1 files changed, 132 insertions, 28 deletions

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index 778f22fd85d..358cecdc6ae 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -22,10 +22,13 @@
 #include <linux/elf.h>
 #include <linux/elfcore.h>
 #include <linux/init.h>
+#include <linux/irq.h>
 #include <linux/types.h>
+#include <linux/irq.h>
 
 #include <asm/processor.h>
 #include <asm/machdep.h>
+#include <asm/kexec.h>
 #include <asm/kdump.h>
 #include <asm/lmb.h>
 #include <asm/firmware.h>
@@ -40,6 +43,7 @@
 
 /* This keeps a track of which one is crashing cpu. */
 int crashing_cpu = -1;
+static cpumask_t cpus_in_crash = CPU_MASK_NONE;
 
 static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
 							       size_t data_len)
@@ -97,34 +101,66 @@ static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
 }
 
 #ifdef CONFIG_SMP
-static atomic_t waiting_for_crash_ipi;
+static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
 
 void crash_ipi_callback(struct pt_regs *regs)
 {
 	int cpu = smp_processor_id();
 
-	if (cpu == crashing_cpu)
-		return;
-
 	if (!cpu_online(cpu))
 		return;
 
-	if (ppc_md.kexec_cpu_down)
-		ppc_md.kexec_cpu_down(1, 1);
-
 	local_irq_disable();
+	if (!cpu_isset(cpu, cpus_in_crash))
+		crash_save_this_cpu(regs, cpu);
+	cpu_set(cpu, cpus_in_crash);
+
+	/*
+	 * Entered via soft-reset - could be the kdump
+	 * process is invoked using soft-reset or user activated
+	 * it if some CPU did not respond to an IPI.
+	 * For soft-reset, the secondary CPU can enter this func
+	 * twice. 1 - using IPI, and 2. soft-reset.
+	 * Tell the kexec CPU that entered via soft-reset and ready
+	 * to go down.
+	 */
+	if (cpu_isset(cpu, cpus_in_sr)) {
+		cpu_clear(cpu, cpus_in_sr);
+		atomic_inc(&enter_on_soft_reset);
+	}
+
+	/*
+	 * Starting the kdump boot.
+	 * This barrier is needed to make sure that all CPUs are stopped.
+	 * If not, soft-reset will be invoked to bring other CPUs.
+	 */
+	while (!cpu_isset(crashing_cpu, cpus_in_crash))
+		cpu_relax();
 
-	crash_save_this_cpu(regs, cpu);
-	atomic_dec(&waiting_for_crash_ipi);
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(1, 1);
 	kexec_smp_wait();
 	/* NOTREACHED */
 }
 
-static void crash_kexec_prepare_cpus(void)
+/*
+ * Wait until all CPUs are entered via soft-reset.
+ */
+static void crash_soft_reset_check(int cpu)
+{
+	unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
+
+	cpu_clear(cpu, cpus_in_sr);
+	while (atomic_read(&enter_on_soft_reset) != ncpus)
+		cpu_relax();
+}
+
+
+static void crash_kexec_prepare_cpus(int cpu)
 {
 	unsigned int msecs;
 
-	atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
+	unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
 
 	crash_send_ipi(crash_ipi_callback);
 	smp_wmb();
@@ -132,14 +168,13 @@ static void crash_kexec_prepare_cpus(void)
 	/*
 	 * FIXME: Until we will have the way to stop other CPUSs reliabally,
 	 * the crash CPU will send an IPI and wait for other CPUs to
-	 * respond. If not, proceed the kexec boot even though we failed to
-	 * capture other CPU states.
+	 * respond.
 	 * Delay of at least 10 seconds.
 	 */
-	printk(KERN_ALERT "Sending IPI to other cpus...\n");
+	printk(KERN_EMERG "Sending IPI to other cpus...\n");
 	msecs = 10000;
-	while ((atomic_read(&waiting_for_crash_ipi) > 0) && (--msecs > 0)) {
-		barrier();
+	while ((cpus_weight(cpus_in_crash) < ncpus) && (--msecs > 0)) {
+		cpu_relax();
 		mdelay(1);
 	}
 
@@ -148,18 +183,71 @@ static void crash_kexec_prepare_cpus(void)
 	/*
 	 * FIXME: In case if we do not get all CPUs, one possibility: ask the
 	 * user to do soft reset such that we get all.
-	 * IPI handler is already set by the panic cpu initially. Therefore,
-	 * all cpus could invoke this handler from die() and the panic CPU
-	 * will call machine_kexec() directly from this handler to do
-	 * kexec boot.
+	 * Soft-reset will be used until better mechanism is implemented.
 	 */
-	if (atomic_read(&waiting_for_crash_ipi))
-		printk(KERN_ALERT "done waiting: %d cpus not responding\n",
-			atomic_read(&waiting_for_crash_ipi));
+	if (cpus_weight(cpus_in_crash) < ncpus) {
+		printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
+			ncpus - cpus_weight(cpus_in_crash));
+		printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
+		cpus_in_sr = CPU_MASK_NONE;
+		atomic_set(&enter_on_soft_reset, 0);
+		while (cpus_weight(cpus_in_crash) < ncpus)
+			cpu_relax();
+	}
+	/*
+	 * Make sure all CPUs are entered via soft-reset if the kdump is
+	 * invoked using soft-reset.
+	 */
+	if (cpu_isset(cpu, cpus_in_sr))
+		crash_soft_reset_check(cpu);
 	/* Leave the IPI callback set */
 }
+
+/*
+ * This function will be called by secondary cpus or by kexec cpu
+ * if soft-reset is activated to stop some CPUs.
+ */
+void crash_kexec_secondary(struct pt_regs *regs)
+{
+	int cpu = smp_processor_id();
+	unsigned long flags;
+	int msecs = 5;
+
+	local_irq_save(flags);
+	/* Wait 5ms if the kexec CPU is not entered yet. */
+	while (crashing_cpu < 0) {
+		if (--msecs < 0) {
+			/*
+			 * Either kdump image is not loaded or
+			 * kdump process is not started - Probably xmon
+			 * exited using 'x'(exit and recover) or
+			 * kexec_should_crash() failed for all running tasks.
+			 */
+			cpu_clear(cpu, cpus_in_sr);
+			local_irq_restore(flags);
+			return;
+		}
+		mdelay(1);
+		cpu_relax();
+	}
+	if (cpu == crashing_cpu) {
+		/*
+		 * Panic CPU will enter this func only via soft-reset.
+		 * Wait until all secondary CPUs entered and
+		 * then start kexec boot.
+		 */
+		crash_soft_reset_check(cpu);
+		cpu_set(crashing_cpu, cpus_in_crash);
+		if (ppc_md.kexec_cpu_down)
+			ppc_md.kexec_cpu_down(1, 0);
+		machine_kexec(kexec_crash_image);
+		/* NOTREACHED */
+	}
+	crash_ipi_callback(regs);
+}
+
 #else
-static void crash_kexec_prepare_cpus(void)
+static void crash_kexec_prepare_cpus(int cpu)
 {
 	/*
 	 * move the secondarys to us so that we can copy
@@ -170,13 +258,19 @@ static void crash_kexec_prepare_cpus(void)
 	smp_release_cpus();
 }
 
+void crash_kexec_secondary(struct pt_regs *regs)
+{
+	cpus_in_sr = CPU_MASK_NONE;
+}
 #endif
 
 void default_machine_crash_shutdown(struct pt_regs *regs)
 {
+	unsigned int irq;
+
 	/*
 	 * This function is only called after the system
-	 * has paniced or is otherwise in a critical state.
+	 * has panicked or is otherwise in a critical state.
 	 * The minimum amount of code to allow a kexec'd kernel
 	 * to run successfully needs to happen here.
 	 *
@@ -186,14 +280,24 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
 	 */
 	local_irq_disable();
 
-	if (ppc_md.kexec_cpu_down)
-		ppc_md.kexec_cpu_down(1, 0);
+	for_each_irq(irq) {
+		struct irq_desc *desc = irq_desc + irq;
+
+		if (desc->status & IRQ_INPROGRESS)
+			desc->chip->end(irq);
+
+		if (!(desc->status & IRQ_DISABLED))
+			desc->chip->disable(irq);
+	}
 
 	/*
 	 * 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_kexec_prepare_cpus();
 	crash_save_this_cpu(regs, crashing_cpu);
+	crash_kexec_prepare_cpus(crashing_cpu);
+	cpu_set(crashing_cpu, cpus_in_crash);
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(1, 0);
 }