[PATCH v2 1/4] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC

Lecopzer Chen
2021-01-09T10:34:38Z

Linux support KAsan for VMALLOC since commit 3c5c3cfb9ef4da9
("kasan: support backing vmalloc space with real shadow memory")

Like how the MODULES_VADDR does now, just not to early populate
the VMALLOC_START between VMALLOC_END.
similarly, the kernel code mapping is now in the VMALLOC area and
should keep these area populated.

Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
---
arch/arm64/mm/kasan_init.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index d8e66c78440e..39b218a64279 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -214,6 +214,7 @@ static void __init kasan_init_shadow(void)
{
u64 kimg_shadow_start, kimg_shadow_end;
u64 mod_shadow_start, mod_shadow_end;
+ u64 vmalloc_shadow_start, vmalloc_shadow_end;
phys_addr_t pa_start, pa_end;
u64 i;

@@ -223,6 +224,9 @@ static void __init kasan_init_shadow(void)
mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);

+ vmalloc_shadow_start = (u64)kasan_mem_to_shadow((void *)VMALLOC_START);
+ vmalloc_shadow_end = (u64)kasan_mem_to_shadow((void *)VMALLOC_END);
+
/*
* We are going to perform proper setup of shadow memory.
* At first we should unmap early shadow (clear_pgds() call below).
@@ -241,12 +245,21 @@ static void __init kasan_init_shadow(void)

kasan_populate_early_shadow(kasan_mem_to_shadow((void *)PAGE_END),
(void *)mod_shadow_start);
- kasan_populate_early_shadow((void *)kimg_shadow_end,
- (void *)KASAN_SHADOW_END);
+ if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
+ kasan_populate_early_shadow((void *)vmalloc_shadow_end,
+ (void *)KASAN_SHADOW_END);
+ if (vmalloc_shadow_start > mod_shadow_end)
+ kasan_populate_early_shadow((void *)mod_shadow_end,
+ (void *)vmalloc_shadow_start);
+
+ } else {
+ kasan_populate_early_shadow((void *)kimg_shadow_end,
+ (void *)KASAN_SHADOW_END);
+ if (kimg_shadow_start > mod_shadow_end)
+ kasan_populate_early_shadow((void *)mod_shadow_end,
+ (void *)kimg_shadow_start);
+ }

- if (kimg_shadow_start > mod_shadow_end)
- kasan_populate_early_shadow((void *)mod_shadow_end,
- (void *)kimg_shadow_start);

for_each_mem_range(i, &pa_start, &pa_end) {
void *start = (void *)__phys_to_virt(pa_start);
--
2.25.1