From f3b7deef8dcaf84fd659108ae300626ea5420f87 Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Mon, 15 Mar 2021 13:20:11 +0000 Subject: [PATCH] arm64: mte: Add asynchronous mode support 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: Will Deacon Reviewed-by: Catalin Marinas Reviewed-by: Andrey Konovalov Acked-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Link: https://lore.kernel.org/r/20210315132019.33202-2-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/memory.h | 4 +++- arch/arm64/include/asm/mte-kasan.h | 9 +++++++-- arch/arm64/kernel/mte.c | 16 ++++++++++++++-- 3 files changed, 24 insertions(+), 5 deletions(-) diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 0aabc3be9a75..8fbc8dab044f 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -243,7 +243,9 @@ 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() +#define arch_enable_tagging() arch_enable_tagging_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 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 b3c70a612c7a..fa755cf94e01 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -107,11 +107,23 @@ 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); +} + +void mte_enable_kernel_async(void) +{ + __mte_enable_kernel("asynchronous", SCTLR_ELx_TCF_ASYNC); } void mte_set_report_once(bool state) -- 2.20.1