Commit d17a1d97 authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Linus Torvalds

x86/mm/kasan: don't use vmemmap_populate() to initialize shadow

The kasan shadow is currently mapped using vmemmap_populate() since that
provides a semi-convenient way to map pages into init_top_pgt.  However,
since that no longer zeroes the mapped pages, it is not suitable for
kasan, which requires zeroed shadow memory.

Add kasan_populate_shadow() interface and use it instead of
vmemmap_populate().  Besides, this allows us to take advantage of
gigantic pages and use them to populate the shadow, which should save us
some memory wasted on page tables and reduce TLB pressure.

Link: http://lkml.kernel.org/r/[email protected]Signed-off-by: default avatarAndrey Ryabinin <[email protected]>
Signed-off-by: default avatarPavel Tatashin <[email protected]>
Cc: Steven Sistare <[email protected]>
Cc: Daniel Jordan <[email protected]>
Cc: Bob Picco <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Alexander Potapenko <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Sam Ravnborg <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: default avatarAndrew Morton <[email protected]>
Signed-off-by: default avatarLinus Torvalds <[email protected]>
parent a4a3ede2
......@@ -110,7 +110,7 @@ config X86
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMAP if X86_64 || X86_PAE
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_KASAN if X86_64 && SPARSEMEM_VMEMMAP
select HAVE_ARCH_KASAN if X86_64
select HAVE_ARCH_KGDB
select HAVE_ARCH_MMAP_RND_BITS if MMU
select HAVE_ARCH_MMAP_RND_COMPAT_BITS if MMU && COMPAT
......
......@@ -4,12 +4,14 @@
#include <linux/bootmem.h>
#include <linux/kasan.h>
#include <linux/kdebug.h>
#include <linux/memblock.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/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/pgtable.h>
......@@ -18,7 +20,134 @@ 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)
static __init void *early_alloc(size_t size, int nid)
{
return memblock_virt_alloc_try_nid_nopanic(size, size,
__pa(MAX_DMA_ADDRESS), BOOTMEM_ALLOC_ACCESSIBLE, nid);
}
static void __init kasan_populate_pmd(pmd_t *pmd, unsigned long addr,
unsigned long end, int nid)
{
pte_t *pte;
if (pmd_none(*pmd)) {
void *p;
if (boot_cpu_has(X86_FEATURE_PSE) &&
((end - addr) == PMD_SIZE) &&
IS_ALIGNED(addr, PMD_SIZE)) {
p = early_alloc(PMD_SIZE, nid);
if (p && pmd_set_huge(pmd, __pa(p), PAGE_KERNEL))
return;
else if (p)
memblock_free(__pa(p), PMD_SIZE);
}
p = early_alloc(PAGE_SIZE, nid);
pmd_populate_kernel(&init_mm, pmd, p);
}
pte = pte_offset_kernel(pmd, addr);
do {
pte_t entry;
void *p;
if (!pte_none(*pte))
continue;
p = early_alloc(PAGE_SIZE, nid);
entry = pfn_pte(PFN_DOWN(__pa(p)), PAGE_KERNEL);
set_pte_at(&init_mm, addr, pte, entry);
} while (pte++, addr += PAGE_SIZE, addr != end);
}
static void __init kasan_populate_pud(pud_t *pud, unsigned long addr,
unsigned long end, int nid)
{
pmd_t *pmd;
unsigned long next;
if (pud_none(*pud)) {
void *p;
if (boot_cpu_has(X86_FEATURE_GBPAGES) &&
((end - addr) == PUD_SIZE) &&
IS_ALIGNED(addr, PUD_SIZE)) {
p = early_alloc(PUD_SIZE, nid);
if (p && pud_set_huge(pud, __pa(p), PAGE_KERNEL))
return;
else if (p)
memblock_free(__pa(p), PUD_SIZE);
}
p = early_alloc(PAGE_SIZE, nid);
pud_populate(&init_mm, pud, p);
}
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
if (!pmd_large(*pmd))
kasan_populate_pmd(pmd, addr, next, nid);
} while (pmd++, addr = next, addr != end);
}
static void __init kasan_populate_p4d(p4d_t *p4d, unsigned long addr,
unsigned long end, int nid)
{
pud_t *pud;
unsigned long next;
if (p4d_none(*p4d)) {
void *p = early_alloc(PAGE_SIZE, nid);
p4d_populate(&init_mm, p4d, p);
}
pud = pud_offset(p4d, addr);
do {
next = pud_addr_end(addr, end);
if (!pud_large(*pud))
kasan_populate_pud(pud, addr, next, nid);
} while (pud++, addr = next, addr != end);
}
static void __init kasan_populate_pgd(pgd_t *pgd, unsigned long addr,
unsigned long end, int nid)
{
void *p;
p4d_t *p4d;
unsigned long next;
if (pgd_none(*pgd)) {
p = early_alloc(PAGE_SIZE, nid);
pgd_populate(&init_mm, pgd, p);
}
p4d = p4d_offset(pgd, addr);
do {
next = p4d_addr_end(addr, end);
kasan_populate_p4d(p4d, addr, next, nid);
} while (p4d++, addr = next, addr != end);
}
static void __init kasan_populate_shadow(unsigned long addr, unsigned long end,
int nid)
{
pgd_t *pgd;
unsigned long next;
addr = addr & PAGE_MASK;
end = round_up(end, PAGE_SIZE);
pgd = pgd_offset_k(addr);
do {
next = pgd_addr_end(addr, end);
kasan_populate_pgd(pgd, addr, next, nid);
} while (pgd++, addr = next, addr != end);
}
static void __init map_range(struct range *range)
{
unsigned long start;
unsigned long end;
......@@ -26,7 +155,7 @@ static int __init map_range(struct range *range)
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);
kasan_populate_shadow(start, end, early_pfn_to_nid(range->start));
}
static void __init clear_pgds(unsigned long start,
......@@ -189,16 +318,16 @@ void __init kasan_init(void)
if (pfn_mapped[i].end == 0)
break;
if (map_range(&pfn_mapped[i]))
panic("kasan: unable to allocate shadow!");
map_range(&pfn_mapped[i]);
}
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_shadow((unsigned long)kasan_mem_to_shadow(_stext),
(unsigned long)kasan_mem_to_shadow(_end),
early_pfn_to_nid(__pa(_stext)));
kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END),
(void *)KASAN_SHADOW_END);
......
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