aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/arch/powerpc/kexec/crash.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kexec/crash.c')
-rw-r--r--arch/powerpc/kexec/crash.c277
1 files changed, 246 insertions, 31 deletions
diff --git a/arch/powerpc/kexec/crash.c b/arch/powerpc/kexec/crash.c
index 80f54723cf6d..a325c1c02f96 100644
--- a/arch/powerpc/kexec/crash.c
+++ b/arch/powerpc/kexec/crash.c
@@ -16,6 +16,8 @@
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/types.h>
+#include <linux/libfdt.h>
+#include <linux/memory.h>
#include <asm/processor.h>
#include <asm/machdep.h>
@@ -24,6 +26,7 @@
#include <asm/setjmp.h>
#include <asm/debug.h>
#include <asm/interrupt.h>
+#include <asm/kexec_ranges.h>
/*
* The primary CPU waits a while for all secondary CPUs to enter. This is to
@@ -40,6 +43,14 @@
#define REAL_MODE_TIMEOUT 10000
static int time_to_dump;
+
+/*
+ * In case of system reset, secondary CPUs enter crash_kexec_secondary with out
+ * having to send an IPI explicitly. So, indicate if the crash is via
+ * system reset to avoid sending another IPI.
+ */
+static int is_via_system_reset;
+
/*
* 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
@@ -101,7 +112,7 @@ void crash_ipi_callback(struct pt_regs *regs)
/* NOTREACHED */
}
-static void crash_kexec_prepare_cpus(int cpu)
+static void crash_kexec_prepare_cpus(void)
{
unsigned int msecs;
volatile unsigned int ncpus = num_online_cpus() - 1;/* Excluding the panic cpu */
@@ -113,7 +124,15 @@ static void crash_kexec_prepare_cpus(int cpu)
if (crash_wake_offline)
ncpus = num_present_cpus() - 1;
- crash_send_ipi(crash_ipi_callback);
+ /*
+ * If we came in via system reset, secondaries enter via crash_kexec_secondary().
+ * So, wait a while for the secondary CPUs to enter for that case.
+ * Else, send IPI to all other CPUs.
+ */
+ if (is_via_system_reset)
+ mdelay(PRIMARY_TIMEOUT);
+ else
+ crash_send_ipi(crash_ipi_callback);
smp_wmb();
again:
@@ -202,7 +221,7 @@ void crash_kexec_secondary(struct pt_regs *regs)
#else /* ! CONFIG_SMP */
-static void crash_kexec_prepare_cpus(int cpu)
+static void crash_kexec_prepare_cpus(void)
{
/*
* move the secondaries to us so that we can copy
@@ -248,6 +267,32 @@ noinstr static void __maybe_unused crash_kexec_wait_realmode(int cpu)
static inline void crash_kexec_wait_realmode(int cpu) {}
#endif /* CONFIG_SMP && CONFIG_PPC64 */
+void crash_kexec_prepare(void)
+{
+ /* Avoid hardlocking with irresponsive CPU holding logbuf_lock */
+ printk_deferred_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();
+
+ crash_kexec_prepare_cpus();
+}
+
/*
* Register a function to be called on shutdown. Only use this if you
* can't reset your device in the second kernel.
@@ -308,38 +353,16 @@ EXPORT_SYMBOL(crash_shutdown_unregister);
void default_machine_crash_shutdown(struct pt_regs *regs)
{
- unsigned int i;
+ volatile unsigned int i;
int (*old_handler)(struct pt_regs *regs);
- /* Avoid hardlocking with irresponsive CPU holding logbuf_lock */
- printk_deferred_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);
+ is_via_system_reset = 1;
- crash_kexec_prepare_cpus(crashing_cpu);
+ if (IS_ENABLED(CONFIG_SMP))
+ crash_smp_send_stop();
+ else
+ crash_kexec_prepare();
crash_save_cpu(regs, crashing_cpu);
@@ -375,3 +398,195 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
if (ppc_md.kexec_cpu_down)
ppc_md.kexec_cpu_down(1, 0);
}
+
+#ifdef CONFIG_CRASH_HOTPLUG
+#undef pr_fmt
+#define pr_fmt(fmt) "crash hp: " fmt
+
+/*
+ * Advertise preferred elfcorehdr size to userspace via
+ * /sys/kernel/crash_elfcorehdr_size sysfs interface.
+ */
+unsigned int arch_crash_get_elfcorehdr_size(void)
+{
+ unsigned long phdr_cnt;
+
+ /* A program header for possible CPUs + vmcoreinfo */
+ phdr_cnt = num_possible_cpus() + 1;
+ if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG))
+ phdr_cnt += CONFIG_CRASH_MAX_MEMORY_RANGES;
+
+ return sizeof(struct elfhdr) + (phdr_cnt * sizeof(Elf64_Phdr));
+}
+
+/**
+ * update_crash_elfcorehdr() - Recreate the elfcorehdr and replace it with old
+ * elfcorehdr in the kexec segment array.
+ * @image: the active struct kimage
+ * @mn: struct memory_notify data handler
+ */
+static void update_crash_elfcorehdr(struct kimage *image, struct memory_notify *mn)
+{
+ int ret;
+ struct crash_mem *cmem = NULL;
+ struct kexec_segment *ksegment;
+ void *ptr, *mem, *elfbuf = NULL;
+ unsigned long elfsz, memsz, base_addr, size;
+
+ ksegment = &image->segment[image->elfcorehdr_index];
+ mem = (void *) ksegment->mem;
+ memsz = ksegment->memsz;
+
+ ret = get_crash_memory_ranges(&cmem);
+ if (ret) {
+ pr_err("Failed to get crash mem range\n");
+ return;
+ }
+
+ /*
+ * The hot unplugged memory is part of crash memory ranges,
+ * remove it here.
+ */
+ if (image->hp_action == KEXEC_CRASH_HP_REMOVE_MEMORY) {
+ base_addr = PFN_PHYS(mn->start_pfn);
+ size = mn->nr_pages * PAGE_SIZE;
+ ret = remove_mem_range(&cmem, base_addr, size);
+ if (ret) {
+ pr_err("Failed to remove hot-unplugged memory from crash memory ranges\n");
+ goto out;
+ }
+ }
+
+ ret = crash_prepare_elf64_headers(cmem, false, &elfbuf, &elfsz);
+ if (ret) {
+ pr_err("Failed to prepare elf header\n");
+ goto out;
+ }
+
+ /*
+ * It is unlikely that kernel hit this because elfcorehdr kexec
+ * segment (memsz) is built with addition space to accommodate growing
+ * number of crash memory ranges while loading the kdump kernel. It is
+ * Just to avoid any unforeseen case.
+ */
+ if (elfsz > memsz) {
+ pr_err("Updated crash elfcorehdr elfsz %lu > memsz %lu", elfsz, memsz);
+ goto out;
+ }
+
+ ptr = __va(mem);
+ if (ptr) {
+ /* Temporarily invalidate the crash image while it is replaced */
+ xchg(&kexec_crash_image, NULL);
+
+ /* Replace the old elfcorehdr with newly prepared elfcorehdr */
+ memcpy((void *)ptr, elfbuf, elfsz);
+
+ /* The crash image is now valid once again */
+ xchg(&kexec_crash_image, image);
+ }
+out:
+ kvfree(cmem);
+ kvfree(elfbuf);
+}
+
+/**
+ * get_fdt_index - Loop through the kexec segment array and find
+ * the index of the FDT segment.
+ * @image: a pointer to kexec_crash_image
+ *
+ * Returns the index of FDT segment in the kexec segment array
+ * if found; otherwise -1.
+ */
+static int get_fdt_index(struct kimage *image)
+{
+ void *ptr;
+ unsigned long mem;
+ int i, fdt_index = -1;
+
+ /* Find the FDT segment index in kexec segment array. */
+ for (i = 0; i < image->nr_segments; i++) {
+ mem = image->segment[i].mem;
+ ptr = __va(mem);
+
+ if (ptr && fdt_magic(ptr) == FDT_MAGIC) {
+ fdt_index = i;
+ break;
+ }
+ }
+
+ return fdt_index;
+}
+
+/**
+ * update_crash_fdt - updates the cpus node of the crash FDT.
+ *
+ * @image: a pointer to kexec_crash_image
+ */
+static void update_crash_fdt(struct kimage *image)
+{
+ void *fdt;
+ int fdt_index;
+
+ fdt_index = get_fdt_index(image);
+ if (fdt_index < 0) {
+ pr_err("Unable to locate FDT segment.\n");
+ return;
+ }
+
+ fdt = __va((void *)image->segment[fdt_index].mem);
+
+ /* Temporarily invalidate the crash image while it is replaced */
+ xchg(&kexec_crash_image, NULL);
+
+ /* update FDT to reflect changes in CPU resources */
+ if (update_cpus_node(fdt))
+ pr_err("Failed to update crash FDT");
+
+ /* The crash image is now valid once again */
+ xchg(&kexec_crash_image, image);
+}
+
+int arch_crash_hotplug_support(struct kimage *image, unsigned long kexec_flags)
+{
+#ifdef CONFIG_KEXEC_FILE
+ if (image->file_mode)
+ return 1;
+#endif
+ return kexec_flags & KEXEC_CRASH_HOTPLUG_SUPPORT;
+}
+
+/**
+ * arch_crash_handle_hotplug_event - Handle crash CPU/Memory hotplug events to update the
+ * necessary kexec segments based on the hotplug event.
+ * @image: a pointer to kexec_crash_image
+ * @arg: struct memory_notify handler for memory hotplug case and NULL for CPU hotplug case.
+ *
+ * Update the kdump image based on the type of hotplug event, represented by image->hp_action.
+ * CPU add: Update the FDT segment to include the newly added CPU.
+ * CPU remove: No action is needed, with the assumption that it's okay to have offline CPUs
+ * part of the FDT.
+ * Memory add/remove: No action is taken as this is not yet supported.
+ */
+void arch_crash_handle_hotplug_event(struct kimage *image, void *arg)
+{
+ struct memory_notify *mn;
+
+ switch (image->hp_action) {
+ case KEXEC_CRASH_HP_REMOVE_CPU:
+ return;
+
+ case KEXEC_CRASH_HP_ADD_CPU:
+ update_crash_fdt(image);
+ break;
+
+ case KEXEC_CRASH_HP_REMOVE_MEMORY:
+ case KEXEC_CRASH_HP_ADD_MEMORY:
+ mn = (struct memory_notify *)arg;
+ update_crash_elfcorehdr(image, mn);
+ return;
+ default:
+ pr_warn_once("Unknown hotplug action\n");
+ }
+}
+#endif /* CONFIG_CRASH_HOTPLUG */