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authorJeff Moyer <jmoyer@redhat.com>2006-06-23 02:05:07 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 07:43:02 -0700
commitc330dda908b5a46469a997eea90b66f2f9f02b34 (patch)
treeaad52aa4e127c366ca185c2122650d7dbb3437a0
parent24bbb1faf3f0420eb252dd0fdc1e477b1d4d73bd (diff)
downloadlinux-c330dda908b5a46469a997eea90b66f2f9f02b34.tar.gz
[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 <jmoyer@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/kexec.h1
-rw-r--r--kernel/kexec.c6
-rw-r--r--kernel/ksysfs.c19
3 files changed, 23 insertions, 3 deletions
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index cfb3410e32b16..6427949ddf994 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 bf39d28e4c0e7..58f0f382597cf 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 f119e098e67b1..9e28478a17a50 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -14,6 +14,7 @@
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>
+#include <linux/kexec.h>
#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
};