x86, NMI: Add back unknown_nmi_panic and nmi_watchdog sysctls

Originally adapted from Huang Ying's patch which moved the
unknown_nmi_panic to the traps.c file.  Because the old nmi
watchdog was deleted before this change happened, the
unknown_nmi_panic sysctl was lost.  This re-adds it.

Also, the nmi_watchdog sysctl was re-implemented and its
documentation updated accordingly.

Patch-inspired-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index cdd2a6e..5e55e46 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1579,20 +1579,12 @@ and is between 256 and 4096 characters. It is defined in the file
 
        nmi_watchdog=   [KNL,BUGS=X86] Debugging features for SMP kernels
                        Format: [panic,][num]
-                       Valid num: 0,1,2
+                       Valid num: 0
                        0 - turn nmi_watchdog off
-                       1 - use the IO-APIC timer for the NMI watchdog
-                       2 - use the local APIC for the NMI watchdog using
-                       a performance counter. Note: This will use one
-                       performance counter and the local APIC's performance
-                       vector.
                        When panic is specified, panic when an NMI watchdog
                        timeout occurs.
                        This is useful when you use a panic=... timeout and
                        need the box quickly up again.
-                       Instead of 1 and 2 it is possible to use the following
-                       symbolic names: lapic and ioapic
-                       Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
 
        netpoll.carrier_timeout=
                        [NET] Specifies amount of time (in seconds) that

diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 2e94eb4..c558e11 100644 (file)
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -99,6 +99,3 @@ static int __init register_trigger_all_cpu_backtrace(void)
 }
 early_initcall(register_trigger_all_cpu_backtrace);
 #endif
-
-/* STUB calls to mimic old nmi_watchdog behaviour */
-int unknown_nmi_panic;

diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index f02c179..bb6f041 100644 (file)
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -83,6 +83,8 @@ EXPORT_SYMBOL_GPL(used_vectors);
 
 static int ignore_nmis;
 
+int unknown_nmi_panic;
+
 static inline void conditional_sti(struct pt_regs *regs)
 {
        if (regs->flags & X86_EFLAGS_IF)
@@ -300,6 +302,13 @@ gp_in_kernel:
        die("general protection fault", regs, error_code);
 }
 
+static int __init setup_unknown_nmi_panic(char *str)
+{
+       unknown_nmi_panic = 1;
+       return 1;
+}
+__setup("unknown_nmi_panic", setup_unknown_nmi_panic);
+
 static notrace __kprobes void
 mem_parity_error(unsigned char reason, struct pt_regs *regs)
 {
@@ -371,7 +380,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
                        reason, smp_processor_id());
 
        printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n");
-       if (panic_on_unrecovered_nmi)
+       if (unknown_nmi_panic || panic_on_unrecovered_nmi)
                panic("NMI: Not continuing");
 
        printk(KERN_EMERG "Dazed and confused, but trying to continue\n");
@@ -397,11 +406,8 @@ static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
                if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT)
                                                        == NOTIFY_STOP)
                        return;
-
-                       unknown_nmi_error(reason, regs);
-#else
-               unknown_nmi_error(reason, regs);
 #endif
+               unknown_nmi_error(reason, regs);
 
                return;
        }

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index cbd97da..4640441 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -745,6 +745,22 @@ static struct ctl_table kern_table[] = {
                .extra1         = &zero,
                .extra2         = &one,
        },
+       {
+               .procname       = "nmi_watchdog",
+               .data           = &watchdog_enabled,
+               .maxlen         = sizeof (int),
+               .mode           = 0644,
+               .proc_handler   = proc_dowatchdog_enabled,
+       },
+#endif
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
+       {
+               .procname       = "unknown_nmi_panic",
+               .data           = &unknown_nmi_panic,
+               .maxlen         = sizeof (int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec,
+       },
 #endif
 #if defined(CONFIG_X86)
        {

diff --git a/kernel/sysctl_binary.c b/kernel/sysctl_binary.c
index 1357c57..4b2545a 100644 (file)
--- a/kernel/sysctl_binary.c
+++ b/kernel/sysctl_binary.c
@@ -136,7 +136,6 @@ static const struct bin_table bin_kern_table[] = {
        { CTL_INT,      KERN_IA64_UNALIGNED,            "ignore-unaligned-usertrap" },
        { CTL_INT,      KERN_COMPAT_LOG,                "compat-log" },
        { CTL_INT,      KERN_MAX_LOCK_DEPTH,            "max_lock_depth" },
-       { CTL_INT,      KERN_NMI_WATCHDOG,              "nmi_watchdog" },
        { CTL_INT,      KERN_PANIC_ON_NMI,              "panic_on_unrecovered_nmi" },
        {}
 };

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index cad4e42..eb17e14 100644 (file)
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -57,6 +57,8 @@ static int __init hardlockup_panic_setup(char *str)
 {
        if (!strncmp(str, "panic", 5))
                hardlockup_panic = 1;
+       else if (!strncmp(str, "0", 1))
+               no_watchdog = 1;
        return 1;
 }
 __setup("nmi_watchdog=", hardlockup_panic_setup);