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From: Peter Zijlstra <peterz@infradead.org>
To: bigeasy@linutronix.de
Cc: mark.rutland@arm.com, maz@kernel.org, catalin.marinas@arm.com,
	will@kernel.org, chenhuacai@kernel.org, kernel@xen0n.name,
	hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com,
	borntraeger@linux.ibm.com, svens@linux.ibm.com,
	pbonzini@redhat.com, wanpengli@tencent.com, vkuznets@redhat.com,
	tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
	dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
	jgross@suse.com, boris.ostrovsky@oracle.com,
	daniel.lezcano@linaro.org, kys@microsoft.com,
	haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com,
	rafael@kernel.org, peterz@infradead.org, longman@redhat.com,
	boqun.feng@gmail.com, pmladek@suse.com, senozhatsky@chromium.org,
	rostedt@goodmis.org, john.ogness@linutronix.de,
	juri.lelli@redhat.com, vincent.guittot@linaro.org,
	dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vschneid@redhat.com, jstultz@google.com,
	sboyd@kernel.org, linux-kernel@vger.kernel.org,
	loongarch@lists.linux.dev, linux-s390@vger.kernel.org,
	kvm@vger.kernel.org, linux-hyperv@vger.kernel.org,
	linux-pm@vger.kernel.org
Subject: [PATCH v2 07/13] math64: Always inline u128 version of mul_u64_u64_shr()
Date: Fri, 19 May 2023 12:21:05 +0200	[thread overview]
Message-ID: <20230519102715.637420396@infradead.org> (raw)
In-Reply-To: 20230519102058.581557770@infradead.org

In order to prevent the following complaint from happening, always
inline the u128 variant of mul_u64_u64_shr() -- which is what x86_64
will use.

  vmlinux.o: warning: objtool: read_hv_sched_clock_tsc+0x5a: call to mul_u64_u64_shr.constprop.0() leaves .noinstr.text section

It should compile into something like:

  asm("mul	%[mul];"
      "shrd	%rdx, %rax, %cl"
      : "+&a" (a)
      : "c" shift, [mul] "r" (mul)
      : "d");

Which is silly not to inline, but it happens.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 include/linux/math64.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -168,7 +168,7 @@ static __always_inline u64 mul_u64_u32_s
 #endif /* mul_u64_u32_shr */
 
 #ifndef mul_u64_u64_shr
-static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
+static __always_inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift)
 {
 	return (u64)(((unsigned __int128)a * mul) >> shift);
 }



  parent reply	other threads:[~2023-05-19 10:34 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-19 10:20 [PATCH v2 00/13] local_clock() vs noinstr Peter Zijlstra
2023-05-19 10:20 ` [PATCH v2 01/13] seqlock/latch: Provide raw_read_seqcount_latch_retry() Peter Zijlstra
2023-05-19 10:21 ` [PATCH v2 02/13] time/sched_clock: Provide sched_clock_noinstr() Peter Zijlstra
2023-05-19 10:21 ` [PATCH v2 03/13] arm64/io: Always inline all of __raw_{read,write}[bwlq]() Peter Zijlstra
2023-05-24 16:40   ` Valentin Schneider
2023-05-19 10:21 ` [PATCH v2 04/13] arm64/arch_timer: Provide noinstr sched_clock_read() functions Peter Zijlstra
2023-05-24 16:40   ` Valentin Schneider
2023-06-02 11:54     ` Peter Zijlstra
2023-06-07  8:58       ` Valentin Schneider
2023-05-19 10:21 ` [PATCH v2 05/13] loongarch: Provide noinstr sched_clock_read() Peter Zijlstra
2023-05-19 10:21 ` [PATCH v2 06/13] s390/time: Provide sched_clock_noinstr() Peter Zijlstra
2023-05-22 14:18   ` Heiko Carstens
2023-05-19 10:21 ` Peter Zijlstra [this message]
2023-05-19 10:21 ` [PATCH v2 08/13] x86/vdso: Fix gettimeofday masking Peter Zijlstra
2023-05-31 15:27   ` Thomas Gleixner
2023-05-31 22:46     ` Thomas Gleixner
2023-05-31 22:46   ` Thomas Gleixner
2023-05-19 10:21 ` [PATCH v2 09/13] clocksource: hyper-v: Adjust hv_read_tsc_page_tsc() to avoid special casing U64_MAX Peter Zijlstra
2023-05-19 18:38   ` Michael Kelley (LINUX)
2023-05-19 10:21 ` [PATCH v2 10/13] clocksource: hyper-v: Provide noinstr sched_clock() Peter Zijlstra
2023-05-19 10:21 ` [PATCH v2 11/13] x86/tsc: Provide sched_clock_noinstr() Peter Zijlstra
2023-05-19 10:21 ` [PATCH v2 12/13] sched/clock: Provide local_clock_noinstr() Peter Zijlstra
2023-05-19 10:21 ` [PATCH v2 13/13] cpuidle: Use local_clock_noinstr() Peter Zijlstra
2023-05-19 14:13   ` Rafael J. Wysocki
2023-05-19 18:48 ` [PATCH v2 00/13] local_clock() vs noinstr Michael Kelley (LINUX)

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