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@@ -0,0 +1,199 @@
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+#include <linux/bootmem.h>
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+#include <linux/kasan.h>
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+#include <linux/kdebug.h>
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+#include <linux/mm.h>
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+#include <linux/sched.h>
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+#include <linux/vmalloc.h>
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+
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+#include <asm/tlbflush.h>
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+#include <asm/sections.h>
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+
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+extern pgd_t early_level4_pgt[PTRS_PER_PGD];
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+extern struct range pfn_mapped[E820_X_MAX];
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+
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+extern unsigned char kasan_zero_page[PAGE_SIZE];
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+
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+static int __init map_range(struct range *range)
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+{
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+ unsigned long start;
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+ unsigned long end;
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+
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+ start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start));
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+ end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end));
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+
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+ /*
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+ * end + 1 here is intentional. We check several shadow bytes in advance
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+ * to slightly speed up fastpath. In some rare cases we could cross
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+ * boundary of mapped shadow, so we just map some more here.
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+ */
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+ return vmemmap_populate(start, end + 1, NUMA_NO_NODE);
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+}
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+
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+static void __init clear_pgds(unsigned long start,
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+ unsigned long end)
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+{
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+ for (; start < end; start += PGDIR_SIZE)
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+ pgd_clear(pgd_offset_k(start));
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+}
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+
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+void __init kasan_map_early_shadow(pgd_t *pgd)
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+{
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+ int i;
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+ unsigned long start = KASAN_SHADOW_START;
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+ unsigned long end = KASAN_SHADOW_END;
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+
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+ for (i = pgd_index(start); start < end; i++) {
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+ pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud)
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+ | _KERNPG_TABLE);
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+ start += PGDIR_SIZE;
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+ }
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+}
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+
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+static int __init zero_pte_populate(pmd_t *pmd, unsigned long addr,
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+ unsigned long end)
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+{
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+ pte_t *pte = pte_offset_kernel(pmd, addr);
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+
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+ while (addr + PAGE_SIZE <= end) {
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+ WARN_ON(!pte_none(*pte));
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+ set_pte(pte, __pte(__pa_nodebug(kasan_zero_page)
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+ | __PAGE_KERNEL_RO));
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+ addr += PAGE_SIZE;
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+ pte = pte_offset_kernel(pmd, addr);
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+ }
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+ return 0;
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+}
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+
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+static int __init zero_pmd_populate(pud_t *pud, unsigned long addr,
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+ unsigned long end)
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+{
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+ int ret = 0;
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+ pmd_t *pmd = pmd_offset(pud, addr);
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+
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+ while (IS_ALIGNED(addr, PMD_SIZE) && addr + PMD_SIZE <= end) {
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+ WARN_ON(!pmd_none(*pmd));
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+ set_pmd(pmd, __pmd(__pa_nodebug(kasan_zero_pte)
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+ | __PAGE_KERNEL_RO));
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+ addr += PMD_SIZE;
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+ pmd = pmd_offset(pud, addr);
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+ }
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+ if (addr < end) {
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+ if (pmd_none(*pmd)) {
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+ void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
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+ if (!p)
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+ return -ENOMEM;
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+ set_pmd(pmd, __pmd(__pa_nodebug(p) | _KERNPG_TABLE));
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+ }
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+ ret = zero_pte_populate(pmd, addr, end);
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+ }
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+ return ret;
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+}
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+
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+
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+static int __init zero_pud_populate(pgd_t *pgd, unsigned long addr,
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+ unsigned long end)
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+{
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+ int ret = 0;
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+ pud_t *pud = pud_offset(pgd, addr);
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+
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+ while (IS_ALIGNED(addr, PUD_SIZE) && addr + PUD_SIZE <= end) {
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+ WARN_ON(!pud_none(*pud));
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+ set_pud(pud, __pud(__pa_nodebug(kasan_zero_pmd)
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+ | __PAGE_KERNEL_RO));
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+ addr += PUD_SIZE;
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+ pud = pud_offset(pgd, addr);
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+ }
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+
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+ if (addr < end) {
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+ if (pud_none(*pud)) {
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+ void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
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+ if (!p)
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+ return -ENOMEM;
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+ set_pud(pud, __pud(__pa_nodebug(p) | _KERNPG_TABLE));
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+ }
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+ ret = zero_pmd_populate(pud, addr, end);
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+ }
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+ return ret;
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+}
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+
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+static int __init zero_pgd_populate(unsigned long addr, unsigned long end)
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+{
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+ int ret = 0;
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+ pgd_t *pgd = pgd_offset_k(addr);
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+
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+ while (IS_ALIGNED(addr, PGDIR_SIZE) && addr + PGDIR_SIZE <= end) {
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+ WARN_ON(!pgd_none(*pgd));
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+ set_pgd(pgd, __pgd(__pa_nodebug(kasan_zero_pud)
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+ | __PAGE_KERNEL_RO));
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+ addr += PGDIR_SIZE;
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+ pgd = pgd_offset_k(addr);
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+ }
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+
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+ if (addr < end) {
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+ if (pgd_none(*pgd)) {
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+ void *p = vmemmap_alloc_block(PAGE_SIZE, NUMA_NO_NODE);
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+ if (!p)
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+ return -ENOMEM;
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+ set_pgd(pgd, __pgd(__pa_nodebug(p) | _KERNPG_TABLE));
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+ }
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+ ret = zero_pud_populate(pgd, addr, end);
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+ }
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+ return ret;
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+}
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+
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+
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+static void __init populate_zero_shadow(const void *start, const void *end)
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+{
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+ if (zero_pgd_populate((unsigned long)start, (unsigned long)end))
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+ panic("kasan: unable to map zero shadow!");
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+}
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+
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+
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+#ifdef CONFIG_KASAN_INLINE
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+static int kasan_die_handler(struct notifier_block *self,
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+ unsigned long val,
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+ void *data)
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+{
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+ if (val == DIE_GPF) {
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+ pr_emerg("CONFIG_KASAN_INLINE enabled");
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+ pr_emerg("GPF could be caused by NULL-ptr deref or user memory access");
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+ }
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+ return NOTIFY_OK;
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+}
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+
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+static struct notifier_block kasan_die_notifier = {
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+ .notifier_call = kasan_die_handler,
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+};
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+#endif
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+
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+void __init kasan_init(void)
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+{
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+ int i;
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+
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+#ifdef CONFIG_KASAN_INLINE
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+ register_die_notifier(&kasan_die_notifier);
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+#endif
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+
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+ memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt));
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+ load_cr3(early_level4_pgt);
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+
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+ clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
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+
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+ populate_zero_shadow((void *)KASAN_SHADOW_START,
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+ kasan_mem_to_shadow((void *)PAGE_OFFSET));
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+
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+ for (i = 0; i < E820_X_MAX; i++) {
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+ if (pfn_mapped[i].end == 0)
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+ break;
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+
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+ if (map_range(&pfn_mapped[i]))
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+ panic("kasan: unable to allocate shadow!");
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+ }
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+
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+ populate_zero_shadow(kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM),
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+ (void *)KASAN_SHADOW_END);
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+
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+ memset(kasan_zero_page, 0, PAGE_SIZE);
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+
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+ load_cr3(init_level4_pgt);
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+}
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Andrey Ryabinin