// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2012 Regents of the University of California
 * Copyright (C) 2019 Western Digital Corporation or its affiliates.
 */

#include <linux/init.h>
#include <linux/mm.h>
#include <linux/memblock.h>
#include <linux/initrd.h>
#include <linux/swap.h>
#include <linux/sizes.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <linux/set_memory.h>

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

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

unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]
                                                        __page_aligned_bss;
EXPORT_SYMBOL(empty_zero_page);

extern char _start[];
#define DTB_EARLY_BASE_VA      PGDIR_SIZE
void *dtb_early_va __initdata;
uintptr_t dtb_early_pa __initdata;

struct pt_alloc_ops {
        pte_t *(*get_pte_virt)(phys_addr_t pa);
        phys_addr_t (*alloc_pte)(uintptr_t va);
#ifndef __PAGETABLE_PMD_FOLDED
        pmd_t *(*get_pmd_virt)(phys_addr_t pa);
        phys_addr_t (*alloc_pmd)(uintptr_t va);
#endif
};

static void __init zone_sizes_init(void)
{
        unsigned long max_zone_pfns[MAX_NR_ZONES] = { 0, };

#ifdef CONFIG_ZONE_DMA32
        max_zone_pfns[ZONE_DMA32] = PFN_DOWN(min(4UL * SZ_1G,
                        (unsigned long) PFN_PHYS(max_low_pfn)));
#endif
        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;

        free_area_init(max_zone_pfns);
}

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

#if defined(CONFIG_MMU) && defined(CONFIG_DEBUG_VM)
static inline void print_mlk(char *name, unsigned long b, unsigned long t)
{
        pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld kB)\n", name, b, t,
                  (((t) - (b)) >> 10));
}

static inline void print_mlm(char *name, unsigned long b, unsigned long t)
{
        pr_notice("%12s : 0x%08lx - 0x%08lx   (%4ld MB)\n", name, b, t,
                  (((t) - (b)) >> 20));
}

static void print_vm_layout(void)
{
        pr_notice("Virtual kernel memory layout:\n");
        print_mlk("fixmap", (unsigned long)FIXADDR_START,
                  (unsigned long)FIXADDR_TOP);
        print_mlm("pci io", (unsigned long)PCI_IO_START,
                  (unsigned long)PCI_IO_END);
        print_mlm("vmemmap", (unsigned long)VMEMMAP_START,
                  (unsigned long)VMEMMAP_END);
        print_mlm("vmalloc", (unsigned long)VMALLOC_START,
                  (unsigned long)VMALLOC_END);
        print_mlm("lowmem", (unsigned long)PAGE_OFFSET,
                  (unsigned long)high_memory);
}
#else
static void print_vm_layout(void) { }
#endif /* CONFIG_DEBUG_VM */

void __init mem_init(void)
{
#ifdef CONFIG_FLATMEM
        BUG_ON(!mem_map);
#endif /* CONFIG_FLATMEM */

        high_memory = (void *)(__va(PFN_PHYS(max_low_pfn)));
        memblock_free_all();

        mem_init_print_info(NULL);
        print_vm_layout();
}

#ifdef CONFIG_BLK_DEV_INITRD
static void __init setup_initrd(void)
{
        phys_addr_t start;
        unsigned long size;

        /* Ignore the virtul address computed during device tree parsing */
        initrd_start = initrd_end = 0;

        if (!phys_initrd_size)
                return;
        /*
         * Round the memory region to page boundaries as per free_initrd_mem()
         * This allows us to detect whether the pages overlapping the initrd
         * are in use, but more importantly, reserves the entire set of pages
         * as we don't want these pages allocated for other purposes.
         */
        start = round_down(phys_initrd_start, PAGE_SIZE);
        size = phys_initrd_size + (phys_initrd_start - start);
        size = round_up(size, PAGE_SIZE);

        if (!memblock_is_region_memory(start, size)) {
                pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region",
                       (u64)start, size);
                goto disable;
        }

        if (memblock_is_region_reserved(start, size)) {
                pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region\n",
                       (u64)start, size);
                goto disable;
        }

        memblock_reserve(start, size);
        /* Now convert initrd to virtual addresses */
        initrd_start = (unsigned long)__va(phys_initrd_start);
        initrd_end = initrd_start + phys_initrd_size;
        initrd_below_start_ok = 1;

        pr_info("Initial ramdisk at: 0x%p (%lu bytes)\n",
                (void *)(initrd_start), size);
        return;
disable:
        pr_cont(" - disabling initrd\n");
        initrd_start = 0;
        initrd_end = 0;
}
#endif /* CONFIG_BLK_DEV_INITRD */

void __init setup_bootmem(void)
{
        phys_addr_t mem_start = 0;
        phys_addr_t start, end = 0;
        phys_addr_t vmlinux_end = __pa_symbol(&_end);
        phys_addr_t vmlinux_start = __pa_symbol(&_start);
        u64 i;

        /* Find the memory region containing the kernel */
        for_each_mem_range(i, &start, &end) {
                phys_addr_t size = end - start;
                if (!mem_start)
                        mem_start = start;
                if (start <= vmlinux_start && vmlinux_end <= end)
                        BUG_ON(size == 0);
        }

        /*
         * The maximal physical memory size is -PAGE_OFFSET.
         * Make sure that any memory beyond mem_start + (-PAGE_OFFSET) is removed
         * as it is unusable by kernel.
         */
        memblock_enforce_memory_limit(mem_start - PAGE_OFFSET);

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

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

#ifdef CONFIG_BLK_DEV_INITRD
        setup_initrd();
#endif /* CONFIG_BLK_DEV_INITRD */

        /*
         * Avoid using early_init_fdt_reserve_self() since __pa() does
         * not work for DTB pointers that are fixmap addresses
         */
        memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va));

        early_init_fdt_scan_reserved_mem();
        memblock_allow_resize();
        memblock_dump_all();
}

#ifdef CONFIG_MMU
static struct pt_alloc_ops pt_ops;

unsigned long va_pa_offset;
EXPORT_SYMBOL(va_pa_offset);
unsigned long pfn_base;
EXPORT_SYMBOL(pfn_base);

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

#define MAX_EARLY_MAPPING_SIZE  SZ_128M

pgd_t early_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);

void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot)
{
        unsigned long addr = __fix_to_virt(idx);
        pte_t *ptep;

        BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);

        ptep = &fixmap_pte[pte_index(addr)];

        if (pgprot_val(prot))
                set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, prot));
        else
                pte_clear(&init_mm, addr, ptep);
        local_flush_tlb_page(addr);
}

static inline pte_t *__init get_pte_virt_early(phys_addr_t pa)
{
        return (pte_t *)((uintptr_t)pa);
}

static inline pte_t *__init get_pte_virt_fixmap(phys_addr_t pa)
{
        clear_fixmap(FIX_PTE);
        return (pte_t *)set_fixmap_offset(FIX_PTE, pa);
}

static inline pte_t *get_pte_virt_late(phys_addr_t pa)
{
        return (pte_t *) __va(pa);
}

static inline phys_addr_t __init alloc_pte_early(uintptr_t va)
{
        /*
         * We only create PMD or PGD early mappings so we
         * should never reach here with MMU disabled.
         */
        BUG();
}

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

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

        vaddr = __get_free_page(GFP_KERNEL);
        if (!vaddr || !pgtable_pte_page_ctor(virt_to_page(vaddr)))
                BUG();
        return __pa(vaddr);
}

static void __init create_pte_mapping(pte_t *ptep,
                                      uintptr_t va, phys_addr_t pa,
                                      phys_addr_t sz, pgprot_t prot)
{
        uintptr_t pte_idx = pte_index(va);

        BUG_ON(sz != PAGE_SIZE);

        if (pte_none(ptep[pte_idx]))
                ptep[pte_idx] = pfn_pte(PFN_DOWN(pa), prot);
}

#ifndef __PAGETABLE_PMD_FOLDED

pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;

#if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
#define NUM_EARLY_PMDS          1UL
#else
#define NUM_EARLY_PMDS          (1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE)
#endif
pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE);
pmd_t early_dtb_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);

static pmd_t *__init get_pmd_virt_early(phys_addr_t pa)
{
        /* Before MMU is enabled */
        return (pmd_t *)((uintptr_t)pa);
}

static pmd_t *__init get_pmd_virt_fixmap(phys_addr_t pa)
{
        clear_fixmap(FIX_PMD);
        return (pmd_t *)set_fixmap_offset(FIX_PMD, pa);
}

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

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

        pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
        BUG_ON(pmd_num >= NUM_EARLY_PMDS);
        return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
}

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

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

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

static void __init create_pmd_mapping(pmd_t *pmdp,
                                      uintptr_t va, phys_addr_t pa,
                                      phys_addr_t sz, pgprot_t prot)
{
        pte_t *ptep;
        phys_addr_t pte_phys;
        uintptr_t pmd_idx = pmd_index(va);

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

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

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

#define pgd_next_t              pmd_t
#define alloc_pgd_next(__va)    pt_ops.alloc_pmd(__va)
#define get_pgd_next_virt(__pa) pt_ops.get_pmd_virt(__pa)
#define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
        create_pmd_mapping(__nextp, __va, __pa, __sz, __prot)
#define fixmap_pgd_next         fixmap_pmd
#else
#define pgd_next_t              pte_t
#define alloc_pgd_next(__va)    pt_ops.alloc_pte(__va)
#define get_pgd_next_virt(__pa) pt_ops.get_pte_virt(__pa)
#define create_pgd_next_mapping(__nextp, __va, __pa, __sz, __prot)      \
        create_pte_mapping(__nextp, __va, __pa, __sz, __prot)
#define fixmap_pgd_next         fixmap_pte
#endif

void __init create_pgd_mapping(pgd_t *pgdp,
                                      uintptr_t va, phys_addr_t pa,
                                      phys_addr_t sz, pgprot_t prot)
{
        pgd_next_t *nextp;
        phys_addr_t next_phys;
        uintptr_t pgd_idx = pgd_index(va);

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

        if (pgd_val(pgdp[pgd_idx]) == 0) {
                next_phys = alloc_pgd_next(va);
                pgdp[pgd_idx] = pfn_pgd(PFN_DOWN(next_phys), PAGE_TABLE);
                nextp = get_pgd_next_virt(next_phys);
                memset(nextp, 0, PAGE_SIZE);
        } else {
                next_phys = PFN_PHYS(_pgd_pfn(pgdp[pgd_idx]));
                nextp = get_pgd_next_virt(next_phys);
        }

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

static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size)
{
        /* Upgrade to PMD_SIZE mappings whenever possible */
        if ((base & (PMD_SIZE - 1)) || (size & (PMD_SIZE - 1)))
                return PAGE_SIZE;

        return PMD_SIZE;
}

/*
 * setup_vm() is called from head.S with MMU-off.
 *
 * Following requirements should be honoured for setup_vm() to work
 * correctly:
 * 1) It should use PC-relative addressing for accessing kernel symbols.
 *    To achieve this we always use GCC cmodel=medany.
 * 2) The compiler instrumentation for FTRACE will not work for setup_vm()
 *    so disable compiler instrumentation when FTRACE is enabled.
 *
 * Currently, the above requirements are honoured by using custom CFLAGS
 * for init.o in mm/Makefile.
 */

#ifndef __riscv_cmodel_medany
#error "setup_vm() is called from head.S before relocate so it should not use absolute addressing."
#endif

asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
        uintptr_t va, pa, end_va;
        uintptr_t load_pa = (uintptr_t)(&_start);
        uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
        uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
#ifndef __PAGETABLE_PMD_FOLDED
        pmd_t fix_bmap_spmd, fix_bmap_epmd;
#endif

        va_pa_offset = PAGE_OFFSET - load_pa;
        pfn_base = PFN_DOWN(load_pa);

        /*
         * Enforce boot alignment requirements of RV32 and
         * RV64 by only allowing PMD or PGD mappings.
         */
        BUG_ON(map_size == PAGE_SIZE);

        /* Sanity check alignment and size */
        BUG_ON((PAGE_OFFSET % PGDIR_SIZE) != 0);
        BUG_ON((load_pa % map_size) != 0);
        BUG_ON(load_sz > MAX_EARLY_MAPPING_SIZE);

        pt_ops.alloc_pte = alloc_pte_early;
        pt_ops.get_pte_virt = get_pte_virt_early;
#ifndef __PAGETABLE_PMD_FOLDED
        pt_ops.alloc_pmd = alloc_pmd_early;
        pt_ops.get_pmd_virt = get_pmd_virt_early;
#endif
        /* Setup early PGD for fixmap */
        create_pgd_mapping(early_pg_dir, FIXADDR_START,
                           (uintptr_t)fixmap_pgd_next, PGDIR_SIZE, PAGE_TABLE);

#ifndef __PAGETABLE_PMD_FOLDED
        /* Setup fixmap PMD */
        create_pmd_mapping(fixmap_pmd, FIXADDR_START,
                           (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE);
        /* Setup trampoline PGD and PMD */
        create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
                           (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE);
        create_pmd_mapping(trampoline_pmd, PAGE_OFFSET,
                           load_pa, PMD_SIZE, PAGE_KERNEL_EXEC);
#else
        /* Setup trampoline PGD */
        create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET,
                           load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC);
#endif

        /*
         * Setup early PGD covering entire kernel which will allows
         * us to reach paging_init(). We map all memory banks later
         * in setup_vm_final() below.
         */
        end_va = PAGE_OFFSET + load_sz;
        for (va = PAGE_OFFSET; va < end_va; va += map_size)
                create_pgd_mapping(early_pg_dir, va,
                                   load_pa + (va - PAGE_OFFSET),
                                   map_size, PAGE_KERNEL_EXEC);

#ifndef __PAGETABLE_PMD_FOLDED
        /* Setup early PMD for DTB */
        create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
                           (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE);
        /* Create two consecutive PMD mappings for FDT early scan */
        pa = dtb_pa & ~(PMD_SIZE - 1);
        create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA,
                           pa, PMD_SIZE, PAGE_KERNEL);
        create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE,
                           pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL);
        dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1));
#else
        /* Create two consecutive PGD mappings for FDT early scan */
        pa = dtb_pa & ~(PGDIR_SIZE - 1);
        create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA,
                           pa, PGDIR_SIZE, PAGE_KERNEL);
        create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE,
                           pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
        dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
#endif
        dtb_early_pa = dtb_pa;

        /*
         * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
         * range can not span multiple pmds.
         */
        BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
                     != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));

#ifndef __PAGETABLE_PMD_FOLDED
        /*
         * Early ioremap fixmap is already created as it lies within first 2MB
         * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
         * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
         * the user if not.
         */
        fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
        fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
        if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
                WARN_ON(1);
                pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
                        pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
                pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
                        fix_to_virt(FIX_BTMAP_BEGIN));
                pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
                        fix_to_virt(FIX_BTMAP_END));

                pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
                pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
        }
#endif
}

static void __init setup_vm_final(void)
{
        uintptr_t va, map_size;
        phys_addr_t pa, start, end;
        u64 i;

        /**
         * MMU is enabled at this point. But page table setup is not complete yet.
         * fixmap page table alloc functions should be used at this point
         */
        pt_ops.alloc_pte = alloc_pte_fixmap;
        pt_ops.get_pte_virt = get_pte_virt_fixmap;
#ifndef __PAGETABLE_PMD_FOLDED
        pt_ops.alloc_pmd = alloc_pmd_fixmap;
        pt_ops.get_pmd_virt = get_pmd_virt_fixmap;
#endif
        /* Setup swapper PGD for fixmap */
        create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
                           __pa_symbol(fixmap_pgd_next),
                           PGDIR_SIZE, PAGE_TABLE);

        /* Map all memory banks */
        for_each_mem_range(i, &start, &end) {
                if (start >= end)
                        break;
                if (start <= __pa(PAGE_OFFSET) &&
                    __pa(PAGE_OFFSET) < end)
                        start = __pa(PAGE_OFFSET);

                map_size = best_map_size(start, end - start);
                for (pa = start; pa < end; pa += map_size) {
                        va = (uintptr_t)__va(pa);
                        create_pgd_mapping(swapper_pg_dir, va, pa,
                                           map_size, PAGE_KERNEL_EXEC);
                }
        }

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

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

        /* generic page allocation functions must be used to setup page table */
        pt_ops.alloc_pte = alloc_pte_late;
        pt_ops.get_pte_virt = get_pte_virt_late;
#ifndef __PAGETABLE_PMD_FOLDED
        pt_ops.alloc_pmd = alloc_pmd_late;
        pt_ops.get_pmd_virt = get_pmd_virt_late;
#endif
}
#else
asmlinkage void __init setup_vm(uintptr_t dtb_pa)
{
#ifdef CONFIG_BUILTIN_DTB
        dtb_early_va = soc_lookup_builtin_dtb();
        if (!dtb_early_va) {
                /* Fallback to first available DTS */
                dtb_early_va = (void *) __dtb_start;
        }
#else
        dtb_early_va = (void *)dtb_pa;
#endif
        dtb_early_pa = dtb_pa;
}

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

#ifdef CONFIG_STRICT_KERNEL_RWX
void mark_rodata_ro(void)
{
        unsigned long text_start = (unsigned long)_text;
        unsigned long text_end = (unsigned long)_etext;
        unsigned long rodata_start = (unsigned long)__start_rodata;
        unsigned long data_start = (unsigned long)_data;
        unsigned long max_low = (unsigned long)(__va(PFN_PHYS(max_low_pfn)));

        set_memory_ro(text_start, (text_end - text_start) >> PAGE_SHIFT);
        set_memory_ro(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
        set_memory_nx(rodata_start, (data_start - rodata_start) >> PAGE_SHIFT);
        set_memory_nx(data_start, (max_low - data_start) >> PAGE_SHIFT);

        debug_checkwx();
}
#endif

static void __init resource_init(void)
{
        struct memblock_region *region;

        for_each_mem_region(region) {
                struct resource *res;

                res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
                if (!res)
                        panic("%s: Failed to allocate %zu bytes\n", __func__,
                              sizeof(struct resource));

                if (memblock_is_nomap(region)) {
                        res->name = "reserved";
                        res->flags = IORESOURCE_MEM;
                } else {
                        res->name = "System RAM";
                        res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
                }
                res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
                res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;

                request_resource(&iomem_resource, res);
        }
}

void __init paging_init(void)
{
        setup_vm_final();
        sparse_init();
        setup_zero_page();
        zone_sizes_init();
        resource_init();
}

#ifdef CONFIG_SPARSEMEM_VMEMMAP
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
                               struct vmem_altmap *altmap)
{
        return vmemmap_populate_basepages(start, end, node, NULL);
}
#endif