watchdog/perf: define dummy watchdog_update_hrtimer_threshold() on co…

…rrect config

Patch series "watchdog/hardlockup: Add the buddy hardlockup detector", v5.

This patch series adds the "buddy" hardlockup detector.  In brief, the
buddy hardlockup detector can detect hardlockups without arch-level
support by having CPUs checkup on a "buddy" CPU periodically.

Given the new design of this patch series, testing all combinations is
fairly difficult. I've attempted to make sure that all combinations of
CONFIG_ options are good, but it wouldn't surprise me if I missed
something. I apologize in advance and I'll do my best to fix any
problems that are found.


This patch (of 18):

The real watchdog_update_hrtimer_threshold() is defined in
kernel/watchdog_hld.c.  That file is included if
CONFIG_HARDLOCKUP_DETECTOR_PERF and the function is defined in that file
if CONFIG_HARDLOCKUP_CHECK_TIMESTAMP.

The dummy version of the function in "nmi.h" didn't get that quite right. 
While this doesn't appear to be a huge deal, it's nice to make it
consistent.

It doesn't break builds because CHECK_TIMESTAMP is only defined by x86 so
others don't get a double definition, and x86 uses perf lockup detector,
so it gets the out of line version.

Link: https://lkml.kernel.org/r/20230519101840.v5.18.Ia44852044cdcb074f387e80df6b45e892965d4a1@changeid
Link: https://lkml.kernel.org/r/20230519101840.v5.1.I8cbb2f4fa740528fcfade4f5439b6cdcdd059251@changeid
Fixes: 7edaeb6 ("kernel/watchdog: Prevent false positives with turbo modes")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Lecopzer Chen <lecopzer.chen@mediatek.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masayoshi Mizuma <msys.mizuma@gmail.com>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Pingfan Liu <kernelfans@gmail.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: Ricardo Neri <ricardo.neri@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Stephen Boyd <swboyd@chromium.org>
Cc: Sumit Garg <sumit.garg@linaro.org>
Cc: Tzung-Bi Shih <tzungbi@chromium.org>
Cc: Will Deacon <will@kernel.org>
Cc: Colin Cross <ccross@android.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/nmi.h

@@ -197,7 +197,7 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh);
 #endif
 
 #if defined(CONFIG_HARDLOCKUP_CHECK_TIMESTAMP) && \
-    defined(CONFIG_HARDLOCKUP_DETECTOR)
+    defined(CONFIG_HARDLOCKUP_DETECTOR_PERF)
 void watchdog_update_hrtimer_threshold(u64 period);
 #else
 static inline void watchdog_update_hrtimer_threshold(u64 period) { }