315 lines
7.4 KiB
C
315 lines
7.4 KiB
C
/*
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* Architecture specific (PPC64) functions for kexec based crash dumps.
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*
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* Copyright (C) 2005, IBM Corp.
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*
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* Created by: Haren Myneni
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*
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*/
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#undef DEBUG
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/reboot.h>
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#include <linux/kexec.h>
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#include <linux/bootmem.h>
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#include <linux/crash_dump.h>
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#include <linux/delay.h>
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#include <linux/elf.h>
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#include <linux/elfcore.h>
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#include <linux/init.h>
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#include <linux/irq.h>
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#include <linux/types.h>
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#include <linux/irq.h>
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#include <asm/processor.h>
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#include <asm/machdep.h>
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#include <asm/kexec.h>
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#include <asm/kdump.h>
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#include <asm/lmb.h>
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#include <asm/firmware.h>
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#include <asm/smp.h>
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#ifdef DEBUG
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#include <asm/udbg.h>
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#define DBG(fmt...) udbg_printf(fmt)
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#else
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#define DBG(fmt...)
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#endif
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/* This keeps a track of which one is crashing cpu. */
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int crashing_cpu = -1;
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static cpumask_t cpus_in_crash = CPU_MASK_NONE;
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cpumask_t cpus_in_sr = CPU_MASK_NONE;
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static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
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size_t data_len)
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{
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struct elf_note note;
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note.n_namesz = strlen(name) + 1;
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note.n_descsz = data_len;
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note.n_type = type;
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memcpy(buf, ¬e, sizeof(note));
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buf += (sizeof(note) +3)/4;
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memcpy(buf, name, note.n_namesz);
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buf += (note.n_namesz + 3)/4;
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memcpy(buf, data, note.n_descsz);
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buf += (note.n_descsz + 3)/4;
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return buf;
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}
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static void final_note(u32 *buf)
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{
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struct elf_note note;
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note.n_namesz = 0;
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note.n_descsz = 0;
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note.n_type = 0;
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memcpy(buf, ¬e, sizeof(note));
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}
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static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
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{
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struct elf_prstatus prstatus;
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u32 *buf;
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if ((cpu < 0) || (cpu >= NR_CPUS))
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return;
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/* Using ELF notes here is opportunistic.
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* I need a well defined structure format
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* for the data I pass, and I need tags
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* on the data to indicate what information I have
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* squirrelled away. ELF notes happen to provide
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* all of that that no need to invent something new.
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*/
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buf = (u32*)per_cpu_ptr(crash_notes, cpu);
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if (!buf)
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return;
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memset(&prstatus, 0, sizeof(prstatus));
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prstatus.pr_pid = current->pid;
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elf_core_copy_regs(&prstatus.pr_reg, regs);
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buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
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sizeof(prstatus));
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final_note(buf);
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}
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#ifdef CONFIG_SMP
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static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
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void crash_ipi_callback(struct pt_regs *regs)
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{
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int cpu = smp_processor_id();
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if (!cpu_online(cpu))
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return;
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local_irq_disable();
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if (!cpu_isset(cpu, cpus_in_crash))
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crash_save_this_cpu(regs, cpu);
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cpu_set(cpu, cpus_in_crash);
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/*
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* Entered via soft-reset - could be the kdump
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* process is invoked using soft-reset or user activated
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* it if some CPU did not respond to an IPI.
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* For soft-reset, the secondary CPU can enter this func
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* twice. 1 - using IPI, and 2. soft-reset.
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* Tell the kexec CPU that entered via soft-reset and ready
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* to go down.
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*/
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if (cpu_isset(cpu, cpus_in_sr)) {
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cpu_clear(cpu, cpus_in_sr);
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atomic_inc(&enter_on_soft_reset);
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}
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/*
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* Starting the kdump boot.
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* This barrier is needed to make sure that all CPUs are stopped.
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* If not, soft-reset will be invoked to bring other CPUs.
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*/
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while (!cpu_isset(crashing_cpu, cpus_in_crash))
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cpu_relax();
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if (ppc_md.kexec_cpu_down)
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ppc_md.kexec_cpu_down(1, 1);
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#ifdef CONFIG_PPC64
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kexec_smp_wait();
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#else
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for (;;); /* FIXME */
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#endif
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/* NOTREACHED */
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}
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/*
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* Wait until all CPUs are entered via soft-reset.
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*/
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static void crash_soft_reset_check(int cpu)
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{
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unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
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cpu_clear(cpu, cpus_in_sr);
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while (atomic_read(&enter_on_soft_reset) != ncpus)
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cpu_relax();
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}
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static void crash_kexec_prepare_cpus(int cpu)
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{
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unsigned int msecs;
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unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
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crash_send_ipi(crash_ipi_callback);
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smp_wmb();
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/*
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* FIXME: Until we will have the way to stop other CPUSs reliabally,
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* the crash CPU will send an IPI and wait for other CPUs to
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* respond.
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* Delay of at least 10 seconds.
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*/
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printk(KERN_EMERG "Sending IPI to other cpus...\n");
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msecs = 10000;
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while ((cpus_weight(cpus_in_crash) < ncpus) && (--msecs > 0)) {
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cpu_relax();
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mdelay(1);
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}
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/* Would it be better to replace the trap vector here? */
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/*
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* FIXME: In case if we do not get all CPUs, one possibility: ask the
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* user to do soft reset such that we get all.
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* Soft-reset will be used until better mechanism is implemented.
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*/
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if (cpus_weight(cpus_in_crash) < ncpus) {
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printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
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ncpus - cpus_weight(cpus_in_crash));
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printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
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cpus_in_sr = CPU_MASK_NONE;
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atomic_set(&enter_on_soft_reset, 0);
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while (cpus_weight(cpus_in_crash) < ncpus)
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cpu_relax();
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}
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/*
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* Make sure all CPUs are entered via soft-reset if the kdump is
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* invoked using soft-reset.
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*/
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if (cpu_isset(cpu, cpus_in_sr))
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crash_soft_reset_check(cpu);
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/* Leave the IPI callback set */
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}
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/*
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* This function will be called by secondary cpus or by kexec cpu
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* if soft-reset is activated to stop some CPUs.
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*/
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void crash_kexec_secondary(struct pt_regs *regs)
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{
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int cpu = smp_processor_id();
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unsigned long flags;
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int msecs = 5;
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local_irq_save(flags);
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/* Wait 5ms if the kexec CPU is not entered yet. */
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while (crashing_cpu < 0) {
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if (--msecs < 0) {
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/*
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* Either kdump image is not loaded or
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* kdump process is not started - Probably xmon
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* exited using 'x'(exit and recover) or
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* kexec_should_crash() failed for all running tasks.
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*/
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cpu_clear(cpu, cpus_in_sr);
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local_irq_restore(flags);
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return;
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}
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mdelay(1);
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cpu_relax();
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}
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if (cpu == crashing_cpu) {
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/*
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* Panic CPU will enter this func only via soft-reset.
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* Wait until all secondary CPUs entered and
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* then start kexec boot.
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*/
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crash_soft_reset_check(cpu);
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cpu_set(crashing_cpu, cpus_in_crash);
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if (ppc_md.kexec_cpu_down)
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ppc_md.kexec_cpu_down(1, 0);
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machine_kexec(kexec_crash_image);
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/* NOTREACHED */
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}
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crash_ipi_callback(regs);
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}
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#else
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static void crash_kexec_prepare_cpus(int cpu)
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{
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/*
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* move the secondarys to us so that we can copy
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* the new kernel 0-0x100 safely
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*
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* do this if kexec in setup.c ?
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*/
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#ifdef CONFIG_PPC64
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smp_release_cpus();
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#else
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/* FIXME */
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#endif
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}
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void crash_kexec_secondary(struct pt_regs *regs)
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{
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cpus_in_sr = CPU_MASK_NONE;
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}
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#endif
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void default_machine_crash_shutdown(struct pt_regs *regs)
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{
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unsigned int irq;
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/*
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* This function is only called after the system
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* has panicked or is otherwise in a critical state.
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* The minimum amount of code to allow a kexec'd kernel
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* to run successfully needs to happen here.
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*
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* In practice this means stopping other cpus in
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* an SMP system.
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* The kernel is broken so disable interrupts.
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*/
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local_irq_disable();
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for_each_irq(irq) {
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struct irq_desc *desc = irq_desc + irq;
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if (desc->status & IRQ_INPROGRESS)
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desc->chip->end(irq);
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if (!(desc->status & IRQ_DISABLED))
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desc->chip->disable(irq);
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}
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/*
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* Make a note of crashing cpu. Will be used in machine_kexec
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* such that another IPI will not be sent.
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*/
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crashing_cpu = smp_processor_id();
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crash_save_this_cpu(regs, crashing_cpu);
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crash_kexec_prepare_cpus(crashing_cpu);
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cpu_set(crashing_cpu, cpus_in_crash);
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if (ppc_md.kexec_cpu_down)
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ppc_md.kexec_cpu_down(1, 0);
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}
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