linux-kernel - Re: [PATCH v6 9/9] x86: jump-labels: use macros instead of inline assembly

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Date:   Tue, 24 Jul 2018 16:29:38 +0000
From:   Nadav Amit <namit@...are.com>
To:     Ingo Molnar <mingo@...nel.org>
CC:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        X86 ML <x86@...nel.org>, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Philippe Ombredanne <pombredanne@...b.com>
Subject: Re: [PATCH v6 9/9] x86: jump-labels: use macros instead of inline
 assembly

at 7:26 AM, Ingo Molnar <mingo@...nel.org> wrote:

> 
> * Nadav Amit <namit@...are.com> wrote:
> 
>> Use assembly macros for jump-labels and call them from inline assembly.
>> This not only makes the code more readable, but also improves
>> compilation decision, specifically inline decisions which GCC base on
>> the number of new lines in inline assembly.
>> 
>> As a result the code size is slightly increased.
>> 
>>   text	   data	    bss	    dec	    hex	filename
>> 18163528 10226300 2957312 31347140 1de51c4 ./vmlinux before
>> 18163608 10227348 2957312 31348268 1de562c ./vmlinux after (+1128)
>> 
>> And functions such as intel_pstate_adjust_policy_max(),
>> kvm_cpu_accept_dm_intr(), kvm_register_readl() are inlined.
>> 
>> Cc: Thomas Gleixner <tglx@...utronix.de>
>> Cc: Ingo Molnar <mingo@...hat.com>
>> Cc: "H. Peter Anvin" <hpa@...or.com>
>> Cc: x86@...nel.org
>> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
>> Cc: Kate Stewart <kstewart@...uxfoundation.org>
>> Cc: Philippe Ombredanne <pombredanne@...b.com>
>> Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
>> Signed-off-by: Nadav Amit <namit@...are.com>
>> ---
>> arch/x86/entry/calling.h          |  2 +-
>> arch/x86/include/asm/jump_label.h | 77 +++++++++++--------------------
>> arch/x86/kernel/macros.S          |  1 +
>> 3 files changed, 30 insertions(+), 50 deletions(-)
> 
> So I tried the series, and this patch causes a silent hard hang on bootup, with no 
> (early-)console messages visible.
> 
> I've attached the config that triggers the problem, built with:
> 
>  gcc version 5.3.1 20160406 (Red Hat 5.3.1-6) (GCC) 
> 
> it's 100% reproducible on both Intel and AMD test systems.
> 
> I'll continue to test the series with this patch left out.
> 
> So both the xtensa build failure and this boot failure needs to be fixed before I 
> can apply this series.

I’ll look into these issues, but I don’t see the config attached.

Thanks,
Nadav