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re: Extending pmap_kenter_pa and pmap_enter.

> I'd like to two add one more argument to pmap_kenter_pa
> and two more to pmap_enter.
> To pmap_kenter_pa, I want to add a vsize_t after the pa argument:
> void pmap_kenter_pa(vaddr_t va, paddr_t pa, vsize_t len, 
>     vm_prot_t prot, u_int flags);
> To pmap_enter, I want to add the same vsize_t afer the pa argument
> but also a struct vm_page * after the vsize_t.
> int pmap_enter(pmap_t pmap, vaddr_t va, paddr_t pa, vsize_t len,
>     struct vm_page *pg, vm_prot_t prot, u_int flags);
> These charge are to take advantage of larger page table entries on
> those platforms that have them.  Since pmap_enter implementations
> almost always do a PHYS_TO_VM_PAGE, and since the caller usually
> has it available, it might as well supply.  If this is to be an
> unmanaged mapping (device page), then NULL will be passed for pg.

since changing pmap APIs is pretty difficult and requires a lot
of coordination, i'd rather add new functions than change the
signature of the existing ones.

we can also provide backup versions of the new ones for platforms
that don't have them yet by simply looping as necessary and/or
dropping the pg argument, based on __HAVE_PMAP_ENTER_WITH_LEN or so.


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