linux/arch/x86/mm/kasan_init_64.c
Ingo Molnar b3d9a13681 Merge branch 'linus' into x86/asm, to pick up fixes and resolve conflicts
Conflicts:
	arch/x86/kernel/cpu/Makefile

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-07 10:53:06 +01:00

225 lines
5.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
#define DISABLE_BRANCH_PROFILING
#define pr_fmt(fmt) "kasan: " fmt
#include <linux/bootmem.h>
#include <linux/kasan.h>
#include <linux/kdebug.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/sched/task.h>
#include <linux/vmalloc.h>
#include <asm/e820/types.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/pgtable.h>
extern struct range pfn_mapped[E820_MAX_ENTRIES];
static p4d_t tmp_p4d_table[PTRS_PER_P4D] __initdata __aligned(PAGE_SIZE);
static int __init map_range(struct range *range)
{
unsigned long start;
unsigned long end;
start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start));
end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end));
return vmemmap_populate(start, end, NUMA_NO_NODE);
}
static void __init clear_pgds(unsigned long start,
unsigned long end)
{
pgd_t *pgd;
/* See comment in kasan_init() */
unsigned long pgd_end = end & PGDIR_MASK;
for (; start < pgd_end; start += PGDIR_SIZE) {
pgd = pgd_offset_k(start);
/*
* With folded p4d, pgd_clear() is nop, use p4d_clear()
* instead.
*/
if (CONFIG_PGTABLE_LEVELS < 5)
p4d_clear(p4d_offset(pgd, start));
else
pgd_clear(pgd);
}
pgd = pgd_offset_k(start);
for (; start < end; start += P4D_SIZE)
p4d_clear(p4d_offset(pgd, start));
}
static inline p4d_t *early_p4d_offset(pgd_t *pgd, unsigned long addr)
{
unsigned long p4d;
if (!IS_ENABLED(CONFIG_X86_5LEVEL))
return (p4d_t *)pgd;
p4d = __pa_nodebug(pgd_val(*pgd)) & PTE_PFN_MASK;
p4d += __START_KERNEL_map - phys_base;
return (p4d_t *)p4d + p4d_index(addr);
}
static void __init kasan_early_p4d_populate(pgd_t *pgd,
unsigned long addr,
unsigned long end)
{
pgd_t pgd_entry;
p4d_t *p4d, p4d_entry;
unsigned long next;
if (pgd_none(*pgd)) {
pgd_entry = __pgd(_KERNPG_TABLE | __pa_nodebug(kasan_zero_p4d));
set_pgd(pgd, pgd_entry);
}
p4d = early_p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
if (!p4d_none(*p4d))
continue;
p4d_entry = __p4d(_KERNPG_TABLE | __pa_nodebug(kasan_zero_pud));
set_p4d(p4d, p4d_entry);
} while (p4d++, addr = next, addr != end && p4d_none(*p4d));
}
static void __init kasan_map_early_shadow(pgd_t *pgd)
{
/* See comment in kasan_init() */
unsigned long addr = KASAN_SHADOW_START & PGDIR_MASK;
unsigned long end = KASAN_SHADOW_END;
unsigned long next;
pgd += pgd_index(addr);
do {
next = pgd_addr_end(addr, end);
kasan_early_p4d_populate(pgd, addr, next);
} while (pgd++, addr = next, addr != end);
}
#ifdef CONFIG_KASAN_INLINE
static int kasan_die_handler(struct notifier_block *self,
unsigned long val,
void *data)
{
if (val == DIE_GPF) {
pr_emerg("CONFIG_KASAN_INLINE enabled\n");
pr_emerg("GPF could be caused by NULL-ptr deref or user memory access\n");
}
return NOTIFY_OK;
}
static struct notifier_block kasan_die_notifier = {
.notifier_call = kasan_die_handler,
};
#endif
void __init kasan_early_init(void)
{
int i;
pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL | _PAGE_ENC;
pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE;
pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE;
p4dval_t p4d_val = __pa_nodebug(kasan_zero_pud) | _KERNPG_TABLE;
for (i = 0; i < PTRS_PER_PTE; i++)
kasan_zero_pte[i] = __pte(pte_val);
for (i = 0; i < PTRS_PER_PMD; i++)
kasan_zero_pmd[i] = __pmd(pmd_val);
for (i = 0; i < PTRS_PER_PUD; i++)
kasan_zero_pud[i] = __pud(pud_val);
for (i = 0; IS_ENABLED(CONFIG_X86_5LEVEL) && i < PTRS_PER_P4D; i++)
kasan_zero_p4d[i] = __p4d(p4d_val);
kasan_map_early_shadow(early_top_pgt);
kasan_map_early_shadow(init_top_pgt);
}
void __init kasan_init(void)
{
int i;
#ifdef CONFIG_KASAN_INLINE
register_die_notifier(&kasan_die_notifier);
#endif
memcpy(early_top_pgt, init_top_pgt, sizeof(early_top_pgt));
/*
* We use the same shadow offset for 4- and 5-level paging to
* facilitate boot-time switching between paging modes.
* As result in 5-level paging mode KASAN_SHADOW_START and
* KASAN_SHADOW_END are not aligned to PGD boundary.
*
* KASAN_SHADOW_START doesn't share PGD with anything else.
* We claim whole PGD entry to make things easier.
*
* KASAN_SHADOW_END lands in the last PGD entry and it collides with
* bunch of things like kernel code, modules, EFI mapping, etc.
* We need to take extra steps to not overwrite them.
*/
if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
void *ptr;
ptr = (void *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
memcpy(tmp_p4d_table, (void *)ptr, sizeof(tmp_p4d_table));
set_pgd(&early_top_pgt[pgd_index(KASAN_SHADOW_END)],
__pgd(__pa(tmp_p4d_table) | _KERNPG_TABLE));
}
load_cr3(early_top_pgt);
__flush_tlb_all();
clear_pgds(KASAN_SHADOW_START & PGDIR_MASK, KASAN_SHADOW_END);
kasan_populate_zero_shadow((void *)(KASAN_SHADOW_START & PGDIR_MASK),
kasan_mem_to_shadow((void *)PAGE_OFFSET));
for (i = 0; i < E820_MAX_ENTRIES; i++) {
if (pfn_mapped[i].end == 0)
break;
if (map_range(&pfn_mapped[i]))
panic("kasan: unable to allocate shadow!");
}
kasan_populate_zero_shadow(
kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
kasan_mem_to_shadow((void *)__START_KERNEL_map));
vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext),
(unsigned long)kasan_mem_to_shadow(_end),
NUMA_NO_NODE);
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
(void *)KASAN_SHADOW_END);
load_cr3(init_top_pgt);
__flush_tlb_all();
/*
* kasan_zero_page has been used as early shadow memory, thus it may
* contain some garbage. Now we can clear and write protect it, since
* after the TLB flush no one should write to it.
*/
memset(kasan_zero_page, 0, PAGE_SIZE);
for (i = 0; i < PTRS_PER_PTE; i++) {
pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO | _PAGE_ENC);
set_pte(&kasan_zero_pte[i], pte);
}
/* Flush TLBs again to be sure that write protection applied. */
__flush_tlb_all();
init_task.kasan_depth = 0;
pr_info("KernelAddressSanitizer initialized\n");
}