Messages in this thread | | | From | Sumit Garg <> | Date | Wed, 4 Nov 2020 18:18:51 +0530 | Subject | Re: [PATCH v7 1/7] arm64: Add framework to turn IPI as NMI |
| |
On Mon, 2 Nov 2020 at 21:03, Masayoshi Mizuma <msys.mizuma@gmail.com> wrote: > > On Mon, Nov 02, 2020 at 05:14:41PM +0530, Sumit Garg wrote: > > Introduce framework to turn an IPI as NMI using pseudo NMIs. The main > > motivation for this feature is to have an IPI that can be leveraged to > > invoke NMI functions on other CPUs. > > > > And current prospective users are NMI backtrace and KGDB CPUs round-up > > whose support is added via future patches. > > > > Signed-off-by: Sumit Garg <sumit.garg@linaro.org> > > --- > > arch/arm64/include/asm/nmi.h | 17 ++++++++++++ > > arch/arm64/kernel/Makefile | 2 +- > > arch/arm64/kernel/ipi_nmi.c | 65 ++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 83 insertions(+), 1 deletion(-) > > create mode 100644 arch/arm64/include/asm/nmi.h > > create mode 100644 arch/arm64/kernel/ipi_nmi.c > > > > diff --git a/arch/arm64/include/asm/nmi.h b/arch/arm64/include/asm/nmi.h > > new file mode 100644 > > index 0000000..4cd14b6 > > --- /dev/null > > +++ b/arch/arm64/include/asm/nmi.h > > @@ -0,0 +1,17 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +#ifndef __ASM_NMI_H > > +#define __ASM_NMI_H > > + > > +#ifndef __ASSEMBLER__ > > + > > +#include <linux/cpumask.h> > > + > > +extern bool arm64_supports_nmi(void); > > +extern void arm64_send_nmi(cpumask_t *mask); > > + > > +void set_smp_dynamic_ipi(int ipi); > > +void dynamic_ipi_setup(int cpu); > > +void dynamic_ipi_teardown(int cpu); > > + > > +#endif /* !__ASSEMBLER__ */ > > +#endif > > diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile > > index bbaf0bc..525a1e0 100644 > > --- a/arch/arm64/kernel/Makefile > > +++ b/arch/arm64/kernel/Makefile > > @@ -17,7 +17,7 @@ obj-y := debug-monitors.o entry.o irq.o fpsimd.o \ > > return_address.o cpuinfo.o cpu_errata.o \ > > cpufeature.o alternative.o cacheinfo.o \ > > smp.o smp_spin_table.o topology.o smccc-call.o \ > > - syscall.o proton-pack.o > > + syscall.o proton-pack.o ipi_nmi.o > > > > targets += efi-entry.o > > > > diff --git a/arch/arm64/kernel/ipi_nmi.c b/arch/arm64/kernel/ipi_nmi.c > > new file mode 100644 > > index 0000000..a945dcf > > --- /dev/null > > +++ b/arch/arm64/kernel/ipi_nmi.c > > @@ -0,0 +1,65 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * NMI support for IPIs > > + * > > + * Copyright (C) 2020 Linaro Limited > > + * Author: Sumit Garg <sumit.garg@linaro.org> > > + */ > > + > > +#include <linux/interrupt.h> > > +#include <linux/irq.h> > > +#include <linux/smp.h> > > + > > +#include <asm/nmi.h> > > + > > +static struct irq_desc *ipi_nmi_desc __read_mostly; > > +static int ipi_nmi_id __read_mostly; > > + > > +bool arm64_supports_nmi(void) > > +{ > > + if (ipi_nmi_desc) > > + return true; > > + > > + return false; > > +} > > + > > +void arm64_send_nmi(cpumask_t *mask) > > +{ > > + if (WARN_ON_ONCE(!ipi_nmi_desc)) > > + return; > > + > > + __ipi_send_mask(ipi_nmi_desc, mask); > > +} > > + > > +static irqreturn_t ipi_nmi_handler(int irq, void *data) > > +{ > > + /* nop, NMI handlers for special features can be added here. */ > > + > > + return IRQ_NONE; > > +} > > + > > > +void dynamic_ipi_setup(int cpu) > > cpu isn't used here, so void is better? > > void dynamic_ipi_setup(void) >
Ack.
> > +{ > > + if (!ipi_nmi_desc) > > + return; > > + > > + if (!prepare_percpu_nmi(ipi_nmi_id)) > > + enable_percpu_nmi(ipi_nmi_id, IRQ_TYPE_NONE); > > +} > > + > > > +void dynamic_ipi_teardown(int cpu) > > Same as here: > void dynamic_ipi_teardown(void) >
Ack.
> > +{ > > + if (!ipi_nmi_desc) > > + return; > > + > > + disable_percpu_nmi(ipi_nmi_id); > > + teardown_percpu_nmi(ipi_nmi_id); > > +} > > + > > +void __init set_smp_dynamic_ipi(int ipi) > > +{ > > + if (!request_percpu_nmi(ipi, ipi_nmi_handler, "IPI", &cpu_number)) { > > + ipi_nmi_desc = irq_to_desc(ipi); > > + ipi_nmi_id = ipi; > > + } > > +} > > -- > > Otherwise, looks good to me. Please feel free to add: > > Reviewed-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> >
Thanks.
-Sumit
> Thanks, > Masa
| |