xref: /openbmc/linux/arch/riscv/include/asm/kasan.h (revision 2cf1c348)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (C) 2019 Andes Technology Corporation */
3 
4 #ifndef __ASM_KASAN_H
5 #define __ASM_KASAN_H
6 
7 #ifndef __ASSEMBLY__
8 
9 #ifdef CONFIG_KASAN
10 
11 /*
12  * The following comment was copied from arm64:
13  * KASAN_SHADOW_START: beginning of the kernel virtual addresses.
14  * KASAN_SHADOW_END: KASAN_SHADOW_START + 1/N of kernel virtual addresses,
15  * where N = (1 << KASAN_SHADOW_SCALE_SHIFT).
16  *
17  * KASAN_SHADOW_OFFSET:
18  * This value is used to map an address to the corresponding shadow
19  * address by the following formula:
20  *     shadow_addr = (address >> KASAN_SHADOW_SCALE_SHIFT) + KASAN_SHADOW_OFFSET
21  *
22  * (1 << (64 - KASAN_SHADOW_SCALE_SHIFT)) shadow addresses that lie in range
23  * [KASAN_SHADOW_OFFSET, KASAN_SHADOW_END) cover all 64-bits of virtual
24  * addresses. So KASAN_SHADOW_OFFSET should satisfy the following equation:
25  *      KASAN_SHADOW_OFFSET = KASAN_SHADOW_END -
26  *                              (1ULL << (64 - KASAN_SHADOW_SCALE_SHIFT))
27  */
28 #define KASAN_SHADOW_SCALE_SHIFT	3
29 
30 #define KASAN_SHADOW_SIZE	(UL(1) << ((VA_BITS - 1) - KASAN_SHADOW_SCALE_SHIFT))
31 /*
32  * Depending on the size of the virtual address space, the region may not be
33  * aligned on PGDIR_SIZE, so force its alignment to ease its population.
34  */
35 #define KASAN_SHADOW_START	((KASAN_SHADOW_END - KASAN_SHADOW_SIZE) & PGDIR_MASK)
36 #define KASAN_SHADOW_END	MODULES_LOWEST_VADDR
37 #define KASAN_SHADOW_OFFSET	_AC(CONFIG_KASAN_SHADOW_OFFSET, UL)
38 
39 void kasan_init(void);
40 asmlinkage void kasan_early_init(void);
41 void kasan_swapper_init(void);
42 
43 #endif
44 #endif
45 #endif /* __ASM_KASAN_H */
46