summaryrefslogtreecommitdiff
path: root/sys/arch/aarch64/include/asan.h
blob: 201b792fe9709506ae5cb5ac14bbc8485dabe92a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
/*	$NetBSD: asan.h,v 1.19 2023/04/16 14:01:51 skrll Exp $	*/

/*
 * Copyright (c) 2018-2020 Maxime Villard, m00nbsd.net
 * All rights reserved.
 *
 * This code is part of the KASAN subsystem of the NetBSD kernel.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/atomic.h>
#include <sys/ksyms.h>

#include <uvm/uvm.h>

#include <aarch64/pmap.h>
#include <aarch64/vmparam.h>
#include <aarch64/armreg.h>
#include <aarch64/machdep.h>

#include <arm/cpufunc.h>

#define __MD_VIRTUAL_SHIFT	48	/* 49bit address space, cut half */
#define __MD_KERNMEM_BASE	0xFFFF000000000000 /* kern mem base address */

#define __MD_SHADOW_SIZE	(1ULL << (__MD_VIRTUAL_SHIFT - KASAN_SHADOW_SCALE_SHIFT))
#define KASAN_MD_SHADOW_START	(AARCH64_DIRECTMAP_END)
#define KASAN_MD_SHADOW_END	(KASAN_MD_SHADOW_START + __MD_SHADOW_SIZE)

static bool __md_early __read_mostly = true;

static inline int8_t *
kasan_md_addr_to_shad(const void *addr)
{
	vaddr_t va = (vaddr_t)addr;
	return (int8_t *)(KASAN_MD_SHADOW_START +
	    ((va - __MD_KERNMEM_BASE) >> KASAN_SHADOW_SCALE_SHIFT));
}

static inline bool
kasan_md_unsupported(vaddr_t addr)
{
	return (addr < VM_MIN_KERNEL_ADDRESS) ||
	    (addr >= VM_KERNEL_IO_BASE);
}

static paddr_t
__md_palloc(void)
{
	paddr_t pa;

	if (__predict_false(__md_early)) {
		pa = (paddr_t)pmapboot_pagealloc();
		return pa;
	}

	vaddr_t va;
	if (!uvm.page_init_done) {
		va = uvm_pageboot_alloc(PAGE_SIZE);
		pa = AARCH64_KVA_TO_PA(va);
	} else {
		struct vm_page *pg;
retry:
		pg = uvm_pagealloc(NULL, 0, NULL, 0);
		if (pg == NULL) {
			uvm_wait(__func__);
			goto retry;
		}

		pa = VM_PAGE_TO_PHYS(pg);
		va = AARCH64_PA_TO_KVA(pa);
	}

	__builtin_memset((void *)va, 0, PAGE_SIZE);
	return pa;
}

static inline paddr_t
__md_palloc_large(void)
{
	struct pglist pglist;
	int ret;

	if (!uvm.page_init_done)
		return 0;

	ret = uvm_pglistalloc(L2_SIZE, 0, ~0UL, L2_SIZE, 0,
	    &pglist, 1, 0);
	if (ret != 0)
		return 0;

	/* The page may not be zeroed. */
	return VM_PAGE_TO_PHYS(TAILQ_FIRST(&pglist));
}

static void
kasan_md_shadow_map_page(vaddr_t va)
{
	pd_entry_t *l0, *l1, *l2, *l3;
	paddr_t l0pa, pa;
	pd_entry_t pde;
	size_t idx;

	l0pa = reg_ttbr1_el1_read();
	if (__predict_false(__md_early)) {
		l0 = (void *)KERN_PHYSTOV(l0pa);
	} else {
		l0 = (void *)AARCH64_PA_TO_KVA(l0pa);
	}

	idx = l0pde_index(va);
	pde = l0[idx];
	if (!l0pde_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l0[idx], pa | L0_TABLE);
	} else {
		pa = l0pde_pa(pde);
	}
	if (__predict_false(__md_early)) {
		l1 = (void *)KERN_PHYSTOV(pa);
	} else {
		l1 = (void *)AARCH64_PA_TO_KVA(pa);
	}

	idx = l1pde_index(va);
	pde = l1[idx];
	if (!l1pde_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l1[idx], pa | L1_TABLE);
	} else {
		pa = l1pde_pa(pde);
	}
	if (__predict_false(__md_early)) {
		l2 = (void *)KERN_PHYSTOV(pa);
	} else {
		l2 = (void *)AARCH64_PA_TO_KVA(pa);
	}

	idx = l2pde_index(va);
	pde = l2[idx];
	if (!l2pde_valid(pde)) {
		/* If possible, use L2_BLOCK to map it in advance. */
		if ((pa = __md_palloc_large()) != 0) {
			atomic_swap_64(&l2[idx], pa | L2_BLOCK |
			    LX_BLKPAG_UXN | LX_BLKPAG_PXN | LX_BLKPAG_AF |
			    LX_BLKPAG_SH_IS | LX_BLKPAG_AP_RW);
			aarch64_tlbi_by_va(va);
			__builtin_memset((void *)va, 0, L2_SIZE);
			return;
		}
		pa = __md_palloc();
		atomic_swap_64(&l2[idx], pa | L2_TABLE);
	} else if (l2pde_is_block(pde)) {
		/* This VA is already mapped as a block. */
		return;
	} else {
		pa = l2pde_pa(pde);
	}
	if (__predict_false(__md_early)) {
		l3 = (void *)KERN_PHYSTOV(pa);
	} else {
		l3 = (void *)AARCH64_PA_TO_KVA(pa);
	}

	idx = l3pte_index(va);
	pde = l3[idx];
	if (!l3pte_valid(pde)) {
		pa = __md_palloc();
		atomic_swap_64(&l3[idx], pa | L3_PAGE | LX_BLKPAG_UXN |
		    LX_BLKPAG_PXN | LX_BLKPAG_AF | LX_BLKPAG_SH_IS |
		    LX_BLKPAG_AP_RW | LX_BLKPAG_ATTR_NORMAL_WB);
	}
	dsb(ishst);
	isb();
}

static void
kasan_md_early_init(void *stack)
{
	kasan_shadow_map(stack, USPACE);
	__md_early = false;
}

static void
kasan_md_init(void)
{

	CTASSERT((__MD_SHADOW_SIZE / L0_SIZE) == 64);

	extern vaddr_t kasan_kernelstart;
	extern vaddr_t kasan_kernelsize;

	kasan_shadow_map((void *)kasan_kernelstart, kasan_kernelsize);

	/* The VAs we've created until now. */
	vaddr_t eva = pmap_growkernel(VM_KERNEL_VM_BASE);
	kasan_shadow_map((void *)VM_KERNEL_VM_BASE, eva - VM_KERNEL_VM_BASE);
}

static inline bool
__md_unwind_end(const char *name)
{
	if (!strncmp(name, "el0_trap", 8) ||
	    !strncmp(name, "el1_trap", 8)) {
		return true;
	}

	return false;
}

static void
kasan_md_unwind(void)
{
	uint64_t lr, *fp;
	const char *mod;
	const char *sym;
	size_t nsym;
	int error;

	fp = (uint64_t *)__builtin_frame_address(0);
	nsym = 0;

	while (1) {
		/*
		 * normal stack frame
		 *  fp[0]  saved fp(x29) value
		 *  fp[1]  saved lr(x30) value
		 */
		lr = fp[1];

		if (lr < VM_MIN_KERNEL_ADDRESS) {
			break;
		}
		error = ksyms_getname(&mod, &sym, (vaddr_t)lr, KSYMS_PROC);
		if (error) {
			break;
		}
		printf("#%zu %p in %s <%s>\n", nsym, (void *)lr, sym, mod);
		if (__md_unwind_end(sym)) {
			break;
		}

		fp = (uint64_t *)fp[0];
		if (fp == NULL) {
			break;
		}
		nsym++;

		if (nsym >= 15) {
			break;
		}
	}
}