@@ -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
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 <andreyknvl@google.com> --- lib/Kconfig.kasan | 46 ++++++++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 14 deletions(-)