From 9a0732efa77418fc85b1bdc5ddee619e62f59545 Mon Sep 17 00:00:00 2001 From: Lecopzer Chen Date: Wed, 24 Mar 2021 12:05:18 +0800 Subject: [PATCH] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC 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. 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 Acked-by: Andrey Konovalov Tested-by: Andrey Konovalov Tested-by: Ard Biesheuvel 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 --- arch/arm64/mm/kasan_init.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c index d8e66c78440e..7598b0a96b64 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_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); -- GitLab