From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
kdump calls machine_crash_shutdown() to shut down non-boot cpus and
save registers' status in per-cpu ELF notes before starting the crash
dump kernel. See kernel_kexec().
ipi_cpu_stop() is a bit modified and used to support this behavior.
Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
---
arch/arm64/include/asm/kexec.h | 47 +++++++++++++++++++++++++++-
arch/arm64/kernel/machine_kexec.c | 65 +++++++++++++++++++++++++++++++++++++--
arch/arm64/kernel/smp.c | 18 ++++++++---
3 files changed, 123 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 04744dc..3dffb1d 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -30,6 +30,21 @@
#ifndef __ASSEMBLY__
+extern bool in_crash_kexec;
+
+static inline bool is_in_crash_kexec(void)
+{
+#ifdef CONFIG_KEXEC_CORE
+ return in_crash_kexec;
+#else
+ return false;
+#endif
+}
+
+#ifndef CONFIG_KEXEC_CORE
+#define crash_save_cpu(regs, cpu)
+#endif
+
/**
* crash_setup_regs() - save registers for the panic kernel
*
@@ -40,7 +55,37 @@
static inline void crash_setup_regs(struct pt_regs *newregs,
struct pt_regs *oldregs)
{
- /* Empty routine needed to avoid build errors. */
+ if (oldregs) {
+ memcpy(newregs, oldregs, sizeof(*newregs));
+ } else {
+ __asm__ __volatile__ (
+ "stp x0, x1, [%3, #16 * 0]\n"
+ "stp x2, x3, [%3, #16 * 1]\n"
+ "stp x4, x5, [%3, #16 * 2]\n"
+ "stp x6, x7, [%3, #16 * 3]\n"
+ "stp x8, x9, [%3, #16 * 4]\n"
+ "stp x10, x11, [%3, #16 * 5]\n"
+ "stp x12, x13, [%3, #16 * 6]\n"
+ "stp x14, x15, [%3, #16 * 7]\n"
+ "stp x16, x17, [%3, #16 * 8]\n"
+ "stp x18, x19, [%3, #16 * 9]\n"
+ "stp x20, x21, [%3, #16 * 10]\n"
+ "stp x22, x23, [%3, #16 * 11]\n"
+ "stp x24, x25, [%3, #16 * 12]\n"
+ "stp x26, x27, [%3, #16 * 13]\n"
+ "stp x28, x29, [%3, #16 * 14]\n"
+ "str x30, [%3, #16 * 15]\n"
+ "mov %0, sp\n"
+ "adr %1, 1f\n"
+ "mrs %2, spsr_el1\n"
+ "1:"
+ : "=r" (newregs->sp),
+ "=r" (newregs->pc),
+ "=r" (newregs->pstate)
+ : "r" (&newregs->regs)
+ : "memory"
+ );
+ }
}
#endif /* __ASSEMBLY__ */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index a375268..0ba2ae4 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -10,6 +10,9 @@
*/
#include <linux/highmem.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/libfdt_env.h>
#include <linux/of_fdt.h>
@@ -25,6 +28,7 @@
extern const unsigned char arm64_relocate_new_kernel[];
extern const unsigned long arm64_relocate_new_kernel_size;
+bool in_crash_kexec;
static unsigned long kimage_start;
/**
@@ -212,13 +216,70 @@ void machine_kexec(struct kimage *kimage)
* relocation is complete.
*/
- cpu_soft_restart(is_hyp_mode_available(),
+ cpu_soft_restart(in_crash_kexec ? 0 : is_hyp_mode_available(),
reboot_code_buffer_phys, kimage->head, kimage_start, 0);
BUG(); /* Should never get here. */
}
+static void machine_kexec_mask_interrupts(void)
+{
+ unsigned int i;
+ struct irq_desc *desc;
+
+ for_each_irq_desc(i, desc) {
+ struct irq_chip *chip;
+ int ret;
+
+ chip = irq_desc_get_chip(desc);
+ if (!chip)
+ continue;
+
+ /*
+ * First try to remove the active state. If this
+ * fails, try to EOI the interrupt.
+ */
+ ret = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
+
+ if (ret && irqd_irq_inprogress(&desc->irq_data) &&
+ chip->irq_eoi)
+ chip->irq_eoi(&desc->irq_data);
+
+ if (chip->irq_mask)
+ chip->irq_mask(&desc->irq_data);
+
+ if (chip->irq_disable && !irqd_irq_disabled(&desc->irq_data))
+ chip->irq_disable(&desc->irq_data);
+ }
+}
+
+/**
+ * machine_crash_shutdown - shutdown non-crashing cpus and save registers
+ */
void machine_crash_shutdown(struct pt_regs *regs)
{
- /* Empty routine needed to avoid build errors. */
+ struct pt_regs dummy_regs;
+ int cpu;
+
+ local_irq_disable();
+
+ in_crash_kexec = true;
+
+ /*
+ * clear and initialize the per-cpu info. This is necessary
+ * because, otherwise, slots for offline cpus would never be
+ * filled up. See smp_send_stop().
+ */
+ memset(&dummy_regs, 0, sizeof(dummy_regs));
+ for_each_possible_cpu(cpu)
+ crash_save_cpu(&dummy_regs, cpu);
+
+ /* shutdown non-crashing cpus */
+ smp_send_stop();
+
+ /* for crashing cpu */
+ crash_save_cpu(regs, smp_processor_id());
+ machine_kexec_mask_interrupts();
+
+ pr_info("Starting crashdump kernel...\n");
}
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index b1adc51..aa45c21 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -37,6 +37,7 @@
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/irq_work.h>
+#include <linux/kexec.h>
#include <asm/alternative.h>
#include <asm/atomic.h>
@@ -44,6 +45,7 @@
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/cpu_ops.h>
+#include <asm/kexec.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -54,6 +56,8 @@
#include <asm/ptrace.h>
#include <asm/virt.h>
+#include "cpu-reset.h"
+
#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>
@@ -683,10 +687,16 @@ static DEFINE_RAW_SPINLOCK(stop_lock);
/*
* ipi_cpu_stop - handle IPI from smp_send_stop()
*/
-static void ipi_cpu_stop(unsigned int cpu)
+static void ipi_cpu_stop(unsigned int cpu, struct pt_regs *regs)
{
- if (system_state == SYSTEM_BOOTING ||
- system_state == SYSTEM_RUNNING) {
+ if (is_in_crash_kexec()) {
+ crash_save_cpu(regs, cpu);
+ /*
+ * printing messages at panic may slow down the shutdown.
+ * So don't fall through dump_stack().
+ */
+ } else if (system_state == SYSTEM_BOOTING ||
+ system_state == SYSTEM_RUNNING) {
raw_spin_lock(&stop_lock);
pr_crit("CPU%u: stopping\n", cpu);
dump_stack();
@@ -727,7 +737,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
case IPI_CPU_STOP:
irq_enter();
- ipi_cpu_stop(cpu);
+ ipi_cpu_stop(cpu, regs);
irq_exit();
break;
--
2.5.0
