From 3e39ce266a273e5751e5792aee248cb8d9630c8b Mon Sep 17 00:00:00 2001
From: Vasily Gorbik <gor@linux.ibm.com>
Date: Fri, 2 Aug 2019 12:42:59 +0200
Subject: [PATCH] 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>
---
arch/s390/Kconfig | 1 +
arch/s390/mm/kasan_init.c | 68 ++++++++++++++++++++++++++++++++-------
2 files changed, 57 insertions(+), 12 deletions(-)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index d4051e88e625..bc88841d335d 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -124,6 +124,7 @@ config S390
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN
+ select HAVE_ARCH_KASAN_VMALLOC
select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_SOFT_DIRTY
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);