RISC-V: Enable the IPI before workqueue_online_cpu()

[ Upstream commit 3908ba2e0b2476e2ec13e15967bf6a37e449f2af ]

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: 63c5484e7495 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/riscv/kernel/sbi-ipi.c b/arch/riscv/kernel/sbi-ipi.c
index 1026e22955ccc3a036e33c10bc1dd1324fce3667..0cc5559c08d8ff2c2e8a74bb9bbecfe8f383c104 100644 (file)
--- a/arch/riscv/kernel/sbi-ipi.c
+++ b/arch/riscv/kernel/sbi-ipi.c
@@ -71,7 +71,7 @@ void __init sbi_ipi_init(void)
         * the masking/unmasking of virtual IPIs is done
         * via generic IPI-Mux
         */
-       cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+       cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_SBI_IPI_STARTING,
                          "irqchip/sbi-ipi:starting",
                          sbi_ipi_starting_cpu, NULL);
 

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 7a5785f405b626c4591e796b096d6c081695e855..0a8fd4a3d04c92d5163d9aa3863ac1f33792caef 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -147,6 +147,7 @@ enum cpuhp_state {
        CPUHP_AP_IRQ_LOONGARCH_STARTING,
        CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
        CPUHP_AP_IRQ_RISCV_IMSIC_STARTING,
+       CPUHP_AP_IRQ_RISCV_SBI_IPI_STARTING,
        CPUHP_AP_ARM_MVEBU_COHERENCY,
        CPUHP_AP_PERF_X86_AMD_UNCORE_STARTING,
        CPUHP_AP_PERF_X86_STARTING,