diff options
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/hwcap.h | 1 | ||||
| -rw-r--r-- | arch/arm64/include/asm/mte.h | 22 | ||||
| -rw-r--r-- | arch/arm64/include/asm/processor.h | 1 | ||||
| -rw-r--r-- | arch/arm64/include/uapi/asm/hwcap.h | 1 |
4 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/hwcap.h b/arch/arm64/include/asm/hwcap.h index f68fbb207473..8db5ec0089db 100644 --- a/arch/arm64/include/asm/hwcap.h +++ b/arch/arm64/include/asm/hwcap.h @@ -108,6 +108,7 @@ #define KERNEL_HWCAP_ECV __khwcap2_feature(ECV) #define KERNEL_HWCAP_AFP __khwcap2_feature(AFP) #define KERNEL_HWCAP_RPRES __khwcap2_feature(RPRES) +#define KERNEL_HWCAP_MTE3 __khwcap2_feature(MTE3) /* * This yields a mask that user programs can use to figure out what diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index 075539f5f1c8..adcb937342f1 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -11,7 +11,9 @@ #ifndef __ASSEMBLY__ #include <linux/bitfield.h> +#include <linux/kasan-enabled.h> #include <linux/page-flags.h> +#include <linux/sched.h> #include <linux/types.h> #include <asm/pgtable-types.h> @@ -86,6 +88,26 @@ static inline int mte_ptrace_copy_tags(struct task_struct *child, #endif /* CONFIG_ARM64_MTE */ +static inline void mte_disable_tco_entry(struct task_struct *task) +{ + if (!system_supports_mte()) + return; + + /* + * Re-enable tag checking (TCO set on exception entry). This is only + * necessary if MTE is enabled in either the kernel or the userspace + * task in synchronous or asymmetric mode (SCTLR_EL1.TCF0 bit 0 is set + * for both). With MTE disabled in the kernel and disabled or + * asynchronous in userspace, tag check faults (including in uaccesses) + * are not reported, therefore there is no need to re-enable checking. + * This is beneficial on microarchitectures where re-enabling TCO is + * expensive. + */ + if (kasan_hw_tags_enabled() || + (task->thread.sctlr_user & (1UL << SCTLR_EL1_TCF0_SHIFT))) + asm volatile(SET_PSTATE_TCO(0)); +} + #ifdef CONFIG_KASAN_HW_TAGS /* Whether the MTE asynchronous mode is enabled. */ DECLARE_STATIC_KEY_FALSE(mte_async_or_asymm_mode); diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index 6f41b65f9962..73e38d9a540c 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -21,6 +21,7 @@ #define MTE_CTRL_TCF_SYNC (1UL << 16) #define MTE_CTRL_TCF_ASYNC (1UL << 17) +#define MTE_CTRL_TCF_ASYMM (1UL << 18) #ifndef __ASSEMBLY__ diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index f03731847d9d..99cb5d383048 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -78,5 +78,6 @@ #define HWCAP2_ECV (1 << 19) #define HWCAP2_AFP (1 << 20) #define HWCAP2_RPRES (1 << 21) +#define HWCAP2_MTE3 (1 << 22) #endif /* _UAPI__ASM_HWCAP_H */ |