Messages in this thread Patch in this message | | | From | Yuichi Ito <> | Subject | [PATCH 2/2] Register IPI_CPU_CRASH_STOP IPI as pseudo-NMI | Date | Thu, 24 Sep 2020 13:42:36 +0900 |
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Register IPI_CPU_CRASH_STOP IPI as pseudo-NMI. For systems that do not support pseudo-NMI, register as a normal IRQ.
Signed-off-by: Yuichi Ito <ito-yuichi@fujitsu.com> --- arch/arm64/kernel/smp.c | 39 +++++++++++++++++++++++++++++++-------- 1 file changed, 31 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index b6bde2675ccc..d929dd7221ff 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -79,6 +79,8 @@ enum ipi_msg_type { static int ipi_irq_base __read_mostly; static int nr_ipi __read_mostly = NR_IPI; static struct irq_desc *ipi_desc[NR_IPI] __read_mostly; +static int ipi_crash_stop = -1; +static int ipi_crash_stop_enable_nmi; static void ipi_setup(int cpu); static void ipi_teardown(int cpu); @@ -954,8 +956,16 @@ static void ipi_setup(int cpu) if (WARN_ON_ONCE(!ipi_irq_base)) return; - for (i = 0; i < nr_ipi; i++) - enable_percpu_irq(ipi_irq_base + i, 0); + for (i = 0; i < nr_ipi; i++) { + if (ipi_irq_base + i == ipi_crash_stop) { + if (!prepare_percpu_nmi(ipi_irq_base + i)) { + enable_percpu_nmi(ipi_irq_base + i, 0); + ipi_crash_stop_enable_nmi = 1; + } else + pr_crit("CPU%u: IPI_CPU_CRASH_STOP cannot be enabled NMI.\n", cpu); + } else + enable_percpu_irq(ipi_irq_base + i, 0); + } } static void ipi_teardown(int cpu) @@ -965,23 +975,37 @@ static void ipi_teardown(int cpu) if (WARN_ON_ONCE(!ipi_irq_base)) return; - for (i = 0; i < nr_ipi; i++) - disable_percpu_irq(ipi_irq_base + i); + for (i = 0; i < nr_ipi; i++) { + if (ipi_irq_base + i == ipi_crash_stop) { + if (ipi_crash_stop_enable_nmi) { + disable_percpu_nmi(ipi_irq_base + i); + teardown_percpu_nmi(ipi_irq_base + i); + } + } else + disable_percpu_irq(ipi_irq_base + i); + } } void __init set_smp_ipi_range(int ipi_base, int n) { - int i; + int i, ret; WARN_ON(n < NR_IPI); nr_ipi = min(n, NR_IPI); + ret = request_percpu_nmi(ipi_base + IPI_CPU_CRASH_STOP, + ipi_handler, "IPI", &cpu_number); + if (!ret) + ipi_crash_stop = ipi_base + IPI_CPU_CRASH_STOP; + for (i = 0; i < nr_ipi; i++) { int err; - err = request_percpu_irq(ipi_base + i, ipi_handler, - "IPI", &cpu_number); - WARN_ON(err); + if (ipi_base + i != ipi_crash_stop) { + err = request_percpu_irq(ipi_base + i, ipi_handler, + "IPI", &cpu_number); + WARN_ON(err); + } ipi_desc[i] = irq_to_desc(ipi_base + i); irq_set_status_flags(ipi_base + i, IRQ_HIDDEN); -- 2.25.1
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