[PATCH -next V6 1/2] riscv: kexec: EOI active and mask all interrupts in kexec crash path

[guoren at kernel.org]

From: Guo Ren <guoren at linux.alibaba.com>

If a crash happens on cpu3 and all interrupts are binding on cpu0, the
bad irq routing will cause the crash kernel can't receive any irq.
Because the crash kernel won't clean up PLIC harts' enable register.
This patch is similar to 'commit 9141a003a491 ("ARM: 7316/1: kexec: EOI
active and mask all interrupts in kexec crash path")'; arm64 and
PowerPC also have a similar mechanism.

Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
Signed-off-by: Guo Ren <guoren at kernel.org>
Reviewed-by: Xianting Tian <xianting.tian at linux.alibaba.com>
Cc: Nick Kossifidis <mick at ics.forth.gr>
Cc: Palmer Dabbelt <palmer at rivosinc.com>
---
 arch/riscv/kernel/machine_kexec.c | 35 +++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
index ee79e6839b86..db41c676e5a2 100644
--- a/arch/riscv/kernel/machine_kexec.c
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -15,6 +15,8 @@
 #include <linux/compiler.h>	/* For unreachable() */
 #include <linux/cpu.h>		/* For cpu_down() */
 #include <linux/reboot.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
 
 /*
  * kexec_image_info - Print received image details
@@ -154,6 +156,37 @@ void crash_smp_send_stop(void)
 	cpus_stopped = 1;
 }
 
+static void machine_kexec_mask_interrupts(void)
+{
+	unsigned int i;
+	struct irq_desc *desc;
+
+	for_each_irq_desc(i, desc) {
+		struct irq_chip *chip;
+		int ret;
+
+		chip = irq_desc_get_chip(desc);
+		if (!chip)
+			continue;
+
+		/*
+		 * First try to remove the active state. If this
+		 * fails, try to EOI the interrupt.
+		 */
+		ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
+
+		if (ret && irqd_irq_inprogress(&desc->irq_data) &&
+		    chip->irq_eoi)
+			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);
+	}
+}
+
 /*
  * machine_crash_shutdown - Prepare to kexec after a kernel crash
  *
@@ -169,6 +202,8 @@ machine_crash_shutdown(struct pt_regs *regs)
 	crash_smp_send_stop();
 
 	crash_save_cpu(regs, smp_processor_id());
+	machine_kexec_mask_interrupts();
+
 	pr_info("Starting crashdump kernel...\n");
 }
 
-- 
2.36.1