[PATCH] powerpc/kasan: Fix KASAN_SHADOW_START on BOOK3S_32
From: Christophe Leroy
Date: Wed Aug 05 2020 - 16:14:53 EST
On BOOK3S_32, when we have modules and strict kernel RWX, modules
are not in vmalloc space but in a dedicated segment that is
below PAGE_OFFSET.
So KASAN_SHADOW_START must take it into account.
MODULES_VADDR can't be used because it is not defined yet
in kasan.h
Fixes: 6ca055322da8 ("powerpc/32s: Use dedicated segment for modules with STRICT_KERNEL_RWX")
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/include/asm/kasan.h | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/kasan.h b/arch/powerpc/include/asm/kasan.h
index d635b96c7ea6..7355ed05e65e 100644
--- a/arch/powerpc/include/asm/kasan.h
+++ b/arch/powerpc/include/asm/kasan.h
@@ -15,11 +15,18 @@
#ifndef __ASSEMBLY__
#include <asm/page.h>
+#include <linux/sizes.h>
#define KASAN_SHADOW_SCALE_SHIFT 3
+#if defined(CONFIG_PPC_BOOK3S_32) && defined(CONFIG_MODULES) && defined(CONFIG_STRICT_KERNEL_RWX)
+#define KASAN_KERN_START ALIGN_DOWN(PAGE_OFFSET - SZ_256M, SZ_256M)
+#else
+#define KASAN_KERN_START PAGE_OFFSET
+#endif
+
#define KASAN_SHADOW_START (KASAN_SHADOW_OFFSET + \
- (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT))
+ (KASAN_KERN_START >> KASAN_SHADOW_SCALE_SHIFT))
#define KASAN_SHADOW_OFFSET ASM_CONST(CONFIG_KASAN_SHADOW_OFFSET)
--
2.25.0