arch/s390/include/asm/kasan.h

   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 extern void kasan_copy_shadow_mapping(void);
  18 extern void kasan_free_early_identity(void);
  19 extern unsigned long kasan_vmax;
  20
  21 /*
  22  * Estimate kasan memory requirements, which it will reserve
  23  * at the very end of available physical memory. To estimate
  24  * that, we take into account that kasan would require
  25  * 1/8 of available physical memory (for shadow memory) +
  26  * creating page tables for the whole memory + shadow memory
  27  * region (1 + 1/8). To keep page tables estimates simple take
  28  * the double of combined ptes size.
  29  *
  30  * physmem parameter has to be already adjusted if not entire physical memory
  31  * would be used (e.g. due to effect of "mem=" option).
  32  */
  33 static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem)
  34 {
  35         unsigned long kasan_needs;
  36         unsigned long pages;
  37         /* for shadow memory */
  38         kasan_needs = round_up(physmem / 8, PAGE_SIZE);
  39         /* for paging structures */
  40         pages = DIV_ROUND_UP(physmem + kasan_needs, PAGE_SIZE);
  41         kasan_needs += DIV_ROUND_UP(pages, _PAGE_ENTRIES) * _PAGE_TABLE_SIZE * 2;
  42
  43         return kasan_needs;
  44 }
  45 #else
  46 static inline void kasan_early_init(void) { }
  47 static inline void kasan_copy_shadow_mapping(void) { }
  48 static inline void kasan_free_early_identity(void) { }
  49 static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem) { return 0; }
  50 #endif
  51
  52 #endif