[PATCH] Add emergency_restart()

When the kernel is working well and we want to restart cleanly
kernel_restart is the function to use.   But in many instances
the kernel wants to reboot when thing are expected to be working
very badly such as from panic or a software watchdog handler.

This patch adds the function emergency_restart() so that
callers can be clear what semantics they expect when calling
restart.  emergency_restart() is expected to be callable
from interrupt context and possibly reliable in even more
trying circumstances.

This is an initial generic implementation for all architectures.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/asm-alpha/emergency-restart.h b/include/asm-alpha/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-alpha/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-arm/emergency-restart.h b/include/asm-arm/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-arm/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-arm26/emergency-restart.h b/include/asm-arm26/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-arm26/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-cris/emergency-restart.h b/include/asm-cris/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-cris/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-frv/emergency-restart.h b/include/asm-frv/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-frv/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-generic/emergency-restart.h b/include/asm-generic/emergency-restart.h
new file mode 100644 (file)
index 0000000..0d68a1e
--- /dev/null
+++ b/include/asm-generic/emergency-restart.h
@@ -0,0 +1,9 @@
+#ifndef _ASM_GENERIC_EMERGENCY_RESTART_H
+#define _ASM_GENERIC_EMERGENCY_RESTART_H
+
+static inline void machine_emergency_restart(void)
+{
+       machine_restart(NULL);
+}
+
+#endif /* _ASM_GENERIC_EMERGENCY_RESTART_H */

diff --git a/include/asm-h8300/emergency-restart.h b/include/asm-h8300/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-h8300/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-i386/emergency-restart.h b/include/asm-i386/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-i386/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-ia64/emergency-restart.h b/include/asm-ia64/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-ia64/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-m32r/emergency-restart.h b/include/asm-m32r/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-m32r/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-m68k/emergency-restart.h b/include/asm-m68k/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-m68k/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-m68knommu/emergency-restart.h b/include/asm-m68knommu/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-m68knommu/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-mips/emergency-restart.h b/include/asm-mips/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-mips/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-parisc/emergency-restart.h b/include/asm-parisc/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-parisc/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-ppc/emergency-restart.h b/include/asm-ppc/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-ppc/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-ppc64/emergency-restart.h b/include/asm-ppc64/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-ppc64/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-s390/emergency-restart.h b/include/asm-s390/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-s390/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-sh/emergency-restart.h b/include/asm-sh/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-sh/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-sh64/emergency-restart.h b/include/asm-sh64/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-sh64/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-sparc/emergency-restart.h b/include/asm-sparc/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-sparc/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-sparc64/emergency-restart.h b/include/asm-sparc64/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-sparc64/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-um/emergency-restart.h b/include/asm-um/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-um/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-v850/emergency-restart.h b/include/asm-v850/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-v850/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-x86_64/emergency-restart.h b/include/asm-x86_64/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-x86_64/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/asm-xtensa/emergency-restart.h b/include/asm-xtensa/emergency-restart.h
new file mode 100644 (file)
index 0000000..108d8c4
--- /dev/null
+++ b/include/asm-xtensa/emergency-restart.h
@@ -0,0 +1,6 @@
+#ifndef _ASM_EMERGENCY_RESTART_H
+#define _ASM_EMERGENCY_RESTART_H
+
+#include <asm-generic/emergency-restart.h>
+
+#endif /* _ASM_EMERGENCY_RESTART_H */

diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index 828ba4f107d908473cf6005127b6ea1980b704ed..3b3266ff1a9508ba1edbb96600cfc280e5fdbef0 100644 (file)
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -64,6 +64,13 @@ extern void kernel_halt(void);
 extern void kernel_power_off(void);
 extern void kernel_kexec(void);
 
 extern void kernel_power_off(void);
 extern void kernel_kexec(void);
 

+/*
+ * Emergency restart, callable from an interrupt handler.
+ */
+
+extern void emergency_restart(void);
+#include <asm/emergency-restart.h>
+

 #endif
 
 #endif /* _LINUX_REBOOT_H */
 #endif
 
 #endif /* _LINUX_REBOOT_H */

diff --git a/kernel/sys.c b/kernel/sys.c
index 31ac41a733298bd68e1385c91300bdd7510dea65..a74039036fb47cf9d27896477add07d4f41cb063 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -361,6 +361,12 @@ out_unlock:
        return retval;
 }
 
        return retval;
 }
 

+void emergency_restart(void)
+{
+       machine_emergency_restart();
+}
+EXPORT_SYMBOL_GPL(emergency_restart);
+

 void kernel_restart(char *cmd)
 {
        notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
 void kernel_restart(char *cmd)
 {
        notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);