[hppa-linux] memory layout

[hppa-linux] memory layout

[Mike Shaver]

rd.c:467: `KERNEL_DS' undeclared (first use in this function)
mmap.c:361: `TASK_UNMAPPED_BASE' undeclared (first use in this function)

It sorta begs the question: what is our memory layout going to look
like?  What goes where?  I'll pore over my PA-RISC book tonight looking
for clues, but I doubt that'll be enough.

What kind of memory layout does HP-UX use, if I might be so bold as to
ask?

Mike

-- 
305756.61 259655.94

Re: [hppa-linux] memory layout

[Kumar]

Talking about only pa1.1 or 32 bit CPUs, I would say the same layout
can be used as Linux on Intel does. That is kernel mapped at 0xc0000000.
So 3 Gig for User space and 1 Gig for kernel. Of course, other ppl may
have different ideas. 

PA has this strange concept of Spaces and they have those 
space registers %sr0 to %sr7. This reminds me of Intel's segment 
registers. And whoever wanted to do any serious OS like Unix on 80386
never liked segments.

					pkd 

On Wed, 17 Mar 1999, Mike Shaver wrote:

> rd.c:467: `KERNEL_DS' undeclared (first use in this function)
> mmap.c:361: `TASK_UNMAPPED_BASE' undeclared (first use in this function)
> 
> It sorta begs the question: what is our memory layout going to look
> like?  What goes where?  I'll pore over my PA-RISC book tonight looking
> for clues, but I doubt that'll be enough.
> 
> What kind of memory layout does HP-UX use, if I might be so bold as to
> ask?
> 
> Mike
> 

Re: [hppa-linux] memory layout

[Mike Shaver]

Kumar wrote:
> 
> Talking about only pa1.1 or 32 bit CPUs, I would say the same layout
> can be used as Linux on Intel does. That is kernel mapped at 0xc0000000.
> So 3 Gig for User space and 1 Gig for kernel. Of course, other ppl may
> have different ideas.

OpenBSD has the same idea, it seems.  From
sys/arch/hppa/include/vmparam.h:

/* user/kernel map constants */
#define VM_MIN_ADDRESS          ((vm_offset_t)0)
#define VM_MAXUSER_ADDRESS      ((vm_offset_t)0xc0000000)
#define VM_MAX_ADDRESS          VM_MAXUSER_ADDRESS
#define VM_MIN_KERNEL_ADDRESS   ((vm_offset_t)0)
#define VM_MAX_KERNEL_ADDRESS   ((vm_offset_t)0xF0000000)

I'll start filling in the x86 numbers blindly, I guess.

> PA has this strange concept of Spaces and they have those
> space registers %sr0 to %sr7. This reminds me of Intel's segment
> registers. And whoever wanted to do any serious OS like Unix on 80386
> never liked segments.

Yeah, I've been trying to figure out whether we should do anything
special with those, but I don't quite understand the whole architecture
yet.

Mike

-- 
311774.80 264634.54

Re: [hppa-linux] memory layout

[Alan Cox]

> Talking about only pa1.1 or 32 bit CPUs, I would say the same layout
> can be used as Linux on Intel does. That is kernel mapped at 0xc0000000.
> So 3 Gig for User space and 1 Gig for kernel. Of course, other ppl may
> have different ideas. 

If you want to run PH/UX binaries then you need to probably follow their
layout

> PA has this strange concept of Spaces and they have those 
> space registers %sr0 to %sr7. This reminds me of Intel's segment 
> registers. And whoever wanted to do any serious OS like Unix on 80386
> never liked segments.

Spaces is more segments done right. The reason we dont use segmentation
to split user/kernel on x86 any more is simply performance - it costs us
1 clock per dword copied to/from luser space.

The m68k people use the 'spaces' equivalent on the m68k quite heavily

Re: [hppa-linux] memory layout

[Mike Shaver]

Alan Cox wrote:
> If you want to run PH/UX binaries then you need to probably follow their
> layout

Yeah, but OpenBSD runs their binaries and seems to use the 0xC0000000
division.

> The m68k people use the 'spaces' equivalent on the m68k quite heavily

So we should be reading up on the spaces use in the arch/m68k code, then
=).

Mike

-- 
351839.03 300276.13

Re: [hppa-linux] memory layout

[Michael Shalayeff]

Making, drinking tea and reading an opus magnum from Mike Shaver:
> Alan Cox wrote:
> > If you want to run PH/UX binaries then you need to probably follow their
> > layout
> 
> Yeah, but OpenBSD runs their binaries and seems to use the 0xC0000000
> division.
hey! thank you very much, but we are not running hp/ux binaries on hppa yet (;
syscalls are done in hpux/lites/mklinux/osf/linux(?;) compatible way.
not all sources are in the repo tho (i'm doing things one at a time)

> > The m68k people use the 'spaces' equivalent on the m68k quite heavily
> 
> So we should be reading up on the spaces use in the arch/m68k code, then
> =).
and hp300 (which is m68k) is doing syscalls throught the trap#n actually
(for both hpux and bsd)

cu

> 
> Mike
> 
> -- 
> 351839.03 300276.13
> 
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-- 
    paranoic mickey       (my employers have changed but, the name has remained)