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-rw-r--r--arch/riscv/mm/kasan_init.c137
1 files changed, 131 insertions, 6 deletions
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index 1434a0225140..993f50571a3b 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -11,7 +11,29 @@
#include <asm/fixmap.h>
#include <asm/pgalloc.h>
+/*
+ * Kasan shadow region must lie at a fixed address across sv39, sv48 and sv57
+ * which is right before the kernel.
+ *
+ * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate
+ * the page global directory with kasan_early_shadow_pmd.
+ *
+ * For sv48 and sv57, the region is not aligned on PGDIR_SIZE so the mapping
+ * must be divided as follows:
+ * - the first PGD entry, although incomplete, is populated with
+ * kasan_early_shadow_pud/p4d
+ * - the PGD entries in the middle are populated with kasan_early_shadow_pud/p4d
+ * - the last PGD entry is shared with the kernel mapping so populated at the
+ * lower levels pud/p4d
+ *
+ * In addition, when shallow populating a kasan region (for example vmalloc),
+ * this region may also not be aligned on PGDIR size, so we must go down to the
+ * pud level too.
+ */
+
extern pgd_t early_pg_dir[PTRS_PER_PGD];
+extern struct pt_alloc_ops _pt_ops __initdata;
+#define pt_ops _pt_ops
static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
{
@@ -35,15 +57,19 @@ static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned
set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE));
}
-static void __init kasan_populate_pmd(pgd_t *pgd, unsigned long vaddr, unsigned long end)
+static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end)
{
phys_addr_t phys_addr;
pmd_t *pmdp, *base_pmd;
unsigned long next;
- base_pmd = (pmd_t *)pgd_page_vaddr(*pgd);
- if (base_pmd == lm_alias(kasan_early_shadow_pmd))
+ if (pud_none(*pud)) {
base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
+ } else {
+ base_pmd = (pmd_t *)pud_pgtable(*pud);
+ if (base_pmd == lm_alias(kasan_early_shadow_pmd))
+ base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
+ }
pmdp = base_pmd + pmd_index(vaddr);
@@ -67,9 +93,72 @@ static void __init kasan_populate_pmd(pgd_t *pgd, unsigned long vaddr, unsigned
* it entirely, memblock could allocate a page at a physical address
* where KASAN is not populated yet and then we'd get a page fault.
*/
- set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
+ set_pud(pud, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
+}
+
+static void __init kasan_populate_pud(pgd_t *pgd,
+ unsigned long vaddr, unsigned long end,
+ bool early)
+{
+ phys_addr_t phys_addr;
+ pud_t *pudp, *base_pud;
+ unsigned long next;
+
+ if (early) {
+ /*
+ * We can't use pgd_page_vaddr here as it would return a linear
+ * mapping address but it is not mapped yet, but when populating
+ * early_pg_dir, we need the physical address and when populating
+ * swapper_pg_dir, we need the kernel virtual address so use
+ * pt_ops facility.
+ */
+ base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));
+ } else {
+ base_pud = (pud_t *)pgd_page_vaddr(*pgd);
+ if (base_pud == lm_alias(kasan_early_shadow_pud))
+ base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
+ }
+
+ pudp = base_pud + pud_index(vaddr);
+
+ do {
+ next = pud_addr_end(vaddr, end);
+
+ if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
+ if (early) {
+ phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd));
+ set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
+ continue;
+ } else {
+ phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
+ if (phys_addr) {
+ set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
+ continue;
+ }
+ }
+ }
+
+ kasan_populate_pmd(pudp, vaddr, next);
+ } while (pudp++, vaddr = next, vaddr != end);
+
+ /*
+ * Wait for the whole PGD to be populated before setting the PGD in
+ * the page table, otherwise, if we did set the PGD before populating
+ * it entirely, memblock could allocate a page at a physical address
+ * where KASAN is not populated yet and then we'd get a page fault.
+ */
+ if (!early)
+ set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE));
}
+#define kasan_early_shadow_pgd_next (pgtable_l4_enabled ? \
+ (uintptr_t)kasan_early_shadow_pud : \
+ (uintptr_t)kasan_early_shadow_pmd)
+#define kasan_populate_pgd_next(pgdp, vaddr, next, early) \
+ (pgtable_l4_enabled ? \
+ kasan_populate_pud(pgdp, vaddr, next, early) : \
+ kasan_populate_pmd((pud_t *)pgdp, vaddr, next))
+
static void __init kasan_populate_pgd(pgd_t *pgdp,
unsigned long vaddr, unsigned long end,
bool early)
@@ -102,7 +191,7 @@ static void __init kasan_populate_pgd(pgd_t *pgdp,
}
}
- kasan_populate_pmd(pgdp, vaddr, next);
+ kasan_populate_pgd_next(pgdp, vaddr, next, early);
} while (pgdp++, vaddr = next, vaddr != end);
}
@@ -157,18 +246,54 @@ static void __init kasan_populate(void *start, void *end)
memset(start, KASAN_SHADOW_INIT, end - start);
}
+static void __init kasan_shallow_populate_pud(pgd_t *pgdp,
+ unsigned long vaddr, unsigned long end,
+ bool kasan_populate)
+{
+ unsigned long next;
+ pud_t *pudp, *base_pud;
+ pmd_t *base_pmd;
+ bool is_kasan_pmd;
+
+ base_pud = (pud_t *)pgd_page_vaddr(*pgdp);
+ pudp = base_pud + pud_index(vaddr);
+
+ if (kasan_populate)
+ memcpy(base_pud, (void *)kasan_early_shadow_pgd_next,
+ sizeof(pud_t) * PTRS_PER_PUD);
+
+ do {
+ next = pud_addr_end(vaddr, end);
+ is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd));
+
+ if (is_kasan_pmd) {
+ base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+ set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE));
+ }
+ } while (pudp++, vaddr = next, vaddr != end);
+}
+
static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
{
unsigned long next;
void *p;
pgd_t *pgd_k = pgd_offset_k(vaddr);
+ bool is_kasan_pgd_next;
do {
next = pgd_addr_end(vaddr, end);
- if (pgd_page_vaddr(*pgd_k) == (unsigned long)lm_alias(kasan_early_shadow_pmd)) {
+ is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) ==
+ (unsigned long)lm_alias(kasan_early_shadow_pgd_next));
+
+ if (is_kasan_pgd_next) {
p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
}
+
+ if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE)
+ continue;
+
+ kasan_shallow_populate_pud(pgd_k, vaddr, next, is_kasan_pgd_next);
} while (pgd_k++, vaddr = next, vaddr != end);
}