On Thu, Jan 14, 2021 at 10:24:25AM +0000, Vincenzo Frascino wrote: > On 1/13/21 6:11 PM, Catalin Marinas wrote: > > On Thu, Jan 07, 2021 at 05:29:07PM +0000, Vincenzo Frascino wrote: > >> static inline void mte_sync_tags(pte_t *ptep, pte_t pte) > >> { > >> } > >> diff --git a/arch/arm64/kernel/entry-common.c > >> b/arch/arm64/kernel/entry-common.c > >> index 5346953e4382..74b020ce72d7 100644 > >> --- a/arch/arm64/kernel/entry-common.c > >> +++ b/arch/arm64/kernel/entry-common.c > >> @@ -37,6 +37,8 @@ static void noinstr enter_from_kernel_mode(struct > >> pt_regs *regs) > >> lockdep_hardirqs_off(CALLER_ADDR0); > >> rcu_irq_enter_check_tick(); > >> trace_hardirqs_off_finish(); > >> + > >> + mte_check_tfsr_el1(); > >> } > >> > >> /* > >> @@ -47,6 +49,8 @@ static void noinstr exit_to_kernel_mode(struct pt_regs > >> *regs) > >> { > >> lockdep_assert_irqs_disabled(); > >> > >> + mte_check_tfsr_el1(); > >> + > >> if (interrupts_enabled(regs)) { > >> if (regs->exit_rcu) { > >> trace_hardirqs_on_prepare(); > >> @@ -243,6 +247,8 @@ asmlinkage void noinstr enter_from_user_mode(void) > >> > >> asmlinkage void noinstr exit_to_user_mode(void) > >> { > >> + mte_check_tfsr_el1(); > > > > While for kernel entry the asynchronous faults are sync'ed automatically > > with TFSR_EL1, we don't have this for exit, so we'd need an explicit > > DSB. But rather than placing it here, it's better if we add a bool sync > > argument to mte_check_tfsr_el1() which issues a dsb() before checking > > the register. I think that's the only place where such argument would be > > true (for now). > > Good point, I will add the dsb() in mte_check_tfsr_el1() but instead of a bool > parameter I will add something more explicit.
Or rename the function to mte_check_tfsr_el1_no_sync() and have a static inline mte_check_tfsr_el1() which issues a dsb() before calling the *no_sync variant. Adding an enum instead here is not worth it (if that's what you meant by not using a bool). -- Catalin