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arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC

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Linux support KAsan for VMALLOC since commit 3c5c3cfb9e
("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.

Before:

MODULE_VADDR: no mapping, no zero shadow at init
VMALLOC_VADDR: backed with zero shadow at init

After:

MODULE_VADDR: no mapping, no zero shadow at init
VMALLOC_VADDR: no mapping, no zero shadow at init

Thus the mapping will get allocated on demand by the core function
of KASAN_VMALLOC.

  -----------  vmalloc_shadow_start
 |           |
 |           |
 |           | <= non-mapping
 |           |
 |           |
 |-----------|
 |///////////|<- kimage shadow with page table mapping.
 |-----------|
 |           |
 |           | <= non-mapping
 |           |
 ------------- vmalloc_shadow_end
 |00000000000|
 |00000000000| <= Zero shadow
 |00000000000|
 ------------- KASAN_SHADOW_END

Signed-off-by: Lecopzer Chen <lecopzer.chen@mediatek.com>
Acked-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Andrey Konovalov <andreyknvl@gmail.com>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20210324040522.15548-2-lecopzer.chen@mediatek.com
[catalin.marinas@arm.com: add a build check on VMALLOC_START != MODULES_END]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Lecopzer Chen 2021-03-24 12:05:18 +08:00 committed by Catalin Marinas
parent 1e28eed176
commit 9a0732efa7
1 changed files with 14 additions and 5 deletions
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19
arch/arm64/mm/kasan_init.c
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@ -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_end;
phys_addr_t pa_start, pa_end;
u64 i;
@ -223,6 +224,8 @@ 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_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 +244,18 @@ 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 (kimg_shadow_start > mod_shadow_end)
kasan_populate_early_shadow((void *)mod_shadow_end,
(void *)kimg_shadow_start);
if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
BUILD_BUG_ON(VMALLOC_START != MODULES_END);
kasan_populate_early_shadow((void *)vmalloc_shadow_end,
(void *)KASAN_SHADOW_END);
} 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);
}
for_each_mem_range(i, &pa_start, &pa_end) {
void *start = (void *)__phys_to_virt(pa_start);