Commit eab0e6e1 authored by Vincenzo Frascino's avatar Vincenzo Frascino Committed by Catalin Marinas
Browse files

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 <will@kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Reviewed-by: default avatarLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Tested-by: default avatarAndrey Konovalov <andreyknvl@google.com>
Signed-off-by: default avatarVincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20210315132019.33202-9-vincenzo.frascino@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 65812c69

arch/arm64/include/asm/mte.h

+4 −0
Original line number Diff line number Diff line
@@ -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)

{

}

arch/arm64/kernel/mte.c

+16 −0
Original line number Diff line number Diff line
@@ -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())

arch/arm64/kernel/suspend.c

+3 −0
Original line number Diff line number Diff line
@@ -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