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powerpc/kdump: Stop all other CPUs before running crash handlers

PATCH In review Anton Blanchard 2 participants 2 messages Aug 3, 2010 PowerPC

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#0 lore raw

PATCH 1/1 powerpc/kdump: Stop all other CPUs before running crash handlers

During kdump we run the crash handlers first then stop all other CPUs. We really want to stop all CPUs as close to the fail as possible and also have a very controlled environment for running the crash handlers, so it makes sense to reverse the order.

---

arch/powerpc/kernel/crash.c +13 -11
Index: powerpc.git/arch/powerpc/kernel/crash.c
===================================================================
@@ -402,6 +402,18 @@ void default_machine_crash_shutdown(stru
 	 */
 	hard_irq_disable();
 
+	/*
+	 * Make a note of crashing cpu. Will be used in machine_kexec
+	 * such that another IPI will not be sent.
+	 */
+	crashing_cpu = smp_processor_id();
+	crash_save_cpu(regs, crashing_cpu);
+	crash_kexec_prepare_cpus(crashing_cpu);
+	cpu_set(crashing_cpu, cpus_in_crash);
+#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
+	crash_kexec_wait_realmode(crashing_cpu);
+#endif
+
 	for_each_irq(i) {
 		struct irq_desc *desc = irq_to_desc(i);
 
@@ -438,18 +450,8 @@ void default_machine_crash_shutdown(stru
 	crash_shutdown_cpu = -1;
 	__debugger_fault_handler = old_handler;
 
-	/*
-	 * Make a note of crashing cpu. Will be used in machine_kexec
-	 * such that another IPI will not be sent.
-	 */
-	crashing_cpu = smp_processor_id();
-	crash_save_cpu(regs, crashing_cpu);
-	crash_kexec_prepare_cpus(crashing_cpu);
-	cpu_set(crashing_cpu, cpus_in_crash);
 	crash_kexec_stop_spus();
-#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
-	crash_kexec_wait_realmode(crashing_cpu);
-#endif
+
 	if (ppc_md.kexec_cpu_down)
 		ppc_md.kexec_cpu_down(1, 0);
 }
Acked-by on v1 1/1
#1 lore raw
Quoted 6 lines · Anton Blanchard

During kdump we run the crash handlers first then stop all other CPUs. We really want to stop all CPUs as close to the fail as possible and also have a very controlled environment for running the crash handlers, so it makes sense to reverse the order.

Looks like a sensible idea!

Quoted 45 lines

---

Index: powerpc.git/arch/powerpc/kernel/crash.c
===================================================================

arch/powerpc/kernel/crash.c +13 -11
@@ -402,6 +402,18 @@ void default_machine_crash_shutdown(stru
 	 */
 	hard_irq_disable();
 
+	/*
+	 * Make a note of crashing cpu. Will be used in machine_kexec
+	 * such that another IPI will not be sent.
+	 */
+	crashing_cpu = smp_processor_id();
+	crash_save_cpu(regs, crashing_cpu);
+	crash_kexec_prepare_cpus(crashing_cpu);
+	cpu_set(crashing_cpu, cpus_in_crash);
+#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
+	crash_kexec_wait_realmode(crashing_cpu);
+#endif
+
 	for_each_irq(i) {
 		struct irq_desc *desc = irq_to_desc(i);
 
@@ -438,18 +450,8 @@ void default_machine_crash_shutdown(stru
 	crash_shutdown_cpu = -1;
 	__debugger_fault_handler = old_handler;
 
-	/*
-	 * Make a note of crashing cpu. Will be used in machine_kexec
-	 * such that another IPI will not be sent.
-	 */
-	crashing_cpu = smp_processor_id();
-	crash_save_cpu(regs, crashing_cpu);
-	crash_kexec_prepare_cpus(crashing_cpu);
-	cpu_set(crashing_cpu, cpus_in_crash);
 	crash_kexec_stop_spus();
-#if defined(CONFIG_PPC_STD_MMU_64) && defined(CONFIG_SMP)
-	crash_kexec_wait_realmode(crashing_cpu);
-#endif
+
 	if (ppc_md.kexec_cpu_down)
 		ppc_md.kexec_cpu_down(1, 0);
 }