1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef __ASM_KASAN_H 3 #define __ASM_KASAN_H 4 5 #include <asm/pgtable.h> 6 7 #ifdef CONFIG_KASAN 8 9 #define KASAN_SHADOW_SCALE_SHIFT 3 10 #define KASAN_SHADOW_SIZE \ 11 (_AC(1, UL) << (_REGION1_SHIFT - KASAN_SHADOW_SCALE_SHIFT)) 12 #define KASAN_SHADOW_OFFSET _AC(CONFIG_KASAN_SHADOW_OFFSET, UL) 13 #define KASAN_SHADOW_START KASAN_SHADOW_OFFSET 14 #define KASAN_SHADOW_END (KASAN_SHADOW_START + KASAN_SHADOW_SIZE) 15 16 extern void kasan_early_init(void); 17 18 /* 19 * Estimate kasan memory requirements, which it will reserve 20 * at the very end of available physical memory. To estimate 21 * that, we take into account that kasan would require 22 * 1/8 of available physical memory (for shadow memory) + 23 * creating page tables for the shadow memory region. 24 * To keep page tables estimates simple take the double of 25 * combined ptes size. 26 * 27 * physmem parameter has to be already adjusted if not entire physical memory 28 * would be used (e.g. due to effect of "mem=" option). 29 */ 30 static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem) 31 { 32 unsigned long kasan_needs; 33 unsigned long pages; 34 /* for shadow memory */ 35 kasan_needs = round_up(physmem / 8, PAGE_SIZE); 36 /* for paging structures */ 37 pages = DIV_ROUND_UP(kasan_needs, PAGE_SIZE); 38 kasan_needs += DIV_ROUND_UP(pages, _PAGE_ENTRIES) * _PAGE_TABLE_SIZE * 2; 39 40 return kasan_needs; 41 } 42 #else 43 static inline void kasan_early_init(void) { } 44 static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem) { return 0; } 45 #endif 46 47 #endif 48