The patch titled
Subject: kasan: introduce CONFIG_KASAN_HW_TAGS
has been removed from the -mm tree. Its filename was
kasan-introduce-config_kasan_hw_tags.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Subject: kasan: introduce CONFIG_KASAN_HW_TAGS
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.
Link: https://lkml.kernel.org/r/44906a209d3a44f9c6f5a21841e90988e365601e.1606161801.git.andreyknvl@xxxxxxxxxx
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Co-developed-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Reviewed-by: Marco Elver <elver@xxxxxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
Tested-by: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Branislav Rankov <Branislav.Rankov@xxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Evgenii Stepanov <eugenis@xxxxxxxxxx>
Cc: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/Kconfig.kasan | 61 +++++++++++++++++++++++++++++++-------------
1 file changed, 44 insertions(+), 17 deletions(-)
--- a/lib/Kconfig.kasan~kasan-introduce-config_kasan_hw_tags
+++ a/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
@@ -15,16 +18,19 @@ config CC_HAS_KASAN_GENERIC
config CC_HAS_KASAN_SW_TAGS
def_bool $(cc-option, -fsanitize=kernel-hwaddress)
+# This option is only required for software KASAN modes.
+# Old GCC versions don't have proper support for no_sanitize_address.
+# See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89124 for details.
config CC_HAS_WORKING_NOSANITIZE_ADDRESS
def_bool !CC_IS_GCC || GCC_VERSION >= 80300
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 CONSTRUCTORS
select STACKDEPOT
help
Enables KASAN (KernelAddressSANitizer) - runtime memory debugger,
@@ -37,18 +43,24 @@ 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 on hardware
+ memory tagging, 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 reports enable CONFIG_STACKTRACE.
config KASAN_GENERIC
bool "Generic mode"
depends on HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC
select SLUB_DEBUG if SLUB
+ select CONSTRUCTORS
help
Enables generic KASAN mode.
@@ -61,8 +73,6 @@ 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).
@@ -70,11 +80,15 @@ config KASAN_SW_TAGS
bool "Software tag-based mode"
depends on HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS
select SLUB_DEBUG if SLUB
+ select CONSTRUCTORS
help
Enables software tag-based KASAN mode.
- This mode requires Top Byte Ignore support by the CPU and therefore
- is only supported for arm64. This mode requires Clang.
+ This mode require software memory tagging support in the form of
+ HWASan-like compiler instrumentation.
+
+ Currently this mode is only implemented for arm64 CPUs and relies on
+ Top Byte Ignore. This mode requires Clang.
This mode consumes about 1/16th of available memory at kernel start
and introduces an overhead of ~20% for the rest of the allocations.
@@ -82,15 +96,27 @@ 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 hardware memory tagging support, and can be used
+ by any architecture that provides it.
+
+ Currently this mode is only implemented for arm64 CPUs starting from
+ ARMv8.5 and relies on Memory Tagging Extension and Top Byte Ignore.
+
endchoice
choice
prompt "Instrumentation type"
+ depends on KASAN_GENERIC || KASAN_SW_TAGS
default KASAN_OUTLINE
config KASAN_OUTLINE
@@ -114,6 +140,7 @@ 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
_
Patches currently in -mm which might be from andreyknvl@xxxxxxxxxx are
