On 2/12/21 9:21 PM, Andrey Konovalov wrote: > On Thu, Feb 11, 2021 at 4:34 PM Vincenzo Frascino > <vincenzo.frasc...@arm.com> wrote: >> >> MTE provides an asynchronous mode for detecting tag exceptions. In >> particular instead of triggering a fault the arm64 core updates a >> register which is checked by the kernel after the asynchronous tag >> check fault has occurred. >> >> Add support for MTE asynchronous mode. >> >> The exception handling mechanism will be added with a future patch. >> >> Note: KASAN HW activates async mode via kasan.mode kernel parameter. >> The default mode is set to synchronous. >> The code that verifies the status of TFSR_EL1 will be added with a >> future patch. >> >> Cc: Catalin Marinas <catalin.mari...@arm.com> >> Cc: Will Deacon <w...@kernel.org> >> Reviewed-by: Catalin Marinas <catalin.mari...@arm.com> >> Reviewed-by: Andrey Konovalov <andreyk...@google.com> >> Signed-off-by: Vincenzo Frascino <vincenzo.frasc...@arm.com> >> --- >> arch/arm64/include/asm/memory.h | 3 ++- >> arch/arm64/include/asm/mte-kasan.h | 9 +++++++-- >> arch/arm64/kernel/mte.c | 19 ++++++++++++++++--- >> 3 files changed, 25 insertions(+), 6 deletions(-) >> >> diff --git a/arch/arm64/include/asm/memory.h >> b/arch/arm64/include/asm/memory.h >> index c759faf7a1ff..91515383d763 100644 >> --- a/arch/arm64/include/asm/memory.h >> +++ b/arch/arm64/include/asm/memory.h >> @@ -243,7 +243,8 @@ static inline const void *__tag_set(const void *addr, u8 >> tag) >> } >> >> #ifdef CONFIG_KASAN_HW_TAGS >> -#define arch_enable_tagging() mte_enable_kernel() >> +#define arch_enable_tagging_sync() mte_enable_kernel_sync() >> +#define arch_enable_tagging_async() mte_enable_kernel_async() > > We need to update KASAN usage of arch_enable_tagging() to > arch_enable_tagging_sync() in this patch as well. Otherwise, this > leaves KASAN broken between this patch and the next one. >
Yes you are right, still can't explain why it did bysect cleanly though. I will introduce temporarily here: #define arch_enable_tagging() arch_enable_tagging_sync() and remove it again in the respective kasan patch. > >> #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 7ab500e2ad17..4acf8bf41cad 100644 >> --- a/arch/arm64/include/asm/mte-kasan.h >> +++ b/arch/arm64/include/asm/mte-kasan.h >> @@ -77,7 +77,8 @@ static inline void mte_set_mem_tag_range(void *addr, >> size_t size, u8 tag) >> } while (curr != end); >> } >> >> -void mte_enable_kernel(void); >> +void mte_enable_kernel_sync(void); >> +void mte_enable_kernel_async(void); >> void mte_init_tags(u64 max_tag); >> >> void mte_set_report_once(bool state); >> @@ -104,7 +105,11 @@ static inline void mte_set_mem_tag_range(void *addr, >> size_t size, u8 tag) >> { >> } >> >> -static inline void mte_enable_kernel(void) >> +static inline void mte_enable_kernel_sync(void) >> +{ >> +} >> + >> +static inline void mte_enable_kernel_async(void) >> { >> } >> >> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c >> index a66c2806fc4d..706b7ab75f31 100644 >> --- a/arch/arm64/kernel/mte.c >> +++ b/arch/arm64/kernel/mte.c >> @@ -107,13 +107,26 @@ void mte_init_tags(u64 max_tag) >> write_sysreg_s(SYS_GCR_EL1_RRND | gcr_kernel_excl, SYS_GCR_EL1); >> } >> >> -void mte_enable_kernel(void) >> +static inline void __mte_enable_kernel(const char *mode, unsigned long tcf) >> { >> /* Enable MTE Sync Mode for EL1. */ >> - sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC); >> + sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, tcf); >> isb(); >> + >> + pr_info_once("MTE: enabled in %s mode at EL1\n", mode); >> +} >> + >> +void mte_enable_kernel_sync(void) >> +{ >> + __mte_enable_kernel("synchronous", SCTLR_ELx_TCF_SYNC); >> +} >> +EXPORT_SYMBOL_GPL(mte_enable_kernel_sync); >> + >> +void mte_enable_kernel_async(void) >> +{ >> + __mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC); >> } >> -EXPORT_SYMBOL_GPL(mte_enable_kernel); >> +EXPORT_SYMBOL_GPL(mte_enable_kernel_async); >> >> void mte_set_report_once(bool state) >> { >> -- >> 2.30.0 >> -- Regards, Vincenzo