cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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kasan_init.c (2822B)

      1/*
      2 * Xtensa KASAN shadow map initialization
      3 *
      4 * This file is subject to the terms and conditions of the GNU General Public
      5 * License.  See the file "COPYING" in the main directory of this archive
      6 * for more details.
      7 *
      8 * Copyright (C) 2017 Cadence Design Systems Inc.
      9 */
     10
     11#include <linux/memblock.h>
     12#include <linux/init_task.h>
     13#include <linux/kasan.h>
     14#include <linux/kernel.h>
     15#include <asm/initialize_mmu.h>
     16#include <asm/tlbflush.h>
     17#include <asm/traps.h>
     18
     19void __init kasan_early_init(void)
     20{
     21	unsigned long vaddr = KASAN_SHADOW_START;
     22	pmd_t *pmd = pmd_off_k(vaddr);
     23	int i;
     24
     25	for (i = 0; i < PTRS_PER_PTE; ++i)
     26		set_pte(kasan_early_shadow_pte + i,
     27			mk_pte(virt_to_page(kasan_early_shadow_page),
     28				PAGE_KERNEL));
     29
     30	for (vaddr = 0; vaddr < KASAN_SHADOW_SIZE; vaddr += PMD_SIZE, ++pmd) {
     31		BUG_ON(!pmd_none(*pmd));
     32		set_pmd(pmd, __pmd((unsigned long)kasan_early_shadow_pte));
     33	}
     34	early_trap_init();
     35}
     36
     37static void __init populate(void *start, void *end)
     38{
     39	unsigned long n_pages = (end - start) / PAGE_SIZE;
     40	unsigned long n_pmds = n_pages / PTRS_PER_PTE;
     41	unsigned long i, j;
     42	unsigned long vaddr = (unsigned long)start;
     43	pmd_t *pmd = pmd_off_k(vaddr);
     44	pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
     45
     46	if (!pte)
     47		panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
     48		      __func__, n_pages * sizeof(pte_t), PAGE_SIZE);
     49
     50	pr_debug("%s: %p - %p\n", __func__, start, end);
     51
     52	for (i = j = 0; i < n_pmds; ++i) {
     53		int k;
     54
     55		for (k = 0; k < PTRS_PER_PTE; ++k, ++j) {
     56			phys_addr_t phys =
     57				memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE,
     58							  0,
     59							  MEMBLOCK_ALLOC_ANYWHERE);
     60
     61			if (!phys)
     62				panic("Failed to allocate page table page\n");
     63
     64			set_pte(pte + j, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
     65		}
     66	}
     67
     68	for (i = 0; i < n_pmds ; ++i, pte += PTRS_PER_PTE)
     69		set_pmd(pmd + i, __pmd((unsigned long)pte));
     70
     71	local_flush_tlb_all();
     72	memset(start, 0, end - start);
     73}
     74
     75void __init kasan_init(void)
     76{
     77	int i;
     78
     79	BUILD_BUG_ON(KASAN_SHADOW_OFFSET != KASAN_SHADOW_START -
     80		     (KASAN_START_VADDR >> KASAN_SHADOW_SCALE_SHIFT));
     81	BUILD_BUG_ON(VMALLOC_START < KASAN_START_VADDR);
     82
     83	/*
     84	 * Replace shadow map pages that cover addresses from VMALLOC area
     85	 * start to the end of KSEG with clean writable pages.
     86	 */
     87	populate(kasan_mem_to_shadow((void *)VMALLOC_START),
     88		 kasan_mem_to_shadow((void *)XCHAL_KSEG_BYPASS_VADDR));
     89
     90	/*
     91	 * Write protect kasan_early_shadow_page and zero-initialize it again.
     92	 */
     93	for (i = 0; i < PTRS_PER_PTE; ++i)
     94		set_pte(kasan_early_shadow_pte + i,
     95			mk_pte(virt_to_page(kasan_early_shadow_page),
     96				PAGE_KERNEL_RO));
     97
     98	local_flush_tlb_all();
     99	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
    100
    101	/* At this point kasan is fully initialized. Enable error messages. */
    102	current->kasan_depth = 0;
    103	pr_info("KernelAddressSanitizer initialized\n");
    104}