powerpc: Remove broken and complicated kdump system reset code (9b00ac06) · Commits · e / devices / android_kernel_fairphone_FP3

arch/powerpc/include/asm/kexec.h

+0 −6

Original line number	Diff line number	Diff line
		@@ -73,11 +73,6 @@ extern void kexec_smp_wait(void); /* get and clear naca physid, wait for
		master to copy new code to 0 */
		extern int crashing_cpu;
		extern void crash_send_ipi(void (crash_ipi_callback)(struct pt_regs ));
		extern cpumask_t cpus_in_sr;
		static inline int kexec_sr_activated(int cpu)
		{
		return cpumask_test_cpu(cpu, &cpus_in_sr);
		}

		struct kimage;
		struct pt_regs;
		@@ -94,7 +89,6 @@ extern void reserve_crashkernel(void);
		extern void machine_kexec_mask_interrupts(void);

		#else /* !CONFIG_KEXEC */
		static inline int kexec_sr_activated(int cpu) { return 0; }
		static inline void crash_kexec_secondary(struct pt_regs *regs) { }

		static inline int overlaps_crashkernel(unsigned long start, unsigned long size)

arch/powerpc/kernel/crash.c

+12 −75

Original line number	Diff line number	Diff line
		@@ -47,7 +47,6 @@
		/* This keeps a track of which one is crashing cpu. */
		int crashing_cpu = -1;
		static cpumask_t cpus_in_crash = CPU_MASK_NONE;
		cpumask_t cpus_in_sr = CPU_MASK_NONE;

		#define CRASH_HANDLER_MAX 3
		/* NULL terminated list of shutdown handles */
		@@ -55,7 +54,6 @@ static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX+1];
		static DEFINE_SPINLOCK(crash_handlers_lock);

		#ifdef CONFIG_SMP
		static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);

		void crash_ipi_callback(struct pt_regs *regs)
		{
		@@ -69,24 +67,9 @@ void crash_ipi_callback(struct pt_regs *regs)
		crash_save_cpu(regs, cpu);
		cpumask_set_cpu(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 (cpumask_test_cpu(cpu, &cpus_in_sr)) {
		cpumask_clear_cpu(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 (!cpumask_test_cpu(crashing_cpu, &cpus_in_crash))
		cpu_relax();
		@@ -103,25 +86,14 @@ void crash_ipi_callback(struct pt_regs *regs)
		/* NOTREACHED */
		}

		/*
		* 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 */

		cpumask_clear_cpu(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;

		unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */

		printk(KERN_EMERG "Sending IPI to other CPUs\n");

		crash_send_ipi(crash_ipi_callback);
		smp_wmb();

		@@ -131,7 +103,6 @@ static void crash_kexec_prepare_cpus(int cpu)
		* respond.
		* Delay of at least 10 seconds.
		*/
		printk(KERN_EMERG "Sending IPI to other cpus...\n");
		msecs = 10000;
		while ((cpumask_weight(&cpus_in_crash) < ncpus) && (--msecs > 0)) {
		cpu_relax();
		@@ -140,69 +111,36 @@ static void crash_kexec_prepare_cpus(int cpu)

		/* Would it be better to replace the trap vector here? */

		/*
		* FIXME: In case if we do not get all CPUs, one possibility: ask the
		* user to do soft reset such that we get all.
		* Soft-reset will be used until better mechanism is implemented.
		*/
		if (cpumask_weight(&cpus_in_crash) < ncpus) {
		printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
		printk(KERN_EMERG "ERROR: %d CPU(s) not responding\n",
		ncpus - cpumask_weight(&cpus_in_crash));
		printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
		cpumask_clear(&cpus_in_sr);
		atomic_set(&enter_on_soft_reset, 0);
		while (cpumask_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 (cpumask_test_cpu(cpu, &cpus_in_sr))
		crash_soft_reset_check(cpu);
		/* Leave the IPI callback set */

		printk(KERN_EMERG "IPI complete\n");
		}

		/*
		* This function will be called by secondary cpus or by kexec cpu
		* if soft-reset is activated to stop some CPUs.
		* This function will be called by secondary cpus.
		*/
		void crash_kexec_secondary(struct pt_regs *regs)
		{
		int cpu = smp_processor_id();
		unsigned long flags;
		int msecs = 5;
		int msecs = 500;

		local_irq_save(flags);
		/* Wait 5ms if the kexec CPU is not entered yet. */

		/* Wait 500ms for the primary crash CPU to signal its progress */
		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.
		*/
		cpumask_clear_cpu(cpu, &cpus_in_sr);
		/* No response, kdump image may not have been loaded */
		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);
		cpumask_set_cpu(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);
		}

		@@ -225,7 +163,6 @@ static void crash_kexec_prepare_cpus(int cpu)

		void crash_kexec_secondary(struct pt_regs *regs)
		{
		cpumask_clear(&cpus_in_sr);
		}
		#endif /* CONFIG_SMP */

arch/powerpc/kernel/traps.c

+13 −20

Original line number	Diff line number	Diff line
		@@ -162,10 +162,20 @@ int die(const char str, struct pt_regs regs, long err)
		printk("\n");
		raw_spin_unlock_irqrestore(&die.lock, flags);

		if (kexec_should_crash(current) \|\|
		kexec_sr_activated(smp_processor_id()))
		/*
		* A system reset (0x100) is a request to dump, so we always send
		* it through the crashdump code.
		*/
		if (kexec_should_crash(current) \|\| (TRAP(regs) == 0x100)) {
		crash_kexec(regs);

		/*
		* We aren't the primary crash CPU. We need to send it
		* to a holding pattern to avoid it ending up in the panic
		* code.
		*/
		crash_kexec_secondary(regs);
		}

		/*
		* While our oops output is serialised by a spinlock, output
		@@ -232,25 +242,8 @@ void system_reset_exception(struct pt_regs *regs)
		return;
		}

		#ifdef CONFIG_KEXEC
		cpumask_set_cpu(smp_processor_id(), &cpus_in_sr);
		#endif

		die("System Reset", regs, SIGABRT);

		/*
		* Some CPUs when released from the debugger will execute this path.
		* These CPUs entered the debugger via a soft-reset. If the CPU was
		* hung before entering the debugger it will return to the hung
		* state when exiting this function. This causes a problem in
		* kdump since the hung CPU(s) will not respond to the IPI sent
		* from kdump. To prevent the problem we call crash_kexec_secondary()
		* here. If a kdump had not been initiated or we exit the debugger
		* with the "exit and recover" command (x) crash_kexec_secondary()
		* will return after 5ms and the CPU returns to its previous state.
		*/
		crash_kexec_secondary(regs);

		/* Must die if the interrupt is not recoverable */
		if (!(regs->msr & MSR_RI))
		panic("Unrecoverable System Reset");