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Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4
From: |
Helge Deller |
Subject: |
Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4 |
Date: |
Fri, 17 Jan 2020 20:57:23 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 |
On 17.01.20 20:23, Richard Henderson wrote:
> On 1/17/20 8:50 AM, Philippe Mathieu-Daudé wrote:
>> On Fri, Jan 17, 2020 at 2:53 AM Richard Henderson
>> <address@hidden> wrote:
>>>
>>> The PA-RISC 1.1 specification says that LDCW must be aligned mod 16
>>> or the operation is undefined. However, real hardware only generates
>>> an unaligned access trap for unaligned mod 4.
>>
>> This Linux kernel commit seems relevant:
>>
>> https://github.com/torvalds/linux/commit/14e256c107304#diff-e85862c7227599cb24e36494f75948d5R159-R164
>>
>> /* From: "Jim Hull" <jim.hull of hp.com>
>> I've attached a summary of the change, but basically, for PA 2.0, as
>> long as the ",CO" (coherent operation) completer is specified, then the
>> 16-byte alignment requirement for ldcw and ldcd is relaxed, and instead
>> they only require "natural" alignment (4-byte for ldcw, 8-byte for
>> ldcd). */
>
> It isn't completely relevant. We don't implement hppa 2.0.
>
> I added a TODO comment for HPPA64, as I said in reply to Dave Anglin elsewhere
> in this thread.
I agree. A TODO comment should be sufficient for now.
Thanks!
Helge
- [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Richard Henderson, 2020/01/16
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Helge Deller, 2020/01/17
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Philippe Mathieu-Daudé, 2020/01/17
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Helge Deller, 2020/01/17
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Richard Henderson, 2020/01/17
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, John David Anglin, 2020/01/17
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Richard Henderson, 2020/01/17
- Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Philippe Mathieu-Daudé, 2020/01/17
Re: [PATCH] target/hppa: Allow, but diagnose, LDCW aligned only mod 4, Philippe Mathieu-Daudé, 2020/01/17