Linux-Kernel Archive: Re: [PATCH v2 03/12] irqchip: mips-gic: Introduce gic_with_each_online_cpu() Re: [PATCH v2 03/12] irqchip: mips-gic: Introduce gic_with_each_online_cpu() From: Marc Zyngier Date: Mon Jun 06 2022 - 09:05:51 EST Next message: Michael Ellerman: "Re: [PATCH v1] kernel/reboot: Change registration order of legacy power-off handler" Previous message: Qi Liu: "[PATCH v6 2/2] Documentation: Add document for UltraSoc SMB drivers" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ] On Wed, 25 May 2022 13:10:21 +0100, Dragan Mladjenovic
wrote: > > From: Paul Burton > > A few pieces of code in the MIPS GIC driver operate on the GIC local > register block for each online CPU, accessing each via the GIC's > other/redirect register block. This patch abstracts the process of > iterating over online CPUs & configuring the other/redirect region to > access their registers through a new gic_with_each_online_cpu() macro. > > This simplifies users of the new macro slightly, and more importantly > prepares us for handling multi-cluster systems where the register > configuration will be done via the CM's GCR_CL_REDIRECT register. By > abstracting all other/redirect block configuration through this macro, > and the __gic_with_next_online_cpu() function which backs it, users will > trivially gain support for multi-cluster when it is implemented in > __gic_with_next_online_cpu(). > > Signed-off-by: Paul Burton > Signed-off-by: Chao-ying Fu > Signed-off-by: Dragan Mladjenovic > > diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c > index ff89b36267dd..4872bebe24cf 100644 > --- a/drivers/irqchip/irq-mips-gic.c > +++ b/drivers/irqchip/irq-mips-gic.c > @@ -65,6 +65,45 @@ static struct gic_all_vpes_chip_data { > bool mask; > } gic_all_vpes_chip_data[GIC_NUM_LOCAL_INTRS]; > > +static int __gic_with_next_online_cpu(int prev) > +{ > + unsigned int cpu; > + > + /* Discover the next online CPU */ > + cpu = cpumask_next(prev, cpu_online_mask); > + > + /* If there isn't one, we're done */ > + if (cpu >= nr_cpu_ids) > + return cpu; > + > + /* > + * Lock access to the next CPU's GIC local register block. > + * > + * In the single cluster case we simply set GIC_VL_OTHER. The caller > + * holds gic_lock so nothing can clobber the value we write. > + */ > + write_gic_vl_other(mips_cm_vp_id(cpu)); > + > + return cpu; > +} > + > +/** > + * gic_with_each_online_cpu() - Iterate over online CPUs, access local registers > + * @cpu: An integer variable to hold the current CPU number > + * > + * Iterate over online CPUs & configure the other/redirect register region to > + * access each CPUs GIC local register block, which can be accessed from the > + * loop body using read_gic_vo_*() or write_gic_vo_*() accessor functions or > + * their derivatives. > + * > + * The caller must hold gic_lock throughout the loop, such that GIC_VL_OTHER > + * cannot be clobbered. > + */ > +#define gic_with_each_online_cpu(cpu) \ nit: please keep the kernel convention of using 'for_each'. This makes it far easier to grep for such iterators when doing bulk refactoring. Also, since there is a requirement to hold the gic_lock, please add a lockdep_assert_held() in the loop so that it can be checked with a lockdep kernel. > + for ((cpu) = __gic_with_next_online_cpu(-1); \ > + (cpu) = __gic_with_next_online_cpu(cpu), \ > + (cpu) < nr_cpu_ids;) > + > static void gic_clear_pcpu_masks(unsigned int intr) > { > unsigned int i; > @@ -357,10 +396,8 @@ static void gic_mask_local_irq_all_vpes(struct irq_data *d) > cd->mask = false; > > spin_lock_irqsave(&gic_lock, flags); > - for_each_online_cpu(cpu) { > - write_gic_vl_other(mips_cm_vp_id(cpu)); > + gic_with_each_online_cpu(cpu) > write_gic_vo_rmask(BIT(intr)); > - } > spin_unlock_irqrestore(&gic_lock, flags); > } > > @@ -375,10 +412,8 @@ static void gic_unmask_local_irq_all_vpes(struct irq_data *d) > cd->mask = true; > > spin_lock_irqsave(&gic_lock, flags); > - for_each_online_cpu(cpu) { > - write_gic_vl_other(mips_cm_vp_id(cpu)); > + gic_with_each_online_cpu(cpu) > write_gic_vo_smask(BIT(intr)); > - } > spin_unlock_irqrestore(&gic_lock, flags); > } > > @@ -532,10 +567,8 @@ static int gic_irq_domain_map(struct irq_domain *d, unsigned int virq, > return -EPERM; > > spin_lock_irqsave(&gic_lock, flags); > - for_each_online_cpu(cpu) { > - write_gic_vl_other(mips_cm_vp_id(cpu)); > + gic_with_each_online_cpu(cpu) > write_gic_vo_map(mips_gic_vx_map_reg(intr), map); > - } > spin_unlock_irqrestore(&gic_lock, flags); > > return 0; Thanks, M. -- Without deviation from the norm, progress is not possible. Next message: Michael Ellerman: "Re: [PATCH v1] kernel/reboot: Change registration order of legacy power-off handler" Previous message: Qi Liu: "[PATCH v6 2/2] Documentation: Add document for UltraSoc SMB drivers" Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
