Messages in this thread Patch in this message | | | From | Vincenzo Frascino <> | Subject | [PATCH v12 6/7] arm64: mte: Save/Restore TFSR_EL1 during suspend | Date | Mon, 8 Feb 2021 16:56:16 +0000 |
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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.
Save/restore the state of the TFSR_EL1 register during the suspend/resume operations to prevent this to happen.
Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/include/asm/mte.h | 4 ++++ arch/arm64/kernel/mte.c | 22 ++++++++++++++++++++++ arch/arm64/kernel/suspend.c | 3 +++ 3 files changed, 29 insertions(+)
diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h index 237bb2f7309d..2d79bcaaeb30 100644 --- a/arch/arm64/include/asm/mte.h +++ b/arch/arm64/include/asm/mte.h @@ -43,6 +43,7 @@ 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); @@ -68,6 +69,9 @@ 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 3332aabda466..5c440967721b 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -25,6 +25,7 @@ u64 gcr_kernel_excl __ro_after_init; +static u64 mte_suspend_tfsr_el1; static bool report_fault_once = true; /* Whether the MTE asynchronous mode is enabled. */ @@ -295,12 +296,33 @@ 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 save the state. + */ + dsb(nsh); + isb(); + + /* Save SYS_TFSR_EL1 before suspend entry */ + mte_suspend_tfsr_el1 = read_sysreg_s(SYS_TFSR_EL1); +} + void mte_suspend_exit(void) { if (!system_supports_mte()) return; update_gcr_el1_excl(gcr_kernel_excl); + + /* Resume SYS_TFSR_EL1 after suspend exit */ + write_sysreg_s(mte_suspend_tfsr_el1, SYS_TFSR_EL1); + + mte_check_tfsr_el1(); } long set_mte_ctrl(struct task_struct *task, unsigned long arg) diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c index a67b37a7a47e..16caa9b32dae 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 -- 2.30.0
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