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authorVasily Gorbik <gor@linux.ibm.com>2023-01-30 02:11:39 +0100
committerHeiko Carstens <hca@linux.ibm.com>2023-02-06 11:13:55 +0100
commit26ced8124a118e8c59d524da9d9f8d5e30502e60 (patch)
tree4934b7012ff110c438a0c912dce2a28fc36e74aa /arch
parents390/boot: avoid page tables memory in kaslr (diff)
downloadlinux-26ced8124a118e8c59d524da9d9f8d5e30502e60.tar.xz
linux-26ced8124a118e8c59d524da9d9f8d5e30502e60.zip
s390/kasan: avoid mapping KASAN shadow for standby memory
KASAN common code is able to handle memory hotplug and create KASAN shadow memory on a fly. Online memory ranges are available from mem_detect, use this information to avoid mapping KASAN shadow for standby memory. Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/s390/boot/kaslr.c2
-rw-r--r--arch/s390/mm/kasan_init.c26
2 files changed, 6 insertions, 22 deletions
diff --git a/arch/s390/boot/kaslr.c b/arch/s390/boot/kaslr.c
index 9cab7bbbfd18..70ff68dd1fee 100644
--- a/arch/s390/boot/kaslr.c
+++ b/arch/s390/boot/kaslr.c
@@ -182,7 +182,7 @@ unsigned long get_random_base(unsigned long safe_addr)
* which vmem and kasan code will use for shadow memory and
* pgtable mapping allocations.
*/
- memory_limit -= kasan_estimate_memory_needs(memory_limit);
+ memory_limit -= kasan_estimate_memory_needs(online_mem_total);
memory_limit -= vmem_estimate_memory_needs(online_mem_total);
safe_addr = ALIGN(safe_addr, THREAD_SIZE);
diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c
index 1aaea718af73..4f6678282726 100644
--- a/arch/s390/mm/kasan_init.c
+++ b/arch/s390/mm/kasan_init.c
@@ -227,26 +227,13 @@ void __init kasan_early_init(void)
p4d_t p4d_z = __p4d(__pa(kasan_early_shadow_pud) | _REGION2_ENTRY);
unsigned long untracked_end = MODULES_VADDR;
unsigned long shadow_alloc_size;
- unsigned long memsize;
+ unsigned long start, end;
+ int i;
kasan_early_detect_facilities();
if (!has_nx)
pte_z = clear_pte_bit(pte_z, __pgprot(_PAGE_NOEXEC));
- memsize = get_mem_detect_end();
- if (!memsize)
- kasan_early_panic("cannot detect physical memory size\n");
- /*
- * Kasan currently supports standby memory but only if it follows
- * online memory (default allocation), i.e. no memory holes.
- * - memsize represents end of online memory
- * - ident_map_size represents online + standby and memory limits
- * accounted.
- * Kasan maps "memsize" right away.
- * [__sha(0), __sha(memsize)] - shadow memory for identity mapping
- * The rest [memsize, ident_map_size] if memsize < ident_map_size
- * could be mapped/unmapped dynamically later during memory hotplug.
- */
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, P4D_SIZE));
BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, P4D_SIZE));
@@ -256,12 +243,8 @@ void __init kasan_early_init(void)
crst_table_init((unsigned long *)kasan_early_shadow_pmd, pmd_val(pmd_z));
memset64((u64 *)kasan_early_shadow_pte, pte_val(pte_z), PTRS_PER_PTE);
- shadow_alloc_size = memsize >> KASAN_SHADOW_SCALE_SHIFT;
-
- if (pgalloc_low + shadow_alloc_size > memsize)
- kasan_early_panic("out of memory during initialisation\n");
-
if (has_edat) {
+ shadow_alloc_size = get_mem_detect_online_total() >> KASAN_SHADOW_SCALE_SHIFT;
segment_pos = round_down(pgalloc_pos, _SEGMENT_SIZE);
segment_low = segment_pos - shadow_alloc_size;
segment_low = round_down(segment_low, _SEGMENT_SIZE);
@@ -299,7 +282,8 @@ void __init kasan_early_init(void)
* +- shadow end ----+---------+- shadow end ---+
*/
/* populate kasan shadow (for identity mapping and zero page mapping) */
- kasan_early_pgtable_populate(__sha(0), __sha(memsize), POPULATE_MAP);
+ for_each_mem_detect_block(i, &start, &end)
+ kasan_early_pgtable_populate(__sha(start), __sha(end), POPULATE_MAP);
if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
untracked_end = VMALLOC_START;
/* shallowly populate kasan shadow for vmalloc and modules */