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-rw-r--r--arch/xtensa/mm/kasan_init.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/arch/xtensa/mm/kasan_init.c b/arch/xtensa/mm/kasan_init.c
new file mode 100644
index 0000000000..f00d122aa8
--- /dev/null
+++ b/arch/xtensa/mm/kasan_init.c
@@ -0,0 +1,102 @@
+/*
+ * Xtensa KASAN shadow map initialization
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2017 Cadence Design Systems Inc.
+ */
+
+#include <linux/memblock.h>
+#include <linux/init_task.h>
+#include <linux/kasan.h>
+#include <linux/kernel.h>
+#include <asm/initialize_mmu.h>
+#include <asm/tlbflush.h>
+
+void __init kasan_early_init(void)
+{
+ unsigned long vaddr = KASAN_SHADOW_START;
+ pmd_t *pmd = pmd_off_k(vaddr);
+ int i;
+
+ for (i = 0; i < PTRS_PER_PTE; ++i)
+ set_pte(kasan_early_shadow_pte + i,
+ mk_pte(virt_to_page(kasan_early_shadow_page),
+ PAGE_KERNEL));
+
+ for (vaddr = 0; vaddr < KASAN_SHADOW_SIZE; vaddr += PMD_SIZE, ++pmd) {
+ BUG_ON(!pmd_none(*pmd));
+ set_pmd(pmd, __pmd((unsigned long)kasan_early_shadow_pte));
+ }
+}
+
+static void __init populate(void *start, void *end)
+{
+ unsigned long n_pages = (end - start) / PAGE_SIZE;
+ unsigned long n_pmds = n_pages / PTRS_PER_PTE;
+ unsigned long i, j;
+ unsigned long vaddr = (unsigned long)start;
+ pmd_t *pmd = pmd_off_k(vaddr);
+ pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
+
+ if (!pte)
+ panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+ __func__, n_pages * sizeof(pte_t), PAGE_SIZE);
+
+ pr_debug("%s: %p - %p\n", __func__, start, end);
+
+ for (i = j = 0; i < n_pmds; ++i) {
+ int k;
+
+ for (k = 0; k < PTRS_PER_PTE; ++k, ++j) {
+ phys_addr_t phys =
+ memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE,
+ 0,
+ MEMBLOCK_ALLOC_ANYWHERE);
+
+ if (!phys)
+ panic("Failed to allocate page table page\n");
+
+ set_pte(pte + j, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
+ }
+ }
+
+ for (i = 0; i < n_pmds ; ++i, pte += PTRS_PER_PTE)
+ set_pmd(pmd + i, __pmd((unsigned long)pte));
+
+ local_flush_tlb_all();
+ memset(start, 0, end - start);
+}
+
+void __init kasan_init(void)
+{
+ int i;
+
+ BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_START -
+ (KASAN_START_VADDR >> KASAN_SHADOW_SCALE_SHIFT));
+ BUILD_BUG_ON(VMALLOC_START < KASAN_START_VADDR);
+
+ /*
+ * Replace shadow map pages that cover addresses from VMALLOC area
+ * start to the end of KSEG with clean writable pages.
+ */
+ populate(kasan_mem_to_shadow((void *)VMALLOC_START),
+ kasan_mem_to_shadow((void *)XCHAL_KSEG_BYPASS_VADDR));
+
+ /*
+ * Write protect kasan_early_shadow_page and zero-initialize it again.
+ */
+ for (i = 0; i < PTRS_PER_PTE; ++i)
+ set_pte(kasan_early_shadow_pte + i,
+ mk_pte(virt_to_page(kasan_early_shadow_page),
+ PAGE_KERNEL_RO));
+
+ local_flush_tlb_all();
+ memset(kasan_early_shadow_page, 0, PAGE_SIZE);
+
+ /* At this point kasan is fully initialized. Enable error messages. */
+ current->kasan_depth = 0;
+ pr_info("KernelAddressSanitizer initialized\n");
+}