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linux/mm/kasan/init.c
Bibo Mao d2f8671045 LoongArch: Set initial pte entry with PAGE_GLOBAL for kernel space 
There are two pages in one TLB entry on LoongArch system. For kernel
space, it requires both two pte entries (buddies) with PAGE_GLOBAL bit
set, otherwise HW treats it as non-global tlb, there will be potential
problems if tlb entry for kernel space is not global. Such as fail to
flush kernel tlb with the function local_flush_tlb_kernel_range() which
supposed only flush tlb with global bit.

Kernel address space areas include percpu, vmalloc, vmemmap, fixmap and
kasan areas. For these areas both two consecutive page table entries
should be enabled with PAGE_GLOBAL bit. So with function set_pte() and
pte_clear(), pte buddy entry is checked and set besides its own pte
entry. However it is not atomic operation to set both two pte entries,
there is problem with test_vmalloc test case.

So function kernel_pte_init() is added to init a pte table when it is
created for kernel address space, and the default initial pte value is
PAGE_GLOBAL rather than zero at beginning. Then only its own pte entry
need update with function set_pte() and pte_clear(), nothing to do with
the pte buddy entry.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2024-10-21 22:11:19 +08:00

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// SPDX-License-Identifier: GPL-2.0
/*
* This file contains KASAN shadow initialization code.
*
* Copyright (c) 2015 Samsung Electronics Co., Ltd.
* Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
*/
#include <linux/memblock.h>
#include <linux/init.h>
#include <linux/kasan.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/pfn.h>
#include <linux/slab.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include "kasan.h"
/*
* This page serves two purposes:
* - It used as early shadow memory. The entire shadow region populated
* with this page, before we will be able to setup normal shadow memory.
* - Latter it reused it as zero shadow to cover large ranges of memory
* that allowed to access, but not handled by kasan (vmalloc/vmemmap ...).
*/
unsigned char kasan_early_shadow_page[PAGE_SIZE] __page_aligned_bss;
#if CONFIG_PGTABLE_LEVELS > 4
p4d_t kasan_early_shadow_p4d[MAX_PTRS_PER_P4D] __page_aligned_bss;
static inline bool kasan_p4d_table(pgd_t pgd)
{
return pgd_page(pgd) == virt_to_page(lm_alias(kasan_early_shadow_p4d));
}
#else
static inline bool kasan_p4d_table(pgd_t pgd)
{
return false;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 3
pud_t kasan_early_shadow_pud[MAX_PTRS_PER_PUD] __page_aligned_bss;
static inline bool kasan_pud_table(p4d_t p4d)
{
return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
}
#else
static inline bool kasan_pud_table(p4d_t p4d)
{
return false;
}
#endif
#if CONFIG_PGTABLE_LEVELS > 2
pmd_t kasan_early_shadow_pmd[MAX_PTRS_PER_PMD] __page_aligned_bss;
static inline bool kasan_pmd_table(pud_t pud)
{
return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
}
#else
static inline bool kasan_pmd_table(pud_t pud)
{
return false;
}
#endif
pte_t kasan_early_shadow_pte[MAX_PTRS_PER_PTE + PTE_HWTABLE_PTRS]
__page_aligned_bss;
static inline bool kasan_pte_table(pmd_t pmd)
{
return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
}
static inline bool kasan_early_shadow_page_entry(pte_t pte)
{
return pte_page(pte) == virt_to_page(lm_alias(kasan_early_shadow_page));
}
static __init void *early_alloc(size_t size, int node)
{
void *ptr = memblock_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
MEMBLOCK_ALLOC_ACCESSIBLE, node);
if (!ptr)
panic("%s: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
__func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));
return ptr;
}
static void __ref zero_pte_populate(pmd_t *pmd, unsigned long addr,
unsigned long end)
{
pte_t *pte = pte_offset_kernel(pmd, addr);
pte_t zero_pte;
zero_pte = pfn_pte(PFN_DOWN(__pa_symbol(kasan_early_shadow_page)),
PAGE_KERNEL);
zero_pte = pte_wrprotect(zero_pte);
while (addr + PAGE_SIZE <= end) {
set_pte_at(&init_mm, addr, pte, zero_pte);
addr += PAGE_SIZE;
pte = pte_offset_kernel(pmd, addr);
}
}
void __weak __meminit kernel_pte_init(void *addr)
{
}
static int __ref zero_pmd_populate(pud_t *pud, unsigned long addr,
unsigned long end)
{
pmd_t *pmd = pmd_offset(pud, addr);
unsigned long next;
do {
next = pmd_addr_end(addr, end);
if (IS_ALIGNED(addr, PMD_SIZE) && end - addr >= PMD_SIZE) {
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (pmd_none(*pmd)) {
pte_t *p;
if (slab_is_available())
p = pte_alloc_one_kernel(&init_mm);
else {
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
kernel_pte_init(p);
}
if (!p)
return -ENOMEM;
pmd_populate_kernel(&init_mm, pmd, p);
}
zero_pte_populate(pmd, addr, next);
} while (pmd++, addr = next, addr != end);
return 0;
}
void __weak __meminit pmd_init(void *addr)
{
}
static int __ref zero_pud_populate(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
pud_t *pud = pud_offset(p4d, addr);
unsigned long next;
do {
next = pud_addr_end(addr, end);
if (IS_ALIGNED(addr, PUD_SIZE) && end - addr >= PUD_SIZE) {
pmd_t *pmd;
pud_populate(&init_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (pud_none(*pud)) {
pmd_t *p;
if (slab_is_available()) {
p = pmd_alloc(&init_mm, pud, addr);
if (!p)
return -ENOMEM;
} else {
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
pmd_init(p);
pud_populate(&init_mm, pud, p);
}
}
zero_pmd_populate(pud, addr, next);
} while (pud++, addr = next, addr != end);
return 0;
}
void __weak __meminit pud_init(void *addr)
{
}
static int __ref zero_p4d_populate(pgd_t *pgd, unsigned long addr,
unsigned long end)
{
p4d_t *p4d = p4d_offset(pgd, addr);
unsigned long next;
do {
next = p4d_addr_end(addr, end);
if (IS_ALIGNED(addr, P4D_SIZE) && end - addr >= P4D_SIZE) {
pud_t *pud;
pmd_t *pmd;
p4d_populate(&init_mm, p4d,
lm_alias(kasan_early_shadow_pud));
pud = pud_offset(p4d, addr);
pud_populate(&init_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (p4d_none(*p4d)) {
pud_t *p;
if (slab_is_available()) {
p = pud_alloc(&init_mm, p4d, addr);
if (!p)
return -ENOMEM;
} else {
p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
pud_init(p);
p4d_populate(&init_mm, p4d, p);
}
}
zero_pud_populate(p4d, addr, next);
} while (p4d++, addr = next, addr != end);
return 0;
}
/**
* kasan_populate_early_shadow - populate shadow memory region with
* kasan_early_shadow_page
* @shadow_start: start of the memory range to populate
* @shadow_end: end of the memory range to populate
*/
int __ref kasan_populate_early_shadow(const void *shadow_start,
const void *shadow_end)
{
unsigned long addr = (unsigned long)shadow_start;
unsigned long end = (unsigned long)shadow_end;
pgd_t *pgd = pgd_offset_k(addr);
unsigned long next;
do {
next = pgd_addr_end(addr, end);
if (IS_ALIGNED(addr, PGDIR_SIZE) && end - addr >= PGDIR_SIZE) {
p4d_t *p4d;
pud_t *pud;
pmd_t *pmd;
/*
* kasan_early_shadow_pud should be populated with pmds
* at this moment.
* [pud,pmd]_populate*() below needed only for
* 3,2 - level page tables where we don't have
* puds,pmds, so pgd_populate(), pud_populate()
* is noops.
*/
pgd_populate(&init_mm, pgd,
lm_alias(kasan_early_shadow_p4d));
p4d = p4d_offset(pgd, addr);
p4d_populate(&init_mm, p4d,
lm_alias(kasan_early_shadow_pud));
pud = pud_offset(p4d, addr);
pud_populate(&init_mm, pud,
lm_alias(kasan_early_shadow_pmd));
pmd = pmd_offset(pud, addr);
pmd_populate_kernel(&init_mm, pmd,
lm_alias(kasan_early_shadow_pte));
continue;
}
if (pgd_none(*pgd)) {
p4d_t *p;
if (slab_is_available()) {
p = p4d_alloc(&init_mm, pgd, addr);
if (!p)
return -ENOMEM;
} else {
pgd_populate(&init_mm, pgd,
early_alloc(PAGE_SIZE, NUMA_NO_NODE));
}
}
zero_p4d_populate(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
return 0;
}
static void kasan_free_pte(pte_t *pte_start, pmd_t *pmd)
{
pte_t *pte;
int i;
for (i = 0; i < PTRS_PER_PTE; i++) {
pte = pte_start + i;
if (!pte_none(ptep_get(pte)))
return;
}
pte_free_kernel(&init_mm, (pte_t *)page_to_virt(pmd_page(*pmd)));
pmd_clear(pmd);
}
static void kasan_free_pmd(pmd_t *pmd_start, pud_t *pud)
{
pmd_t *pmd;
int i;
for (i = 0; i < PTRS_PER_PMD; i++) {
pmd = pmd_start + i;
if (!pmd_none(*pmd))
return;
}
pmd_free(&init_mm, (pmd_t *)page_to_virt(pud_page(*pud)));
pud_clear(pud);
}
static void kasan_free_pud(pud_t *pud_start, p4d_t *p4d)
{
pud_t *pud;
int i;
for (i = 0; i < PTRS_PER_PUD; i++) {
pud = pud_start + i;
if (!pud_none(*pud))
return;
}
pud_free(&init_mm, (pud_t *)page_to_virt(p4d_page(*p4d)));
p4d_clear(p4d);
}
static void kasan_free_p4d(p4d_t *p4d_start, pgd_t *pgd)
{
p4d_t *p4d;
int i;
for (i = 0; i < PTRS_PER_P4D; i++) {
p4d = p4d_start + i;
if (!p4d_none(*p4d))
return;
}
p4d_free(&init_mm, (p4d_t *)page_to_virt(pgd_page(*pgd)));
pgd_clear(pgd);
}
static void kasan_remove_pte_table(pte_t *pte, unsigned long addr,
unsigned long end)
{
unsigned long next;
pte_t ptent;
for (; addr < end; addr = next, pte++) {
next = (addr + PAGE_SIZE) & PAGE_MASK;
if (next > end)
next = end;
ptent = ptep_get(pte);
if (!pte_present(ptent))
continue;
if (WARN_ON(!kasan_early_shadow_page_entry(ptent)))
continue;
pte_clear(&init_mm, addr, pte);
}
}
static void kasan_remove_pmd_table(pmd_t *pmd, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pmd++) {
pte_t *pte;
next = pmd_addr_end(addr, end);
if (!pmd_present(*pmd))
continue;
if (kasan_pte_table(*pmd)) {
if (IS_ALIGNED(addr, PMD_SIZE) &&
IS_ALIGNED(next, PMD_SIZE)) {
pmd_clear(pmd);
continue;
}
}
pte = pte_offset_kernel(pmd, addr);
kasan_remove_pte_table(pte, addr, next);
kasan_free_pte(pte_offset_kernel(pmd, 0), pmd);
}
}
static void kasan_remove_pud_table(pud_t *pud, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, pud++) {
pmd_t *pmd, *pmd_base;
next = pud_addr_end(addr, end);
if (!pud_present(*pud))
continue;
if (kasan_pmd_table(*pud)) {
if (IS_ALIGNED(addr, PUD_SIZE) &&
IS_ALIGNED(next, PUD_SIZE)) {
pud_clear(pud);
continue;
}
}
pmd = pmd_offset(pud, addr);
pmd_base = pmd_offset(pud, 0);
kasan_remove_pmd_table(pmd, addr, next);
kasan_free_pmd(pmd_base, pud);
}
}
static void kasan_remove_p4d_table(p4d_t *p4d, unsigned long addr,
unsigned long end)
{
unsigned long next;
for (; addr < end; addr = next, p4d++) {
pud_t *pud;
next = p4d_addr_end(addr, end);
if (!p4d_present(*p4d))
continue;
if (kasan_pud_table(*p4d)) {
if (IS_ALIGNED(addr, P4D_SIZE) &&
IS_ALIGNED(next, P4D_SIZE)) {
p4d_clear(p4d);
continue;
}
}
pud = pud_offset(p4d, addr);
kasan_remove_pud_table(pud, addr, next);
kasan_free_pud(pud_offset(p4d, 0), p4d);
}
}
void kasan_remove_zero_shadow(void *start, unsigned long size)
{
unsigned long addr, end, next;
pgd_t *pgd;
addr = (unsigned long)kasan_mem_to_shadow(start);
end = addr + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
return;
for (; addr < end; addr = next) {
p4d_t *p4d;
next = pgd_addr_end(addr, end);
pgd = pgd_offset_k(addr);
if (!pgd_present(*pgd))
continue;
if (kasan_p4d_table(*pgd)) {
if (IS_ALIGNED(addr, PGDIR_SIZE) &&
IS_ALIGNED(next, PGDIR_SIZE)) {
pgd_clear(pgd);
continue;
}
}
p4d = p4d_offset(pgd, addr);
kasan_remove_p4d_table(p4d, addr, next);
kasan_free_p4d(p4d_offset(pgd, 0), pgd);
}
}
int kasan_add_zero_shadow(void *start, unsigned long size)
{
int ret;
void *shadow_start, *shadow_end;
shadow_start = kasan_mem_to_shadow(start);
shadow_end = shadow_start + (size >> KASAN_SHADOW_SCALE_SHIFT);
if (WARN_ON((unsigned long)start % KASAN_MEMORY_PER_SHADOW_PAGE) ||
WARN_ON(size % KASAN_MEMORY_PER_SHADOW_PAGE))
return -EINVAL;
ret = kasan_populate_early_shadow(shadow_start, shadow_end);
if (ret)
kasan_remove_zero_shadow(start, size);
return ret;
}
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