[hppa-linux] memory layout
Thu, 18 Mar 1999 00:55:53 -0500
> 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
/* 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