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authorVasily Gorbik <gor@linux.ibm.com>2019-08-02 12:42:59 +0200
committerVasily Gorbik <gor@linux.ibm.com>2019-12-11 19:56:59 +0100
commit3e39ce266a273e5751e5792aee248cb8d9630c8b (patch)
tree729b1ac0d497523ab830af0ac974126b1e68d0cf /arch/s390/mm
parent1b68ac8678a8e9993deebd55014cbe803e78ca02 (diff)
s390/kasan: add KASAN_VMALLOC support
Add KASAN_VMALLOC support which now enables vmalloc memory area access checks as well as enables usage of VMAP_STACK under kasan. KASAN_VMALLOC changes the way vmalloc and modules areas shadow memory is handled. With this new approach only top level page tables are pre-populated and lower levels are filled dynamically upon memory allocation. Acked-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r--arch/s390/mm/kasan_init.c68
1 files changed, 56 insertions, 12 deletions
diff --git a/arch/s390/mm/kasan_init.c b/arch/s390/mm/kasan_init.c
index 460f25572940..06345616a646 100644
--- a/arch/s390/mm/kasan_init.c
+++ b/arch/s390/mm/kasan_init.c
@@ -82,7 +82,8 @@ static pte_t * __init kasan_early_pte_alloc(void)
enum populate_mode {
POPULATE_ONE2ONE,
POPULATE_MAP,
- POPULATE_ZERO_SHADOW
+ POPULATE_ZERO_SHADOW,
+ POPULATE_SHALLOW
};
static void __init kasan_early_vmemmap_populate(unsigned long address,
unsigned long end,
@@ -116,6 +117,12 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
pgd_populate(&init_mm, pg_dir, p4_dir);
}
+ if (IS_ENABLED(CONFIG_KASAN_S390_4_LEVEL_PAGING) &&
+ mode == POPULATE_SHALLOW) {
+ address = (address + P4D_SIZE) & P4D_MASK;
+ continue;
+ }
+
p4_dir = p4d_offset(pg_dir, address);
if (p4d_none(*p4_dir)) {
if (mode == POPULATE_ZERO_SHADOW &&
@@ -130,6 +137,12 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
p4d_populate(&init_mm, p4_dir, pu_dir);
}
+ if (!IS_ENABLED(CONFIG_KASAN_S390_4_LEVEL_PAGING) &&
+ mode == POPULATE_SHALLOW) {
+ address = (address + PUD_SIZE) & PUD_MASK;
+ continue;
+ }
+
pu_dir = pud_offset(p4_dir, address);
if (pud_none(*pu_dir)) {
if (mode == POPULATE_ZERO_SHADOW &&
@@ -195,6 +208,9 @@ static void __init kasan_early_vmemmap_populate(unsigned long address,
page = kasan_early_shadow_page;
pte_val(*pt_dir) = __pa(page) | pgt_prot_zero;
break;
+ case POPULATE_SHALLOW:
+ /* should never happen */
+ break;
}
}
address += PAGE_SIZE;
@@ -313,22 +329,50 @@ void __init kasan_early_init(void)
init_mm.pgd = early_pg_dir;
/*
* Current memory layout:
- * +- 0 -------------+ +- shadow start -+
- * | 1:1 ram mapping | /| 1/8 ram |
- * +- end of ram ----+ / +----------------+
- * | ... gap ... |/ | kasan |
- * +- shadow start --+ | zero |
- * | 1/8 addr space | | page |
- * +- shadow end -+ | mapping |
- * | ... gap ... |\ | (untracked) |
- * +- modules vaddr -+ \ +----------------+
- * | 2Gb | \| unmapped | allocated per module
- * +-----------------+ +- shadow end ---+
+ * +- 0 -------------+ +- shadow start -+
+ * | 1:1 ram mapping | /| 1/8 ram |
+ * | | / | |
+ * +- end of ram ----+ / +----------------+
+ * | ... gap ... | / | |
+ * | |/ | kasan |
+ * +- shadow start --+ | zero |
+ * | 1/8 addr space | | page |
+ * +- shadow end -+ | mapping |
+ * | ... gap ... |\ | (untracked) |
+ * +- vmalloc area -+ \ | |
+ * | vmalloc_size | \ | |
+ * +- modules vaddr -+ \ +----------------+
+ * | 2Gb | \| unmapped | allocated per module
+ * +-----------------+ +- shadow end ---+
+ *
+ * Current memory layout (KASAN_VMALLOC):
+ * +- 0 -------------+ +- shadow start -+
+ * | 1:1 ram mapping | /| 1/8 ram |
+ * | | / | |
+ * +- end of ram ----+ / +----------------+
+ * | ... gap ... | / | kasan |
+ * | |/ | zero |
+ * +- shadow start --+ | page |
+ * | 1/8 addr space | | mapping |
+ * +- shadow end -+ | (untracked) |
+ * | ... gap ... |\ | |
+ * +- vmalloc area -+ \ +- vmalloc area -+
+ * | vmalloc_size | \ |shallow populate|
+ * +- modules vaddr -+ \ +- modules area -+
+ * | 2Gb | \|shallow populate|
+ * +-----------------+ +- shadow end ---+
*/
/* populate kasan shadow (for identity mapping and zero page mapping) */
kasan_early_vmemmap_populate(__sha(0), __sha(memsize), POPULATE_MAP);
if (IS_ENABLED(CONFIG_MODULES))
untracked_mem_end = vmax - MODULES_LEN;
+ if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
+ untracked_mem_end = vmax - vmalloc_size - MODULES_LEN;
+ /* shallowly populate kasan shadow for vmalloc and modules */
+ kasan_early_vmemmap_populate(__sha(untracked_mem_end),
+ __sha(vmax), POPULATE_SHALLOW);
+ }
+ /* populate kasan shadow for untracked memory */
kasan_early_vmemmap_populate(__sha(max_physmem_end),
__sha(untracked_mem_end),
POPULATE_ZERO_SHADOW);