[PATCH 1/3] arm64: kasan: don't populate vmalloc area for CONFIG_KASAN_VMALLOC

[Lecopzer Chen]

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 at 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..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