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Re: [PATCH 2/3] i386: add io_map_cached
From: |
Justus Winter |
Subject: |
Re: [PATCH 2/3] i386: add io_map_cached |
Date: |
Thu, 15 May 2014 12:32:41 +0200 |
User-agent: |
alot/0.3.4 |
Quoting Samuel Thibault (2014-05-15 02:13:13)
> Hello,
>
> Justus Winter, le Fri 02 May 2014 21:33:01 +0200, a écrit :
> > io_map_cached is like io_map, but reuses the old mapping if it is
> > applicable.
>
> But AIUI, if it is not applicable, it does not unmap the previous
> mapping, so we lose virtual memory.
>
> A really transparent io_map_cached seems not really feasible, since you
> never know what the caller will do with the pointer.
Right, I did this b/c I didn't know how to do this properly.
> I'm wondering: why not just use phystokv() in acpi.c instead?
I'm assuming that you meant to say "why not just use phystokv() in
*like in* acpi.c instead?" ? Because there I do, and it works fine to
locate the rsdpv1 table (whatever that is). But accessing this
physical address with phystokv() fails b/c it is outside the mapped
range (for me, that was with stock gnumach and the qemu ACPI
implementation).
Justus
Re: [PATCH 1/3] ddb: add "halt" command, Samuel Thibault, 2014/05/02