Messages in this thread | | | From | Andrey Konovalov <> | Date | Thu, 21 Jan 2021 18:41:07 +0100 | Subject | Re: [PATCH v5 5/6] arm64: mte: Expose execution mode |
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On Thu, Jan 21, 2021 at 5:40 PM Vincenzo Frascino <vincenzo.frascino@arm.com> wrote: > > 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 >
(See my comment on patch #6.)
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