/*
* Architecture specific (PPC64) functions for kexec based crash dumps.
*
* Copyright (C) 2005, IBM Corp.
*
* Created by: Haren Myneni
*
* This source code is licensed under the GNU General Public License,
* Version 2. See the file COPYING for more details.
*
*/
#undef DEBUG
#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/reboot.h>
#include <linux/kexec.h>
#include <linux/bootmem.h>
#include <linux/crash_dump.h>
#include <linux/delay.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/types.h>
#include <asm/processor.h>
#include <asm/machdep.h>
#include <asm/kdump.h>
#include <asm/lmb.h>
#include <asm/firmware.h>
#include <asm/smp.h>
#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif
/* This keeps a track of which one is crashing cpu. */
int crashing_cpu = -1;
static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
size_t data_len)
{
struct elf_note note;
note.n_namesz = strlen(name) + 1;
note.n_descsz = data_len;
note.n_type = type;
memcpy(buf, ¬e, sizeof(note));
buf += (sizeof(note) +3)/4;
memcpy(buf, name, note.n_namesz);
buf += (note.n_namesz + 3)/4;
memcpy(buf, data, note.n_descsz);
buf += (note.n_descsz + 3)/4;
return buf;
}
static void final_note(u32 *buf)
{
struct elf_note note;
note.n_namesz = 0;
note.n_descsz = 0;
note.n_type = 0;
memcpy(buf, ¬e, sizeof(note));
}
static void crash_save_this_cpu(struct pt_regs *regs, int cpu)
{
struct elf_prstatus prstatus;
u32 *buf;
if ((cpu < 0) || (cpu >= NR_CPUS))
return;
/* Using ELF notes here is opportunistic.
* I need a well defined structure format
* for the data I pass, and I need tags
* on the data to indicate what information I have
* squirrelled away. ELF notes happen to provide
* all of that that no need to invent something new.
*/
buf = &crash_notes[cpu][0];
memset(&prstatus, 0, sizeof(prstatus));
prstatus.pr_pid = current->pid;
elf_core_copy_regs(&prstatus.pr_reg, regs);
buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
sizeof(prstatus));
final_note(buf);
}
/* FIXME Merge this with xmon_save_regs ?? */
static inline void crash_get_current_regs(struct pt_regs *regs)
{
unsigned long tmp1, tmp2;
__asm__ __volatile__ (
"std 0,0(%2)\n"
"std 1,8(%2)\n"
"std 2,16(%2)\n"
"std 3,24(%2)\n"
"std 4,32(%2)\n"
"std 5,40(%2)\n"
"std 6,48(%2)\n"
"std 7,56(%2)\n"
"std 8,64(%2)\n"
"std 9,72(%2)\n"
"std 10,80(%2)\n"
"std 11,88(%2)\n"
"std 12,96(%2)\n"
"std 13,104(%2)\n"
"std 14,112(%2)\n"
"std 15,120(%2)\n"
"std 16,128(%2)\n"
"std 17,136(%2)\n"
"std 18,144(%2)\n"
"std 19,152(%2)\n"
"std 20,160(%2)\n"
"std 21,168(%2)\n"
"std 22,176(%2)\n"
"std 23,184(%2)\n"
"std 24,192(%2)\n"
"std 25,200(%2)\n"
"std 26,208(%2)\n"
"std 27,216(%2)\n"
"std 28,224(%2)\n"
"std 29,232(%2)\n"
"std 30,240(%2)\n"
"std 31,248(%2)\n"
"mfmsr %0\n"
"std %0, 264(%2)\n"
"mfctr %0\n"
"std %0, 280(%2)\n"
"mflr %0\n"
"std %0, 288(%2)\n"
"bl 1f\n"
"1: mflr %1\n"
"std %1, 256(%2)\n"
"mtlr %0\n"
"mfxer %0\n"
"std %0, 296(%2)\n"
: "=&r" (tmp1), "=&r" (tmp2)
: "b" (regs));
}
/* We may have saved_regs from where the error came from
* or it is NULL if via a direct panic().
*/
static void crash_save_self(struct pt_regs *saved_regs)
{
struct pt_regs regs;
int cpu;
cpu = smp_processor_id();
if (saved_regs)
memcpy(®s, saved_regs, sizeof(regs));
else
crash_get_current_regs(®s);
crash_save_this_cpu(®s, cpu);
}
#ifdef CONFIG_SMP
static atomic_t waiting_for_crash_ipi;
void crash_ipi_callback(struct pt_regs *regs)
{
int cpu = smp_processor_id();
if (cpu == crashing_cpu)
return;
if (!cpu_online(cpu))
return;
if (ppc_md.kexec_cpu_down)
ppc_md.kexec_cpu_down(1, 1);
local_irq_disable();
crash_save_this_cpu(regs, cpu);
atomic_dec(&waiting_for_crash_ipi);
kexec_smp_wait();
/* NOTREACHED */
}
static void crash_kexec_prepare_cpus(void)
{
unsigned int msecs;
atomic_set(&waiting_for_crash_ipi, num_online_cpus() - 1);
crash_send_ipi(crash_ipi_callback);
smp_wmb();
/*
* FIXME: Until we will have the way to stop other CPUSs reliabally,
* the crash CPU will send an IPI and wait for other CPUs to
* respond. If not, proceed the kexec boot even though we failed to
* capture other CPU states.
*/
msecs = 1000000;
while ((atomic_read(&waiting_for_crash_ipi) > 0) && (--msecs > 0)) {
barrier();
mdelay(1);
}
/* 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.
* IPI handler is already set by the panic cpu initially. Therefore,
* all cpus could invoke this handler from die() and the panic CPU
* will call machine_kexec() directly from this handler to do
* kexec boot.
*/
if (atomic_read(&waiting_for_crash_ipi))
printk(KERN_ALERT "done waiting: %d cpus not responding\n",
atomic_read(&waiting_for_crash_ipi));
/* Leave the IPI callback set */
}
#else
static void crash_kexec_prepare_cpus(void)
{
/*
* move the secondarys to us so that we can copy
* the new kernel 0-0x100 safely
*
* do this if kexec in setup.c ?
*/
smp_release_cpus();
}
#endif
void default_machine_crash_shutdown(struct pt_regs *regs)
{
/*
* This function is only called after the system
* has paniced or is otherwise in a critical state.
* The minimum amount of code to allow a kexec'd kernel
* to run successfully needs to happen here.
*
* In practice this means stopping other cpus in
* an SMP system.
* The kernel is broken so disable interrupts.
*/
local_irq_disable();
if (ppc_md.kexec_cpu_down)
ppc_md.kexec_cpu_down(1, 0);
/*
* Make a note of crashing cpu. Will be used in machine_kexec
* such that another IPI will not be sent.
*/
crashing_cpu = smp_processor_id();
crash_kexec_prepare_cpus();
crash_save_self(regs);
}
