/* * 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> #include <asm/traps.h> void __init kasan_early_init(void) { unsigned long vaddr = KASAN_SHADOW_START; pgd_t *pgd = pgd_offset_k(vaddr); pmd_t *pmd = pmd_offset(pgd, 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)); } early_trap_init(); } 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; pgd_t *pgd = pgd_offset_k(vaddr); pmd_t *pmd = pmd_offset(pgd, vaddr); pte_t *pte = memblock_alloc(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_alloc_base(PAGE_SIZE, PAGE_SIZE, MEMBLOCK_ALLOC_ANYWHERE); 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"); }