Merge remote-tracking branch 'stable/linux-3.0.y' into develop-3.0-jb

[firefly-linux-kernel-4.4.55.git] / arch / arm / kernel / smp.c

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index e7f92a4321f370d0c9e9f9dc73460a0be65c014a..ff956e7d95017fb9ef537cb4f40726636b01c24c 100644 (file)
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -53,6 +53,7 @@ enum ipi_msg_type {
        IPI_CALL_FUNC,
        IPI_CALL_FUNC_SINGLE,
        IPI_CPU_STOP,
+       IPI_CPU_BACKTRACE,
 };
 
 int __cpuinit __cpu_up(unsigned int cpu)
@@ -279,8 +280,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
        struct mm_struct *mm = &init_mm;
        unsigned int cpu = smp_processor_id();
 
-       printk("CPU%u: Booted secondary processor\n", cpu);
-
        /*
         * All kernel threads share the same mm context; grab a
         * reference and switch to it.
@@ -292,6 +291,8 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
        enter_lazy_tlb(mm, current);
        local_flush_tlb_all();
 
+       printk("CPU%u: Booted secondary processor\n", cpu);
+
        cpu_init();
        preempt_disable();
        trace_hardirqs_off();
@@ -301,19 +302,11 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
         */
        platform_secondary_init(cpu);
 
-       /*
-        * Enable local interrupts.
-        */
        notify_cpu_starting(cpu);
-       local_irq_enable();
-       local_fiq_enable();
-
-       /*
-        * Setup the percpu timer for this CPU.
-        */
-       percpu_timer_setup();
 
+#ifndef CONFIG_PLAT_RK
        calibrate_delay();
+#endif
 
        smp_store_cpu_info(cpu);
 
@@ -323,8 +316,14 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
         * before we continue.
         */
        set_cpu_online(cpu, true);
-       while (!cpu_active(cpu))
-               cpu_relax();
+
+       /*
+        * Setup the percpu timer for this CPU.
+        */
+       percpu_timer_setup();
+
+       local_irq_enable();
+       local_fiq_enable();
 
        /*
         * OK, it's off to the idle thread for us
@@ -405,6 +404,7 @@ static const char *ipi_types[NR_IPI] = {
        S(IPI_CALL_FUNC, "Function call interrupts"),
        S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"),
        S(IPI_CPU_STOP, "CPU stop interrupts"),
+       S(IPI_CPU_BACKTRACE, "CPU backtrace"),
 };
 
 void show_ipi_list(struct seq_file *p, int prec)
@@ -555,6 +555,58 @@ static void ipi_cpu_stop(unsigned int cpu)
                cpu_relax();
 }
 
+static cpumask_t backtrace_mask;
+static DEFINE_RAW_SPINLOCK(backtrace_lock);
+
+/* "in progress" flag of arch_trigger_all_cpu_backtrace */
+static unsigned long backtrace_flag;
+
+void smp_send_all_cpu_backtrace(void)
+{
+       unsigned int this_cpu = smp_processor_id();
+       int i;
+
+       if (test_and_set_bit(0, &backtrace_flag))
+               /*
+                * If there is already a trigger_all_cpu_backtrace() in progress
+                * (backtrace_flag == 1), don't output double cpu dump infos.
+                */
+               return;
+
+       cpumask_copy(&backtrace_mask, cpu_online_mask);
+       cpu_clear(this_cpu, backtrace_mask);
+
+       pr_info("Backtrace for cpu %d (current):\n", this_cpu);
+       dump_stack();
+
+       pr_info("\nsending IPI to all other CPUs:\n");
+       smp_cross_call(&backtrace_mask, IPI_CPU_BACKTRACE);
+
+       /* Wait for up to 10 seconds for all other CPUs to do the backtrace */
+       for (i = 0; i < 10 * 1000; i++) {
+               if (cpumask_empty(&backtrace_mask))
+                       break;
+               mdelay(1);
+       }
+
+       clear_bit(0, &backtrace_flag);
+       smp_mb__after_clear_bit();
+}
+
+/*
+ * ipi_cpu_backtrace - handle IPI from smp_send_all_cpu_backtrace()
+ */
+static void ipi_cpu_backtrace(unsigned int cpu, struct pt_regs *regs)
+{
+       if (cpu_isset(cpu, backtrace_mask)) {
+               raw_spin_lock(&backtrace_lock);
+               pr_warning("IPI backtrace for cpu %d\n", cpu);
+               show_regs(regs);
+               raw_spin_unlock(&backtrace_lock);
+               cpu_clear(cpu, backtrace_mask);
+       }
+}
+
 /*
  * Main handler for inter-processor interrupts
  */
@@ -587,6 +639,10 @@ asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs)
                ipi_cpu_stop(cpu);
                break;
 
+       case IPI_CPU_BACKTRACE:
+               ipi_cpu_backtrace(cpu, regs);
+               break;
+
        default:
                printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
                       cpu, ipinr);