1// SPDX-License-Identifier: GPL-2.0
2
3#define DISABLE_BRANCH_PROFILING
4
5#include <linux/kasan.h>
6#include <linux/printk.h>
7#include <linux/memblock.h>
8#include <linux/sched/task.h>
9#include <asm/pgalloc.h>
10#include <asm/code-patching.h>
11#include <mm/mmu_decl.h>
12
13static pgprot_t __init kasan_prot_ro(void)
14{
15	if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE))
16		return PAGE_READONLY;
17
18	return PAGE_KERNEL_RO;
19}
20
21static void __init kasan_populate_pte(pte_t *ptep, pgprot_t prot)
22{
23	unsigned long va = (unsigned long)kasan_early_shadow_page;
24	phys_addr_t pa = __pa(kasan_early_shadow_page);
25	int i;
26
27	for (i = 0; i < PTRS_PER_PTE; i++, ptep++)
28		__set_pte_at(&init_mm, va, ptep, pfn_pte(PHYS_PFN(pa), prot), 1);
29}
30
31int __init kasan_init_shadow_page_tables(unsigned long k_start, unsigned long k_end)
32{
33	pmd_t *pmd;
34	unsigned long k_cur, k_next;
35
36	pmd = pmd_off_k(k_start);
37
38	for (k_cur = k_start; k_cur != k_end; k_cur = k_next, pmd++) {
39		pte_t *new;
40
41		k_next = pgd_addr_end(k_cur, k_end);
42		if ((void *)pmd_page_vaddr(*pmd) != kasan_early_shadow_pte)
43			continue;
44
45		new = memblock_alloc(PTE_FRAG_SIZE, PTE_FRAG_SIZE);
46
47		if (!new)
48			return -ENOMEM;
49		kasan_populate_pte(new, PAGE_KERNEL);
50		pmd_populate_kernel(&init_mm, pmd, new);
51	}
52	return 0;
53}
54
55int __init __weak kasan_init_region(void *start, size_t size)
56{
57	unsigned long k_start = (unsigned long)kasan_mem_to_shadow(start);
58	unsigned long k_end = (unsigned long)kasan_mem_to_shadow(start + size);
59	unsigned long k_cur;
60	int ret;
61	void *block;
62
63	ret = kasan_init_shadow_page_tables(k_start, k_end);
64	if (ret)
65		return ret;
66
67	k_start = k_start & PAGE_MASK;
68	block = memblock_alloc(k_end - k_start, PAGE_SIZE);
69	if (!block)
70		return -ENOMEM;
71
72	for (k_cur = k_start & PAGE_MASK; k_cur < k_end; k_cur += PAGE_SIZE) {
73		pmd_t *pmd = pmd_off_k(k_cur);
74		void *va = block + k_cur - k_start;
75		pte_t pte = pfn_pte(PHYS_PFN(__pa(va)), PAGE_KERNEL);
76
77		__set_pte_at(&init_mm, k_cur, pte_offset_kernel(pmd, k_cur), pte, 0);
78	}
79	flush_tlb_kernel_range(k_start, k_end);
80	return 0;
81}
82
83void __init
84kasan_update_early_region(unsigned long k_start, unsigned long k_end, pte_t pte)
85{
86	unsigned long k_cur;
87
88	for (k_cur = k_start; k_cur != k_end; k_cur += PAGE_SIZE) {
89		pmd_t *pmd = pmd_off_k(k_cur);
90		pte_t *ptep = pte_offset_kernel(pmd, k_cur);
91
92		if (pte_page(*ptep) != virt_to_page(lm_alias(kasan_early_shadow_page)))
93			continue;
94
95		__set_pte_at(&init_mm, k_cur, ptep, pte, 0);
96	}
97
98	flush_tlb_kernel_range(k_start, k_end);
99}
100
101static void __init kasan_remap_early_shadow_ro(void)
102{
103	pgprot_t prot = kasan_prot_ro();
104	phys_addr_t pa = __pa(kasan_early_shadow_page);
105
106	kasan_populate_pte(kasan_early_shadow_pte, prot);
107
108	kasan_update_early_region(KASAN_SHADOW_START, KASAN_SHADOW_END,
109				  pfn_pte(PHYS_PFN(pa), prot));
110}
111
112static void __init kasan_unmap_early_shadow_vmalloc(void)
113{
114	unsigned long k_start = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_START);
115	unsigned long k_end = (unsigned long)kasan_mem_to_shadow((void *)VMALLOC_END);
116
117	kasan_update_early_region(k_start, k_end, __pte(0));
118
119#ifdef MODULES_VADDR
120	k_start = (unsigned long)kasan_mem_to_shadow((void *)MODULES_VADDR);
121	k_end = (unsigned long)kasan_mem_to_shadow((void *)MODULES_END);
122	kasan_update_early_region(k_start, k_end, __pte(0));
123#endif
124}
125
126void __init kasan_mmu_init(void)
127{
128	int ret;
129
130	if (early_mmu_has_feature(MMU_FTR_HPTE_TABLE)) {
131		ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
132
133		if (ret)
134			panic("kasan: kasan_init_shadow_page_tables() failed");
135	}
136}
137
138void __init kasan_init(void)
139{
140	phys_addr_t base, end;
141	u64 i;
142	int ret;
143
144	for_each_mem_range(i, &base, &end) {
145		phys_addr_t top = min(end, total_lowmem);
146
147		if (base >= top)
148			continue;
149
150		ret = kasan_init_region(__va(base), top - base);
151		if (ret)
152			panic("kasan: kasan_init_region() failed");
153	}
154
155	if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
156		ret = kasan_init_shadow_page_tables(KASAN_SHADOW_START, KASAN_SHADOW_END);
157
158		if (ret)
159			panic("kasan: kasan_init_shadow_page_tables() failed");
160	}
161
162	kasan_remap_early_shadow_ro();
163
164	clear_page(kasan_early_shadow_page);
165
166	/* At this point kasan is fully initialized. Enable error messages */
167	init_task.kasan_depth = 0;
168	pr_info("KASAN init done\n");
169}
170
171void __init kasan_late_init(void)
172{
173	if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
174		kasan_unmap_early_shadow_vmalloc();
175}
176
177void __init kasan_early_init(void)
178{
179	unsigned long addr = KASAN_SHADOW_START;
180	unsigned long end = KASAN_SHADOW_END;
181	unsigned long next;
182	pmd_t *pmd = pmd_off_k(addr);
183
184	BUILD_BUG_ON(KASAN_SHADOW_START & ~PGDIR_MASK);
185
186	kasan_populate_pte(kasan_early_shadow_pte, PAGE_KERNEL);
187
188	do {
189		next = pgd_addr_end(addr, end);
190		pmd_populate_kernel(&init_mm, pmd, kasan_early_shadow_pte);
191	} while (pmd++, addr = next, addr != end);
192}
193