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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init_book3s_64.c (3126B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * KASAN for 64-bit Book3S powerpc
      4 *
      5 * Copyright 2019-2022, Daniel Axtens, IBM Corporation.
      6 */
      7
      8/*
      9 * ppc64 turns on virtual memory late in boot, after calling into generic code
     10 * like the device-tree parser, so it uses this in conjunction with a hook in
     11 * outline mode to avoid invalid access early in boot.
     12 */
     13
     14#define DISABLE_BRANCH_PROFILING
     15
     16#include <linux/kasan.h>
     17#include <linux/printk.h>
     18#include <linux/sched/task.h>
     19#include <linux/memblock.h>
     20#include <asm/pgalloc.h>
     21
     22DEFINE_STATIC_KEY_FALSE(powerpc_kasan_enabled_key);
     23
     24static void __init kasan_init_phys_region(void *start, void *end)
     25{
     26	unsigned long k_start, k_end, k_cur;
     27	void *va;
     28
     29	if (start >= end)
     30		return;
     31
     32	k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE);
     33	k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE);
     34
     35	va = memblock_alloc(k_end - k_start, PAGE_SIZE);
     36	for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE)
     37		map_kernel_page(k_cur, __pa(va), PAGE_KERNEL);
     38}
     39
     40void __init kasan_init(void)
     41{
     42	/*
     43	 * We want to do the following things:
     44	 *  1) Map real memory into the shadow for all physical memblocks
     45	 *     This takes us from c000... to c008...
     46	 *  2) Leave a hole over the shadow of vmalloc space. KASAN_VMALLOC
     47	 *     will manage this for us.
     48	 *     This takes us from c008... to c00a...
     49	 *  3) Map the 'early shadow'/zero page over iomap and vmemmap space.
     50	 *     This takes us up to where we start at c00e...
     51	 */
     52
     53	void *k_start = kasan_mem_to_shadow((void *)RADIX_VMALLOC_END);
     54	void *k_end = kasan_mem_to_shadow((void *)RADIX_VMEMMAP_END);
     55	phys_addr_t start, end;
     56	u64 i;
     57	pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);
     58
     59	if (!early_radix_enabled()) {
     60		pr_warn("KASAN not enabled as it requires radix!");
     61		return;
     62	}
     63
     64	for_each_mem_range(i, &start, &end)
     65		kasan_init_phys_region((void *)start, (void *)end);
     66
     67	for (i = 0; i < PTRS_PER_PTE; i++)
     68		__set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
     69			     &kasan_early_shadow_pte[i], zero_pte, 0);
     70
     71	for (i = 0; i < PTRS_PER_PMD; i++)
     72		pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i],
     73				    kasan_early_shadow_pte);
     74
     75	for (i = 0; i < PTRS_PER_PUD; i++)
     76		pud_populate(&init_mm, &kasan_early_shadow_pud[i],
     77			     kasan_early_shadow_pmd);
     78
     79	/* map the early shadow over the iomap and vmemmap space */
     80	kasan_populate_early_shadow(k_start, k_end);
     81
     82	/* mark early shadow region as RO and wipe it */
     83	zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
     84	for (i = 0; i < PTRS_PER_PTE; i++)
     85		__set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
     86			     &kasan_early_shadow_pte[i], zero_pte, 0);
     87
     88	/*
     89	 * clear_page relies on some cache info that hasn't been set up yet.
     90	 * It ends up looping ~forever and blows up other data.
     91	 * Use memset instead.
     92	 */
     93	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
     94
     95	static_branch_inc(&powerpc_kasan_enabled_key);
     96
     97	/* Enable error messages */
     98	init_task.kasan_depth = 0;
     99	pr_info("KASAN init done\n");
    100}
    101
    102void __init kasan_late_init(void) { }