x86, nmi_watchdog: Remove ARCH_HAS_NMI_WATCHDOG and rely on CONFIG_HARDLOCKUP_DETECTOR

The x86 arch has shifted its use of the nmi_watchdog from a
local implementation to the global one provide by
kernel/watchdog.c.  This shift has caused a whole bunch of
compile problems under different config options.  I attempt to
simplify things with the patch below.

In order to simplify things, I had to come to terms with the
meaning of two terms ARCH_HAS_NMI_WATCHDOG and
CONFIG_HARDLOCKUP_DETECTOR.  Basically they mean the same thing,
the former on a local level and the latter on a global level.

With the old x86 nmi watchdog gone, there is no need to rely on
defining the ARCH_HAS_NMI_WATCHDOG variable because it doesn't
make sense any more.  x86 will now use the global
implementation.

The changes below do a few things.  First it changes the few
places that relied on ARCH_HAS_NMI_WATCHDOG to use
CONFIG_X86_LOCAL_APIC (the former was an alias for the latter
anyway, so nothing unusual here).  Those pieces of code were
relying more on local apic functionality the nmi watchdog
functionality, so the change should make sense.

Second, I removed the x86 implementation of
touch_nmi_watchdog().  It isn't need now, instead x86 will rely
on kernel/watchdog.c's implementation.

Third, I removed the #define ARCH_HAS_NMI_WATCHDOG itself from
x86.  And tweaked the include/linux/nmi.h file to tell users to
look for an externally defined touch_nmi_watchdog in the case of
ARCH_HAS_NMI_WATCHDOG _or_ CONFIG_HARDLOCKUP_DETECTOR. This
changes removes some of the ugliness in that file.

Finally, I added a Kconfig dependency for
CONFIG_HARDLOCKUP_DETECTOR that said you can't have
ARCH_HAS_NMI_WATCHDOG _and_ CONFIG_HARDLOCKUP_DETECTOR.  You can
only have one nmi_watchdog.

Tested with
ARCH=i386: allnoconfig, defconfig, allyesconfig, (various broken
configs) ARCH=x86_64: allnoconfig, defconfig, allyesconfig,
(various broken configs)

Hopefully, after this patch I won't get any more compile broken
emails. :-)

v3:
  changed a couple of 'linux/nmi.h' -> 'asm/nmi.h' to pick-up correct function
  prototypes when CONFIG_HARDLOCKUP_DETECTOR is not set.
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1293044403-14117-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/irq.h

@@ -15,10 +15,6 @@ static inline int irq_canonicalize(int irq)
 	return ((irq == 2) ? 9 : irq);
 }
 
-#ifdef CONFIG_X86_LOCAL_APIC
-# define ARCH_HAS_NMI_WATCHDOG
-#endif
-
 #ifdef CONFIG_X86_32
 extern void irq_ctx_init(int cpu);
 #else

arch/x86/include/asm/nmi.h

@@ -5,7 +5,7 @@
 #include <asm/irq.h>
 #include <asm/io.h>
 
-#ifdef ARCH_HAS_NMI_WATCHDOG
+#ifdef CONFIG_X86_LOCAL_APIC
 
 extern void die_nmi(char *str, struct pt_regs *regs, int do_panic);
 extern int avail_to_resrv_perfctr_nmi_bit(unsigned int);

arch/x86/kernel/apic/hw_nmi.c

@@ -17,7 +17,6 @@
 #include <linux/nmi.h>
 #include <linux/module.h>
 
-#ifdef ARCH_HAS_NMI_WATCHDOG
 #ifdef CONFIG_HARDLOCKUP_DETECTOR
 u64 hw_nmi_get_sample_period(void)
 {
@@ -25,15 +24,6 @@ u64 hw_nmi_get_sample_period(void)
 }
 #endif
 
-#ifndef CONFIG_HARDLOCKUP_DETECTOR
-void touch_nmi_watchdog(void)
-{
-	touch_softlockup_watchdog();
-}
-EXPORT_SYMBOL(touch_nmi_watchdog);
-#endif
-#endif
-
 #ifdef arch_trigger_all_cpu_backtrace
 /* For reliability, we're prepared to waste bits here. */
 static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;

arch/x86/kernel/cpu/perfctr-watchdog.c

@@ -16,7 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/bitops.h>
 #include <linux/smp.h>
-#include <linux/nmi.h>
+#include <asm/nmi.h>
 #include <linux/kprobes.h>
 
 #include <asm/apic.h>

arch/x86/oprofile/op_model_p4.c

@@ -11,7 +11,7 @@
 #include <linux/oprofile.h>
 #include <linux/smp.h>
 #include <linux/ptrace.h>
-#include <linux/nmi.h>
+#include <asm/nmi.h>
 #include <asm/msr.h>
 #include <asm/fixmap.h>
 #include <asm/apic.h>

drivers/watchdog/hpwdt.c

@@ -642,7 +642,7 @@ static struct notifier_block die_notifier = {
  */
 
 #ifdef CONFIG_HPWDT_NMI_DECODING
-#ifdef ARCH_HAS_NMI_WATCHDOG
+#ifdef CONFIG_X86_LOCAL_APIC
 static void __devinit hpwdt_check_nmi_decoding(struct pci_dev *dev)
 {
 	/*
@@ -657,7 +657,7 @@ static void __devinit hpwdt_check_nmi_decoding(struct pci_dev *dev)
 	dev_warn(&dev->dev, "NMI decoding is disabled. "
 		"Your kernel does not support a NMI Watchdog.\n");
 }
-#endif /* ARCH_HAS_NMI_WATCHDOG */
+#endif /* CONFIG_X86_LOCAL_APIC */
 
 static int __devinit hpwdt_init_nmi_decoding(struct pci_dev *dev)
 {

include/linux/nmi.h

@@ -14,18 +14,14 @@
  * may be used to reset the timeout - for code which intentionally
  * disables interrupts for a long time. This call is stateless.
  */
-#ifdef ARCH_HAS_NMI_WATCHDOG
+#if defined(ARCH_HAS_NMI_WATCHDOG) || defined(CONFIG_HARDLOCKUP_DETECTOR)
 #include <asm/nmi.h>
 extern void touch_nmi_watchdog(void);
 #else
-#ifndef CONFIG_HARDLOCKUP_DETECTOR
 static inline void touch_nmi_watchdog(void)
 {
 	touch_softlockup_watchdog();
 }
-#else
-extern void touch_nmi_watchdog(void);
-#endif
 #endif
 
 /*

lib/Kconfig.debug

@@ -173,7 +173,8 @@ config LOCKUP_DETECTOR
 	  An NMI is generated every 60 seconds or so to check for hardlockups.
 
 config HARDLOCKUP_DETECTOR
-	def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
+	def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
+		 !ARCH_HAS_NMI_WATCHDOG
 
 config BOOTPARAM_SOFTLOCKUP_PANIC
 	bool "Panic (Reboot) On Soft Lockups"