Unverified Commit 3908ba2e authored by Nick Hu's avatar Nick Hu Committed by Palmer Dabbelt
Browse files

RISC-V: Enable the IPI before workqueue_online_cpu() 



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: 63c5484e ("workqueue: Add multiple affinity scopes and interface to select them")
Signed-off-by: default avatarNick Hu <nick.hu@sifive.com>
Reviewed-by: default avatarAnup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20240717031714.1946036-1-nick.hu@sifive.com


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent 0c710050

arch/riscv/kernel/sbi-ipi.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -148,6 +148,7 @@ 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,