Messages in this thread Patch in this message | | | From | Vincenzo Frascino <> | Subject | [PATCH v5 5/6] arm64: mte: Expose execution mode | Date | Thu, 21 Jan 2021 16:39:42 +0000 |
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MTE enabled arm64 HW can be configured in synchronous or asynchronous tagging mode of execution. In synchronous mode, an exception is triggered if a tag check fault occurs. In asynchronous mode, if a tag check fault occurs, the TFSR_EL1 register is updated asynchronously. The kernel checks the corresponding bits periodically.
Introduce an API that exposes the mode of execution to the kernel.
Note: This API will be used by KASAN KUNIT tests to forbid the execution when async mode is enable.
Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/include/asm/memory.h | 1 + arch/arm64/include/asm/mte-kasan.h | 6 ++++++ arch/arm64/kernel/mte.c | 8 ++++++++ 3 files changed, 15 insertions(+)
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index df96b9c10b81..1d4eef519fa6 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -233,6 +233,7 @@ static inline const void *__tag_set(const void *addr, u8 tag) #ifdef CONFIG_KASAN_HW_TAGS #define arch_enable_tagging_sync() mte_enable_kernel_sync() #define arch_enable_tagging_async() mte_enable_kernel_async() +#define arch_is_mode_sync() mte_is_mode_sync() #define arch_set_tagging_report_once(state) mte_set_report_once(state) #define arch_init_tags(max_tag) mte_init_tags(max_tag) #define arch_get_random_tag() mte_get_random_tag() diff --git a/arch/arm64/include/asm/mte-kasan.h b/arch/arm64/include/asm/mte-kasan.h index 76b6a5988ce5..c216160e805c 100644 --- a/arch/arm64/include/asm/mte-kasan.h +++ b/arch/arm64/include/asm/mte-kasan.h @@ -31,6 +31,7 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag); void mte_enable_kernel_sync(void); void mte_enable_kernel_async(void); +bool mte_is_mode_sync(void); void mte_init_tags(u64 max_tag); void mte_set_report_once(bool state); @@ -64,6 +65,11 @@ static inline void mte_enable_kernel_sync(void) { } +static inline bool mte_is_mode_sync(void) +{ + return false; +} + static inline void mte_init_tags(u64 max_tag) { } diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index 7763ac1f2917..1cc3fc173b97 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -26,6 +26,7 @@ u64 gcr_kernel_excl __ro_after_init; static bool report_fault_once = true; +static bool __mte_mode_sync = true; static void mte_sync_page_tags(struct page *page, pte_t *ptep, bool check_swap) { @@ -169,9 +170,16 @@ void mte_enable_kernel_sync(void) void mte_enable_kernel_async(void) { + __mte_mode_sync = false; + __mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC); } +bool mte_is_mode_sync(void) +{ + return __mte_mode_sync; +} + void mte_set_report_once(bool state) { WRITE_ONCE(report_fault_once, state); -- 2.30.0
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