// SPDX-License-Identifier: GPL-2.0-only
/*
 *  linux/arch/arm/mm/init.c
 *
 *  Copyright (C) 1995-2005 Russell King
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/mman.h>
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/export.h>
#include <linux/nodemask.h>
#include <linux/initrd.h>
#include <linux/of_fdt.h>
#include <linux/highmem.h>
#include <linux/gfp.h>
#include <linux/memblock.h>
#include <linux/dma-contiguous.h>
#include <linux/sizes.h>
#include <linux/stop_machine.h>
#include <linux/swiotlb.h>

#include <asm/cp15.h>
#include <asm/mach-types.h>
#include <asm/memblock.h>
#include <asm/memory.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/set_memory.h>
#include <asm/system_info.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>
#include <asm/ptdump.h>

#include <asm/mach/arch.h>
#include <asm/mach/map.h>

#include "mm.h"

#ifdef CONFIG_CPU_CP15_MMU
unsigned long __init __clear_cr(unsigned long mask)
{
        cr_alignment = cr_alignment & ~mask;
        return cr_alignment;
}
#endif

#ifdef CONFIG_BLK_DEV_INITRD
static int __init parse_tag_initrd(const struct tag *tag)
{
        pr_warn("ATAG_INITRD is deprecated; "
                "please update your bootloader.\n");
        phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
        phys_initrd_size = tag->u.initrd.size;
        return 0;
}

__tagtable(ATAG_INITRD, parse_tag_initrd);

static int __init parse_tag_initrd2(const struct tag *tag)
{
        phys_initrd_start = tag->u.initrd.start;
        phys_initrd_size = tag->u.initrd.size;
        return 0;
}

__tagtable(ATAG_INITRD2, parse_tag_initrd2);
#endif

static void __init find_limits(unsigned long *min, unsigned long *max_low,
                               unsigned long *max_high)
{
        *max_low = PFN_DOWN(memblock_get_current_limit());
        *min = PFN_UP(memblock_start_of_DRAM());
        *max_high = PFN_DOWN(memblock_end_of_DRAM());
}

#ifdef CONFIG_ZONE_DMA

phys_addr_t arm_dma_zone_size __read_mostly;
EXPORT_SYMBOL(arm_dma_zone_size);

/*
 * The DMA mask corresponding to the maximum bus address allocatable
 * using GFP_DMA.  The default here places no restriction on DMA
 * allocations.  This must be the smallest DMA mask in the system,
 * so a successful GFP_DMA allocation will always satisfy this.
 */
phys_addr_t arm_dma_limit;
unsigned long arm_dma_pfn_limit;
#endif

void __init setup_dma_zone(const struct machine_desc *mdesc)
{
#ifdef CONFIG_ZONE_DMA
        if (mdesc->dma_zone_size) {
                arm_dma_zone_size = mdesc->dma_zone_size;
                arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
        } else
                arm_dma_limit = 0xffffffff;
        arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
#endif
}

static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
        unsigned long max_high)
{
        unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };

#ifdef CONFIG_ZONE_DMA
        max_zone_pfn[ZONE_DMA] = min(arm_dma_pfn_limit, max_low);
#endif
        max_zone_pfn[ZONE_NORMAL] = max_low;
#ifdef CONFIG_HIGHMEM
        max_zone_pfn[ZONE_HIGHMEM] = max_high;
#endif
        free_area_init(max_zone_pfn);
}

#ifdef CONFIG_HAVE_ARCH_PFN_VALID
int pfn_valid(unsigned long pfn)
{
        phys_addr_t addr = __pfn_to_phys(pfn);

        if (__phys_to_pfn(addr) != pfn)
                return 0;

        return memblock_is_map_memory(addr);
}
EXPORT_SYMBOL(pfn_valid);
#endif

static bool arm_memblock_steal_permitted = true;

phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
{
        phys_addr_t phys;

        BUG_ON(!arm_memblock_steal_permitted);

        phys = memblock_phys_alloc(size, align);
        if (!phys)
                panic("Failed to steal %pa bytes at %pS\n",
                      &size, (void *)_RET_IP_);

        memblock_free(phys, size);
        memblock_remove(phys, size);

        return phys;
}

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

        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 - disabling initrd\n",
                       (u64)start, size);
                return;
        }

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

        memblock_reserve(start, size);

        /* Now convert initrd to virtual addresses */
        initrd_start = __phys_to_virt(phys_initrd_start);
        initrd_end = initrd_start + phys_initrd_size;
#endif
}

#ifdef CONFIG_CPU_ICACHE_MISMATCH_WORKAROUND
void check_cpu_icache_size(int cpuid)
{
        u32 size, ctr;

        asm("mrc p15, 0, %0, c0, c0, 1" : "=r" (ctr));

        size = 1 << ((ctr & 0xf) + 2);
        if (cpuid != 0 && icache_size != size)
                pr_info("CPU%u: detected I-Cache line size mismatch, workaround enabled\n",
                        cpuid);
        if (icache_size > size)
                icache_size = size;
}
#endif

void __init arm_memblock_init(const struct machine_desc *mdesc)
{
        /* Register the kernel text, kernel data and initrd with memblock. */
        memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);

        arm_initrd_init();

        arm_mm_memblock_reserve();

        /* reserve any platform specific memblock areas */
        if (mdesc->reserve)
                mdesc->reserve();

        early_init_fdt_reserve_self();
        early_init_fdt_scan_reserved_mem();

        /* reserve memory for DMA contiguous allocations */
        dma_contiguous_reserve(arm_dma_limit);

        arm_memblock_steal_permitted = false;
        memblock_dump_all();
}

void __init bootmem_init(void)
{
        memblock_allow_resize();

        find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);

        early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
                      (phys_addr_t)max_low_pfn << PAGE_SHIFT);

        /*
         * sparse_init() tries to allocate memory from memblock, so must be
         * done after the fixed reservations
         */
        sparse_init();

        /*
         * Now free the memory - free_area_init needs
         * the sparse mem_map arrays initialized by sparse_init()
         * for memmap_init_zone(), otherwise all PFNs are invalid.
         */
        zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
}

/*
 * Poison init memory with an undefined instruction (ARM) or a branch to an
 * undefined instruction (Thumb).
 */
static inline void poison_init_mem(void *s, size_t count)
{
        u32 *p = (u32 *)s;
        for (; count != 0; count -= 4)
                *p++ = 0xe7fddef0;
}

static inline void __init
free_memmap(unsigned long start_pfn, unsigned long end_pfn)
{
        struct page *start_pg, *end_pg;
        phys_addr_t pg, pgend;

        /*
         * Convert start_pfn/end_pfn to a struct page pointer.
         */
        start_pg = pfn_to_page(start_pfn - 1) + 1;
        end_pg = pfn_to_page(end_pfn - 1) + 1;

        /*
         * Convert to physical addresses, and
         * round start upwards and end downwards.
         */
        pg = PAGE_ALIGN(__pa(start_pg));
        pgend = __pa(end_pg) & PAGE_MASK;

        /*
         * If there are free pages between these,
         * free the section of the memmap array.
         */
        if (pg < pgend)
                memblock_free_early(pg, pgend - pg);
}

/*
 * The mem_map array can get very big.  Free the unused area of the memory map.
 */
static void __init free_unused_memmap(void)
{
        unsigned long start, prev_end = 0;
        struct memblock_region *reg;

        /*
         * This relies on each bank being in address order.
         * The banks are sorted previously in bootmem_init().
         */
        for_each_memblock(memory, reg) {
                start = memblock_region_memory_base_pfn(reg);

#ifdef CONFIG_SPARSEMEM
                /*
                 * Take care not to free memmap entries that don't exist
                 * due to SPARSEMEM sections which aren't present.
                 */
                start = min(start,
                                 ALIGN(prev_end, PAGES_PER_SECTION));
#else
                /*
                 * Align down here since the VM subsystem insists that the
                 * memmap entries are valid from the bank start aligned to
                 * MAX_ORDER_NR_PAGES.
                 */
                start = round_down(start, MAX_ORDER_NR_PAGES);
#endif
                /*
                 * If we had a previous bank, and there is a space
                 * between the current bank and the previous, free it.
                 */
                if (prev_end && prev_end < start)
                        free_memmap(prev_end, start);

                /*
                 * Align up here since the VM subsystem insists that the
                 * memmap entries are valid from the bank end aligned to
                 * MAX_ORDER_NR_PAGES.
                 */
                prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
                                 MAX_ORDER_NR_PAGES);
        }

#ifdef CONFIG_SPARSEMEM
        if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
                free_memmap(prev_end,
                            ALIGN(prev_end, PAGES_PER_SECTION));
#endif
}

#ifdef CONFIG_HIGHMEM
static inline void free_area_high(unsigned long pfn, unsigned long end)
{
        for (; pfn < end; pfn++)
                free_highmem_page(pfn_to_page(pfn));
}
#endif

static void __init free_highpages(void)
{
#ifdef CONFIG_HIGHMEM
        unsigned long max_low = max_low_pfn;
        struct memblock_region *mem, *res;

        /* set highmem page free */
        for_each_memblock(memory, mem) {
                unsigned long start = memblock_region_memory_base_pfn(mem);
                unsigned long end = memblock_region_memory_end_pfn(mem);

                /* Ignore complete lowmem entries */
                if (end <= max_low)
                        continue;

                if (memblock_is_nomap(mem))
                        continue;

                /* Truncate partial highmem entries */
                if (start < max_low)
                        start = max_low;

                /* Find and exclude any reserved regions */
                for_each_memblock(reserved, res) {
                        unsigned long res_start, res_end;

                        res_start = memblock_region_reserved_base_pfn(res);
                        res_end = memblock_region_reserved_end_pfn(res);

                        if (res_end < start)
                                continue;
                        if (res_start < start)
                                res_start = start;
                        if (res_start > end)
                                res_start = end;
                        if (res_end > end)
                                res_end = end;
                        if (res_start != start)
                                free_area_high(start, res_start);
                        start = res_end;
                        if (start == end)
                                break;
                }

                /* And now free anything which remains */
                if (start < end)
                        free_area_high(start, end);
        }
#endif
}

/*
 * mem_init() marks the free areas in the mem_map and tells us how much
 * memory is free.  This is done after various parts of the system have
 * claimed their memory after the kernel image.
 */
void __init mem_init(void)
{
#ifdef CONFIG_ARM_LPAE
        swiotlb_init(1);
#endif

        set_max_mapnr(pfn_to_page(max_pfn) - mem_map);

        /* this will put all unused low memory onto the freelists */
        free_unused_memmap();
        memblock_free_all();

#ifdef CONFIG_SA1111
        /* now that our DMA memory is actually so designated, we can free it */
        free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
#endif

        free_highpages();

        mem_init_print_info(NULL);

        /*
         * Check boundaries twice: Some fundamental inconsistencies can
         * be detected at build time already.
         */
#ifdef CONFIG_MMU
        BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
        BUG_ON(TASK_SIZE                                > MODULES_VADDR);
#endif

#ifdef CONFIG_HIGHMEM
        BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
        BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
#endif
}

#ifdef CONFIG_STRICT_KERNEL_RWX
struct section_perm {
        const char *name;
        unsigned long start;
        unsigned long end;
        pmdval_t mask;
        pmdval_t prot;
        pmdval_t clear;
};

/* First section-aligned location at or after __start_rodata. */
extern char __start_rodata_section_aligned[];

static struct section_perm nx_perms[] = {
        /* Make pages tables, etc before _stext RW (set NX). */
        {
                .name   = "pre-text NX",
                .start  = PAGE_OFFSET,
                .end    = (unsigned long)_stext,
                .mask   = ~PMD_SECT_XN,
                .prot   = PMD_SECT_XN,
        },
        /* Make init RW (set NX). */
        {
                .name   = "init NX",
                .start  = (unsigned long)__init_begin,
                .end    = (unsigned long)_sdata,
                .mask   = ~PMD_SECT_XN,
                .prot   = PMD_SECT_XN,
        },
        /* Make rodata NX (set RO in ro_perms below). */
        {
                .name   = "rodata NX",
                .start  = (unsigned long)__start_rodata_section_aligned,
                .end    = (unsigned long)__init_begin,
                .mask   = ~PMD_SECT_XN,
                .prot   = PMD_SECT_XN,
        },
};

static struct section_perm ro_perms[] = {
        /* Make kernel code and rodata RX (set RO). */
        {
                .name   = "text/rodata RO",
                .start  = (unsigned long)_stext,
                .end    = (unsigned long)__init_begin,
#ifdef CONFIG_ARM_LPAE
                .mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
                .prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
#else
                .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
                .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
                .clear  = PMD_SECT_AP_WRITE,
#endif
        },
};

/*
 * Updates section permissions only for the current mm (sections are
 * copied into each mm). During startup, this is the init_mm. Is only
 * safe to be called with preemption disabled, as under stop_machine().
 */
static inline void section_update(unsigned long addr, pmdval_t mask,
                                  pmdval_t prot, struct mm_struct *mm)
{
        pmd_t *pmd;

        pmd = pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, addr), addr), addr), addr);

#ifdef CONFIG_ARM_LPAE
        pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
#else
        if (addr & SECTION_SIZE)
                pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
        else
                pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
#endif
        flush_pmd_entry(pmd);
        local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
}

/* Make sure extended page tables are in use. */
static inline bool arch_has_strict_perms(void)
{
        if (cpu_architecture() < CPU_ARCH_ARMv6)
                return false;

        return !!(get_cr() & CR_XP);
}

static void set_section_perms(struct section_perm *perms, int n, bool set,
                              struct mm_struct *mm)
{
        size_t i;
        unsigned long addr;

        if (!arch_has_strict_perms())
                return;

        for (i = 0; i < n; i++) {
                if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
                    !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
                        pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
                                perms[i].name, perms[i].start, perms[i].end,
                                SECTION_SIZE);
                        continue;
                }

                for (addr = perms[i].start;
                     addr < perms[i].end;
                     addr += SECTION_SIZE)
                        section_update(addr, perms[i].mask,
                                set ? perms[i].prot : perms[i].clear, mm);
        }

}

/**
 * update_sections_early intended to be called only through stop_machine
 * framework and executed by only one CPU while all other CPUs will spin and
 * wait, so no locking is required in this function.
 */
static void update_sections_early(struct section_perm perms[], int n)
{
        struct task_struct *t, *s;

        for_each_process(t) {
                if (t->flags & PF_KTHREAD)
                        continue;
                for_each_thread(t, s)
                        if (s->mm)
                                set_section_perms(perms, n, true, s->mm);
        }
        set_section_perms(perms, n, true, current->active_mm);
        set_section_perms(perms, n, true, &init_mm);
}

static int __fix_kernmem_perms(void *unused)
{
        update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
        return 0;
}

static void fix_kernmem_perms(void)
{
        stop_machine(__fix_kernmem_perms, NULL, NULL);
}

static int __mark_rodata_ro(void *unused)
{
        update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
        return 0;
}

static int kernel_set_to_readonly __read_mostly;

void mark_rodata_ro(void)
{
        kernel_set_to_readonly = 1;
        stop_machine(__mark_rodata_ro, NULL, NULL);
        debug_checkwx();
}

void set_kernel_text_rw(void)
{
        if (!kernel_set_to_readonly)
                return;

        set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
                                current->active_mm);
}

void set_kernel_text_ro(void)
{
        if (!kernel_set_to_readonly)
                return;

        set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
                                current->active_mm);
}

#else
static inline void fix_kernmem_perms(void) { }
#endif /* CONFIG_STRICT_KERNEL_RWX */

void free_initmem(void)
{
        fix_kernmem_perms();

        poison_init_mem(__init_begin, __init_end - __init_begin);
        if (!machine_is_integrator() && !machine_is_cintegrator())
                free_initmem_default(-1);
}

#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
        if (start == initrd_start)
                start = round_down(start, PAGE_SIZE);
        if (end == initrd_end)
                end = round_up(end, PAGE_SIZE);

        poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
        free_reserved_area((void *)start, (void *)end, -1, "initrd");
}
#endif