED(CONFIG_64BIT)) {
                max_mapped_addr = __va_to_pa_nodebug(-PAGE_SIZE);
                memblock_reserve(max_mapped_addr, (phys_addr_t)-max_mapped_addr);
        }

        phys_ram_end = memblock_end_of_DRAM();
        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 __meminitdata;

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 *__meminit 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 __meminit 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 __meminit 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 *__meminit 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 __meminit 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 __meminit 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 *__meminit 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 __meminit 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 *__meminit 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 __meminit alloc_p4d_late(uintptr_t va)
{
        unsigned long vaddr;

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

static void __meminit 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 __meminit 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 __meminit 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 __meminit best_map_size(phys_addr_t pa, uintptr_t va, phys_addr_t size)
{
        if (debug_pagealloc_enabled())
                return PAGE_SIZE;

        if (pgtable_l5_enabled &&
            !(pa & (P4D_SIZE - 1)) && !(va & (P4D_SIZE - 1)) && size >= P4D_SIZE)
                return P4D_SIZE;

        if (pgtable_l4_enabled &&
            !(pa & (PUD_SIZE - 1)) && !(va & (PUD_SIZE - 1)) && size >= PUD_SIZE)
                return PUD_SIZE;

        if (IS_ENABLED(CONFIG_64BIT) &&
            !(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 __meminit 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);
}
#else
static __meminit 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);

static void __init set_mmap_rnd_bits_max(void)
{
        mmap_rnd_bits_max = MMAP_VA_BITS - PAGE_SHIFT - 3;
}

/*
 * 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, start_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 */
        start_va = kernel_map.virt_addr + (uintptr_t)&_sdata - (uintptr_t)&_start;
        end_va = kernel_map.virt_addr + kernel_map.size;
        for (va = start_va; va < end_va; va += PMD_SIZE)
                create_pgd_mapping(pgdir, va,
                                   kernel_map.phys_addr + (va - start_va),
                                   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(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);
extern u64 __init __pi_get_kaslr_seed_zkr(const 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_zkr(dtb_pa);
                u32 kernel_size = (uintptr_t)(&_end) - (uintptr_t)(&_start);
                u32 nr_pos;

                if (kaslr_seed == 0)
                        kaslr_seed = __pi_get_kaslr_seed(dtb_pa);
                /*
                 * 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;

#ifdef CONFIG_XIP_KERNEL
#ifdef CONFIG_64BIT
        kernel_map.page_offset = PAGE_OFFSET_L3;
#else
        kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL);
#endif
        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)(&_start);

        kernel_map.va_kernel_xip_text_pa_offset = kernel_map.virt_addr - kernel_map.xiprom;
        kernel_map.va_kernel_xip_data_pa_offset = kernel_map.virt_addr - kernel_map.phys_addr
                                                + (uintptr_t)&_sdata - (uintptr_t)&_start;
#else
        kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL);
        kernel_map.phys_addr = (uintptr_t)(&_start);
        kernel_map.size = (uintptr_t)(&_end) - kernel_map.phys_addr;
        kernel_map.va_kernel_pa_offset = kernel_map.virt_addr - kernel_map.phys_addr;
#endif

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

        memory_limit = KERN_VIRT_SIZE;

        /* 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 __meminit create_linear_mapping_range(phys_addr_t start, phys_addr_t end,
                                                  uintptr_t fixed_map_size, const pgprot_t *pgprot)
{
        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 ? *pgprot : 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);

                create_linear_mapping_range(start, end, 0, NULL);
        }

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

        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, NULL);

        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_CRASH_RESERVE))
                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();
#ifdef CONFIG_SPARSEMEM_VMEMMAP
        /* The entire VMEMMAP region has been populated. Flush TLB for this region */
        local_flush_tlb_kernel_range(VMEMMAP_START, VMEMMAP_END);
#endif
        zone_sizes_init();
        arch_reserve_crashkernel();
        memblock_dump_all();
}

#ifdef CONFIG_SPARSEMEM_VMEMMAP
void __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
                               unsigned long addr, unsigned long next)
{
        pmd_set_huge(pmd, virt_to_phys(p), PAGE_KERNEL);
}

int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node,
                                unsigned long addr, unsigned long next)
{
        vmemmap_verify((pte_t *)pmdp, node, addr, next);
        return 1;
}

int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
                               struct vmem_altmap *altmap)
{
        /*
         * Note that SPARSEMEM_VMEMMAP is only selected for rv64 and that we
         * can't use hugepage mappings for 2-level page table because in case of
         * memory hotplug, we are not able to update all the page tables with
         * the new PMDs.
         */
        return vmemmap_populate_hugepages(start, end, node, altmap);
}
#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);
}

#define PAGE_END KASAN_SHADOW_START

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");
        if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) {
                preallocate_pgd_pages_range(VMEMMAP_START, VMEMMAP_END, "vmemmap");
                preallocate_pgd_pages_range(PAGE_OFFSET, PAGE_END, "direct map");
                if (IS_ENABLED(CONFIG_KASAN))
                        preallocate_pgd_pages_range(KASAN_SHADOW_START, KASAN_SHADOW_END, "kasan");
        }
}
#endif

#ifdef CONFIG_EXECMEM
#ifdef CONFIG_MMU
static struct execmem_info execmem_info __ro_after_init;

struct execmem_info __init *execmem_arch_setup(void)
{
        execmem_info = (struct execmem_info){
                .ranges = {
                        [EXECMEM_DEFAULT] = {
                                .start  = MODULES_VADDR,
                                .end    = MODULES_END,
                                .pgprot = PAGE_KERNEL,
                                .alignment = 1,
                        },
                        [EXECMEM_KPROBES] = {
                                .start  = VMALLOC_START,
                                .end    = VMALLOC_END,
                                .pgprot = PAGE_KERNEL_READ_EXEC,
                                .alignment = 1,
                        },
                        [EXECMEM_BPF] = {
                                .start  = BPF_JIT_REGION_START,
                                .end    = BPF_JIT_REGION_END,
                                .pgprot = PAGE_KERNEL,
                                .alignment = PAGE_SIZE,
                        },
                },
        };

        return &execmem_info;
}
#endif /* CONFIG_MMU */
#endif /* CONFIG_EXECMEM */

#ifdef CONFIG_MEMORY_HOTPLUG
static void __meminit free_pte_table(pte_t *pte_start, pmd_t *pmd)
{
        struct page *page = pmd_page(*pmd);
        struct ptdesc *ptdesc = page_ptdesc(page);
        pte_t *pte;
        int i;

        for (i = 0; i < PTRS_PER_PTE; i++) {
                pte = pte_start + i;
                if (!pte_none(*pte))
                        return;
        }

        pagetable_pte_dtor(ptdesc);
        if (PageReserved(page))
                free_reserved_page(page);
        else
                pagetable_free(ptdesc);
        pmd_clear(pmd);
}

static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud)
{
        struct page *page = pud_page(*pud);
        struct ptdesc *ptdesc = page_ptdesc(page);
        pmd_t *pmd;
        int i;

        for (i = 0; i < PTRS_PER_PMD; i++) {
                pmd = pmd_start + i;
                if (!pmd_none(*pmd))
                        return;
        }

        pagetable_pmd_dtor(ptdesc);
        if (PageReserved(page))
                free_reserved_page(page);
        else
                pagetable_free(ptdesc);
        pud_clear(pud);
}

static void __meminit free_pud_table(pud_t *pud_start, p4d_t *p4d)
{
        struct page *page = p4d_page(*p4d);
        pud_t *pud;
        int i;

        for (i = 0; i < PTRS_PER_PUD; i++) {
                pud = pud_start + i;
                if (!pud_none(*pud))
                        return;
        }

        if (PageReserved(page))
                free_reserved_page(page);
        else
                free_pages((unsigned long)page_address(page), 0);
        p4d_clear(p4d);
}

static void __meminit free_vmemmap_storage(struct page *page, size_t size,
                                           struct vmem_altmap *altmap)
{
        int order = get_order(size);

        if (altmap) {
                vmem_altmap_free(altmap, size >> PAGE_SHIFT);
                return;
        }

        if (PageReserved(page)) {
                unsigned int nr_pages = 1 << order;

                while (nr_pages--)
                        free_reserved_page(page++);
                return;
        }

        free_pages((unsigned long)page_address(page), order);
}

static void __meminit remove_pte_mapping(pte_t *pte_base, unsigned long addr, unsigned long end,
                                         bool is_vmemmap, struct vmem_altmap *altmap)
{
        unsigned long next;
        pte_t *ptep, pte;

        for (; addr < end; addr = next) {
                next = (addr + PAGE_SIZE) & PAGE_MASK;
                if (next > end)
                        next = end;

                ptep = pte_base + pte_index(addr);
                pte = ptep_get(ptep);
                if (!pte_present(*ptep))
                        continue;

                pte_clear(&init_mm, addr, ptep);
                if (is_vmemmap)
                        free_vmemmap_storage(pte_page(pte), PAGE_SIZE, altmap);
        }
}

static void __meminit remove_pmd_mapping(pmd_t *pmd_base, unsigned long addr, unsigned long end,
                                         bool is_vmemmap, struct vmem_altmap *altmap)
{
        unsigned long next;
        pte_t *pte_base;
        pmd_t *pmdp, pmd;

        for (; addr < end; addr = next) {
                next = pmd_addr_end(addr, end);
                pmdp = pmd_base + pmd_index(addr);
                pmd = pmdp_get(pmdp);
                if (!pmd_present(pmd))
                        continue;

                if (pmd_leaf(pmd)) {
                        pmd_clear(pmdp);
                        if (is_vmemmap)
                                free_vmemmap_storage(pmd_page(pmd), PMD_SIZE, altmap);
                        continue;
                }

                pte_base = (pte_t *)pmd_page_vaddr(*pmdp);
                remove_pte_mapping(pte_base, addr, next, is_vmemmap, altmap);
                free_pte_table(pte_base, pmdp);
        }
}

static void __meminit remove_pud_mapping(pud_t *pud_base, unsigned long addr, unsigned long end,
                                         bool is_vmemmap, struct vmem_altmap *altmap)
{
        unsigned long next;
        pud_t *pudp, pud;
        pmd_t *pmd_base;

        for (; addr < end; addr = next) {
                next = pud_addr_end(addr, end);
                pudp = pud_base + pud_index(addr);
                pud = pudp_get(pudp);
                if (!pud_present(pud))
                        continue;

                if (pud_leaf(pud)) {
                        if (pgtable_l4_enabled) {
                                pud_clear(pudp);
                                if (is_vmemmap)
                                        free_vmemmap_storage(pud_page(pud), PUD_SIZE, altmap);
                        }
                        continue;
                }

                pmd_base = pmd_offset(pudp, 0);
                remove_pmd_mapping(pmd_base, addr, next, is_vmemmap, altmap);

                if (pgtable_l4_enabled)
                        free_pmd_table(pmd_base, pudp);
        }
}

static void __meminit remove_p4d_mapping(p4d_t *p4d_base, unsigned long addr, unsigned long end,
                                         bool is_vmemmap, struct vmem_altmap *altmap)
{
        unsigned long next;
        p4d_t *p4dp, p4d;
        pud_t *pud_base;

        for (; addr < end; addr = next) {
                next = p4d_addr_end(addr, end);
                p4dp = p4d_base + p4d_index(addr);
                p4d = p4dp_get(p4dp);
                if (!p4d_present(p4d))
                        continue;

                if (p4d_leaf(p4d)) {
                        if (pgtable_l5_enabled) {
                                p4d_clear(p4dp);
                                if (is_vmemmap)
                                        free_vmemmap_storage(p4d_page(p4d), P4D_SIZE, altmap);
                        }
                        continue;
                }

                pud_base = pud_offset(p4dp, 0);
                remove_pud_mapping(pud_base, addr, next, is_vmemmap, altmap);

                if (pgtable_l5_enabled)
                        free_pud_table(pud_base, p4dp);
        }
}

static void __meminit remove_pgd_mapping(unsigned long va, unsigned long end, bool is_vmemmap,
                                         struct vmem_altmap *altmap)
{
        unsigned long addr, next;
        p4d_t *p4d_base;
        pgd_t *pgd;

        for (addr = va; addr < end; addr = next) {
                next = pgd_addr_end(addr, end);
                pgd = pgd_offset_k(addr);

                if (!pgd_present(*pgd))
                        continue;

                if (pgd_leaf(*pgd))
                        continue;

                p4d_base = p4d_offset(pgd, 0);
                remove_p4d_mapping(p4d_base, addr, next, is_vmemmap, altmap);
        }

        flush_tlb_all();
}

static void __meminit remove_linear_mapping(phys_addr_t start, u64 size)
{
        unsigned long va = (unsigned long)__va(start);
        unsigned long end = (unsigned long)__va(start + size);

        remove_pgd_mapping(va, end, false, NULL);
}

struct range arch_get_mappable_range(void)
{
        struct range mhp_range;

        mhp_range.start = __pa(PAGE_OFFSET);
        mhp_range.end = __pa(PAGE_END - 1);
        return mhp_range;
}

int __ref arch_add_memory(int nid, u64 start, u64 size, struct mhp_params *params)
{
        int ret = 0;

        create_linear_mapping_range(start, start + size, 0, &params->pgprot);
        ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, params);
        if (ret) {
                remove_linear_mapping(start, size);
                goto out;
        }

        max_pfn = PFN_UP(start + size);
        max_low_pfn = max_pfn;

 out:
        flush_tlb_all();
        return ret;
}

void __ref arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
{
        __remove_pages(start >> PAGE_SHIFT, size >> PAGE_SHIFT, altmap);
        remove_linear_mapping(start, size);
        flush_tlb_all();
}

void __ref vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap)
{
        remove_pgd_mapping(start, end, true, altmap);
}
#endif /* CONFIG_MEMORY_HOTPLUG */