From eab0e6e17d876381b4d47996eef3b5fd46ea4011 Mon Sep 17 00:00:00 2001 From: Vincenzo Frascino Date: Mon, 15 Mar 2021 13:20:18 +0000 Subject: [PATCH] arm64: mte: Report async tag faults before suspend When MTE async mode is enabled TFSR_EL1 contains the accumulative asynchronous tag check faults for EL1 and EL0. During the suspend/resume operations the firmware might perform some operations that could change the state of the register resulting in a spurious tag check fault report. Report asynchronous tag faults before suspend and clear the TFSR_EL1 register after resume to prevent this to happen. Cc: Will Deacon Cc: Lorenzo Pieralisi Reviewed-by: Catalin Marinas Reviewed-by: Lorenzo Pieralisi Acked-by: Andrey Konovalov Tested-by: Andrey Konovalov Signed-off-by: Vincenzo Frascino Link: https://lore.kernel.org/r/20210315132019.33202-9-vincenzo.frascino@arm.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/mte.h | 4 ++++ arch/arm64/kernel/mte.c | 16 ++++++++++++++++ arch/arm64/kernel/suspend.c | 3 +++ 3 files changed, 23 insertions(+) diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index 9a929620ca5d..a38abc15186c 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -41,6 +41,7 @@ void mte_sync_tags(pte_t *ptep, pte_t pte); void mte_copy_page_tags(void *kto, const void *kfrom); void flush_mte_state(void); void mte_thread_switch(struct task_struct *next); +void mte_suspend_enter(void); void mte_suspend_exit(void); long set_mte_ctrl(struct task_struct *task, unsigned long arg); long get_mte_ctrl(struct task_struct *task); @@ -66,6 +67,9 @@ static inline void flush_mte_state(void) static inline void mte_thread_switch(struct task_struct *next) { } +static inline void mte_suspend_enter(void) +{ +} static inline void mte_suspend_exit(void) { } diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index b6336fbe4c14..820bad94870e 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -265,6 +265,22 @@ void mte_thread_switch(struct task_struct *next) mte_check_tfsr_el1(); } +void mte_suspend_enter(void) +{ + if (!system_supports_mte()) + return; + + /* + * The barriers are required to guarantee that the indirect writes + * to TFSR_EL1 are synchronized before we report the state. + */ + dsb(nsh); + isb(); + + /* Report SYS_TFSR_EL1 before suspend entry */ + mte_check_tfsr_el1(); +} + void mte_suspend_exit(void) { if (!system_supports_mte()) diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c index d7564891ffe1..6fdc8292b4f5 100644 --- a/arch/arm64/kernel/suspend.c +++ b/arch/arm64/kernel/suspend.c @@ -91,6 +91,9 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long)) unsigned long flags; struct sleep_stack_data state; + /* Report any MTE async fault before going to suspend */ + mte_suspend_enter(); + /* * From this point debug exceptions are disabled to prevent * updates to mdscr register (saved and restored along with -- 2.20.1