diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/Kconfig.kexec | 4 | ||||
| -rw-r--r-- | kernel/crash_core.c | 31 | ||||
| -rw-r--r-- | kernel/kexec.c | 5 | ||||
| -rw-r--r-- | kernel/ksysfs.c | 15 |
4 files changed, 55 insertions, 0 deletions
diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec index 727190571544..9bfe68fe9676 100644 --- a/kernel/Kconfig.kexec +++ b/kernel/Kconfig.kexec @@ -143,4 +143,8 @@ config CRASH_MAX_MEMORY_RANGES memory buffer/segment size under 1MiB. This represents a sane choice to accommodate both baremetal and virtual machine configurations. + For the kexec_load() syscall path, CRASH_MAX_MEMORY_RANGES is part of + the computation behind the value provided through the + /sys/kernel/crash_elfcorehdr_size attribute. + endmenu diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 40388ad51034..34dc7bddfd77 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -740,6 +740,33 @@ subsys_initcall(crash_notes_memory_init); #ifdef CONFIG_CRASH_HOTPLUG #undef pr_fmt #define pr_fmt(fmt) "crash hp: " fmt + +/* + * This routine utilized when the crash_hotplug sysfs node is read. + * It reflects the kernel's ability/permission to update the crash + * elfcorehdr directly. + */ +int crash_check_update_elfcorehdr(void) +{ + int rc = 0; + + /* Obtain lock while reading crash information */ + if (!kexec_trylock()) { + pr_info("kexec_trylock() failed, elfcorehdr may be inaccurate\n"); + return 0; + } + if (kexec_crash_image) { + if (kexec_crash_image->file_mode) + rc = 1; + else + rc = kexec_crash_image->update_elfcorehdr; + } + /* Release lock now that update complete */ + kexec_unlock(); + + return rc; +} + /* * To accurately reflect hot un/plug changes of cpu and memory resources * (including onling and offlining of those resources), the elfcorehdr @@ -770,6 +797,10 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu) image = kexec_crash_image; + /* Check that updating elfcorehdr is permitted */ + if (!(image->file_mode || image->update_elfcorehdr)) + goto out; + if (hp_action == KEXEC_CRASH_HP_ADD_CPU || hp_action == KEXEC_CRASH_HP_REMOVE_CPU) pr_debug("hp_action %u, cpu %u\n", hp_action, cpu); diff --git a/kernel/kexec.c b/kernel/kexec.c index 92d301f98776..107f355eac10 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -129,6 +129,11 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, if (flags & KEXEC_PRESERVE_CONTEXT) image->preserve_context = 1; +#ifdef CONFIG_CRASH_HOTPLUG + if (flags & KEXEC_UPDATE_ELFCOREHDR) + image->update_elfcorehdr = 1; +#endif + ret = machine_kexec_prepare(image); if (ret) goto out; diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index aad7a3bfd846..1d4bc493b2f4 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -165,6 +165,18 @@ static ssize_t vmcoreinfo_show(struct kobject *kobj, } KERNEL_ATTR_RO(vmcoreinfo); +#ifdef CONFIG_CRASH_HOTPLUG +static ssize_t crash_elfcorehdr_size_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + unsigned int sz = crash_get_elfcorehdr_size(); + + return sysfs_emit(buf, "%u\n", sz); +} +KERNEL_ATTR_RO(crash_elfcorehdr_size); + +#endif + #endif /* CONFIG_CRASH_CORE */ /* whether file capabilities are enabled */ @@ -255,6 +267,9 @@ static struct attribute * kernel_attrs[] = { #endif #ifdef CONFIG_CRASH_CORE &vmcoreinfo_attr.attr, +#ifdef CONFIG_CRASH_HOTPLUG + &crash_elfcorehdr_size_attr.attr, +#endif #endif #ifndef CONFIG_TINY_RCU &rcu_expedited_attr.attr, |