3908ba2e0b
Sometimes the hotplug cpu stalls at the arch_cpu_idle() for a while after
workqueue_online_cpu(). When cpu stalls at the idle loop, the reschedule
IPI is pending. However the enable bit is not enabled yet so the cpu stalls
at WFI until watchdog timeout. Therefore enable the IPI before the
workqueue_online_cpu() to fix the issue.
Fixes: 63c5484e74 ("workqueue: Add multiple affinity scopes and interface to select them")
Signed-off-by: Nick Hu <nick.hu@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20240717031714.1946036-1-nick.hu@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
87 lines
1.9 KiB
C
87 lines
1.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Multiplex several IPIs over a single HW IPI.
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*
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* Copyright (c) 2022 Ventana Micro Systems Inc.
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*/
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#define pr_fmt(fmt) "riscv: " fmt
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#include <linux/cpu.h>
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#include <linux/init.h>
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#include <linux/irq.h>
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#include <linux/irqchip/chained_irq.h>
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#include <linux/irqdomain.h>
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#include <asm/sbi.h>
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DEFINE_STATIC_KEY_FALSE(riscv_sbi_for_rfence);
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EXPORT_SYMBOL_GPL(riscv_sbi_for_rfence);
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static int sbi_ipi_virq;
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static void sbi_ipi_handle(struct irq_desc *desc)
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{
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struct irq_chip *chip = irq_desc_get_chip(desc);
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chained_irq_enter(chip, desc);
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csr_clear(CSR_IP, IE_SIE);
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ipi_mux_process();
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chained_irq_exit(chip, desc);
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}
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static int sbi_ipi_starting_cpu(unsigned int cpu)
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{
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enable_percpu_irq(sbi_ipi_virq, irq_get_trigger_type(sbi_ipi_virq));
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return 0;
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}
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void __init sbi_ipi_init(void)
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{
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int virq;
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struct irq_domain *domain;
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if (riscv_ipi_have_virq_range())
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return;
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domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(),
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DOMAIN_BUS_ANY);
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if (!domain) {
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pr_err("unable to find INTC IRQ domain\n");
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return;
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}
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sbi_ipi_virq = irq_create_mapping(domain, RV_IRQ_SOFT);
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if (!sbi_ipi_virq) {
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pr_err("unable to create INTC IRQ mapping\n");
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return;
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}
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virq = ipi_mux_create(BITS_PER_BYTE, sbi_send_ipi);
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if (virq <= 0) {
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pr_err("unable to create muxed IPIs\n");
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irq_dispose_mapping(sbi_ipi_virq);
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return;
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}
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irq_set_chained_handler(sbi_ipi_virq, sbi_ipi_handle);
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/*
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* Don't disable IPI when CPU goes offline because
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* the masking/unmasking of virtual IPIs is done
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* via generic IPI-Mux
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*/
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cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_SBI_IPI_STARTING,
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"irqchip/sbi-ipi:starting",
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sbi_ipi_starting_cpu, NULL);
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riscv_ipi_set_virq_range(virq, BITS_PER_BYTE);
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pr_info("providing IPIs using SBI IPI extension\n");
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/*
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* Use the SBI remote fence extension to avoid
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* the extra context switch needed to handle IPIs.
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*/
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static_branch_enable(&riscv_sbi_for_rfence);
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}
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