From: Eric DeVolder <eric.devolder@oracle.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org,
kexec@lists.infradead.org, ebiederm@xmission.com,
dyoung@redhat.com, bhe@redhat.com, vgoyal@redhat.com
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, hpa@zytor.com,
nramas@linux.microsoft.com, thomas.lendacky@amd.com,
robh@kernel.org, efault@gmx.de, rppt@kernel.org,
david@redhat.com, konrad.wilk@oracle.com,
boris.ostrovsky@oracle.com, eric.devolder@oracle.com
Subject: [PATCH v7 4/8] crash: add generic infrastructure for crash hotplug support
Date: Wed, 13 Apr 2022 12:42:33 -0400 [thread overview]
Message-ID: <20220413164237.20845-5-eric.devolder@oracle.com> (raw)
In-Reply-To: <20220413164237.20845-1-eric.devolder@oracle.com>
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 <eric.devolder@oracle.com>
---
include/linux/kexec.h | 16 +++++++
kernel/crash_core.c | 101 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 117 insertions(+)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index f93f2591fc1e..02daff1f47dd 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;
+ unsigned 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 int cpu);
+#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..ecf746243ab2 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 +496,99 @@ 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 int cpu)
+{
+ pr_warn("crash hp: %s not implemented", __func__);
+}
+
+static void crash_hotplug_handler(unsigned int hp_action,
+ unsigned int cpu)
+{
+ /* 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, cpu %u", hp_action, cpu);
+
+ /* 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, cpu);
+
+ /* 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;
+
+ switch (val) {
+ case MEM_ONLINE:
+ crash_hotplug_handler(KEXEC_CRASH_HP_ADD_MEMORY, -1U);
+ break;
+
+ case MEM_OFFLINE:
+ crash_hotplug_handler(KEXEC_CRASH_HP_REMOVE_MEMORY, -1U);
+ 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);
+ return 0;
+}
+
+static int crash_cpuhp_offline(unsigned int cpu)
+{
+ crash_hotplug_handler(KEXEC_CRASH_HP_REMOVE_CPU, cpu);
+ 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
next prev parent reply other threads:[~2022-04-13 16:43 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-13 16:42 [PATCH v7 0/8] crash: Kernel handling of CPU and memory hot un/plug Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 1/8] x86/crash: fix minor typo/bug in debug message Eric DeVolder
2022-04-13 17:52 ` [tip: x86/kdump] x86/crash: Fix " tip-bot2 for Eric DeVolder
2022-04-28 9:49 ` [PATCH v7 1/8] x86/crash: fix " David Hildenbrand
2022-04-13 16:42 ` [PATCH v7 2/8] x86/crash: Introduce new options to support cpu and memory hotplug Eric DeVolder
2022-04-14 13:59 ` Borislav Petkov
2022-04-18 22:03 ` Eric DeVolder
2022-04-19 10:32 ` Borislav Petkov
2022-04-19 21:58 ` Eric DeVolder
2022-04-25 19:25 ` Borislav Petkov
2022-04-26 20:08 ` Eric DeVolder
2022-04-27 10:48 ` Borislav Petkov
2022-04-26 4:21 ` Sourabh Jain
2022-04-26 14:39 ` Eric DeVolder
2022-04-29 6:41 ` Sourabh Jain
2022-05-05 16:31 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 3/8] crash: prototype change for crash_prepare_elf64_headers Eric DeVolder
2022-04-13 16:42 ` Eric DeVolder [this message]
2022-04-14 2:45 ` [PATCH v7 4/8] crash: add generic infrastructure for crash hotplug support Baoquan He
2022-04-14 22:29 ` Eric DeVolder
2022-04-18 3:17 ` Baoquan He
2022-04-26 4:06 ` Sourabh Jain
2022-04-26 5:22 ` Baoquan He
2022-04-28 5:18 ` Sourabh Jain
2022-05-04 18:11 ` Eric DeVolder
2022-05-05 5:45 ` Baoquan He
2022-05-05 9:59 ` Sourabh Jain
2022-05-05 11:04 ` Baoquan He
2022-05-05 13:35 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 5/8] kexec: exclude elfcorehdr from the segment digest Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 6/8] kexec: exclude hot remove cpu from elfcorehdr notes Eric DeVolder
2022-04-14 2:48 ` Baoquan He
2022-04-14 22:31 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 7/8] x86/crash: Add x86 crash hotplug support for kexec_file_load Eric DeVolder
2022-04-14 2:52 ` Baoquan He
2022-04-14 22:32 ` Eric DeVolder
2022-04-13 16:42 ` [PATCH v7 8/8] x86/crash: Add x86 crash hotplug support for kexec_load Eric DeVolder
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