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FROMGIT: arm64: mte: Report async tag faults before suspend

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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.

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: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20210315132019.33202-9-vincenzo.frascino@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Bug: 170327579
Bug: 172318110
(cherry picked from commit eab0e6e17d
 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/
 for-next/mte-async-kernel-mode)
Signed-off-by: Alexander Potapenko <glider@google.com>
Change-Id: I16efc3a886e57ac2f0a4f8a1bc70afcf17a86f26
This commit is contained in:
Vincenzo Frascino 2021-03-15 13:20:18 +00:00 • committed by Alexander Potapenko
commit d5a19199c7
3 changed files with 23 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

4
arch/arm64/include/asm/mte.h
View file

@ -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)
{
}

16
arch/arm64/kernel/mte.c
View file

@ -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())

3
arch/arm64/kernel/suspend.c
View file

@ -92,6 +92,9 @@ 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