// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2019 Andes Technology Corporation

#include <linux/pfn.h>
#include <linux/init_task.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>
#include <asm/pgalloc.h>

/*
 * Kasan shadow region must lie at a fixed address across sv39, sv48 and sv57
 * which is right before the kernel.
 *
 * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate
 * the page global directory with kasan_early_shadow_pmd.
 *
 * For sv48 and sv57, the region start is aligned on PGDIR_SIZE whereas the end
 * region is not and then we have to go down to the PUD level.
 */

static pgd_t tmp_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
static p4d_t tmp_p4d[PTRS_PER_P4D] __page_aligned_bss;
static pud_t tmp_pud[PTRS_PER_PUD] __page_aligned_bss;

static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
{
        phys_addr_t phys_addr;
        pte_t *ptep, *p;

        if (pmd_none(pmdp_get(pmd))) {
                p = memblock_alloc_or_panic(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
                set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(p)), PAGE_TABLE));
        }

        ptep = pte_offset_kernel(pmd, vaddr);

        do {
                if (pte_none(ptep_get(ptep))) {
                        phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
                        set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL));
                        memset(__va(phys_addr), KASAN_SHADOW_INIT, PAGE_SIZE);
                }
        } while (ptep++, vaddr += PAGE_SIZE, vaddr != end);
}

static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end)
{
        phys_addr_t phys_addr;
        pmd_t *pmdp, *p;
        unsigned long next;

        if (pud_none(pudp_get(pud))) {
                p = memblock_alloc_or_panic(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
                set_pud(pud, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
        }

        pmdp = pmd_offset(pud, vaddr);

        do {
                next = pmd_addr_end(vaddr, end);

                if (pmd_none(pmdp_get(pmdp)) && IS_ALIGNED(vaddr, PMD_SIZE) &&
                    (next - vaddr) >= PMD_SIZE) {
                        phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
                        if (phys_addr) {
                                set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
                                memset(__va(phys_addr), KASAN_SHADOW_INIT, PMD_SIZE);
                                continue;
                        }
                }

                kasan_populate_pte(pmdp, vaddr, next);
        } while (pmdp++, vaddr = next, vaddr != end);
}

static void __init kasan_populate_pud(p4d_t *p4d,
                                      unsigned long vaddr, unsigned long end)
{
        phys_addr_t phys_addr;
        pud_t *pudp, *p;
        unsigned long next;

        if (p4d_none(p4dp_get(p4d))) {
                p = memblock_alloc_or_panic(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
                set_p4d(p4d, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
        }

        pudp = pud_offset(p4d, vaddr);

        do {
                next = pud_addr_end(vaddr, end);

                if (pud_none(pudp_get(pudp)) && IS_ALIGNED(vaddr, PUD_SIZE) &&
                    (next - vaddr) >= PUD_SIZE) {
                        phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
                        if (phys_addr) {
                                set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
                                memset(__va(phys_addr), KASAN_SHADOW_INIT, PUD_SIZE);
                                continue;
                        }
                }

                kasan_populate_pmd(pudp, vaddr, next);
        } while (pudp++, vaddr = next, vaddr != end);
}

static void __init kasan_populate_p4d(pgd_t *pgd,
                                      unsigned long vaddr, unsigned long end)
{
        phys_addr_t phys_addr;
        p4d_t *p4dp, *p;
        unsigned long next;

        if (pgd_none(pgdp_get(pgd))) {
                p = memblock_alloc_or_panic(PTRS_PER_P4D * sizeof(p4d_t), PAGE_SIZE);
                set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
        }

        p4dp = p4d_offset(pgd, vaddr);

        do {
                next = p4d_addr_end(vaddr, end);

                if (p4d_none(p4dp_get(p4dp)) && IS_ALIGNED(vaddr, P4D_SIZE) &&
                    (next - vaddr) >= P4D_SIZE) {
                        phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
                        if (phys_addr) {
                                set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
                                memset(__va(phys_addr), KASAN_SHADOW_INIT, P4D_SIZE);
                                continue;
                        }
                }

                kasan_populate_pud(p4dp, vaddr, next);
        } while (p4dp++, vaddr = next, vaddr != end);
}

static void __init kasan_populate_pgd(pgd_t *pgdp,
                                      unsigned long vaddr, unsigned long end)
{
        phys_addr_t phys_addr;
        unsigned long next;

        do {
                next = pgd_addr_end(vaddr, end);

                if (pgd_none(pgdp_get(pgdp)) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
                    (next - vaddr) >= PGDIR_SIZE) {
                        phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
                        if (phys_addr) {
                                set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
                                memset(__va(phys_addr), KASAN_SHADOW_INIT, PGDIR_SIZE);
                                continue;
                        }
                }

                kasan_populate_p4d(pgdp, vaddr, next);
        } while (pgdp++, vaddr = next, vaddr != end);
}

static void __init kasan_early_clear_pud(p4d_t *p4dp,
                                         unsigned long vaddr, unsigned long end)
{
        pud_t *pudp, *base_pud;
        unsigned long next;

        if (!pgtable_l4_enabled) {
                pudp = (pud_t *)p4dp;
        } else {
                base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(p4dp_get(p4dp))));
                pudp = base_pud + pud_index(vaddr);
        }

        do {
                next = pud_addr_end(vaddr, end);

                if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
                        pud_clear(pudp);
                        continue;
                }

                BUG();
        } while (pudp++, vaddr = next, vaddr != end);
}

static void __init kasan_early_clear_p4d(pgd_t *pgdp,
                                         unsigned long vaddr, unsigned long end)
{
        p4d_t *p4dp, *base_p4d;
        unsigned long next;

        if (!pgtable_l5_enabled) {
                p4dp = (p4d_t *)pgdp;
        } else {
                base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(pgdp_get(pgdp))));
                p4dp = base_p4d + p4d_index(vaddr);
        }

        do {
                next = p4d_addr_end(vaddr, end);

                if (pgtable_l4_enabled && IS_ALIGNED(vaddr, P4D_SIZE) &&
                    (next - vaddr) >= P4D_SIZE) {
                        p4d_clear(p4dp);
                        continue;
                }

                kasan_early_clear_pud(p4dp, vaddr, next);
        } while (p4dp++, vaddr = next, vaddr != end);
}

static void __init kasan_early_clear_pgd(pgd_t *pgdp,
                                         unsigned long vaddr, unsigned long end)
{
        unsigned long next;

        do {
                next = pgd_addr_end(vaddr, end);

                if (pgtable_l5_enabled && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
                    (next - vaddr) >= PGDIR_SIZE) {
                        pgd_clear(pgdp);
                        continue;
                }

                kasan_early_clear_p4d(pgdp, vaddr, next);
        } while (pgdp++, vaddr = next, vaddr != end);
}

static void __init kasan_early_populate_pud(p4d_t *p4dp,
                                            unsigned long vaddr,
                                            unsigned long end)
{
        pud_t *pudp, *base_pud;
        phys_addr_t phys_addr;
        unsigned long next;

        if (!pgtable_l4_enabled) {
                pudp = (pud_t *)p4dp;
        } else {
                base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(p4dp_get(p4dp))));
                pudp = base_pud + pud_index(vaddr);
        }

        do {
                next = pud_addr_end(vaddr, end);

                if (pud_none(pudp_get(pudp)) && IS_ALIGNED(vaddr, PUD_SIZE) &&
                    (next - vaddr) >= PUD_SIZE) {
                        phys_addr = __pa((uintptr_t)kasan_early_shadow_pmd);
                        set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
                        continue;
                }

                BUG();
        } while (pudp++, vaddr = next, vaddr != end);
}

static void __init kasan_early_populate_p4d(pgd_t *pgdp,
                                            unsigned long vaddr,
                                            unsigned long end)
{
        p4d_t *p4dp, *base_p4d;
        phys_addr_t phys_addr;
        unsigned long next;

        /*
         * We can't use pgd_page_vaddr here as it would return a linear
         * mapping address but it is not mapped yet, but when populating
         * early_pg_dir, we need the physical address and when populating
         * swapper_pg_dir, we need the kernel virtual address so use
         * pt_ops facility.
         * Note that this test is then completely equivalent to
         * p4dp = p4d_offset(pgdp, vaddr)
         */
        if (!pgtable_l5_enabled) {
                p4dp = (p4d_t *)pgdp;
        } else {
                base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(pgdp_get(pgdp))));
                p4dp = base_p4d + p4d_index(vaddr);
        }

        do {
                next = p4d_addr_end(vaddr, end);

                if (p4d_none(p4dp_get(p4dp)) && IS_ALIGNED(vaddr, P4D_SIZE) &&
                    (next - vaddr) >= P4D_SIZE) {
                        phys_addr = __pa((uintptr_t)kasan_early_shadow_pud);
                        set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
                        continue;
                }

                kasan_early_populate_pud(p4dp, vaddr, next);
        } while (p4dp++, vaddr = next, vaddr != end);
}

static void __init kasan_early_populate_pgd(pgd_t *pgdp,
                                            unsigned long vaddr,
                                            unsigned long end)
{
        phys_addr_t phys_addr;
        unsigned long next;

        do {
                next = pgd_addr_end(vaddr, end);

                if (pgd_none(pgdp_get(pgdp)) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
                    (next - vaddr) >= PGDIR_SIZE) {
                        phys_addr = __pa((uintptr_t)kasan_early_shadow_p4d);
                        set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
                        continue;
                }

                kasan_early_populate_p4d(pgdp, vaddr, next);
        } while (pgdp++, vaddr = next, vaddr != end);
}

asmlinkage void __init kasan_early_init(void)
{
        uintptr_t i;

        BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
                KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));

        for (i = 0; i < PTRS_PER_PTE; ++i)
                set_pte(kasan_early_shadow_pte + i,
                        pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL));

        for (i = 0; i < PTRS_PER_PMD; ++i)
                set_pmd(kasan_early_shadow_pmd + i,
                        pfn_pmd(PFN_DOWN
                                (__pa((uintptr_t)kasan_early_shadow_pte)),
                                PAGE_TABLE));

        if (pgtable_l4_enabled) {
                for (i = 0; i < PTRS_PER_PUD; ++i)
                        set_pud(kasan_early_shadow_pud + i,
                                pfn_pud(PFN_DOWN
                                        (__pa(((uintptr_t)kasan_early_shadow_pmd))),
                                        PAGE_TABLE));
        }

        if (pgtable_l5_enabled) {
                for (i = 0; i < PTRS_PER_P4D; ++i)
                        set_p4d(kasan_early_shadow_p4d + i,
                                pfn_p4d(PFN_DOWN
                                        (__pa(((uintptr_t)kasan_early_shadow_pud))),
                                        PAGE_TABLE));
        }

        kasan_early_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
                                 KASAN_SHADOW_START, KASAN_SHADOW_END);

        local_flush_tlb_all();
}

void __init kasan_swapper_init(void)
{
        kasan_early_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
                                 KASAN_SHADOW_START, KASAN_SHADOW_END);

        local_flush_tlb_all();
}

static void __init kasan_populate(void *start, void *end)
{
        unsigned long vaddr = (unsigned long)start & PAGE_MASK;
        unsigned long vend = PAGE_ALIGN((unsigned long)end);

        kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend);
}

static void __init kasan_shallow_populate_pud(p4d_t *p4d,
                                              unsigned long vaddr, unsigned long end)
{
        unsigned long next;
        void *p;
        pud_t *pud_k = pud_offset(p4d, vaddr);

        do {
                next = pud_addr_end(vaddr, end);

                if (pud_none(pudp_get(pud_k))) {
                        p = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
                        set_pud(pud_k, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
                        continue;
                }

                BUG();
        } while (pud_k++, vaddr = next, vaddr != end);
}

static void __init kasan_shallow_populate_p4d(pgd_t *pgd,
                                              unsigned long vaddr, unsigned long end)
{
        unsigned long next;
        void *p;
        p4d_t *p4d_k = p4d_offset(pgd, vaddr);

        do {
                next = p4d_addr_end(vaddr, end);

                if (p4d_none(p4dp_get(p4d_k))) {
                        p = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
                        set_p4d(p4d_k, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
                        continue;
                }

                kasan_shallow_populate_pud(p4d_k, vaddr, end);
        } while (p4d_k++, vaddr = next, vaddr != end);
}

static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
{
        unsigned long next;
        void *p;
        pgd_t *pgd_k = pgd_offset_k(vaddr);

        do {
                next = pgd_addr_end(vaddr, end);

                if (pgd_none(pgdp_get(pgd_k))) {
                        p = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
                        set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
                        continue;
                }

                kasan_shallow_populate_p4d(pgd_k, vaddr, next);
        } while (pgd_k++, vaddr = next, vaddr != end);
}

static void __init kasan_shallow_populate(void *start, void *end)
{
        unsigned long vaddr = (unsigned long)start & PAGE_MASK;
        unsigned long vend = PAGE_ALIGN((unsigned long)end);

        kasan_shallow_populate_pgd(vaddr, vend);
}

#ifdef CONFIG_KASAN_VMALLOC
void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
{
        kasan_populate(kasan_mem_to_shadow(start),
                       kasan_mem_to_shadow(start + size));
}
#endif

static void __init create_tmp_mapping(void)
{
        void *ptr;
        p4d_t *base_p4d;

        /*
         * We need to clean the early mapping: this is hard to achieve "in-place",
         * so install a temporary mapping like arm64 and x86 do.
         */
        memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(pgd_t) * PTRS_PER_PGD);

        /* Copy the last p4d since it is shared with the kernel mapping. */
        if (pgtable_l5_enabled) {
                ptr = (p4d_t *)pgd_page_vaddr(pgdp_get(pgd_offset_k(KASAN_SHADOW_END)));
                memcpy(tmp_p4d, ptr, sizeof(p4d_t) * PTRS_PER_P4D);
                set_pgd(&tmp_pg_dir[pgd_index(KASAN_SHADOW_END)],
                        pfn_pgd(PFN_DOWN(__pa(tmp_p4d)), PAGE_TABLE));
                base_p4d = tmp_p4d;
        } else {
                base_p4d = (p4d_t *)tmp_pg_dir;
        }

        /* Copy the last pud since it is shared with the kernel mapping. */
        if (pgtable_l4_enabled) {
                ptr = (pud_t *)p4d_page_vaddr(p4dp_get(base_p4d + p4d_index(KASAN_SHADOW_END)));
                memcpy(tmp_pud, ptr, sizeof(pud_t) * PTRS_PER_PUD);
                set_p4d(&base_p4d[p4d_index(KASAN_SHADOW_END)],
                        pfn_p4d(PFN_DOWN(__pa(tmp_pud)), PAGE_TABLE));
        }
}

void __init kasan_init(void)
{
        phys_addr_t p_start, p_end;
        u64 i;

        create_tmp_mapping();
        csr_write(CSR_SATP, PFN_DOWN(__pa(tmp_pg_dir)) | satp_mode);

        kasan_early_clear_pgd(pgd_offset_k(KASAN_SHADOW_START),
                              KASAN_SHADOW_START, KASAN_SHADOW_END);

        kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)FIXADDR_START),
                                    (void *)kasan_mem_to_shadow((void *)VMALLOC_START));

        if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
                kasan_shallow_populate(
                        (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
                        (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
                /* Shallow populate modules and BPF which are vmalloc-allocated */
                kasan_shallow_populate(
                        (void *)kasan_mem_to_shadow((void *)MODULES_VADDR),
                        (void *)kasan_mem_to_shadow((void *)MODULES_END));
        } else {
                kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)VMALLOC_START),
                                            (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
        }

        /* Populate the linear mapping */
        for_each_mem_range(i, &p_start, &p_end) {
                void *start = (void *)__va(p_start);
                void *end = (void *)__va(p_end);

                if (start >= end)
                        break;

                kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
        }

        /* Populate kernel */
        kasan_populate(kasan_mem_to_shadow((const void *)MODULES_END),
                       kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G));

        for (i = 0; i < PTRS_PER_PTE; i++)
                set_pte(&kasan_early_shadow_pte[i],
                        mk_pte(virt_to_page(kasan_early_shadow_page),
                               __pgprot(_PAGE_PRESENT | _PAGE_READ |
                                        _PAGE_ACCESSED)));

        memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
        init_task.kasan_depth = 0;

        csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | satp_mode);
        local_flush_tlb_all();
        kasan_init_generic();
}