diff options
| -rw-r--r-- | arch/s390/boot/kaslr.c | 30 | ||||
| -rw-r--r-- | arch/s390/include/asm/kasan.h | 26 |
2 files changed, 34 insertions, 22 deletions
diff --git a/arch/s390/boot/kaslr.c b/arch/s390/boot/kaslr.c index d844a5ef9089..987a9eaf228a 100644 --- a/arch/s390/boot/kaslr.c +++ b/arch/s390/boot/kaslr.c @@ -7,6 +7,7 @@ #include <asm/cpacf.h> #include <asm/timex.h> #include <asm/sclp.h> +#include <asm/kasan.h> #include "compressed/decompressor.h" #include "boot.h" @@ -179,34 +180,19 @@ unsigned long get_random_base(unsigned long safe_addr) if (memory_end_set) memory_limit = min(memory_limit, memory_end); + /* + * Avoid putting kernel in the end of physical memory + * which kasan will use for shadow memory and early pgtable + * mapping allocations. + */ + memory_limit -= kasan_estimate_memory_needs(memory_limit); + if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && INITRD_START && INITRD_SIZE) { if (safe_addr < INITRD_START + INITRD_SIZE) safe_addr = INITRD_START + INITRD_SIZE; } safe_addr = ALIGN(safe_addr, THREAD_SIZE); - if ((IS_ENABLED(CONFIG_KASAN))) { - /* - * 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. - */ - memory_limit = get_mem_detect_end(); - if (memory_end_set && memory_limit > memory_end) - memory_limit = memory_end; - - /* for shadow memory */ - kasan_needs = memory_limit / 8; - /* for paging structures */ - kasan_needs += (memory_limit + kasan_needs) / PAGE_SIZE / - _PAGE_ENTRIES * _PAGE_TABLE_SIZE * 2; - memory_limit -= kasan_needs; - } - kernel_size = vmlinux.image_size + vmlinux.bss_size; if (safe_addr + kernel_size > memory_limit) return 0; 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 |