| Message ID | 20210121163943.9889-6-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: ARMv8.5-A: MTE: Add async mode support | expand |
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.)
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);
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(+)