Upon CPU and memory changes, a generic crash_hotplug_handler() dispatches the hot plug/unplug event to the architecture specific arch_crash_hotplug_handler(). During the process, the kexec_mutex is held.
To support cpu hotplug, a callback is registered to capture the CPUHP_AP_ONLINE_DYN online and ofline events via cpuhp_setup_state_nocalls(). To support memory hotplug, a notifier is registered to capture the MEM_ONLINE and MEM_OFFLINE events via register_memory_notifier(). The cpu callback and memory notifier then call crash_hotplug_handler() to handle the hot plug/unplug event. Signed-off-by: Eric DeVolder <[email protected]> --- include/linux/kexec.h | 16 +++++++ kernel/crash_core.c | 108 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 124 insertions(+) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index f93f2591fc1e..40e426cfd795 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -306,6 +306,13 @@ struct kimage { /* Information for loading purgatory */ struct purgatory_info purgatory_info; + +#ifdef CONFIG_CRASH_HOTPLUG + bool hotplug_event; + int offlinecpu; + bool elfcorehdr_index_valid; + int elfcorehdr_index; +#endif #endif #ifdef CONFIG_IMA_KEXEC @@ -322,6 +329,15 @@ struct kimage { unsigned long elf_load_addr; }; +#ifdef CONFIG_CRASH_HOTPLUG +void arch_crash_hotplug_handler(struct kimage *image, + unsigned int hp_action, unsigned long a, unsigned long b); +#define KEXEC_CRASH_HP_REMOVE_CPU 0 +#define KEXEC_CRASH_HP_ADD_CPU 1 +#define KEXEC_CRASH_HP_REMOVE_MEMORY 2 +#define KEXEC_CRASH_HP_ADD_MEMORY 3 +#endif /* CONFIG_CRASH_HOTPLUG */ + /* kexec interface functions */ extern void machine_kexec(struct kimage *image); extern int machine_kexec_prepare(struct kimage *image); diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 256cf6db573c..76959d440f71 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -9,12 +9,17 @@ #include <linux/init.h> #include <linux/utsname.h> #include <linux/vmalloc.h> +#include <linux/highmem.h> +#include <linux/memory.h> +#include <linux/cpuhotplug.h> #include <asm/page.h> #include <asm/sections.h> #include <crypto/sha1.h> +#include "kexec_internal.h" + /* vmcoreinfo stuff */ unsigned char *vmcoreinfo_data; size_t vmcoreinfo_size; @@ -491,3 +496,106 @@ static int __init crash_save_vmcoreinfo_init(void) } subsys_initcall(crash_save_vmcoreinfo_init); + +#ifdef CONFIG_CRASH_HOTPLUG +void __weak arch_crash_hotplug_handler(struct kimage *image, + unsigned int hp_action, unsigned long a, unsigned long b) +{ + pr_warn("crash hp: %s not implemented", __func__); +} + +static void crash_hotplug_handler(unsigned int hp_action, + unsigned long a, unsigned long b) +{ + /* Obtain lock while changing crash information */ + if (!mutex_trylock(&kexec_mutex)) + return; + + /* Check kdump is loaded */ + if (kexec_crash_image) { + pr_debug("crash hp: hp_action %u, a %lu, b %lu", hp_action, + a, b); + + /* Needed in order for the segments to be updated */ + arch_kexec_unprotect_crashkres(); + + /* Flag to differentiate between normal load and hotplug */ + kexec_crash_image->hotplug_event = true; + + /* Now invoke arch-specific update handler */ + arch_crash_hotplug_handler(kexec_crash_image, hp_action, a, b); + + /* No longer handling a hotplug event */ + kexec_crash_image->hotplug_event = false; + + /* Change back to read-only */ + arch_kexec_protect_crashkres(); + } + + /* Release lock now that update complete */ + mutex_unlock(&kexec_mutex); +} + +#if defined(CONFIG_MEMORY_HOTPLUG) +static int crash_memhp_notifier(struct notifier_block *nb, + unsigned long val, void *v) +{ + struct memory_notify *mhp = v; + unsigned long start, end; + + start = mhp->start_pfn << PAGE_SHIFT; + end = ((mhp->start_pfn + mhp->nr_pages) << PAGE_SHIFT) - 1; + + switch (val) { + case MEM_ONLINE: + crash_hotplug_handler(KEXEC_CRASH_HP_ADD_MEMORY, + start, end-start); + break; + + case MEM_OFFLINE: + crash_hotplug_handler(KEXEC_CRASH_HP_REMOVE_MEMORY, + start, end-start); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block crash_memhp_nb = { + .notifier_call = crash_memhp_notifier, + .priority = 0 +}; +#endif + +#if defined(CONFIG_HOTPLUG_CPU) +static int crash_cpuhp_online(unsigned int cpu) +{ + crash_hotplug_handler(KEXEC_CRASH_HP_ADD_CPU, cpu, 0); + return 0; +} + +static int crash_cpuhp_offline(unsigned int cpu) +{ + crash_hotplug_handler(KEXEC_CRASH_HP_REMOVE_CPU, cpu, 0); + return 0; +} +#endif + +static int __init crash_hotplug_init(void) +{ + int result = 0; + +#if defined(CONFIG_MEMORY_HOTPLUG) + register_memory_notifier(&crash_memhp_nb); +#endif + +#if defined(CONFIG_HOTPLUG_CPU) + result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, + "crash/cpuhp", + crash_cpuhp_online, crash_cpuhp_offline); +#endif + + return result; +} + +subsys_initcall(crash_hotplug_init); +#endif /* CONFIG_CRASH_HOTPLUG */ -- 2.27.0 _______________________________________________ kexec mailing list [email protected] http://lists.infradead.org/mailman/listinfo/kexec
