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Message-ID: <f0f029c5-b095-d713-114f-dc7d5c092d8a@loongson.cn>
Date: Wed, 26 Apr 2023 08:46:54 +0800
From: maobibo <maobibo@...ngson.cn>
To: WANG Xuerui <kernel@...0n.name>,
Peter Zijlstra <peterz@...radead.org>
Cc: Frederic Weisbecker <frederic@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Huacai Chen <chenhuacai@...nel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Anna-Maria Behnsen <anna-maria@...utronix.de>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: Loongson (and other $ARCHs?) idle VS timer enqueue
在 2023/4/25 21:28, WANG Xuerui 写道:
> On 2023/4/25 21:25, maobibo wrote:
>>
>>
>> 在 2023/4/25 19:49, Peter Zijlstra 写道:
>
> <snip>
>
>>>
>>> diff --git a/arch/loongarch/kernel/genex.S b/arch/loongarch/kernel/genex.S
>>> index 44ff1ff64260..3c8a6bab98fe 100644
>>> --- a/arch/loongarch/kernel/genex.S
>>> +++ b/arch/loongarch/kernel/genex.S
>>> @@ -18,27 +18,31 @@
>>> .align 5
>>> SYM_FUNC_START(__arch_cpu_idle)
>>> - /* start of rollback region */
>>> - LONG_L t0, tp, TI_FLAGS
>>> - nop
>>> - andi t0, t0, _TIF_NEED_RESCHED
>>> - bnez t0, 1f
>>> - nop
>>> - nop
>>> - nop
>>> + /* start of idle interrupt region */
>>> + move t0, CSR_CRMD_IE
>> addi.d t0, zero, CSR_CRMD_IE can be used here, move is used for reg to reg
>
> Or better: li.d t0, CSR_CRMD_IE (prefer pseudo-instruction over concrete ones whenever it helps readability). We don't need to support ancient in-house toolchains without support for even li. ;-)
I am not familiar with compiler:(, how many actual instructions does
pseudo-instr li.d takes? It will be ok if it uses only one intr, else
there will be problem.
Regards
Bibo, Mao
>
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