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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2023 Loongson Technology Corporation Limited
*/
#define pr_fmt(fmt) "kasan: " fmt
#include <linux/kasan.h>
#include <linux/memblock.h>
#include <linux/sched/task.h>
#include <asm/tlbflush.h>
#include <asm/pgalloc.h>
#include <asm-generic/sections.h>
static pgd_t kasan_pg_dir[PTRS_PER_PGD] __initdata __aligned(PAGE_SIZE);
#ifdef __PAGETABLE_PUD_FOLDED
#define __p4d_none(early, p4d) (0)
#else
#define __p4d_none(early, p4d) (early ? (p4d_val(p4d) == 0) : \
(__pa(p4d_val(p4d)) == (unsigned long)__pa(kasan_early_shadow_pud)))
#endif
#ifdef __PAGETABLE_PMD_FOLDED
#define __pud_none(early, pud) (0)
#else
#define __pud_none(early, pud) (early ? (pud_val(pud) == 0) : \
(__pa(pud_val(pud)) == (unsigned long)__pa(kasan_early_shadow_pmd)))
#endif
#define __pmd_none(early, pmd) (early ? (pmd_val(pmd) == 0) : \
(__pa(pmd_val(pmd)) == (unsigned long)__pa(kasan_early_shadow_pte)))
#define __pte_none(early, pte) (early ? pte_none(pte) : \
((pte_val(pte) & _PFN_MASK) == (unsigned long)__pa(kasan_early_shadow_page)))
bool kasan_early_stage = true;
void *kasan_mem_to_shadow(const void *addr)
{
if (!kasan_arch_is_ready()) {
return (void *)(kasan_early_shadow_page);
} else {
unsigned long maddr = (unsigned long)addr;
unsigned long xrange = (maddr >> XRANGE_SHIFT) & 0xffff;
unsigned long offset = 0;
if (maddr >= FIXADDR_START)
return (void *)(kasan_early_shadow_page);
maddr &= XRANGE_SHADOW_MASK;
switch (xrange) {
case XKPRANGE_CC_SEG:
offset = XKPRANGE_CC_SHADOW_OFFSET;
break;
case XKPRANGE_UC_SEG:
offset = XKPRANGE_UC_SHADOW_OFFSET;
break;
case XKVRANGE_VC_SEG:
offset = XKVRANGE_VC_SHADOW_OFFSET;
break;
default:
WARN_ON(1);
return NULL;
}
return (void *)((maddr >> KASAN_SHADOW_SCALE_SHIFT) + offset);
}
}
const void *kasan_shadow_to_mem(const void *shadow_addr)
{
unsigned long addr = (unsigned long)shadow_addr;
if (unlikely(addr > KASAN_SHADOW_END) ||
unlikely(addr < KASAN_SHADOW_START)) {
WARN_ON(1);
return NULL;
}
if (addr >= XKVRANGE_VC_SHADOW_OFFSET)
return (void *)(((addr - XKVRANGE_VC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKVRANGE_VC_START);
else if (addr >= XKPRANGE_UC_SHADOW_OFFSET)
return (void *)(((addr - XKPRANGE_UC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_UC_START);
else if (addr >= XKPRANGE_CC_SHADOW_OFFSET)
return (void *)(((addr - XKPRANGE_CC_SHADOW_OFFSET) << KASAN_SHADOW_SCALE_SHIFT) + XKPRANGE_CC_START);
else {
WARN_ON(1);
return NULL;
}
}
/*
* Alloc memory for shadow memory page table.
*/
static phys_addr_t __init kasan_alloc_zeroed_page(int node)
{
void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
__pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
if (!p)
panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
__func__, PAGE_SIZE, PAGE_SIZE, node, __pa(MAX_DMA_ADDRESS));
return __pa(p);
}
static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node, bool early)
{
if (__pmd_none(early, READ_ONCE(*pmdp))) {
phys_addr_t pte_phys = early ?
__pa_symbol(kasan_early_shadow_pte) : kasan_alloc_zeroed_page(node);
if (!early)
memcpy(__va(pte_phys), kasan_early_shadow_pte, sizeof(kasan_early_shadow_pte));
pmd_populate_kernel(NULL, pmdp, (pte_t *)__va(pte_phys));
}
return pte_offset_kernel(pmdp, addr);
}
static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node, bool early)
{
if (__pud_none(early, READ_ONCE(*pudp))) {
phys_addr_t pmd_phys = early ?
__pa_symbol(kasan_early_shadow_pmd) : kasan_alloc_zeroed_page(node);
if (!early)
memcpy(__va(pmd_phys), kasan_early_shadow_pmd, sizeof(kasan_early_shadow_pmd));
pud_populate(&init_mm, pudp, (pmd_t *)__va(pmd_phys));
}
return pmd_offset(pudp, addr);
}
static pud_t *__init kasan_pud_offset(p4d_t *p4dp, unsigned long addr, int node, bool early)
{
if (__p4d_none(early, READ_ONCE(*p4dp))) {
phys_addr_t pud_phys = early ?
__pa_symbol(kasan_early_shadow_pud) : kasan_alloc_zeroed_page(node);
if (!early)
memcpy(__va(pud_phys), kasan_early_shadow_pud, sizeof(kasan_early_shadow_pud));
p4d_populate(&init_mm, p4dp, (pud_t *)__va(pud_phys));
}
return pud_offset(p4dp, addr);
}
static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
unsigned long end, int node, bool early)
{
unsigned long next;
pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
do {
phys_addr_t page_phys = early ?
__pa_symbol(kasan_early_shadow_page)
: kasan_alloc_zeroed_page(node);
next = addr + PAGE_SIZE;
set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
} while (ptep++, addr = next, addr != end && __pte_none(early, READ_ONCE(*ptep)));
}
static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
unsigned long end, int node, bool early)
{
unsigned long next;
pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
do {
next = pmd_addr_end(addr, end);
kasan_pte_populate(pmdp, addr, next, node, early);
} while (pmdp++, addr = next, addr != end && __pmd_none(early, READ_ONCE(*pmdp)));
}
static void __init kasan_pud_populate(p4d_t *p4dp, unsigned long addr,
unsigned long end, int node, bool early)
{
unsigned long next;
pud_t *pudp = kasan_pud_offset(p4dp, addr, node, early);
do {
next = pud_addr_end(addr, end);
kasan_pmd_populate(pudp, addr, next, node, early);
} while (pudp++, addr = next, addr != end);
}
static void __init kasan_p4d_populate(pgd_t *pgdp, unsigned long addr,
unsigned long end, int node, bool early)
{
unsigned long next;
p4d_t *p4dp = p4d_offset(pgdp, addr);
do {
next = p4d_addr_end(addr, end);
kasan_pud_populate(p4dp, addr, next, node, early);
} while (p4dp++, addr = next, addr != end);
}
static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
int node, bool early)
{
unsigned long next;
pgd_t *pgdp;
pgdp = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
kasan_p4d_populate(pgdp, addr, next, node, early);
} while (pgdp++, addr = next, addr != end);
}
/* Set up full kasan mappings, ensuring that the mapped pages are zeroed */
static void __init kasan_map_populate(unsigned long start, unsigned long end,
int node)
{
kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
}
asmlinkage void __init kasan_early_init(void)
{
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
}
static inline void kasan_set_pgd(pgd_t *pgdp, pgd_t pgdval)
{
WRITE_ONCE(*pgdp, pgdval);
}
static void __init clear_pgds(unsigned long start, unsigned long end)
{
/*
* Remove references to kasan page tables from
* swapper_pg_dir. pgd_clear() can't be used
* here because it's nop on 2,3-level pagetable setups
*/
for (; start < end; start += PGDIR_SIZE)
kasan_set_pgd((pgd_t *)pgd_offset_k(start), __pgd(0));
}
void __init kasan_init(void)
{
u64 i;
phys_addr_t pa_start, pa_end;
/*
* PGD was populated as invalid_pmd_table or invalid_pud_table
* in pagetable_init() which depends on how many levels of page
* table you are using, but we had to clean the gpd of kasan
* shadow memory, as the pgd value is none-zero.
* The assertion pgd_none is going to be false and the formal populate
* afterwards is not going to create any new pgd at all.
*/
memcpy(kasan_pg_dir, swapper_pg_dir, sizeof(kasan_pg_dir));
csr_write64(__pa_symbol(kasan_pg_dir), LOONGARCH_CSR_PGDH);
local_flush_tlb_all();
clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
/* Maps everything to a single page of zeroes */
kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE, true);
kasan_populate_early_shadow(kasan_mem_to_shadow((void *)VMALLOC_START),
kasan_mem_to_shadow((void *)KFENCE_AREA_END));
kasan_early_stage = false;
/* Populate the linear mapping */
for_each_mem_range(i, &pa_start, &pa_end) {
void *start = (void *)phys_to_virt(pa_start);
void *end = (void *)phys_to_virt(pa_end);
if (start >= end)
break;
kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
(unsigned long)kasan_mem_to_shadow(end), NUMA_NO_NODE);
}
/* Populate modules mapping */
kasan_map_populate((unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR),
(unsigned long)kasan_mem_to_shadow((void *)MODULES_END), NUMA_NO_NODE);
/*
* KAsan may reuse the contents of kasan_early_shadow_pte directly, so we
* should make sure that it maps the zero page read-only.
*/
for (i = 0; i < PTRS_PER_PTE; i++)
set_pte(&kasan_early_shadow_pte[i],
pfn_pte(__phys_to_pfn(__pa_symbol(kasan_early_shadow_page)), PAGE_KERNEL_RO));
memset(kasan_early_shadow_page, 0, PAGE_SIZE);
csr_write64(__pa_symbol(swapper_pg_dir), LOONGARCH_CSR_PGDH);
local_flush_tlb_all();
/* At this point kasan is fully initialized. Enable error messages */
init_task.kasan_depth = 0;
pr_info("KernelAddressSanitizer initialized.\n");
}
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