Merge "ARM64: smp: implement arch_trigger_all_cpus_backtrace using IPI" (c30e0fc0) · Commits · e / devices / android_kernel_sony_msm8994

arch/arm64/include/asm/hardirq.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -20,7 +20,7 @@
		#include <linux/threads.h>
		#include <asm/irq.h>

		#define NR_IPI 6
		#define NR_IPI 7

		typedef struct {
		unsigned int __softirq_pending;

arch/arm64/include/asm/irq.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -7,4 +7,7 @@ extern void (handle_arch_irq)(struct pt_regs );
		extern void migrate_irqs(void);
		extern void set_handle_irq(void (handle_irq)(struct pt_regs ));

		void arch_trigger_all_cpu_backtrace(void);
		#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace

		#endif

arch/arm64/kernel/smp.c

+72 −0

Original line number	Diff line number	Diff line
		@@ -64,6 +64,7 @@ enum ipi_msg_type {
		IPI_CPU_STOP,
		IPI_TIMER,
		IPI_WAKEUP,
		IPI_CPU_BACKTRACE,
		};

		/*
		@@ -477,6 +478,7 @@ static const char *ipi_types[NR_IPI] = {
		S(IPI_CPU_STOP, "CPU stop interrupts"),
		S(IPI_TIMER, "Timer broadcast interrupts"),
		S(IPI_WAKEUP, "CPU wakeup interrupts"),
		S(IPI_CPU_BACKTRACE, "CPU backtrace"),
		};

		void show_ipi_list(struct seq_file *p, int prec)
		@@ -532,6 +534,72 @@ static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
		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;

		static 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");
		if (!cpus_empty(backtrace_mask))
		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_warn("IPI backtrace for cpu %d\n", cpu);
		show_regs(regs);
		raw_spin_unlock(&backtrace_lock);
		cpu_clear(cpu, backtrace_mask);
		}
		}

		#ifdef CONFIG_SMP
		void arch_trigger_all_cpu_backtrace(void)
		{
		smp_send_all_cpu_backtrace();
		}
		#else
		void arch_trigger_all_cpu_backtrace(void)
		{
		dump_stack();
		}
		#endif


		/*
		* Main handler for inter-processor interrupts
		*/
		@@ -576,6 +644,10 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
		case IPI_WAKEUP:
		break;

		case IPI_CPU_BACKTRACE:
		ipi_cpu_backtrace(cpu, regs);
		break;

		default:
		pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr);
		break;