From: John David Anglin <dave.anglin@bell.net>
To: Helge Deller <deller@gmx.de>,
linux-parisc@vger.kernel.org,
James Bottomley <James.Bottomley@hansenpartnership.com>
Subject: Re: [PATCH][RFC] parisc: Use local tlb purges only on UP machines
Date: Sun, 25 Sep 2022 15:27:29 -0400 [thread overview]
Message-ID: <67ff767d-5db9-384b-f144-1cd34d9f4f86@bell.net> (raw)
In-Reply-To: <114efb2d-7f09-6a80-43d7-2a132146774f@gmx.de>
On 2022-09-25 2:58 p.m., Helge Deller wrote:
> On 9/25/22 20:44, John David Anglin wrote:
>> On 2022-09-25 2:19 p.m., John David Anglin wrote:
>>>> One goal of that patch was to drop the CONFIG_PA20 ifdef case,
>>>> because a 32-bit kernel could be compiled for PA8000 in which case
>>>> the "pdtlb,l" will burn the machine.
>>> Don't think so. "pdtlb,l" is available on all PA 2.0 machines. It's not 64-bit specific.
>> There is some difference in implementation between PA 1.1 and 2.0. 64-bit register
>> values are used in the PA 2.0 implementation.
>
> That's right.
> But if you build a 32-bit kernel and choose to optimize for PA8x00 CPUs,
> the CONFIG_PA20 is set and the local-purge is used unconditionally.
> That breaks e.g. when running such a kernel in qemu (which is 32-bit only).
I don't think that's a valid kernel configuration for qemu. It only supports the PA 1.1
instruction set. PA8x00 CPUs always support the PA 2.0 instruction set even when running
in 32-bit mode.
> See my just-posted patch.
Dave
--
John David Anglin dave.anglin@bell.net
next prev parent reply other threads:[~2022-09-25 19:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-25 6:56 [PATCH][RFC] parisc: Use local tlb purges only on UP machines Helge Deller
2022-09-25 14:33 ` John David Anglin
2022-09-25 17:51 ` Helge Deller
2022-09-25 18:19 ` John David Anglin
2022-09-25 18:44 ` John David Anglin
2022-09-25 18:58 ` Helge Deller
2022-09-25 19:27 ` John David Anglin [this message]
2022-09-25 20:00 ` Helge Deller
2022-09-25 20:21 ` John David Anglin
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