From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB71CC433F5 for ; Sun, 10 Apr 2022 12:14:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238754AbiDJMQg (ORCPT ); Sun, 10 Apr 2022 08:16:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232013AbiDJMQf (ORCPT ); Sun, 10 Apr 2022 08:16:35 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E67FF3D1EF; Sun, 10 Apr 2022 05:14:23 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1649592860; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OFmRIgWsEfS1u8csltcfGL85/93nZMY90Oa0fL8OYn8=; b=iT0LHVcBBKaQRnyzmg4Y+pQ1Zje/qhPE8eV5XllPWuJ4R+iBHPdx9bCyQ9QdsjydL8HFvk 1w0gYfwVe8VW8lKPFCmaDWBNh8ISxg3cRTHc7GVEmrmpCBQx3AiuVbn0LBkwJB1vOoL/tp G5//ftF7PNePvQAGZiqfIbJJxRm2MIYMzrUxHy86ge44t8xM3X4Cl7WSN59H3Cq6YzkbcI FzjQFrDr9PL0DJ98d09c3GnDHeGuSUQ21h1ZlqSlyPuztoLNeEgo9qJe3mnLB0zYgBKpBu Zl6CBbqroeK/y5EOHWcTkUXPHEjKjgfyppbAHZn3B6XT5mwPT2FSDXHvyDkvhA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1649592860; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=OFmRIgWsEfS1u8csltcfGL85/93nZMY90Oa0fL8OYn8=; b=ZowN3hDL00e5KRJGyl0d0NcP84qDlITpO7vwsVPu9kvaRTv5XnipOOoo0K4Pv//bkRseYI YFGsrNPSqm8U+tAQ== To: Pete Swain , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "H. Peter Anvin" , Paolo Bonzini , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , John Stultz , Stephen Boyd , "Maciej W. Rozycki" , Johan Hovold , Feng Tang , "Paul E. McKenney" , Juergen Gross , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Pete Swain Subject: Re: [PATCH 2/2] timers: retpoline mitigation for time funcs In-Reply-To: <20220218221820.950118-2-swine@google.com> References: <20220218221820.950118-1-swine@google.com> <20220218221820.950118-2-swine@google.com> Date: Sun, 10 Apr 2022 14:14:20 +0200 Message-ID: <87r165gmoz.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Fri, Feb 18 2022 at 14:18, Pete Swain wrote: > Adds indirect call exports for clock reads from tsc, apic, > hrtimer, via clock-event, timekeeper & posix interfaces. Sure, but why? > Signed-off-by: Pete Swain > --- > arch/x86/kernel/apic/apic.c | 8 +++++--- > arch/x86/kernel/tsc.c | 3 ++- > include/linux/hrtimer.h | 19 ++++++++++++++++--- > kernel/time/clockevents.c | 9 ++++++--- > kernel/time/hrtimer.c | 3 ++- > kernel/time/posix-cpu-timers.c | 4 ++-- > kernel/time/posix-timers.c | 3 ++- > kernel/time/timekeeping.c | 2 +- > 8 files changed, 36 insertions(+), 15 deletions(-) Can this please be split up properly? > diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c > index b70344bf6600..523a569dd35e 100644 > --- a/arch/x86/kernel/apic/apic.c > +++ b/arch/x86/kernel/apic/apic.c > @@ -463,15 +463,17 @@ EXPORT_SYMBOL_GPL(setup_APIC_eilvt); > /* > * Program the next event, relative to now > */ > -static int lapic_next_event(unsigned long delta, > +INDIRECT_CALLABLE_SCOPE > +int lapic_next_event(unsigned long delta, > struct clock_event_device *evt) So this was formatted properly: static int lapic_next_event(unsigned long delta, struct clock_event_device *evt) Now it turned into garbage: INDIRECT_CALLABLE_SCOPE int lapic_next_event(unsigned long delta, struct clock_event_device *evt) while: INDIRECT_CALLABLE_SCOPE int lapic_next_event(unsigned long delta, struct clock_event_device *evt) or INDIRECT_CALLABLE_SCOPE int lapic_next_event(unsigned long delta, struct clock_event_device *evt) are both what a reader would expect. Similar issues all over the place. > diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c > index a698196377be..ff2868d5ddea 100644 > --- a/arch/x86/kernel/tsc.c > +++ b/arch/x86/kernel/tsc.c > @@ -1090,7 +1090,8 @@ static void tsc_resume(struct clocksource *cs) > * checking the result of read_tsc() - cycle_last for being negative. > * That works because CLOCKSOURCE_MASK(64) does not mask out any bit. > */ > -static u64 read_tsc(struct clocksource *cs) > +INDIRECT_CALLABLE_SCOPE > +u64 read_tsc(struct clocksource *cs) What's the extra line for? > { > return (u64)rdtsc_ordered(); > } > diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h > index 0ee140176f10..9d2d110f0b8c 100644 > --- a/include/linux/hrtimer.h > +++ b/include/linux/hrtimer.h > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > struct hrtimer_clock_base; > struct hrtimer_cpu_base; > @@ -297,14 +298,17 @@ static inline s64 hrtimer_get_expires_ns(const struct hrtimer *timer) > return ktime_to_ns(timer->node.expires); > } > > +INDIRECT_CALLABLE_DECLARE(extern ktime_t ktime_get(void)); > + > static inline ktime_t hrtimer_expires_remaining(const struct hrtimer *timer) > { > - return ktime_sub(timer->node.expires, timer->base->get_time()); > + return ktime_sub(timer->node.expires, > + INDIRECT_CALL_1(timer->base->get_time, ktime_get)); This wants a proper explanation in a changelog for the hrtimer check, why this is optimized for ktime_get(). > } > > static inline ktime_t hrtimer_cb_get_time(struct hrtimer *timer) > { > - return timer->base->get_time(); > + return INDIRECT_CALL_1(timer->base->get_time, ktime_get); > } > > static inline int hrtimer_is_hres_active(struct hrtimer *timer) > @@ -503,7 +507,9 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval); > static inline u64 hrtimer_forward_now(struct hrtimer *timer, > ktime_t interval) > { > - return hrtimer_forward(timer, timer->base->get_time(), interval); > + return hrtimer_forward(timer, > + INDIRECT_CALL_1(timer->base->get_time, ktime_get), > + interval); > } > > /* Precise sleep: */ > @@ -536,4 +542,11 @@ int hrtimers_dead_cpu(unsigned int cpu); > #define hrtimers_dead_cpu NULL > #endif > > +struct clock_event_device; > +INDIRECT_CALLABLE_DECLARE(extern __weak u64 read_tsc(struct clocksource *cs)); > +INDIRECT_CALLABLE_DECLARE(extern int thread_cpu_clock_get( > + const clockid_t which_clock, struct timespec64 *tp)); > +INDIRECT_CALLABLE_DECLARE(extern __weak int lapic_next_deadline( > + unsigned long delta, struct clock_event_device *evt)); > + No. This is not how it works. This is a generic header and x86 specific muck has no place here. > #endif > diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c > index 003ccf338d20..ac15412e87c4 100644 > --- a/kernel/time/clockevents.c > +++ b/kernel/time/clockevents.c > @@ -245,7 +245,8 @@ static int clockevents_program_min_delta(struct clock_event_device *dev) > > dev->retries++; > clc = ((unsigned long long) delta * dev->mult) >> dev->shift; > - if (dev->set_next_event((unsigned long) clc, dev) == 0) > + if (INDIRECT_CALL_1(dev->set_next_event, lapic_next_deadline, > + (unsigned long) clc, dev) == 0) No. We are not sprinkling x86'isms into generic code. > diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c > index 96b4e7810426..d8bf325fa84e 100644 > --- a/kernel/time/posix-cpu-timers.c > +++ b/kernel/time/posix-cpu-timers.c > @@ -1596,8 +1596,8 @@ static int thread_cpu_clock_getres(const clockid_t which_clock, > { > return posix_cpu_clock_getres(THREAD_CLOCK, tp); > } > -static int thread_cpu_clock_get(const clockid_t which_clock, > - struct timespec64 *tp) > +INDIRECT_CALLABLE_SCOPE > +int thread_cpu_clock_get(const clockid_t which_clock, struct timespec64 *tp) > { > return posix_cpu_clock_get(THREAD_CLOCK, tp); > } > diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c > index 1cd10b102c51..35eac10ee796 100644 > --- a/kernel/time/posix-timers.c > +++ b/kernel/time/posix-timers.c > @@ -1089,7 +1089,8 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, > if (!kc) > return -EINVAL; > > - error = kc->clock_get_timespec(which_clock, &kernel_tp); > + error = INDIRECT_CALL_1(kc->clock_get_timespec, thread_cpu_clock_get, > + which_clock, &kernel_tp); The argument for selecting thread_cpu_clock_get() as optimization target is? > > if (!error && put_timespec64(&kernel_tp, tp)) > error = -EFAULT; > diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c > index dcdcb85121e4..2b1a3b146614 100644 > --- a/kernel/time/timekeeping.c > +++ b/kernel/time/timekeeping.c > @@ -190,7 +190,7 @@ static inline u64 tk_clock_read(const struct tk_read_base *tkr) > { > struct clocksource *clock = READ_ONCE(tkr->clock); > > - return clock->read(clock); > + return INDIRECT_CALL_1(clock->read, read_tsc, clock); Again. No X86 muck here. Thanks, tglx