LoongArch: Add irq_work support via self IPIs

Add irq_work support for LoongArch via self IPIs. This make it possible
to run works in hardware interrupt context, which is a prerequisite for
NOHZ_FULL.

Implement:
 - arch_irq_work_raise()
 - arch_irq_work_has_interrupt()

Reviewed-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

diff --git a/arch/loongarch/include/asm/hardirq.h b/arch/loongarch/include/asm/hardirq.h
index d41138abcf26d60f75c4d5ebe74d9abd9e38afc7..1d7feb7195157206d6fa22ec756749c90d50d7b9 100644 (file)
--- a/arch/loongarch/include/asm/hardirq.h
+++ b/arch/loongarch/include/asm/hardirq.h
@@ -12,11 +12,12 @@
 extern void ack_bad_irq(unsigned int irq);
 #define ack_bad_irq ack_bad_irq
 
-#define NR_IPI 2
+#define NR_IPI 3
 
 enum ipi_msg_type {
        IPI_RESCHEDULE,
        IPI_CALL_FUNCTION,
+       IPI_IRQ_WORK,
 };
 
 typedef struct {

diff --git a/arch/loongarch/include/asm/irq_work.h b/arch/loongarch/include/asm/irq_work.h
new file mode 100644 (file)
index 0000000..d63076e
--- /dev/null
+++ b/arch/loongarch/include/asm/irq_work.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_LOONGARCH_IRQ_WORK_H
+#define _ASM_LOONGARCH_IRQ_WORK_H
+
+static inline bool arch_irq_work_has_interrupt(void)
+{
+       return IS_ENABLED(CONFIG_SMP);
+}
+
+#endif /* _ASM_LOONGARCH_IRQ_WORK_H */

diff --git a/arch/loongarch/include/asm/smp.h b/arch/loongarch/include/asm/smp.h
index 278700cfee887b024c230e5fc4de5c4bac822b45..50db503f44e3c754ed0703e76d82075d3f020031 100644 (file)
--- a/arch/loongarch/include/asm/smp.h
+++ b/arch/loongarch/include/asm/smp.h
@@ -69,9 +69,11 @@ extern int __cpu_logical_map[NR_CPUS];
 #define ACTION_BOOT_CPU        0
 #define ACTION_RESCHEDULE      1
 #define ACTION_CALL_FUNCTION   2
+#define ACTION_IRQ_WORK                3
 #define SMP_BOOT_CPU           BIT(ACTION_BOOT_CPU)
 #define SMP_RESCHEDULE         BIT(ACTION_RESCHEDULE)
 #define SMP_CALL_FUNCTION      BIT(ACTION_CALL_FUNCTION)
+#define SMP_IRQ_WORK           BIT(ACTION_IRQ_WORK)
 
 struct secondary_data {
        unsigned long stack;

diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
index 1633ed4f692f603c26dea62bea9c5b534ba92a74..4272d24474453416096eaf2f209346ef37554f3a 100644 (file)
--- a/arch/loongarch/kernel/paravirt.c
+++ b/arch/loongarch/kernel/paravirt.c
@@ -2,6 +2,7 @@
 #include <linux/export.h>
 #include <linux/types.h>
 #include <linux/interrupt.h>
+#include <linux/irq_work.h>
 #include <linux/jump_label.h>
 #include <linux/kvm_para.h>
 #include <linux/static_call.h>
@@ -97,6 +98,11 @@ static irqreturn_t pv_ipi_interrupt(int irq, void *dev)
                info->ipi_irqs[IPI_CALL_FUNCTION]++;
        }
 
+       if (action & SMP_IRQ_WORK) {
+               irq_work_run();
+               info->ipi_irqs[IPI_IRQ_WORK]++;
+       }
+
        return IRQ_HANDLED;
 }
 

diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c
index 03b2b7669cf5ddd24779ba292d536ebe747fab03..ca405ab86aaef69837de7f9c799759045dc52066 100644 (file)
--- a/arch/loongarch/kernel/smp.c
+++ b/arch/loongarch/kernel/smp.c
@@ -13,6 +13,7 @@
 #include <linux/cpumask.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
+#include <linux/irq_work.h>
 #include <linux/profile.h>
 #include <linux/seq_file.h>
 #include <linux/smp.h>
@@ -70,6 +71,7 @@ static DEFINE_PER_CPU(int, cpu_state);
 static const char *ipi_types[NR_IPI] __tracepoint_string = {
        [IPI_RESCHEDULE] = "Rescheduling interrupts",
        [IPI_CALL_FUNCTION] = "Function call interrupts",
+       [IPI_IRQ_WORK] = "IRQ work interrupts",
 };
 
 void show_ipi_list(struct seq_file *p, int prec)
@@ -217,6 +219,13 @@ void arch_smp_send_reschedule(int cpu)
 }
 EXPORT_SYMBOL_GPL(arch_smp_send_reschedule);
 
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+       mp_ops.send_ipi_single(smp_processor_id(), ACTION_IRQ_WORK);
+}
+#endif
+
 static irqreturn_t loongson_ipi_interrupt(int irq, void *dev)
 {
        unsigned int action;
@@ -234,6 +243,11 @@ static irqreturn_t loongson_ipi_interrupt(int irq, void *dev)
                per_cpu(irq_stat, cpu).ipi_irqs[IPI_CALL_FUNCTION]++;
        }
 
+       if (action & SMP_IRQ_WORK) {
+               irq_work_run();
+               per_cpu(irq_stat, cpu).ipi_irqs[IPI_IRQ_WORK]++;
+       }
+
        return IRQ_HANDLED;
 }