[okl4-developer] CONFIG_UTCB_SIZE and UTCB_SIZE

[Tomas Hruby]

OK, mine utcb is also under 512 so I set CONFIG_UTCB_SIZE to 512 as
well. For some reason I thought it should ba a page, maybe confused by
the 12 in x86 code ... I seems to work nicely now.

Cheers, T.

On Tue, Aug 26, 2008 at 04:32:27PM +1000, Geoffrey Lee wrote:
> On Tue, Aug 26, 2008 at 12:26:19PM +1000, Tomas Hruby wrote:
> > Hi,
> 
> Hi Tomas
> 
> > 
> > I would like to ask what is the relationship between CONFIG_UTCB_SIZE
> > and UTCB_SIZE. The former is a kernel define and it is (12) for x86.
> > It shouldbe probably (1 << 12) and we have discussed this already so I
> > assume it is (1 << 12). However UTCB_SIZE is defined in userspace l4
> > lib and is defined as (1 << 9) for x86. When l4test calls
> > L4_ThreadControl() in initThreads() it sets utcb to utcbbase +
> > (2)*UTCB_SIZE. My first question is why (2)* ?
> > 
> > When the utcb gets in the SYS_THREAD_CONTROL() handler it checks
> > whether the address is CONFIG_UTCB_SIZE aligned. This test fails since
> > the address is (2)*UTCB_SIZE aligned. I am setting the sizes to
> > CONFIG_UTCB_SIZE == (1 << 13) and UTCB_SIZE == (1 << 9). So I ran into
> > the problem described above. I believe that x86 would have the same
> > troubles.
> 
> This seems to be an issue.  I think the CONFIG_UTCB_SIZE define
> should be set to the actual architecture-dependent size of the UTCB
> for that particular architecture, e.g. for x86 it would be ( 1 << 9)
> i.e. 512.
> 
> 	-gl
> 
> 
> > 
> > Therefore I wanted to set the UTCB_SIZE to (1 << 13) as well. For some
> > reason which I cannot explain if I change the value of UTCB_BITS
> > to anything larger than 9 OpenBoot crashes when loading the image. Is
> > this value used by the build system to layout something in
> > compiletime? I have no clue what does this value changes in the image :(
> > 
> > Cheers,
> > 
> > 			Tomas
> > 
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> > 
> 
> -- 
> 
> 
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