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// 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>
DEFINE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key);
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(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((void *)start, (void *)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);
static_branch_inc(&powerpc_kasan_enabled_key);
/* Enable error messages */
init_task.kasan_depth = 0;
pr_info("KASAN init done\n");
}
void __init kasan_late_init(void) { }
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