Message ID | 20210219172530.45805-1-marcan@marcan.st (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | None | expand |
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 >
On 20/02/2021 03.26, Mark Rutland wrote: > 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! Any chance you can do a rebase on top of torvalds/master? Since Marc's nVHE changes went in, we're going to need to add a workaround patch for the M1's lack of nVHE mode, which is going to be in the next version of my M1 bringup series - but right now that would involve telling people to merge two trees to build a base to apply it on, which is sub-optimal.
On Tue, Feb 23, 2021 at 02:39:11AM +0900, Hector Martin wrote: > On 20/02/2021 03.26, Mark Rutland wrote: > > 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! Any chance you can do a rebase on top of torvalds/master? Since > Marc's nVHE changes went in, we're going to need to add a workaround patch > for the M1's lack of nVHE mode, which is going to be in the next version of > my M1 bringup series - but right now that would involve telling people to > merge two trees to build a base to apply it on, which is sub-optimal. I generally try to base on a stable tag/commit, so I'd prefer to avoid rebasing the development branch until rc1 if possible. I've pushed out a new arm64-fiq-mainline-20210222 tag rebased atop torvalds/master: git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git arm64-fiq-mainline-20210222 https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/tag/?h=arm64-fiq-mainline-20210222 ... leaving the main branch atop v5.11. Is that good enough for now? If that's painful for development I can shuffle the main branch along too. Thanks, Mark.
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); }
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. 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. -- 2.30.0