Re: [PATCH v3 18/23] arm64: mte: Restore the GCR_EL1 register after a suspend

Lorenzo Pieralisi
2020-04-23T15:24:00Z

On Tue, Apr 21, 2020 at 03:25:58PM +0100, Catalin Marinas wrote:
> The CPU resume/suspend routines only take care of the common system
> registers. Restore GCR_EL1 in addition via the __cpu_suspend_exit()
> function.
>
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
> ---
>
> Notes:
> New in v3.
>
> arch/arm64/include/asm/mte.h | 4 ++++
> arch/arm64/kernel/mte.c | 8 ++++++++
> arch/arm64/kernel/suspend.c | 4 ++++
> 3 files changed, 16 insertions(+)

Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

> diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h
> index 3dc0a7977124..22eb3e06f311 100644
> --- a/arch/arm64/include/asm/mte.h
> +++ b/arch/arm64/include/asm/mte.h
> @@ -12,6 +12,7 @@ int mte_memcmp_pages(const void *page1_addr, const void *page2_addr);
> #ifdef CONFIG_ARM64_MTE
> void flush_mte_state(void);
> void mte_thread_switch(struct task_struct *next);
> +void mte_suspend_exit(void);
> long set_mte_ctrl(unsigned long arg);
> long get_mte_ctrl(void);
> #else
> @@ -21,6 +22,9 @@ static inline void flush_mte_state(void)
> static inline void mte_thread_switch(struct task_struct *next)
> {
> }
> +static inline void mte_suspend_exit(void)
> +{
> +}
> static inline long set_mte_ctrl(unsigned long arg)
> {
> return 0;
> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
> index 212b9fac294d..fa4a4196b248 100644
> --- a/arch/arm64/kernel/mte.c
> +++ b/arch/arm64/kernel/mte.c
> @@ -76,6 +76,14 @@ void mte_thread_switch(struct task_struct *next)
> update_gcr_el1_excl(next->thread.gcr_incl);
> }
>
> +void mte_suspend_exit(void)
> +{
> + if (!system_supports_mte())
> + return;
> +
> + update_gcr_el1_excl(current->thread.gcr_incl);
> +}
> +
> long set_mte_ctrl(unsigned long arg)
> {
> u64 tcf0;
> diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c
> index 9405d1b7f4b0..1d405b73d009 100644
> --- a/arch/arm64/kernel/suspend.c
> +++ b/arch/arm64/kernel/suspend.c
> @@ -9,6 +9,7 @@
> #include <asm/daifflags.h>
> #include <asm/debug-monitors.h>
> #include <asm/exec.h>
> +#include <asm/mte.h>
> #include <asm/pgtable.h>
> #include <asm/memory.h>
> #include <asm/mmu_context.h>
> @@ -74,6 +75,9 @@ void notrace __cpu_suspend_exit(void)
> */
> if (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE)
> arm64_set_ssbd_mitigation(false);
> +
> + /* Restore additional MTE-specific configuration */
> + mte_suspend_exit();
> }
>
> /*