From: Janosch Frank <frankja@linux.ibm.com>
To: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org,
nrb@linux.ibm.com, hca@linux.ibm.com
Subject: Re: [kvm-unit-tests PATCH] lib: s390x: css: Name inline assembly arguments and clean them up
Date: Wed, 5 Feb 2025 13:08:50 +0100 [thread overview]
Message-ID: <5d04e2c8-68df-4d6c-9ef8-0fc0d72e791f@linux.ibm.com> (raw)
In-Reply-To: <20250205112550.45a6b2cd@p-imbrenda>
On 2/5/25 11:25 AM, Claudio Imbrenda wrote:
> On Tue, 4 Feb 2025 09:51:33 +0000
> Janosch Frank <frankja@linux.ibm.com> wrote:
>
>> Less need to count the operands makes the code easier to read.
>>
>> Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
>> ---
>>
>> This one has been gathering dust for a while.
>> rfc->v1: Moved to Q constraint (thanks Heiko)
>>
>> ---
>
> [...]
>
>> asm volatile(" .insn rre,0xb25f0000,%2,0\n"
>> - " ipm %0\n"
>> - " srl %0,28\n"
>> - : "=d" (cc), "=m" (p)
>> + " ipm %[cc]\n"
>> + " srl %[cc],28\n"
>> + : [cc] "=d" (cc), "=m" (p)
>> : "d" (p), "m" (p)
>
> this bit (which you did not touch) is actually the most confusing to me.
> what's the point of separately specifying both "d" and "m" constraints
> for (p) ? (and it also has a "=m" in the output clobberlist)
I'll add a second patch to bring this into line with the kernel's
ioasm.c implementation.
next prev parent reply other threads:[~2025-02-05 12:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-04 9:51 [kvm-unit-tests PATCH] lib: s390x: css: Name inline assembly arguments and clean them up Janosch Frank
2025-02-04 12:55 ` Nico Boehr
2025-02-05 8:17 ` Janosch Frank
2025-02-05 10:25 ` Claudio Imbrenda
2025-02-05 12:08 ` Janosch Frank [this message]
2025-02-06 10:36 ` Janosch Frank
2025-02-06 12:03 ` Claudio Imbrenda
2025-02-06 12:42 ` Nico Boehr
2025-02-06 17:22 ` Claudio Imbrenda
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