linux-kernel - [PATCH 1/3] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN

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Message-Id: <20210103171137.153834-2-lecopzer@gmail.com>
Date:   Mon,  4 Jan 2021 01:11:35 +0800
From:   Lecopzer Chen <lecopzer@...il.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        kasan-dev@...glegroups.com, linux-arm-kernel@...ts.infradead.org
Cc:     dan.j.williams@...el.com, aryabinin@...tuozzo.com,
        glider@...gle.com, dvyukov@...gle.com, akpm@...ux-foundation.org,
        linux-mediatek@...ts.infradead.org, yj.chiang@...iatek.com,
        will@...nel.org, catalin.marinas@....com,
        Lecopzer Chen <lecopzer@...il.com>,
        Lecopzer Chen <lecopzer.chen@...iatek.com>
Subject: [PATCH 1/3] 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.
similarly, the kernel code mapping is now in the VMALLOC area and
should keep these area populated.

Signed-off-by: Lecopzer Chen <lecopzer.chen@...iatek.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..d7ad3f1e9c4d 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