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Date:   Wed, 10 Apr 2019 09:01:52 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>,
        Ashok Raj <ashok.raj@intel.com>,
        Andi Kleen <andi.kleen@intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org,
        Ricardo Neri <ricardo.neri@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>,
        Clemens Ladisch <clemens@ladisch.de>,
        Arnd Bergmann <arnd@arndb.de>,
        Philippe Ombredanne <pombredanne@nexb.com>,
        Kate Stewart <kstewart@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Mimi Zohar <zohar@linux.ibm.com>,
        Jan Kiszka <jan.kiszka@siemens.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Nayna Jain <nayna@linux.ibm.com>
Subject: Re: [RFC PATCH v2 12/14] x86/watchdog/hardlockup/hpet: Determine if
 HPET timer caused NMI
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On Tue, Apr 09, 2019 at 06:19:57PM -0700, Ricardo Neri wrote:
> On Tue, Apr 09, 2019 at 01:28:17PM +0200, Peter Zijlstra wrote:
> > > @@ -147,6 +161,14 @@ static void set_periodic(struct hpet_hld_data *hdata)
> > >   */
> > >  static bool is_hpet_wdt_interrupt(struct hpet_hld_data *hdata)
> > >  {
> > > +	if (smp_processor_id() == hdata->handling_cpu) {
> > > +		unsigned long tsc_curr;
> > 
> > TSC is u64
> 
> In x86_64, isn't u64 an unsigned long? Do you mean to consider the
> 32-bit case?

Unless none of this code is available for x86_32, you pretty much have
to consider 32bit.

But even then, using u64 for 64bit values is the right thing.