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Date:      Thu, 24 Sep 2015 20:14:36 +0100
From:      Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
To:        Marius Strobl <marius@alchemy.franken.de>
Cc:        Alexey Dokuchaev <danfe@FreeBSD.org>,  "freebsd-sparc64@freebsd.org" <freebsd-sparc64@freebsd.org>
Subject:   Re: PCI range checking under qemu-system-sparc64
Message-ID:  <56044B9C.8030105@ilande.co.uk>
In-Reply-To: <20150923204336.GO18789@alchemy.franken.de>
References:  <20150916031030.GA6711@FreeBSD.org> <55F9C2B8.7030605@ilande.co.uk> <20150916211914.GD18789@alchemy.franken.de> <20150917082817.GA71811@FreeBSD.org> <55FBB662.4080708@ilande.co.uk> <20150919211420.GK18789@alchemy.franken.de> <55FDEA3C.1010804@ilande.co.uk> <20150920043630.GA36162@FreeBSD.org> <20150922221404.GA81100@alchemy.franken.de> <560260A9.9010505@ilande.co.uk> <20150923204336.GO18789@alchemy.franken.de>

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On 23/09/15 21:43, Marius Strobl wrote:

> On Wed, Sep 23, 2015 at 09:19:53AM +0100, Mark Cave-Ayland wrote:
>>
>> I've had a quick look through the relevant PDFs and the definitions I
>> have for tick/stick are this:
>>
>> tick:
>>   bit  63: NPT (Non-Privileged Trap enable - defaults to 1)
>>   bits 62 - 0: CPU cycle counter
>>
>> tick_cmpr:
>>   bit  63: Interrupt disable (1 = no interrupt)
>>   bits 62 - 0: counter compare value
>>
>> stick:
>>   bit  63: Reserved (reads 0, no write)
>>   bits 62 - 0: stick register count value
> 
> I cannot confirm that, the specification for the first sun4u CPU
> having a %stick register (UltraSPARC III, see 1, p. 6-105) up to
> the latest architecture specification (see 2, p. 60) say that bit
> 32 of %stick is NPT, just as with %tick. Same for the specification
> the Fujitsu SPARC64 processors follow (3, p. 90).

Interesting. The document I'm referring to in my local collection is the
UltraSPARC IIe specification which you can find a copy at
http://www.coris.org.uk/misc/Sundocs/USIIe_ext_1.1.pdf (see page 29). I
don't see this as necessarily being a conflict, it just seems that the
IIe allows unprivileged access to %stick.


ATB,

Mark.




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