379 lines
8.8 KiB
C
379 lines
8.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Architecture specific (PPC64) functions for kexec based crash dumps.
|
|
*
|
|
* Copyright (C) 2005, IBM Corp.
|
|
*
|
|
* Created by: Haren Myneni
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/reboot.h>
|
|
#include <linux/kexec.h>
|
|
#include <linux/export.h>
|
|
#include <linux/crash_dump.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/irq.h>
|
|
#include <linux/types.h>
|
|
|
|
#include <asm/processor.h>
|
|
#include <asm/machdep.h>
|
|
#include <asm/kexec.h>
|
|
#include <asm/prom.h>
|
|
#include <asm/smp.h>
|
|
#include <asm/setjmp.h>
|
|
#include <asm/debug.h>
|
|
#include <asm/interrupt.h>
|
|
|
|
/*
|
|
* The primary CPU waits a while for all secondary CPUs to enter. This is to
|
|
* avoid sending an IPI if the secondary CPUs are entering
|
|
* crash_kexec_secondary on their own (eg via a system reset).
|
|
*
|
|
* The secondary timeout has to be longer than the primary. Both timeouts are
|
|
* in milliseconds.
|
|
*/
|
|
#define PRIMARY_TIMEOUT 500
|
|
#define SECONDARY_TIMEOUT 1000
|
|
|
|
#define IPI_TIMEOUT 10000
|
|
#define REAL_MODE_TIMEOUT 10000
|
|
|
|
static int time_to_dump;
|
|
/*
|
|
* crash_wake_offline should be set to 1 by platforms that intend to wake
|
|
* up offline cpus prior to jumping to a kdump kernel. Currently powernv
|
|
* sets it to 1, since we want to avoid things from happening when an
|
|
* offline CPU wakes up due to something like an HMI (malfunction error),
|
|
* which propagates to all threads.
|
|
*/
|
|
int crash_wake_offline;
|
|
|
|
#define CRASH_HANDLER_MAX 3
|
|
/* List of shutdown handles */
|
|
static crash_shutdown_t crash_shutdown_handles[CRASH_HANDLER_MAX];
|
|
static DEFINE_SPINLOCK(crash_handlers_lock);
|
|
|
|
static unsigned long crash_shutdown_buf[JMP_BUF_LEN];
|
|
static int crash_shutdown_cpu = -1;
|
|
|
|
static int handle_fault(struct pt_regs *regs)
|
|
{
|
|
if (crash_shutdown_cpu == smp_processor_id())
|
|
longjmp(crash_shutdown_buf, 1);
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
static atomic_t cpus_in_crash;
|
|
void crash_ipi_callback(struct pt_regs *regs)
|
|
{
|
|
static cpumask_t cpus_state_saved = CPU_MASK_NONE;
|
|
|
|
int cpu = smp_processor_id();
|
|
|
|
hard_irq_disable();
|
|
if (!cpumask_test_cpu(cpu, &cpus_state_saved)) {
|
|
crash_save_cpu(regs, cpu);
|
|
cpumask_set_cpu(cpu, &cpus_state_saved);
|
|
}
|
|
|
|
atomic_inc(&cpus_in_crash);
|
|
smp_mb__after_atomic();
|
|
|
|
/*
|
|
* Starting the kdump boot.
|
|
* This barrier is needed to make sure that all CPUs are stopped.
|
|
*/
|
|
while (!time_to_dump)
|
|
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 */
|
|
}
|
|
|
|
static void crash_kexec_prepare_cpus(int cpu)
|
|
{
|
|
unsigned int msecs;
|
|
unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
|
|
int tries = 0;
|
|
int (*old_handler)(struct pt_regs *regs);
|
|
|
|
printk(KERN_EMERG "Sending IPI to other CPUs\n");
|
|
|
|
if (crash_wake_offline)
|
|
ncpus = num_present_cpus() - 1;
|
|
|
|
crash_send_ipi(crash_ipi_callback);
|
|
smp_wmb();
|
|
|
|
again:
|
|
/*
|
|
* FIXME: Until we will have the way to stop other CPUs reliably,
|
|
* the crash CPU will send an IPI and wait for other CPUs to
|
|
* respond.
|
|
*/
|
|
msecs = IPI_TIMEOUT;
|
|
while ((atomic_read(&cpus_in_crash) < ncpus) && (--msecs > 0))
|
|
mdelay(1);
|
|
|
|
/* Would it be better to replace the trap vector here? */
|
|
|
|
if (atomic_read(&cpus_in_crash) >= ncpus) {
|
|
printk(KERN_EMERG "IPI complete\n");
|
|
return;
|
|
}
|
|
|
|
printk(KERN_EMERG "ERROR: %d cpu(s) not responding\n",
|
|
ncpus - atomic_read(&cpus_in_crash));
|
|
|
|
/*
|
|
* If we have a panic timeout set then we can't wait indefinitely
|
|
* for someone to activate system reset. We also give up on the
|
|
* second time through if system reset fail to work.
|
|
*/
|
|
if ((panic_timeout > 0) || (tries > 0))
|
|
return;
|
|
|
|
/*
|
|
* A system reset will cause all CPUs to take an 0x100 exception.
|
|
* The primary CPU returns here via setjmp, and the secondary
|
|
* CPUs reexecute the crash_kexec_secondary path.
|
|
*/
|
|
old_handler = __debugger;
|
|
__debugger = handle_fault;
|
|
crash_shutdown_cpu = smp_processor_id();
|
|
|
|
if (setjmp(crash_shutdown_buf) == 0) {
|
|
printk(KERN_EMERG "Activate system reset (dumprestart) "
|
|
"to stop other cpu(s)\n");
|
|
|
|
/*
|
|
* A system reset will force all CPUs to execute the
|
|
* crash code again. We need to reset cpus_in_crash so we
|
|
* wait for everyone to do this.
|
|
*/
|
|
atomic_set(&cpus_in_crash, 0);
|
|
smp_mb();
|
|
|
|
while (atomic_read(&cpus_in_crash) < ncpus)
|
|
cpu_relax();
|
|
}
|
|
|
|
crash_shutdown_cpu = -1;
|
|
__debugger = old_handler;
|
|
|
|
tries++;
|
|
goto again;
|
|
}
|
|
|
|
/*
|
|
* This function will be called by secondary cpus.
|
|
*/
|
|
void crash_kexec_secondary(struct pt_regs *regs)
|
|
{
|
|
unsigned long flags;
|
|
int msecs = SECONDARY_TIMEOUT;
|
|
|
|
local_irq_save(flags);
|
|
|
|
/* Wait for the primary crash CPU to signal its progress */
|
|
while (crashing_cpu < 0) {
|
|
if (--msecs < 0) {
|
|
/* No response, kdump image may not have been loaded */
|
|
local_irq_restore(flags);
|
|
return;
|
|
}
|
|
|
|
mdelay(1);
|
|
}
|
|
|
|
crash_ipi_callback(regs);
|
|
}
|
|
|
|
#else /* ! CONFIG_SMP */
|
|
|
|
static void crash_kexec_prepare_cpus(int cpu)
|
|
{
|
|
/*
|
|
* move the secondaries 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)
|
|
{
|
|
}
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/* wait for all the CPUs to hit real mode but timeout if they don't come in */
|
|
#if defined(CONFIG_SMP) && defined(CONFIG_PPC64)
|
|
static void __maybe_unused crash_kexec_wait_realmode(int cpu)
|
|
{
|
|
unsigned int msecs;
|
|
int i;
|
|
|
|
msecs = REAL_MODE_TIMEOUT;
|
|
for (i=0; i < nr_cpu_ids && msecs > 0; i++) {
|
|
if (i == cpu)
|
|
continue;
|
|
|
|
while (paca_ptrs[i]->kexec_state < KEXEC_STATE_REAL_MODE) {
|
|
barrier();
|
|
if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0))
|
|
break;
|
|
msecs--;
|
|
mdelay(1);
|
|
}
|
|
}
|
|
mb();
|
|
}
|
|
#else
|
|
static inline void crash_kexec_wait_realmode(int cpu) {}
|
|
#endif /* CONFIG_SMP && CONFIG_PPC64 */
|
|
|
|
/*
|
|
* Register a function to be called on shutdown. Only use this if you
|
|
* can't reset your device in the second kernel.
|
|
*/
|
|
int crash_shutdown_register(crash_shutdown_t handler)
|
|
{
|
|
unsigned int i, rc;
|
|
|
|
spin_lock(&crash_handlers_lock);
|
|
for (i = 0 ; i < CRASH_HANDLER_MAX; i++)
|
|
if (!crash_shutdown_handles[i]) {
|
|
/* Insert handle at first empty entry */
|
|
crash_shutdown_handles[i] = handler;
|
|
rc = 0;
|
|
break;
|
|
}
|
|
|
|
if (i == CRASH_HANDLER_MAX) {
|
|
printk(KERN_ERR "Crash shutdown handles full, "
|
|
"not registered.\n");
|
|
rc = 1;
|
|
}
|
|
|
|
spin_unlock(&crash_handlers_lock);
|
|
return rc;
|
|
}
|
|
EXPORT_SYMBOL(crash_shutdown_register);
|
|
|
|
int crash_shutdown_unregister(crash_shutdown_t handler)
|
|
{
|
|
unsigned int i, rc;
|
|
|
|
spin_lock(&crash_handlers_lock);
|
|
for (i = 0 ; i < CRASH_HANDLER_MAX; i++)
|
|
if (crash_shutdown_handles[i] == handler)
|
|
break;
|
|
|
|
if (i == CRASH_HANDLER_MAX) {
|
|
printk(KERN_ERR "Crash shutdown handle not found\n");
|
|
rc = 1;
|
|
} else {
|
|
/* Shift handles down */
|
|
for (; i < (CRASH_HANDLER_MAX - 1); i++)
|
|
crash_shutdown_handles[i] =
|
|
crash_shutdown_handles[i+1];
|
|
/*
|
|
* Reset last entry to NULL now that it has been shifted down,
|
|
* this will allow new handles to be added here.
|
|
*/
|
|
crash_shutdown_handles[i] = NULL;
|
|
rc = 0;
|
|
}
|
|
|
|
spin_unlock(&crash_handlers_lock);
|
|
return rc;
|
|
}
|
|
EXPORT_SYMBOL(crash_shutdown_unregister);
|
|
|
|
void default_machine_crash_shutdown(struct pt_regs *regs)
|
|
{
|
|
unsigned int i;
|
|
int (*old_handler)(struct pt_regs *regs);
|
|
|
|
/* Avoid hardlocking with irresponsive CPU holding logbuf_lock */
|
|
printk_nmi_enter();
|
|
|
|
/*
|
|
* 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();
|
|
|
|
/*
|
|
* 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();
|
|
|
|
/*
|
|
* If we came in via system reset, wait a while for the secondary
|
|
* CPUs to enter.
|
|
*/
|
|
if (TRAP(regs) == INTERRUPT_SYSTEM_RESET)
|
|
mdelay(PRIMARY_TIMEOUT);
|
|
|
|
crash_kexec_prepare_cpus(crashing_cpu);
|
|
|
|
crash_save_cpu(regs, crashing_cpu);
|
|
|
|
time_to_dump = 1;
|
|
|
|
crash_kexec_wait_realmode(crashing_cpu);
|
|
|
|
machine_kexec_mask_interrupts();
|
|
|
|
/*
|
|
* Call registered shutdown routines safely. Swap out
|
|
* __debugger_fault_handler, and replace on exit.
|
|
*/
|
|
old_handler = __debugger_fault_handler;
|
|
__debugger_fault_handler = handle_fault;
|
|
crash_shutdown_cpu = smp_processor_id();
|
|
for (i = 0; i < CRASH_HANDLER_MAX && crash_shutdown_handles[i]; i++) {
|
|
if (setjmp(crash_shutdown_buf) == 0) {
|
|
/*
|
|
* Insert syncs and delay to ensure
|
|
* instructions in the dangerous region don't
|
|
* leak away from this protected region.
|
|
*/
|
|
asm volatile("sync; isync");
|
|
/* dangerous region */
|
|
crash_shutdown_handles[i]();
|
|
asm volatile("sync; isync");
|
|
}
|
|
}
|
|
crash_shutdown_cpu = -1;
|
|
__debugger_fault_handler = old_handler;
|
|
|
|
if (ppc_md.kexec_cpu_down)
|
|
ppc_md.kexec_cpu_down(1, 0);
|
|
}
|