[PATCH 25/35] kasan: introduce CONFIG_KASAN_HW_TAGS
From: Andrey Konovalov <hidden>
Date: 2020-08-14 17:29:52
Also in:
linux-mm, lkml
Subsystem:
kasan, library code, the rest · Maintainers:
Andrey Ryabinin, Andrew Morton, Linus Torvalds
This patch adds a configuration option for a new KASAN mode called hardware tag-based KASAN. This mode uses the memory tagging approach like the software tag-based mode, but relies on arm64 Memory Tagging Extension feature for tag management and access checking. Signed-off-by: Andrey Konovalov <redacted> --- lib/Kconfig.kasan | 46 ++++++++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 14 deletions(-)
diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index e500c18cbe79..0d4160ce5ee8 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan@@ -6,7 +6,10 @@ config HAVE_ARCH_KASAN config HAVE_ARCH_KASAN_SW_TAGS bool -config HAVE_ARCH_KASAN_VMALLOC +config HAVE_ARCH_KASAN_HW_TAGS + bool + +config HAVE_ARCH_KASAN_VMALLOC bool config CC_HAS_KASAN_GENERIC
@@ -20,10 +23,11 @@ config CC_HAS_WORKING_NOSANITIZE_ADDRESS menuconfig KASAN bool "KASAN: runtime memory debugger" - depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \ - (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS) + depends on (((HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \ + (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)) && \ + CC_HAS_WORKING_NOSANITIZE_ADDRESS) || \ + HAVE_ARCH_KASAN_HW_TAGS depends on (SLUB && SYSFS) || (SLAB && !DEBUG_SLAB) - depends on CC_HAS_WORKING_NOSANITIZE_ADDRESS select SLUB_DEBUG if SLUB select CONSTRUCTORS select STACKDEPOT
@@ -38,13 +42,18 @@ choice prompt "KASAN mode" default KASAN_GENERIC help - KASAN has two modes: generic KASAN (similar to userspace ASan, - x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC) and - software tag-based KASAN (a version based on software memory - tagging, arm64 only, similar to userspace HWASan, enabled with - CONFIG_KASAN_SW_TAGS). + KASAN has three modes: + 1. generic KASAN (similar to userspace ASan, + x86_64/arm64/xtensa, enabled with CONFIG_KASAN_GENERIC), + 2. software tag-based KASAN (arm64 only, based on software + memory tagging (similar to userspace HWASan), enabled with + CONFIG_KASAN_SW_TAGS), and + 3. hardware tag-based KASAN (arm64-only, based hardware + memory tagging (MTE), enabled with CONFIG_KASAN_HW_TAGS). + + All KASAN modes are strictly debugging features. - Both generic and tag-based KASAN are strictly debugging features. + For better error detection enable CONFIG_STACKTRACE. config KASAN_GENERIC bool "Generic mode"
@@ -61,8 +70,6 @@ config KASAN_GENERIC and introduces an overhead of ~x1.5 for the rest of the allocations. The performance slowdown is ~x3. - For better error detection enable CONFIG_STACKTRACE. - Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB (the resulting kernel does not boot).
@@ -83,15 +90,25 @@ config KASAN_SW_TAGS casting and comparison, as it embeds tags into the top byte of each pointer. - For better error detection enable CONFIG_STACKTRACE. - Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB (the resulting kernel does not boot). +config KASAN_HW_TAGS + bool "Hardware tag-based mode" + depends on HAVE_ARCH_KASAN_HW_TAGS + depends on SLUB + help + Enables hardware tag-based KASAN mode. + + This mode requires both Memory Tagging Extension and Top Byte Ignore + support by the CPU and therefore is only supported for modern arm64 + CPUs (MTE added in ARMv8.5 ISA). + endchoice choice prompt "Instrumentation type" + depends on KASAN_GENERIC || KASAN_SW_TAGS default KASAN_OUTLINE config KASAN_OUTLINE
@@ -115,6 +132,7 @@ endchoice config KASAN_STACK_ENABLE bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST + depends on KASAN_GENERIC || KASAN_SW_TAGS help The LLVM stack address sanitizer has a know problem that causes excessive stack usage in a lot of functions, see
--
2.28.0.220.ged08abb693-goog
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