1 files changed, 119 insertions, 28 deletions

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index e253a45dcf10..b537cfa4e09b 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -24,9 +24,11 @@
 #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>
@@ -41,6 +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)
@@ -98,34 +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);
 
-        crash_save_this_cpu(regs, cpu);
-        atomic_dec(&waiting_for_crash_ipi);
+        /*
+         * 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();
+
+        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();
@@ -133,14 +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);
         }
 
@@ -149,18 +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 (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 (atomic_read(&waiting_for_crash_ipi))
-                printk(KERN_ALERT "done waiting: %d cpus not responding\n",
-                        atomic_read(&waiting_for_crash_ipi));
+        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
@@ -171,6 +258,10 @@ 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)
@@ -199,14 +290,14 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
                         desc->handler->disable(irq);
         }
 
-        if (ppc_md.kexec_cpu_down)
-                ppc_md.kexec_cpu_down(1, 0);
-
         /*
          * 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);
 }