From c330dda908b5a46469a997eea90b66f2f9f02b34 Mon Sep 17 00:00:00 2001 From: Jeff Moyer Date: Fri, 23 Jun 2006 02:05:07 -0700 Subject: [PATCH] [PATCH] Add a sysfs file to determine if a kexec kernel is loaded Create two files in /sys/kernel, kexec_loaded and kexec_crash_loaded. Each file contains a simple boolean value indicating whether the relevant kernel has been loaded into memory. The motivation for this is geared around support. Signed-off-by: Jeff Moyer Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/kexec.h | 1 + kernel/kexec.c | 6 +++--- kernel/ksysfs.c | 19 +++++++++++++++++++ 3 files changed, 23 insertions(+), 3 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index cfb3410..6427949 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -106,6 +106,7 @@ extern struct page *kimage_alloc_control_pages(struct kimage *image, extern void crash_kexec(struct pt_regs *); int kexec_should_crash(struct task_struct *); extern struct kimage *kexec_image; +extern struct kimage *kexec_crash_image; #define KEXEC_ON_CRASH 0x00000001 #define KEXEC_ARCH_MASK 0xffff0000 diff --git a/kernel/kexec.c b/kernel/kexec.c index bf39d28..58f0f38 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -902,14 +902,14 @@ static int kimage_load_segment(struct kimage *image, * kexec does not sync, or unmount filesystems so if you need * that to happen you need to do that yourself. */ -struct kimage *kexec_image = NULL; -static struct kimage *kexec_crash_image = NULL; +struct kimage *kexec_image; +struct kimage *kexec_crash_image; /* * A home grown binary mutex. * Nothing can wait so this mutex is safe to use * in interrupt context :) */ -static int kexec_lock = 0; +static int kexec_lock; asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment __user *segments, diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index f119e09..9e28478 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -14,6 +14,7 @@ #include #include #include +#include #define KERNEL_ATTR_RO(_name) \ static struct subsys_attribute _name##_attr = __ATTR_RO(_name) @@ -48,6 +49,20 @@ static ssize_t uevent_helper_store(struct subsystem *subsys, const char *page, s KERNEL_ATTR_RW(uevent_helper); #endif +#ifdef CONFIG_KEXEC +static ssize_t kexec_loaded_show(struct subsystem *subsys, char *page) +{ + return sprintf(page, "%d\n", !!kexec_image); +} +KERNEL_ATTR_RO(kexec_loaded); + +static ssize_t kexec_crash_loaded_show(struct subsystem *subsys, char *page) +{ + return sprintf(page, "%d\n", !!kexec_crash_image); +} +KERNEL_ATTR_RO(kexec_crash_loaded); +#endif /* CONFIG_KEXEC */ + decl_subsys(kernel, NULL, NULL); EXPORT_SYMBOL_GPL(kernel_subsys); @@ -56,6 +71,10 @@ static struct attribute * kernel_attrs[] = { &uevent_seqnum_attr.attr, &uevent_helper_attr.attr, #endif +#ifdef CONFIG_KEXEC + &kexec_loaded_attr.attr, + &kexec_crash_loaded_attr.attr, +#endif NULL }; -- 1.8.2.3