Messages in this thread | | | Date | Fri, 19 Feb 2021 18:26:41 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH 7/8 v1.5] arm64: Always keep DAIF.[IF] in sync |
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On Sat, Feb 20, 2021 at 02:25:30AM +0900, Hector Martin wrote: > Apple SoCs (A11 and newer) have some interrupt sources hardwired to the > FIQ line. We implement support for this by simply treating IRQs and FIQs > the same way in the interrupt vectors. > > To support these systems, the FIQ mask bit needs to be kept in sync with > the IRQ mask bit, so both kinds of exceptions are masked together. No > other platforms should be delivering FIQ exceptions right now, and we > already unmask FIQ in normal process context, so this should not have an > effect on other systems - if spurious FIQs were arriving, they would > already panic the kernel.
This looks good to me; I've picked this up and pushed out my arm64/fiq branch [1,2] incorporating this, tagged as arm64-fiq-20210219.
I'll give this version a few days to gather comments before I post a v2.
[1] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git arm64/fiq [2] https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/log/?h=arm64/fiqA
Thanks, Mark.
> > Signed-off-by: Hector Martin <marcan@marcan.st> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: James Morse <james.morse@arm.com> > Cc: Marc Zyngier <maz@kernel.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Will Deacon <will@kernel.org> > > --- > arch/arm64/include/asm/arch_gicv3.h | 2 +- > arch/arm64/include/asm/assembler.h | 8 ++++---- > arch/arm64/include/asm/daifflags.h | 10 +++++----- > arch/arm64/include/asm/irqflags.h | 16 +++++++--------- > arch/arm64/kernel/entry.S | 12 +++++++----- > arch/arm64/kernel/process.c | 2 +- > arch/arm64/kernel/smp.c | 1 + > 7 files changed, 26 insertions(+), 25 deletions(-) > > This is the updated patch after addressing the comments in the original > v2 review; we're moving it to this series now, so please review it in > this context. > > diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h > index 880b9054d75c..934b9be582d2 100644 > --- a/arch/arm64/include/asm/arch_gicv3.h > +++ b/arch/arm64/include/asm/arch_gicv3.h > @@ -173,7 +173,7 @@ static inline void gic_pmr_mask_irqs(void) > > static inline void gic_arch_enable_irqs(void) > { > - asm volatile ("msr daifclr, #2" : : : "memory"); > + asm volatile ("msr daifclr, #3" : : : "memory"); > } > > #endif /* __ASSEMBLY__ */ > diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h > index bf125c591116..53ff8c71eed7 100644 > --- a/arch/arm64/include/asm/assembler.h > +++ b/arch/arm64/include/asm/assembler.h > @@ -40,9 +40,9 @@ > msr daif, \flags > .endm > > - /* IRQ is the lowest priority flag, unconditionally unmask the rest. */ > - .macro enable_da_f > - msr daifclr, #(8 | 4 | 1) > + /* IRQ/FIQ are the lowest priority flags, unconditionally unmask the rest. */ > + .macro enable_da > + msr daifclr, #(8 | 4) > .endm > > /* > @@ -50,7 +50,7 @@ > */ > .macro save_and_disable_irq, flags > mrs \flags, daif > - msr daifset, #2 > + msr daifset, #3 > .endm > > .macro restore_irq, flags > diff --git a/arch/arm64/include/asm/daifflags.h b/arch/arm64/include/asm/daifflags.h > index 1c26d7baa67f..5eb7af9c4557 100644 > --- a/arch/arm64/include/asm/daifflags.h > +++ b/arch/arm64/include/asm/daifflags.h > @@ -13,8 +13,8 @@ > #include <asm/ptrace.h> > > #define DAIF_PROCCTX 0 > -#define DAIF_PROCCTX_NOIRQ PSR_I_BIT > -#define DAIF_ERRCTX (PSR_I_BIT | PSR_A_BIT) > +#define DAIF_PROCCTX_NOIRQ (PSR_I_BIT | PSR_F_BIT) > +#define DAIF_ERRCTX (PSR_A_BIT | PSR_I_BIT | PSR_F_BIT) > #define DAIF_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT) > > > @@ -47,7 +47,7 @@ static inline unsigned long local_daif_save_flags(void) > if (system_uses_irq_prio_masking()) { > /* If IRQs are masked with PMR, reflect it in the flags */ > if (read_sysreg_s(SYS_ICC_PMR_EL1) != GIC_PRIO_IRQON) > - flags |= PSR_I_BIT; > + flags |= PSR_I_BIT | PSR_F_BIT; > } > > return flags; > @@ -69,7 +69,7 @@ static inline void local_daif_restore(unsigned long flags) > bool irq_disabled = flags & PSR_I_BIT; > > WARN_ON(system_has_prio_mask_debugging() && > - !(read_sysreg(daif) & PSR_I_BIT)); > + (read_sysreg(daif) & (PSR_I_BIT | PSR_F_BIT)) != (PSR_I_BIT | PSR_F_BIT)); > > if (!irq_disabled) { > trace_hardirqs_on(); > @@ -86,7 +86,7 @@ static inline void local_daif_restore(unsigned long flags) > * If interrupts are disabled but we can take > * asynchronous errors, we can take NMIs > */ > - flags &= ~PSR_I_BIT; > + flags &= ~(PSR_I_BIT | PSR_F_BIT); > pmr = GIC_PRIO_IRQOFF; > } else { > pmr = GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET; > diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h > index ff328e5bbb75..b57b9b1e4344 100644 > --- a/arch/arm64/include/asm/irqflags.h > +++ b/arch/arm64/include/asm/irqflags.h > @@ -12,15 +12,13 @@ > > /* > * Aarch64 has flags for masking: Debug, Asynchronous (serror), Interrupts and > - * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'dai' > + * FIQ exceptions, in the 'daif' register. We mask and unmask them in 'daif' > * order: > * Masking debug exceptions causes all other exceptions to be masked too/ > - * Masking SError masks irq, but not debug exceptions. Masking irqs has no > - * side effects for other flags. Keeping to this order makes it easier for > - * entry.S to know which exceptions should be unmasked. > - * > - * FIQ is never expected, but we mask it when we disable debug exceptions, and > - * unmask it at all other times. > + * Masking SError masks IRQ/FIQ, but not debug exceptions. IRQ and FIQ are > + * always masked and unmasked together, and have no side effects for other > + * flags. Keeping to this order makes it easier for entry.S to know which > + * exceptions should be unmasked. > */ > > /* > @@ -35,7 +33,7 @@ static inline void arch_local_irq_enable(void) > } > > asm volatile(ALTERNATIVE( > - "msr daifclr, #2 // arch_local_irq_enable", > + "msr daifclr, #3 // arch_local_irq_enable", > __msr_s(SYS_ICC_PMR_EL1, "%0"), > ARM64_HAS_IRQ_PRIO_MASKING) > : > @@ -54,7 +52,7 @@ static inline void arch_local_irq_disable(void) > } > > asm volatile(ALTERNATIVE( > - "msr daifset, #2 // arch_local_irq_disable", > + "msr daifset, #3 // arch_local_irq_disable", > __msr_s(SYS_ICC_PMR_EL1, "%0"), > ARM64_HAS_IRQ_PRIO_MASKING) > : > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > index acc677672277..af04ce5088ca 100644 > --- a/arch/arm64/kernel/entry.S > +++ b/arch/arm64/kernel/entry.S > @@ -533,7 +533,7 @@ alternative_endif > > .macro el1_interrupt_handler, handler:req > gic_prio_irq_setup pmr=x20, tmp=x1 > - enable_da_f > + enable_da > > mov x0, sp > bl enter_el1_irq_or_nmi > @@ -544,8 +544,10 @@ alternative_endif > ldr x24, [tsk, #TSK_TI_PREEMPT] // get preempt count > alternative_if ARM64_HAS_IRQ_PRIO_MASKING > /* > - * DA_F were cleared at start of handling. If anything is set in DAIF, > - * we come back from an NMI, so skip preemption > + * DA were cleared at start of handling, and IF are cleared by > + * the GIC irqchip driver using gic_arch_enable_irqs() for > + * normal IRQs. If anything is set, it means we come back from > + * an NMI instead of a normal IRQ, so skip preemption > */ > mrs x0, daif > orr x24, x24, x0 > @@ -562,7 +564,7 @@ alternative_else_nop_endif > .macro el0_interrupt_handler, handler:req > gic_prio_irq_setup pmr=x20, tmp=x0 > user_exit_irqoff > - enable_da_f > + enable_da > > tbz x22, #55, 1f > bl do_el0_irq_bp_hardening > @@ -763,7 +765,7 @@ el0_error_naked: > mov x0, sp > mov x1, x25 > bl do_serror > - enable_da_f > + enable_da > b ret_to_user > SYM_CODE_END(el0_error) > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > index 6616486a58fe..34ec400288d0 100644 > --- a/arch/arm64/kernel/process.c > +++ b/arch/arm64/kernel/process.c > @@ -84,7 +84,7 @@ static void noinstr __cpu_do_idle_irqprio(void) > unsigned long daif_bits; > > daif_bits = read_sysreg(daif); > - write_sysreg(daif_bits | PSR_I_BIT, daif); > + write_sysreg(daif_bits | PSR_I_BIT | PSR_F_BIT, daif); > > /* > * Unmask PMR before going idle to make sure interrupts can > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > index ad00f99ee9b0..9dee8a17b1ac 100644 > --- a/arch/arm64/kernel/smp.c > +++ b/arch/arm64/kernel/smp.c > @@ -188,6 +188,7 @@ static void init_gic_priority_masking(void) > cpuflags = read_sysreg(daif); > > WARN_ON(!(cpuflags & PSR_I_BIT)); > + WARN_ON(!(cpuflags & PSR_F_BIT)); > > gic_write_pmr(GIC_PRIO_IRQON | GIC_PRIO_PSR_I_SET); > } > -- > 2.30.0 >
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