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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>
This commit is contained in:
Vasily Gorbik 2019-08-02 12:42:59 +02:00
parent 1b68ac8678
commit 3e39ce266a
2 changed files with 57 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/s390/Kconfig
View File

@ -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

68
arch/s390/mm/kasan_init.c
View File

@ -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);