[v4,1/2] kexec: Consolidate machine_kexec_mask_interrupts() implementation

Commit Message

Eliav Farber Nov. 29, 2024, 11:31 a.m. UTC

Move the machine_kexec_mask_interrupts function to a common location in
kernel/kexec_core.c, removing duplicate implementations from architecture
specific files (arch/arm, arch/arm64, arch/powerpc, and arch/riscv).

This consolidation reduces code duplication and improves maintainability.

The unified function includes an architecture-specific behavior for
CONFIG_ARM64 by conditionally clearing the active interrupt state before
handling other interrupt masking operations.

Signed-off-by: Eliav Farber <[e-mail]>
---
V4 -> V3: Add missing <linux/irqdec.h> include.

 arch/arm/kernel/machine_kexec.c   | 23 ---------------------
 arch/arm64/kernel/machine_kexec.c | 31 -----------------------------
 arch/powerpc/include/asm/kexec.h  |  1 -
 arch/powerpc/kexec/core.c         | 22 ---------------------
 arch/riscv/kernel/machine_kexec.c | 23 ---------------------
 include/linux/kexec.h             |  2 ++
 kernel/kexec_core.c               | 33 +++++++++++++++++++++++++++++++
 7 files changed, 35 insertions(+), 100 deletions(-)

Comments

Thomas Gleixner Nov. 29, 2024, 1:30 p.m. UTC | #1

On Fri, Nov 29 2024 at 11:31, Eliav Farber wrote:
> Move the machine_kexec_mask_interrupts function to a common location in
> kernel/kexec_core.c, removing duplicate implementations from architecture
> specific files (arch/arm, arch/arm64, arch/powerpc, and arch/riscv).

Can you please move this into kernel/irq/kexec.c?

It's pure interrupt core internal code and there is no point to make
core internal functions visible to random other code just because.

> +void machine_kexec_mask_interrupts(void)
> +{
> +	unsigned int i;
> +	struct irq_desc *desc;

	struct irq_desc *desc;
        unsigned int i;

please

> +	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_ARM64)) {

This should not be CONFIG_ARM64. Add something like:

config GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD
	bool

and select this from ARM64?

> +			/*
> +			 * First try to remove the active state. If this fails, try to EOI the
> +			 * interrupt.

This comment does not really explain what this is about. I know you
copied it from the ARM64 implementation, but it should explain what this
actually means. Something like:

         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.

or something like that.

> +			 */
> +			check_eoi = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);

Looking deeper. This function actually cannot be called from this
context. It does:

          irq_get_desc_buslock(irq, &flags, 0);

which means for any interrupt which has an actual buslock implementation
it will end up in a sleepable function and deadlock in the worst case.

Marc?

> +		}
> +
> +		if (check_eoi && chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
> +			chip->irq_eoi(&desc->irq_data);

Thanks,

        tglx

Patch

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 80ceb5bd2680..dd430477e7c1 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -127,29 +127,6 @@  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;
-
-		chip = irq_desc_get_chip(desc);
-		if (!chip)
-			continue;
-
-		if (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);
-	}
-}
-
 void machine_crash_shutdown(struct pt_regs *regs)
 {
 	local_irq_disable();
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 82e2203d86a3..6f121a0164a4 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -207,37 +207,6 @@  void machine_kexec(struct kimage *kimage)
 	BUG(); /* Should never get here. */
 }
 
-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 - shutdown non-crashing cpus and save registers
  */
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 270ee93a0f7d..601e569303e1 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -61,7 +61,6 @@  struct pt_regs;
 extern void kexec_smp_wait(void);	/* get and clear naca physid, wait for
 					  master to copy new code to 0 */
 extern void default_machine_kexec(struct kimage *image);
-extern void machine_kexec_mask_interrupts(void);
 
 void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_code_buffer,
 			 unsigned long start_address) __noreturn;
diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
index b8333a49ea5d..58a930a47422 100644
--- a/arch/powerpc/kexec/core.c
+++ b/arch/powerpc/kexec/core.c
@@ -22,28 +22,6 @@ 
 #include <asm/setup.h>
 #include <asm/firmware.h>
 
-void machine_kexec_mask_interrupts(void) {
-	unsigned int i;
-	struct irq_desc *desc;
-
-	for_each_irq_desc(i, desc) {
-		struct irq_chip *chip;
-
-		chip = irq_desc_get_chip(desc);
-		if (!chip)
-			continue;
-
-		if (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);
-	}
-}
-
 #ifdef CONFIG_CRASH_DUMP
 void machine_crash_shutdown(struct pt_regs *regs)
 {
diff --git a/arch/riscv/kernel/machine_kexec.c b/arch/riscv/kernel/machine_kexec.c
index 3c830a6f7ef4..2306ce3e5f22 100644
--- a/arch/riscv/kernel/machine_kexec.c
+++ b/arch/riscv/kernel/machine_kexec.c
@@ -114,29 +114,6 @@  void machine_shutdown(void)
 #endif
 }
 
-static void machine_kexec_mask_interrupts(void)
-{
-	unsigned int i;
-	struct irq_desc *desc;
-
-	for_each_irq_desc(i, desc) {
-		struct irq_chip *chip;
-
-		chip = irq_desc_get_chip(desc);
-		if (!chip)
-			continue;
-
-		if (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);
-	}
-}
-
 /*
  * machine_crash_shutdown - Prepare to kexec after a kernel crash
  *
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index f0e9f8eda7a3..9dac0524c0be 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -375,6 +375,8 @@  extern void machine_kexec(struct kimage *image);
 extern int machine_kexec_prepare(struct kimage *image);
 extern void machine_kexec_cleanup(struct kimage *image);
 extern int kernel_kexec(void);
+extern void machine_kexec_mask_interrupts(void);
+
 extern struct page *kimage_alloc_control_pages(struct kimage *image,
 						unsigned int order);
 
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index c0caa14880c3..777191458544 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -40,6 +40,7 @@ 
 #include <linux/hugetlb.h>
 #include <linux/objtool.h>
 #include <linux/kmsg_dump.h>
+#include <linux/irqdesc.h>
 
 #include <asm/page.h>
 #include <asm/sections.h>
@@ -1072,3 +1073,35 @@  int kernel_kexec(void)
 	kexec_unlock();
 	return error;
 }
+
+void machine_kexec_mask_interrupts(void)
+{
+	unsigned int i;
+	struct irq_desc *desc;
+
+	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_ARM64)) {
+			/*
+			 * First try to remove the active state. If this fails, 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);
+	}
+}