I don't see any reason to keep the extra compat code.
Would be good to g/c, IMO.

Jaromir

Andrew Brown wrote:
> i've been skimming through the compat mmap routines on my way to
> cleaning things up to make "top down" memory allocation work properly,
> and i've found a few things that confuse me.  as an example, here's a
> snippet from ibcs2_sys_mmap() in compat/ibcs2/ibcs2_misc.c:
> 
> 	SCARG(&mm, prot) = SCARG(uap, prot);
> 	SCARG(&mm, len) = SCARG(uap, len);
> 	SCARG(&mm, flags) = SCARG(uap, flags) & ~_MAP_NEW;
> 	SCARG(&mm, fd) = SCARG(uap, fd);
> 	SCARG(&mm, addr) = SCARG(uap, addr);
> 	SCARG(&mm, pos) = SCARG(uap, off);
> 
> 	rp = (void *) round_page((vaddr_t)p->p_vmspace->vm_daddr + MAXDSIZ);
> 	if ((SCARG(&mm, flags) & MAP_FIXED) == 0 &&
> 	    SCARG(&mm, addr) != 0 && SCARG(&mm, addr) < rp)
> 		SCARG(&mm, addr) = rp;
> 
> 	return sys_mmap(p, &mm, retval);
> 
> as you can see, the parameters to the compat call are copied and then
> passed to the "native" sys_mmap() call.  what i don't understand is
> the reasoning for the gyrations on the addr parameter.  the
> circumstances under which rp is assigned to SCARG(&mm, addr) are the
> same as the ones where sys_mmap() would do exactly the same thing like
> this:
> 
> 	if (flags & MAP_FIXED) {
> 		...
> 	} else {
> 		...
> 		addr = MAX(addr, round_page((vaddr_t)p->p_vmspace->vm_daddr +
> 					    MAXDSIZ));
> 	}
> 
> why the extra work?
> 
> this is the virtually same as sunos_sys_mmap(), svr4_sys_mmap(),
> svr4_sys_mmap64(), and ultrix_sys_mmap().
> 
> i can see why it might be done in svr4_32_sys_mmap(), maybe in
> svr4_32_sys_mmap64(), and sunos32_sys_mmap().  they're designed to
> operate in a mixed 32/64 bit environment, right?
> 
> the way that px_mmap_info() works is similar, but different in that it
> calls on uvm_mmap() to do the work, so it needs to pick a reasonable
> default itself, though i wonder if it couldn't be converted to use
> sys_mmap() instead.
> 
> -- 
> |-----< "CODE WARRIOR" >-----|
> codewarrior@daemon.org             * "ah!  i see you have the internet
> twofsonet@graffiti.com (Andrew Brown)                that goes *ping*!"
> werdna@squooshy.com       * "information is power -- share the wealth."
> 


-- 
Jaromir Dolecek <jdolecek@NetBSD.org>            http://www.NetBSD.org/
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-=- sometimes levitate or glow.   Do not let this distract you.''     -=-