[PATCH v2] powerpc: Move arch_trigger_cpumask_backtrace from nmi.h to irq.h

[Douglas Anderson]

The powerpc architecture was the only one that defined
arch_trigger_cpumask_backtrace() in asm/nmi.h instead of
asm/irq.h. Move it to be consistent.

This fixes compile time errors introduced by commit 7ca8fe94aa92
("watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH"). That commit
caused <asm/nmi.h> to stop being included if the hardlockup detector
wasn't enabled. The specific errors were:
  error: implicit declaration of function ‘nmi_cpu_backtrace’
  error: implicit declaration of function ‘nmi_trigger_cpumask_backtrace’

NOTE: when moving this into irq.h, we also change the guards from just
checking if "CONFIG_NMI_IPI" is defined to also checking if
"CONFIG_PPC_BOOK3S_64" is defined. This matches the code in
arch/powerpc/kernel/stacktrace.c. Previously this worked because
<asm.nmi.h> was included if "CONFIG_HAVE_HARDLOCKUP_DETECTOR_ARCH" was
defined. For powerpc that's only selected if "CONFIG_PPC_BOOK3S_64" is
defined.

Fixes: 7ca8fe94aa92 ("watchdog/hardlockup: define HARDLOCKUP_DETECTOR_ARCH")
Reported-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Closes: https://lore.kernel.org/r/871qi5otdh.fsf@mail.lhotse
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
I'd expect that this would land in Andrew Morton's tree along with the
other lockup detector stuff.

Changes in v2:
- Change the guards to include CONFIG_PPC_BOOK3S_64.

 arch/powerpc/include/asm/irq.h | 6 ++++++
 arch/powerpc/include/asm/nmi.h | 6 ------
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
index 94dffa1dd223..f257cacb49a9 100644
--- a/arch/powerpc/include/asm/irq.h
+++ b/arch/powerpc/include/asm/irq.h
@@ -53,5 +53,11 @@ void __do_IRQ(struct pt_regs *regs);
 
 int irq_choose_cpu(const struct cpumask *mask);
 
+#if defined(CONFIG_PPC_BOOK3S_64) && defined(CONFIG_NMI_IPI)
+extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
+					   bool exclude_self);
+#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
+#endif
+
 #endif /* _ASM_IRQ_H */
 #endif /* __KERNEL__ */
diff --git a/arch/powerpc/include/asm/nmi.h b/arch/powerpc/include/asm/nmi.h
index ce25318c3902..49a75340c3e0 100644
--- a/arch/powerpc/include/asm/nmi.h
+++ b/arch/powerpc/include/asm/nmi.h
@@ -9,12 +9,6 @@ void watchdog_hardlockup_set_timeout_pct(u64 pct);
 static inline void watchdog_hardlockup_set_timeout_pct(u64 pct) {}
 #endif
 
-#ifdef CONFIG_NMI_IPI
-extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
-					   bool exclude_self);
-#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
-#endif
-
 extern void hv_nmi_check_nonrecoverable(struct pt_regs *regs);
 
 #endif /* _ASM_NMI_H */
-- 
2.41.0.162.gfafddb0af9-goog