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 | 34 +++++++++++++++++++++++++++++++++-
arch/arm64/kernel/machine_kexec.c | 31 +++++++++++++++++++++++++++++--
arch/arm64/kernel/smp.c | 16 ++++++++++++++--
3 files changed, 76 insertions(+), 5 deletions(-)
diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index 46d63cd..555a955 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h
@@ -30,6 +30,8 @@
#if !defined(__ASSEMBLY__)
+extern bool in_crash_kexec;
+
/**
* crash_setup_regs() - save registers for the panic kernel
*
@@ -40,7 +42,37 @@
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 /* !defined(__ASSEMBLY__) */
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index da28a26..d2d7e90 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -9,6 +9,7 @@
* published by the Free Software Foundation.
*/
+#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/of_fdt.h>
#include <linux/slab.h>
@@ -23,6 +24,7 @@
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;
/**
@@ -203,13 +205,38 @@ void machine_kexec(struct kimage *kimage)
*/
cpu_soft_restart(virt_to_phys(cpu_reset),
- is_hyp_mode_available(),
+ in_crash_kexec ? 0 : is_hyp_mode_available(),
reboot_code_buffer_phys, kimage->head, kimage_start);
BUG(); /* Should never get here. */
}
+/**
+ * machine_crash_shutdown - shutdown non-boot 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-boot cpus */
+ smp_send_stop();
+
+ /* for boot cpu */
+ crash_save_cpu(regs, smp_processor_id());
+
+ pr_info("Starting crashdump kernel...\n");
}
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index b1adc51..15aabef 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>
@@ -54,6 +55,8 @@
#include <asm/ptrace.h>
#include <asm/virt.h>
+#include "cpu-reset.h"
+
#define CREATE_TRACE_POINTS
#include <trace/events/ipi.h>
@@ -683,8 +686,12 @@ 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)
{
+#ifdef CONFIG_KEXEC
+ /* printing messages may slow down the shutdown. */
+ if (!in_crash_kexec)
+#endif
if (system_state == SYSTEM_BOOTING ||
system_state == SYSTEM_RUNNING) {
raw_spin_lock(&stop_lock);
@@ -697,6 +704,11 @@ static void ipi_cpu_stop(unsigned int cpu)
local_irq_disable();
+#ifdef CONFIG_KEXEC
+ if (in_crash_kexec)
+ crash_save_cpu(regs, cpu);
+#endif /* CONFIG_KEXEC */
+
while (1)
cpu_relax();
}
@@ -727,7 +739,7 @@ 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
