d04c56f73c
This implements a lazy strategy for disabling interrupts. This means that local_irq_disable() et al. just clear the 'interrupts are enabled' flag in the paca. If an interrupt comes along, the interrupt entry code notices that interrupts are supposed to be disabled, and clears the EE bit in SRR1, clears the 'interrupts are hard-enabled' flag in the paca, and returns. This means that interrupts only actually get disabled in the processor when an interrupt comes along. When interrupts are enabled by local_irq_enable() et al., the code sets the interrupts-enabled flag in the paca, and then checks whether interrupts got hard-disabled. If so, it also sets the EE bit in the MSR to hard-enable the interrupts. This has the potential to improve performance, and also makes it easier to make a kernel that can boot on iSeries and on other 64-bit machines, since this lazy-disable strategy is very similar to the soft-disable strategy that iSeries already uses. This version renames paca->proc_enabled to paca->soft_enabled, and changes a couple of soft-disables in the kexec code to hard-disables, which should fix the crash that Michael Ellerman saw. This doesn't yet use a reserved CR field for the soft_enabled and hard_enabled flags. This applies on top of Stephen Rothwell's patches to make it possible to build a combined iSeries/other kernel. Signed-off-by: Paul Mackerras <paulus@samba.org>
315 lines
7.4 KiB
C
315 lines
7.4 KiB
C
/*
|
|
* 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/irq.h>
|
|
#include <linux/types.h>
|
|
#include <linux/irq.h>
|
|
|
|
#include <asm/processor.h>
|
|
#include <asm/machdep.h>
|
|
#include <asm/kexec.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 cpumask_t cpus_in_crash = CPU_MASK_NONE;
|
|
cpumask_t cpus_in_sr = CPU_MASK_NONE;
|
|
|
|
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 = (u32*)per_cpu_ptr(crash_notes, cpu);
|
|
if (!buf)
|
|
return;
|
|
|
|
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);
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
static atomic_t enter_on_soft_reset = ATOMIC_INIT(0);
|
|
|
|
void crash_ipi_callback(struct pt_regs *regs)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
|
|
if (!cpu_online(cpu))
|
|
return;
|
|
|
|
hard_irq_disable();
|
|
if (!cpu_isset(cpu, cpus_in_crash))
|
|
crash_save_this_cpu(regs, cpu);
|
|
cpu_set(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 (cpu_isset(cpu, cpus_in_sr)) {
|
|
cpu_clear(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 (!cpu_isset(crashing_cpu, cpus_in_crash))
|
|
cpu_relax();
|
|
|
|
if (ppc_md.kexec_cpu_down)
|
|
ppc_md.kexec_cpu_down(1, 1);
|
|
|
|
#ifdef CONFIG_PPC64
|
|
kexec_smp_wait();
|
|
#else
|
|
for (;;); /* FIXME */
|
|
#endif
|
|
|
|
/* 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 */
|
|
|
|
cpu_clear(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 */
|
|
|
|
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.
|
|
* Delay of at least 10 seconds.
|
|
*/
|
|
printk(KERN_EMERG "Sending IPI to other cpus...\n");
|
|
msecs = 10000;
|
|
while ((cpus_weight(cpus_in_crash) < ncpus) && (--msecs > 0)) {
|
|
cpu_relax();
|
|
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.
|
|
* Soft-reset will be used until better mechanism is implemented.
|
|
*/
|
|
if (cpus_weight(cpus_in_crash) < ncpus) {
|
|
printk(KERN_EMERG "done waiting: %d cpu(s) not responding\n",
|
|
ncpus - cpus_weight(cpus_in_crash));
|
|
printk(KERN_EMERG "Activate soft-reset to stop other cpu(s)\n");
|
|
cpus_in_sr = CPU_MASK_NONE;
|
|
atomic_set(&enter_on_soft_reset, 0);
|
|
while (cpus_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 (cpu_isset(cpu, cpus_in_sr))
|
|
crash_soft_reset_check(cpu);
|
|
/* Leave the IPI callback set */
|
|
}
|
|
|
|
/*
|
|
* This function will be called by secondary cpus or by kexec cpu
|
|
* if soft-reset is activated to stop some CPUs.
|
|
*/
|
|
void crash_kexec_secondary(struct pt_regs *regs)
|
|
{
|
|
int cpu = smp_processor_id();
|
|
unsigned long flags;
|
|
int msecs = 5;
|
|
|
|
local_irq_save(flags);
|
|
/* Wait 5ms if the kexec CPU is not entered yet. */
|
|
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.
|
|
*/
|
|
cpu_clear(cpu, cpus_in_sr);
|
|
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);
|
|
cpu_set(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);
|
|
}
|
|
|
|
#else
|
|
static void crash_kexec_prepare_cpus(int cpu)
|
|
{
|
|
/*
|
|
* move the secondarys to us so that we can copy
|
|
* the new kernel 0-0x100 safely
|
|
*
|
|
* do this if kexec in setup.c ?
|
|
*/
|
|
#ifdef CONFIG_PPC64
|
|
smp_release_cpus();
|
|
#else
|
|
/* FIXME */
|
|
#endif
|
|
}
|
|
|
|
void crash_kexec_secondary(struct pt_regs *regs)
|
|
{
|
|
cpus_in_sr = CPU_MASK_NONE;
|
|
}
|
|
#endif
|
|
|
|
void default_machine_crash_shutdown(struct pt_regs *regs)
|
|
{
|
|
unsigned int irq;
|
|
|
|
/*
|
|
* This function is only called after the system
|
|
* has panicked 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.
|
|
*/
|
|
hard_irq_disable();
|
|
|
|
for_each_irq(irq) {
|
|
struct irq_desc *desc = irq_desc + irq;
|
|
|
|
if (desc->status & IRQ_INPROGRESS)
|
|
desc->chip->eoi(irq);
|
|
|
|
if (!(desc->status & IRQ_DISABLED))
|
|
desc->chip->disable(irq);
|
|
}
|
|
|
|
/*
|
|
* 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_save_this_cpu(regs, crashing_cpu);
|
|
crash_kexec_prepare_cpus(crashing_cpu);
|
|
cpu_set(crashing_cpu, cpus_in_crash);
|
|
if (ppc_md.kexec_cpu_down)
|
|
ppc_md.kexec_cpu_down(1, 0);
|
|
}
|