From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/7] x86/boot: Introduce helpers for serial I/O
Date: Thu, 28 Mar 2019 16:51:46 +0200 [thread overview]
Message-ID: <20190328145146.GH9224@smile.fi.intel.com> (raw)
In-Reply-To: <20190328143447.GN22720@zn.tnic>
On Thu, Mar 28, 2019 at 03:34:47PM +0100, Borislav Petkov wrote:
> On Thu, Mar 28, 2019 at 04:20:01PM +0200, Andy Shevchenko wrote:
> > By name and by what it's handling (only byte accesses to I/O or MMIO).
>
> Your series does only byte accesses so you can use byte variant.
>
> > My point is, that doing branch(es) on each I/O call is not good as simple
> > calling the proper (pre-defined) I/O accessor.
>
> What branches?
Something like this at the end
if (mmio32)
...
else if (mmio)
...
else if (whatever)
...
else
...
> You do a branch and *then* you do an IO call.
Yes.
> What does "not good" even mean?
We still export global flag variable, on top of this we need an additional
branch which we can avoid for free.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2019-03-28 14:51 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-19 18:43 [PATCH v2 0/7] x86/boot: Enable earlyprintk for HS UARTs Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 1/7] x86/boot: Convert early_serial_base to unsigned long Andy Shevchenko
2019-03-28 8:28 ` Borislav Petkov
2019-03-28 9:09 ` Andy Shevchenko
2019-03-28 10:54 ` Borislav Petkov
2019-03-19 18:43 ` [PATCH v2 2/7] x86/boot: Introduce helpers for serial I/O Andy Shevchenko
2019-03-28 12:32 ` Borislav Petkov
2019-03-28 13:11 ` Andy Shevchenko
2019-03-28 13:28 ` Borislav Petkov
2019-03-28 13:52 ` Andy Shevchenko
2019-03-28 14:05 ` Borislav Petkov
2019-03-28 14:20 ` Andy Shevchenko
2019-03-28 14:34 ` Borislav Petkov
2019-03-28 14:51 ` Andy Shevchenko [this message]
2019-03-19 18:43 ` [PATCH v2 3/7] x86/boot: Split out parse_serial_port() helper for earlyprintk Andy Shevchenko
2019-03-28 12:35 ` Borislav Petkov
2019-03-28 13:15 ` Andy Shevchenko
2019-03-28 13:39 ` Borislav Petkov
2019-03-28 13:50 ` Andy Shevchenko
2019-03-28 14:03 ` Borislav Petkov
2019-03-28 14:23 ` Andy Shevchenko
2019-03-28 14:35 ` Borislav Petkov
2019-03-28 14:49 ` Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 4/7] x86/boot: Allow longer parameter list " Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 5/7] x86/boot: Add MMIO byte accessors Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 6/7] x86/boot: Introduce MMIO accessors and their support in earlyprintk Andy Shevchenko
2019-03-19 18:43 ` [PATCH v2 7/7] x86/boot: Support nocfg parameter for earlyprintk Andy Shevchenko
2019-03-20 15:05 ` Randy Dunlap
2019-03-20 15:17 ` Andy Shevchenko
2019-03-20 15:19 ` Randy Dunlap
2019-03-20 16:15 ` Andy Shevchenko
2019-03-20 16:30 ` Borislav Petkov
2019-03-20 17:29 ` Andy Shevchenko
2019-03-28 13:03 ` Borislav Petkov
2019-03-28 13:21 ` Andy Shevchenko
2019-03-28 13:42 ` Borislav Petkov
2019-03-28 14:00 ` Andy Shevchenko
2019-03-28 14:13 ` Borislav Petkov
2019-03-28 14:27 ` Andy Shevchenko
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