x86: add unknown_nmi_panic kernel parameter

It's not possible to enable the unknown_nmi_panic sysctl option
until init is run. It's useful to be able to panic the kernel
during boot too, this adds a parameter to enable this option.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 09ad745..06fbb3a 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2158,6 +2158,10 @@ and is between 256 and 4096 characters. It is defined in the file
                        Note that genuine overcurrent events won't be
                        reported either.
 
                        Note that genuine overcurrent events won't be
                        reported either.
 

+       unknown_nmi_panic
+                       [X86-32,X86-64]
+                       Set unknown_nmi_panic=1 early on boot.
+

        usbcore.autosuspend=
                        [USB] The autosuspend time delay (in seconds) used
                        for newly-detected USB devices (default 2).  This
        usbcore.autosuspend=
                        [USB] The autosuspend time delay (in seconds) used
                        for newly-detected USB devices (default 2).  This

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index ec024b3..e0b44b7 100644 (file)
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -448,6 +448,13 @@ nmi_watchdog_tick(struct pt_regs *regs, unsigned reason)
 
 #ifdef CONFIG_SYSCTL
 
 
 #ifdef CONFIG_SYSCTL
 

+static int __init setup_unknown_nmi_panic(char *str)
+{
+       unknown_nmi_panic = 1;
+       return 1;
+}
+__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
+

 static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
 {
        unsigned char reason = get_nmi_reason();
 static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
 {
        unsigned char reason = get_nmi_reason();