Messages in this thread | | | From | Pingfan Liu <> | Date | Tue, 8 Dec 2020 18:00:12 +0800 | Subject | Re: [PATCH] arm64/irq: report bug if NR_IPI greater than max SGI during compile time |
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On Tue, Dec 8, 2020 at 5:51 PM Marc Zyngier <maz@kernel.org> wrote: > > On 2020-12-08 09:43, Pingfan Liu wrote: > > On Tue, Dec 8, 2020 at 5:31 PM Marc Zyngier <maz@kernel.org> wrote: > >> > >> On 2020-12-08 09:21, Pingfan Liu wrote: > >> > Although there is a runtime WARN_ON() when NR_IPR > max SGI, it had > >> > better > >> > do the check during built time, and associate these related code > >> > together. > >> > > >> > Signed-off-by: Pingfan Liu <kernelfans@gmail.com> > >> > Cc: Catalin Marinas <catalin.marinas@arm.com> > >> > Cc: Will Deacon <will@kernel.org> > >> > Cc: Thomas Gleixner <tglx@linutronix.de> > >> > Cc: Jason Cooper <jason@lakedaemon.net> > >> > Cc: Marc Zyngier <maz@kernel.org> > >> > Cc: Mark Rutland <mark.rutland@arm.com> > >> > To: linux-arm-kernel@lists.infradead.org > >> > Cc: linux-kernel@vger.kernel.org > >> > --- > >> > arch/arm64/kernel/smp.c | 2 ++ > >> > drivers/irqchip/irq-gic-v3.c | 2 +- > >> > drivers/irqchip/irq-gic.c | 2 +- > >> > include/linux/irqchip/arm-gic-common.h | 2 ++ > >> > 4 files changed, 6 insertions(+), 2 deletions(-) > >> > > >> > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c > >> > index 18e9727..9fc383c 100644 > >> > --- a/arch/arm64/kernel/smp.c > >> > +++ b/arch/arm64/kernel/smp.c > >> > @@ -33,6 +33,7 @@ > >> > #include <linux/kernel_stat.h> > >> > #include <linux/kexec.h> > >> > #include <linux/kvm_host.h> > >> > +#include <linux/irqchip/arm-gic-common.h> > >> > > >> > #include <asm/alternative.h> > >> > #include <asm/atomic.h> > >> > @@ -76,6 +77,7 @@ enum ipi_msg_type { > >> > IPI_WAKEUP, > >> > NR_IPI > >> > }; > >> > +static_assert(NR_IPI <= MAX_SGI_NUM); > >> > >> I am trying *very hard* to remove dependencies between the > >> architecture > >> code and random drivers, so this kind of check really is > >> counter-productive. > >> > >> Driver code should not have to know the number of IPIs, because there > >> is > >> no requirement that all IPIs should map 1:1 to SGIs. Conflating the > >> two > > > > Just curious about this. Is there an IPI which is not implemented by > > SGI? Or mapping several IPIs to a single SGI, and scatter out due to a > > global variable value? > > We currently have a single NS SGI left, and I'd like to move some of the > non-critical IPIs over to dispatching mechanism (the two "CPU stop" IPIs > definitely are candidate for merging). That's not implemented yet, but > I don't see a need to add checks that would otherwise violate this > IPI/SGI distinction.
Got it. Thanks for your detailed explanation.
Regards, Pingfan
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