From: David Laight <David.Laight@ACULAB.COM>
To: 'Guenter Roeck' <linux@roeck-us.net>,
'Armin Wolf' <W_Armin@gmx.de>,
"pali@kernel.org" <pali@kernel.org>
Cc: "jdelvare@suse.com" <jdelvare@suse.com>,
"linux-hwmon@vger.kernel.org" <linux-hwmon@vger.kernel.org>,
"linux-assembly@vger.kernel.org" <linux-assembly@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2] hwmon: (dell-smm) Improve assembly code
Date: Sun, 20 Feb 2022 18:03:15 +0000 [thread overview]
Message-ID: <075c56861e1e454188db1088b78d3ee2@AcuMS.aculab.com> (raw)
In-Reply-To: <7d387f96-1561-2eec-43e2-b971ff79d734@roeck-us.net>
From: Guenter Roeck
> Sent: 20 February 2022 15:30
>
> On 2/20/22 04:20, David Laight wrote:
> > From: Armin Wolf
> >> Sent: 19 February 2022 21:10
> >>
> >> The new assembly code works on both 32 bit and 64 bit
> >> cpus and allows for more compiler optimisations by not
> >> requiring smm_regs to be packed. Also since the
> >> SMM handler seems to modify the carry flag, the new
> >> code informs the compiler that the flags register
> >> needs to be saved/restored. Since clang runs out of
> >> registers on 32 bit x86 when using CC_OUT, we need
> >> to execute "setc" ourself.
> >
> > You always need to save anything from the flags register
> > inside the asm block - it is never valit afterwards.
> >
>
> Does that matter here ? I thought setcc is used to get the carry flag.
The code is ok, just the comment is not really right.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2022-02-20 18:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-19 21:10 Armin Wolf
2022-02-20 12:20 ` David Laight
2022-02-20 15:30 ` Guenter Roeck
2022-02-20 18:03 ` David Laight [this message]
2022-02-20 18:48 ` David Laight
2022-02-20 19:05 ` Armin Wolf
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