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// SPDX-License-Identifier: GPL-2.0
#define DISABLE_BRANCH_PROFILING
#include <linux/kasan.h>
#include <linux/printk.h>
#include <linux/memblock.h>
#include <linux/sched/task.h>
#include <linux/vmalloc.h>
#include <asm/pgalloc.h>
#include <asm/code-patching.h>
#include <mm/mmu_decl.h>
static void kasan_populate_pte(pte_t *ptep, pgprot_t prot)
{
unsigned long va = (unsigned long)kasan_early_shadow_page;
phys_addr_t pa = __pa(kasan_early_shadow_page);
int i;
for (i = 0; i < PTRS_PER_PTE; i++, ptep++)
__set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 0);
}
static int kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
{
pmd_t *pmd;
unsigned long k_cur, k_next;
pmd = pmd_offset(pud_offset(pgd_offset_k(k_start), k_start), k_start);
for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
pte_t *new;
k_next = pgd_addr_end(k_cur, k_end);
if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
continue;
new = pte_alloc_one_kernel(&init_mm);
if (!new)
return -ENOMEM;
kasan_populate_pte(new, PAGE_KERNEL_RO);
pmd_populate_kernel(&init_mm, pmd, new);
}
return 0;
}
static void __ref *kasan_get_one_page(void)
{
if (slab_is_available())
return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
return memblock_alloc(PAGE_SIZE, PAGE_SIZE);
}
static int __ref kasan_init_region(void *start, size_t size)
{
unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);
unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);
unsigned long k_cur;
int ret;
void *block = NULL;
ret = kasan_init_shadow_page_tables(k_start, k_end);
if (ret)
return ret;
if (!slab_is_available())
block = memblock_alloc(k_end - k_start, PAGE_SIZE);
for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE) {
pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(k_cur), k_cur), k_cur);
void *va = block ? block + k_cur - k_start : kasan_get_one_page();
pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);
if (!va)
return -ENOMEM;
__set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0);
}
flush_tlb_kernel_range(k_start, k_end);
return 0;
}
static void __init kasan_remap_early_shadow_ro(void)
{
kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL_RO);
flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
}
void __init kasan_mmu_init(void)
{
int ret;
struct memblock_region *reg;
for_each_memblock(memory, reg) {
phys_addr_t base = reg->base;
phys_addr_t top = min(base + reg->size, total_lowmem);
if (base >= top)
continue;
ret = kasan_init_region(__va(base), top - base);
if (ret)
panic("kasan: kasan_init_region() failed");
}
}
void __init kasan_init(void)
{
kasan_remap_early_shadow_ro();
clear_page(kasan_early_shadow_page);
/* At this point kasan is fully initialized. Enable error messages */
init_task.kasan_depth = 0;
pr_info("KASAN init done\n");
}
#ifdef CONFIG_MODULES
void *module_alloc(unsigned long size)
{
void *base = vmalloc_exec(size);
if (!base)
return NULL;
if (!kasan_init_region(base, size))
return base;
vfree(base);
return NULL;
}
#endif
void __init kasan_early_init(void)
{
unsigned long addr = KASAN_SHADOW_START;
unsigned long end = KASAN_SHADOW_END;
unsigned long next;
pmd_t *pmd = pmd_offset(pud_offset(pgd_offset_k(addr), addr), addr);
BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK);
kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL);
do {
next = pgd_addr_end(addr, end);
pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte);
} while (pmd++, addr = next, addr != end);
if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
WARN(true, "KASAN not supported on hash 6xx");
}
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