Currently populate_zero_shadow() uses some x86_64 specific
functions/macroses and only with 4-level pagetables.
This patch generalizes populate_zero_shadow() making
possible to reuse it for other architectures later.
The main changes are:
* Use p?d_populate*() instead of set_p?d()
* Use memblock allocator directly instead of vmemmap_alloc_block()
Signed-off-by: Andrey Ryabinin <a.ryabinin@xxxxxxxxxxx>
---
arch/x86/mm/kasan_init_64.c | 115 +++++++++++++++++++++++++++-----------------
1 file changed, 72 insertions(+), 43 deletions(-)
diff --git a/arch/x86/mm/kasan_init_64.c b/arch/x86/mm/kasan_init_64.c
index 4860906..853dab4 100644
--- a/arch/x86/mm/kasan_init_64.c
+++ b/arch/x86/mm/kasan_init_64.c
@@ -2,9 +2,11 @@
#include <linux/kasan.h>
#include <linux/kdebug.h>
#include <linux/mm.h>
+#include <linux/pfn.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>
+#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
@@ -49,15 +51,23 @@ void __init kasan_map_early_shadow(pgd_t *pgd)
}
}
+static __init void *early_alloc(size_t size, int node)
+{
+ return memblock_virt_alloc_try_nid(size, size, __pa(MAX_DMA_ADDRESS),
+ BOOTMEM_ALLOC_ACCESSIBLE, node);
+}
+
static int __init 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(kasan_zero_page)), PAGE_KERNEL);
+ zero_pte = pte_wrprotect(zero_pte);
while (addr + PAGE_SIZE <= end) {
- WARN_ON(!pte_none(*pte));
- set_pte(pte, __pte(__pa_nodebug(kasan_zero_page)
- | __PAGE_KERNEL_RO));
+ set_pte_at(&init_mm, addr, pte, zero_pte);
addr += PAGE_SIZE;
pte = pte_offset_kernel(pmd, addr);
}
@@ -69,50 +79,55 @@ static int __init zero_pmd_populate(pud_t *pud, unsigned long addr,
{
int ret = 0;
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, kasan_zero_pte);
+ continue;
+ }
- while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) {
- WARN_ON(!pmd_none(*pmd));
- set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte)
- | __PAGE_KERNEL_RO));
- addr += PMD_SIZE;
- pmd = pmd_offset(pud, addr);
- }
- if (addr < end) {
if (pmd_none(*pmd)) {
- void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+ void *p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
if (!p)
return -ENOMEM;
- set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE));
+ pmd_populate_kernel(&init_mm, pmd, p);
}
- ret = zero_pte_populate(pmd, addr, end);
- }
+ zero_pte_populate(pmd, addr, pmd_addr_end(addr, end));
+ } while (pmd++, addr = next, addr != end);
+
return ret;
}
-
static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
unsigned long end)
{
int ret = 0;
pud_t *pud = pud_offset(pgd, addr);
+ unsigned long next;
- while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) {
- WARN_ON(!pud_none(*pud));
- set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd)
- | __PAGE_KERNEL_RO));
- addr += PUD_SIZE;
- pud = pud_offset(pgd, addr);
- }
+ 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, kasan_zero_pmd);
+ pmd = pmd_offset(pud, addr);
+ pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+ continue;
+ }
- if (addr < end) {
if (pud_none(*pud)) {
- void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+ void *p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
if (!p)
return -ENOMEM;
- set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE));
+ pud_populate(&init_mm, pud, p);
}
- ret = zero_pmd_populate(pud, addr, end);
- }
+ zero_pmd_populate(pud, addr, pud_addr_end(addr, end));
+ } while (pud++, addr = next, addr != end);
+
return ret;
}
@@ -120,35 +135,49 @@ static int __init zero_pgd_populate(unsigned long addr, unsigned long end)
{
int ret = 0;
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) {
+ pud_t *pud;
+ pmd_t *pmd;
+
+ /*
+ * kasan_zero_pud should be populated with pmds
+ * at this moment.
+ * [pud,pmd]_populate*() bellow 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, kasan_zero_pud);
+ pud = pud_offset(pgd, addr);
+ pud_populate(&init_mm, pud, kasan_zero_pmd);
+ pmd = pmd_offset(pud, addr);
+ pmd_populate_kernel(&init_mm, pmd, kasan_zero_pte);
+ continue;
+ }
- while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) {
- WARN_ON(!pgd_none(*pgd));
- set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud)
- | __PAGE_KERNEL_RO));
- addr += PGDIR_SIZE;
- pgd = pgd_offset_k(addr);
- }
-
- if (addr < end) {
if (pgd_none(*pgd)) {
- void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
+ void *p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
if (!p)
return -ENOMEM;
- set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE));
+ pgd_populate(&init_mm, pgd, p);
}
- ret = zero_pud_populate(pgd, addr, end);
- }
+ zero_pud_populate(pgd, addr, next);
+ } while (pgd++, addr = next, addr != end);
+
return ret;
}
-
static void __init populate_zero_shadow(const void *start, const void *end)
{
if (zero_pgd_populate((unsigned long)start, (unsigned long)end))
panic("kasan: unable to map zero shadow!");
}
-
#ifdef CONFIG_KASAN_INLINE
static int kasan_die_handler(struct notifier_block *self,
unsigned long val,
--
2.4.0
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