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authorJeff Moyer <jmoyer@redhat.com>2006-06-23 05:05:07 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 10:43:02 -0400
commitc330dda908b5a46469a997eea90b66f2f9f02b34 (patch)
treeaad52aa4e127c366ca185c2122650d7dbb3437a0
parent24bbb1faf3f0420eb252dd0fdc1e477b1d4d73bd (diff)
[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 cfb3410e32b1..6427949ddf99 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,
106extern void crash_kexec(struct pt_regs *); 106extern void crash_kexec(struct pt_regs *);
107int kexec_should_crash(struct task_struct *); 107int kexec_should_crash(struct task_struct *);
108extern struct kimage *kexec_image; 108extern struct kimage *kexec_image;
109extern struct kimage *kexec_crash_image;
109 110
110#define KEXEC_ON_CRASH 0x00000001 111#define KEXEC_ON_CRASH 0x00000001
111#define KEXEC_ARCH_MASK 0xffff0000 112#define KEXEC_ARCH_MASK 0xffff0000
diff --git a/kernel/kexec.c b/kernel/kexec.c
index bf39d28e4c0e..58f0f382597c 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -902,14 +902,14 @@ static int kimage_load_segment(struct kimage *image,
902 * kexec does not sync, or unmount filesystems so if you need 902 * kexec does not sync, or unmount filesystems so if you need
903 * that to happen you need to do that yourself. 903 * that to happen you need to do that yourself.
904 */ 904 */
905struct kimage *kexec_image = NULL; 905struct kimage *kexec_image;
906static struct kimage *kexec_crash_image = NULL; 906struct kimage *kexec_crash_image;
907/* 907/*
908 * A home grown binary mutex. 908 * A home grown binary mutex.
909 * Nothing can wait so this mutex is safe to use 909 * Nothing can wait so this mutex is safe to use
910 * in interrupt context :) 910 * in interrupt context :)
911 */ 911 */
912static int kexec_lock = 0; 912static int kexec_lock;
913 913
914asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments, 914asmlinkage long sys_kexec_load(unsigned long entry, unsigned long nr_segments,
915 struct kexec_segment __user *segments, 915 struct kexec_segment __user *segments,
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index f119e098e67b..9e28478a17a5 100644
--- a/kernel/ksysfs.c
+++ b/kernel/ksysfs.c
@@ -14,6 +14,7 @@
14#include <linux/sysfs.h> 14#include <linux/sysfs.h>
15#include <linux/module.h> 15#include <linux/module.h>
16#include <linux/init.h> 16#include <linux/init.h>
17#include <linux/kexec.h>
17 18
18#define KERNEL_ATTR_RO(_name) \ 19#define KERNEL_ATTR_RO(_name) \
19static struct subsys_attribute _name##_attr = __ATTR_RO(_name) 20static 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
48KERNEL_ATTR_RW(uevent_helper); 49KERNEL_ATTR_RW(uevent_helper);
49#endif 50#endif
50 51
52#ifdef CONFIG_KEXEC
53static ssize_t kexec_loaded_show(struct subsystem *subsys, char *page)
54{
55 return sprintf(page, "%d\n", !!kexec_image);
56}
57KERNEL_ATTR_RO(kexec_loaded);
58
59static ssize_t kexec_crash_loaded_show(struct subsystem *subsys, char *page)
60{
61 return sprintf(page, "%d\n", !!kexec_crash_image);
62}
63KERNEL_ATTR_RO(kexec_crash_loaded);
64#endif /* CONFIG_KEXEC */
65
51decl_subsys(kernel, NULL, NULL); 66decl_subsys(kernel, NULL, NULL);
52EXPORT_SYMBOL_GPL(kernel_subsys); 67EXPORT_SYMBOL_GPL(kernel_subsys);
53 68
@@ -56,6 +71,10 @@ static struct attribute * kernel_attrs[] = {
56 &uevent_seqnum_attr.attr, 71 &uevent_seqnum_attr.attr,
57 &uevent_helper_attr.attr, 72 &uevent_helper_attr.attr,
58#endif 73#endif
74#ifdef CONFIG_KEXEC
75 &kexec_loaded_attr.attr,
76 &kexec_crash_loaded_attr.attr,
77#endif
59 NULL 78 NULL
60}; 79};
61 80