From 48d2f0407be7a36e8f20be37ec9121e021ef3964 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@csgroup.eu>
Date: Wed, 5 Aug 2020 15:27:29 +0000
Subject: [PATCH] powerpc/kasan: Fix KASAN_SHADOW_START on BOOK3S_32
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@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/6eddca2d5611fd57312a88eae31278c87a8fc99d.1596641224.git.christophe.leroy@csgroup.eu
---
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 d635b96c7ea69..7355ed05e65ed 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)
--
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