The patch titled
Subject: kasan, arm64: adjust shadow size for tag-based mode
has been added to the -mm tree. Its filename is
kasan-arm64-adjust-shadow-size-for-tag-based-mode.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/kasan-arm64-adjust-shadow-size-for-tag-based-mode.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/kasan-arm64-adjust-shadow-size-for-tag-based-mode.patch
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------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan, arm64: adjust shadow size for tag-based mode
Tag-based KASAN uses 1 shadow byte for 16 bytes of kernel memory, so it
requires 1/16th of the kernel virtual address space for the shadow memory.
This commit sets KASAN_SHADOW_SCALE_SHIFT to 4 when the tag-based KASAN
mode is enabled.
Link: http://lkml.kernel.org/r/95fa472a03a8ff268e24b8730ebd108922824e74.1543337629.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Reviewed-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Reviewed-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/arch/arm64/include/asm/memory.h~kasan-arm64-adjust-shadow-size-for-tag-based-mode
+++ a/arch/arm64/include/asm/memory.h
@@ -74,12 +74,11 @@
#define KERNEL_END _end
/*
- * KASAN requires 1/8th of the kernel virtual address space for the shadow
- * region. KASAN can bloat the stack significantly, so double the (minimum)
- * stack size when KASAN is in use.
+ * Generic and tag-based KASAN require 1/8th and 1/16th of the kernel virtual
+ * address space for the shadow region respectively. They can bloat the stack
+ * significantly, so double the (minimum) stack size when they are in use.
*/
#ifdef CONFIG_KASAN
-#define KASAN_SHADOW_SCALE_SHIFT 3
#define KASAN_SHADOW_SIZE (UL(1) << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
#define KASAN_THREAD_SHIFT 1
#else
--- a/arch/arm64/Makefile~kasan-arm64-adjust-shadow-size-for-tag-based-mode
+++ a/arch/arm64/Makefile
@@ -91,10 +91,19 @@ else
TEXT_OFFSET := 0x00080000
endif
+ifeq ($(CONFIG_KASAN_SW_TAGS), y)
+KASAN_SHADOW_SCALE_SHIFT := 4
+else
+KASAN_SHADOW_SCALE_SHIFT := 3
+endif
+
+KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
+KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
+KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
+
# KASAN_SHADOW_OFFSET = VA_START + (1 << (VA_BITS - KASAN_SHADOW_SCALE_SHIFT))
# - (1 << (64 - KASAN_SHADOW_SCALE_SHIFT))
# in 32-bit arithmetic
-KASAN_SHADOW_SCALE_SHIFT := 3
KASAN_SHADOW_OFFSET := $(shell printf "0x%08x00000000\n" $$(( \
(0xffffffff & (-1 << ($(CONFIG_ARM64_VA_BITS) - 32))) \
+ (1 << ($(CONFIG_ARM64_VA_BITS) - 32 - $(KASAN_SHADOW_SCALE_SHIFT))) \
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
kasan-mm-change-hooks-signatures.patch
kasan-slub-handle-pointer-tags-in-early_kmem_cache_node_alloc.patch
kasan-move-common-generic-and-tag-based-code-to-commonc.patch
kasan-rename-source-files-to-reflect-the-new-naming-scheme.patch
kasan-add-config_kasan_generic-and-config_kasan_sw_tags.patch
kasan-arm64-adjust-shadow-size-for-tag-based-mode.patch
kasan-rename-kasan_zero_page-to-kasan_early_shadow_page.patch
kasan-initialize-shadow-to-0xff-for-tag-based-mode.patch
arm64-move-untagged_addr-macro-from-uaccessh-to-memoryh.patch
kasan-add-tag-related-helper-functions.patch
kasan-arm64-untag-address-in-_virt_addr_is_linear.patch
kasan-preassign-tags-to-objects-with-ctors-or-slab_typesafe_by_rcu.patch
kasan-arm64-fix-up-fault-handling-logic.patch
kasan-arm64-enable-top-byte-ignore-for-the-kernel.patch
kasan-mm-perform-untagged-pointers-comparison-in-krealloc.patch
kasan-split-out-generic_reportc-from-reportc.patch
kasan-add-bug-reporting-routines-for-tag-based-mode.patch
mm-move-obj_to_index-to-include-linux-slab_defh.patch
kasan-add-hooks-implementation-for-tag-based-mode.patch
kasan-arm64-add-brk-handler-for-inline-instrumentation.patch
kasan-mm-arm64-tag-non-slab-memory-allocated-via-pagealloc.patch
kasan-add-__must_check-annotations-to-kasan-hooks.patch
kasan-arm64-select-have_arch_kasan_sw_tags.patch
kasan-update-documentation.patch
kasan-add-spdx-license-identifier-mark-to-source-files.patch
