// SPDX-License-Identifier: GPL-2.0
/*
 * KASAN for 64-bit Book3S powerpc
 *
 * Copyright 2019-2022, Daniel Axtens, IBM Corporation.
 */

/*
 * ppc64 turns on virtual memory late in boot, after calling into generic code
 * like the device-tree parser, so it uses this in conjunction with a hook in
 * outline mode to avoid invalid access early in boot.
 */

#define DISABLE_BRANCH_PROFILING

#include <linux/kasan.h>
#include <linux/printk.h>
#include <linux/sched/task.h>
#include <linux/memblock.h>
#include <asm/pgalloc.h>

static void __init kasan_init_phys_region(void *start, void *end)
{
        unsigned long k_start, k_end, k_cur;
        void *va;

        if (start >= end)
                return;

        k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE);
        k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE);

        va = memblock_alloc_or_panic(k_end - k_start, PAGE_SIZE);
        for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE)
                map_kernel_page(k_cur, __pa(va), PAGE_KERNEL);
}

void __init kasan_init(void)
{
        /*
         * We want to do the following things:
         *  1) Map real memory into the shadow for all physical memblocks
         *     This takes us from c000... to c008...
         *  2) Leave a hole over the shadow of vmalloc space. KASAN_VMALLOC
         *     will manage this for us.
         *     This takes us from c008... to c00a...
         *  3) Map the 'early shadow'/zero page over iomap and vmemmap space.
         *     This takes us up to where we start at c00e...
         */

        void *k_start = kasan_mem_to_shadow((void *)RADIX_VMALLOC_END);
        void *k_end = kasan_mem_to_shadow((void *)RADIX_VMEMMAP_END);
        phys_addr_t start, end;
        u64 i;
        pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);

        if (!early_radix_enabled()) {
                pr_warn("KASAN not enabled as it requires radix!");
                return;
        }

        for_each_mem_range(i, &start, &end)
                kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end));

        for (i = 0; i < PTRS_PER_PTE; i++)
                __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
                             &kasan_early_shadow_pte[i], zero_pte, 0);

        for (i = 0; i < PTRS_PER_PMD; i++)
                pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i],
                                    kasan_early_shadow_pte);

        for (i = 0; i < PTRS_PER_PUD; i++)
                pud_populate(&init_mm, &kasan_early_shadow_pud[i],
                             kasan_early_shadow_pmd);

        /* map the early shadow over the iomap and vmemmap space */
        kasan_populate_early_shadow(k_start, k_end);

        /* mark early shadow region as RO and wipe it */
        zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
        for (i = 0; i < PTRS_PER_PTE; i++)
                __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
                             &kasan_early_shadow_pte[i], zero_pte, 0);

        /*
         * clear_page relies on some cache info that hasn't been set up yet.
         * It ends up looping ~forever and blows up other data.
         * Use memset instead.
         */
        memset(kasan_early_shadow_page, 0, PAGE_SIZE);

        /* Enable error messages */
        init_task.kasan_depth = 0;
        kasan_init_generic();
}

void __init kasan_early_init(void) { }

void __init kasan_late_init(void) { }