diff options
Diffstat (limited to 'arch/s390/include/asm/kasan.h')
| -rw-r--r-- | arch/s390/include/asm/kasan.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/s390/include/asm/kasan.h b/arch/s390/include/asm/kasan.h index eea62586e719..76f351bd6645 100644 --- a/arch/s390/include/asm/kasan.h +++ b/arch/s390/include/asm/kasan.h @@ -17,10 +17,36 @@ extern void kasan_early_init(void); extern void kasan_copy_shadow_mapping(void); extern void kasan_free_early_identity(void); extern unsigned long kasan_vmax; + +/* + * Estimate kasan memory requirements, which it will reserve + * at the very end of available physical memory. To estimate + * that, we take into account that kasan would require + * 1/8 of available physical memory (for shadow memory) + + * creating page tables for the whole memory + shadow memory + * region (1 + 1/8). To keep page tables estimates simple take + * the double of combined ptes size. + * + * physmem parameter has to be already adjusted if not entire physical memory + * would be used (e.g. due to effect of "mem=" option). + */ +static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem) +{ + unsigned long kasan_needs; + unsigned long pages; + /* for shadow memory */ + kasan_needs = round_up(physmem / 8, PAGE_SIZE); + /* for paging structures */ + pages = DIV_ROUND_UP(physmem + kasan_needs, PAGE_SIZE); + kasan_needs += DIV_ROUND_UP(pages, _PAGE_ENTRIES) * _PAGE_TABLE_SIZE * 2; + + return kasan_needs; +} #else static inline void kasan_early_init(void) { } static inline void kasan_copy_shadow_mapping(void) { } static inline void kasan_free_early_identity(void) { } +static inline unsigned long kasan_estimate_memory_needs(unsigned long physmem) { return 0; } #endif #endif |