cc53291521
Implementing the machine_crash_shutdown which will be called by crash_kexec (called in case of a panic, sysrq etc.). Disable the interrupts, shootdown cpus using debugger IPI and collect regs for all CPUs. elfcorehdr= specifies the location of elf core header stored by the crashed kernel. This command line option will be passed by the kexec-tools to capture kernel. savemaxmem= specifies the actual memory size that the first kernel has and this value will be used for dumping in the capture kernel. This command line option will be passed by the kexec-tools to capture kernel. Signed-off-by: Haren Myneni <haren@us.ibm.com> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
265 lines
6.0 KiB
C
265 lines
6.0 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/irq.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/types.h>
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#include <asm/processor.h>
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#include <asm/machdep.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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#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 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 = &crash_notes[cpu][0];
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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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/* FIXME Merge this with xmon_save_regs ?? */
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static inline void crash_get_current_regs(struct pt_regs *regs)
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{
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unsigned long tmp1, tmp2;
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__asm__ __volatile__ (
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"std 0,0(%2)\n"
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"std 1,8(%2)\n"
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"std 2,16(%2)\n"
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"std 3,24(%2)\n"
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"std 4,32(%2)\n"
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"std 5,40(%2)\n"
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"std 6,48(%2)\n"
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"std 7,56(%2)\n"
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"std 8,64(%2)\n"
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"std 9,72(%2)\n"
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"std 10,80(%2)\n"
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"std 11,88(%2)\n"
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"std 12,96(%2)\n"
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"std 13,104(%2)\n"
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"std 14,112(%2)\n"
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"std 15,120(%2)\n"
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"std 16,128(%2)\n"
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"std 17,136(%2)\n"
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"std 18,144(%2)\n"
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"std 19,152(%2)\n"
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"std 20,160(%2)\n"
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"std 21,168(%2)\n"
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"std 22,176(%2)\n"
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"std 23,184(%2)\n"
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"std 24,192(%2)\n"
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"std 25,200(%2)\n"
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"std 26,208(%2)\n"
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"std 27,216(%2)\n"
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"std 28,224(%2)\n"
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"std 29,232(%2)\n"
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"std 30,240(%2)\n"
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"std 31,248(%2)\n"
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"mfmsr %0\n"
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"std %0, 264(%2)\n"
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"mfctr %0\n"
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"std %0, 280(%2)\n"
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"mflr %0\n"
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"std %0, 288(%2)\n"
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"bl 1f\n"
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"1: mflr %1\n"
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"std %1, 256(%2)\n"
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"mtlr %0\n"
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"mfxer %0\n"
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"std %0, 296(%2)\n"
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: "=&r" (tmp1), "=&r" (tmp2)
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: "b" (regs));
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}
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/* We may have saved_regs from where the error came from
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* or it is NULL if via a direct panic().
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*/
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static void crash_save_self(struct pt_regs *saved_regs)
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{
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struct pt_regs regs;
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int cpu;
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cpu = smp_processor_id();
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if (saved_regs)
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memcpy(®s, saved_regs, sizeof(regs));
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else
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crash_get_current_regs(®s);
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crash_save_this_cpu(®s, cpu);
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}
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#ifdef CONFIG_SMP
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static atomic_t waiting_for_crash_ipi;
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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 == crashing_cpu)
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return;
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if (!cpu_online(cpu))
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return;
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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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local_irq_disable();
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crash_save_this_cpu(regs, cpu);
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atomic_dec(&waiting_for_crash_ipi);
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kexec_smp_wait();
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/* NOTREACHED */
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}
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static void crash_kexec_prepare_cpus(void)
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{
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unsigned int msecs;
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atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
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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. If not, proceed the kexec boot even though we failed to
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* capture other CPU states.
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*/
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msecs = 1000000;
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while ((atomic_read(&waiting_for_crash_ipi) > 0) && (--msecs > 0)) {
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barrier();
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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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* IPI handler is already set by the panic cpu initially. Therefore,
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* all cpus could invoke this handler from die() and the panic CPU
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* will call machine_kexec() directly from this handler to do
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* kexec boot.
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*/
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if (atomic_read(&waiting_for_crash_ipi))
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printk(KERN_ALERT "done waiting: %d cpus not responding\n",
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atomic_read(&waiting_for_crash_ipi));
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/* Leave the IPI callback set */
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}
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#else
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static void crash_kexec_prepare_cpus(void)
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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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smp_release_cpus();
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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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/*
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* This function is only called after the system
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* has paniced 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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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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* 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_kexec_prepare_cpus();
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crash_save_self(regs);
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}
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