kexec: Consolidate machine_kexec_mask_interrupts() implementation

Consolidate the machine_kexec_mask_interrupts implementation into a common
function located in a new file: kernel/irq/kexec.c. This removes duplicate
implementations from architecture-specific files in arch/arm, arch/arm64,
arch/powerpc, and arch/riscv, reducing code duplication and improving
maintainability.

The new implementation retains architecture-specific behavior for
CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD, which was previously implemented
for ARM64. When enabled (currently for ARM64), it clears the active state
of interrupts forwarded to virtual machines (VMs) before handling other
interrupt masking operations.

Signed-off-by: Eliav Farber <farbere@amazon.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20241204142003.32859-2-farbere@amazon.com
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>

kernel/irq/Kconfig

@@ -141,6 +141,12 @@ config GENERIC_IRQ_DEBUGFS
 
 	  If you don't know what to do here, say N.
 
+# Clear forwarded VM interrupts during kexec.
+# This option ensures the kernel clears active states for interrupts
+# forwarded to virtual machines (VMs) during a machine kexec.
+config GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD
+	bool
+
 endmenu
 
 config GENERIC_IRQ_MULTI_HANDLER

kernel/irq/Makefile

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 
-obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o
+obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o kexec.o
 obj-$(CONFIG_IRQ_TIMINGS) += timings.o
 ifeq ($(CONFIG_TEST_IRQ_TIMINGS),y)
 	CFLAGS_timings.o += -DDEBUG

kernel/irq/kexec.c

@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqdesc.h>
+#include <linux/irqnr.h>
+
+#include "internals.h"
+
+void machine_kexec_mask_interrupts(void)
+{
+	struct irq_desc *desc;
+	unsigned int i;
+
+	for_each_irq_desc(i, desc) {
+		struct irq_chip *chip;
+		int check_eoi = 1;
+
+		chip = irq_desc_get_chip(desc);
+		if (!chip)
+			continue;
+
+		if (IS_ENABLED(CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD)) {
+			/*
+			 * First try to remove the active state from an interrupt which is forwarded
+			 * to a VM. If the interrupt is not forwarded, try to EOI the interrupt.
+			 */
+			check_eoi = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
+		}
+
+		if (check_eoi && chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
+			chip->irq_eoi(&desc->irq_data);
+
+		if (chip->irq_mask)
+			chip->irq_mask(&desc->irq_data);
+
+		if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
+			chip->irq_disable(&desc->irq_data);
+	}
+}