Re: Current kernel with http://gnats.netbsd.org/39965 and pmap patches

Nice work!  I have confirmed that this fixes the ATARITT kernel boot issue 
on the TT030.

I could install up until the bootloader halting issue described yesterday. 
Tomorrow I will file a PR on the bootloader issue, I just want to zero my 
drive first to confirm that doesn't help.

David Ross
[email protected]

----- Original Message ----- 
From: "T. Makinen" <[email protected]>
To: "Izumi Tsutsui" <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Tuesday, December 30, 2008 11:48 AM
Subject: Re: Current kernel with http://gnats.netbsd.org/39965 and pmap 
patches


> On Tue, Dec 30, 2008 at 6:53 PM, Izumi Tsutsui <[email protected]> 
> wrote:
>> Okay, with a quick glance, reloc operation for options RELOC_KERNEL
>> is done after all necessary bootstrap STEs and PTEs are initialized,
>> so we have to carefully use the following three types of addresses
>> in the start_c() function:
>>
>> (1) physicall address before relocation
>>  This should be used to fetch global variables in start_c()
>>  before relocation (including page table addresses initialized
>>  during bootstrap).
>>
>> (2) physicall address after relocation
>>  This should be used for physical address pointers
>>  which will be used after MMU is enabled.
>>  (including PA values stored into STEs and PTEs)
>>
>> (3) kernel virtual address
>>  This should be used for virtual address pointers
>>  which will be used after MMU is enabled, and
>>  for virtual address to calculate STE/PTE indexes during bootstrap.
>>
>> On the other hand, (1) and (3) have the same values
>> (at least in kernel text/data/bss) and some variables
>> used in start_c() have both meanings.
>> It actually confuses readers...
>>
>> I've cleaned up various variables in atari_init.c (attached)
>> (BTW that means it's no longer sync'ed with amiga ;-p).
>
> That's good :) Amiga uses also independent variables for vstart and 
> pstart;
> I think that atari_init.c is now clearer.
>
>> Summary of changes are:
>>
>> - use independent variables for (1) and (3) (pstart and vstart etc.)
>>  even if they have the same values (since they have different meanings)
>>
>> - only global Sysseg_pa and Sysptmap_pa belong (2),
>>  so initialize them as (1) first and
>>  use explicit address reloc conversion for PTE and STE values,
>>  then update these global variables as (2)
>>  after all bootstrap initialization is complete
>>
>> - make mmu0[34]0_setup() (and cpu_init_kcorehdr()) take
>>  Sysseg_pa (before relocation) as an arg, to avoid reference of
>>  global Sysseg_pa (it could be changed at some point as noted above)
>>
>> - use properly variable types (st_entry_t, pt_entry_t etc) for 
>> readability
>>  (XXX: we should also use paddr_t/vaddr_t/psize_t/vsize_t properly)
>>
>> - don't map Sysptmap and kernel page tables with PG_CI
>>  but only do so for Sysseg on 040/060
>>  (amiga pmap seems to have the same bug, though
>>   those KVA ranges seem used only for debug printfs)
>>
>> - misc style nits
>>
>> ...I'm afraid I'd put various botches, though.
>> (it's really hard to implement without real hardware ;-)
>>
>> I've also put new kernels with this change:
>> http://www.ceres.dti.ne.jp/~tsutsui/netbsd/netbsd-ATARITT-HEAD-20081230.gz
>> http://www.ceres.dti.ne.jp/~tsutsui/netbsd/netbsd-BOOT-HEAD-20081230.gz
>> http://www.ceres.dti.ne.jp/~tsutsui/netbsd/netbsd-FALCON-HEAD-20081230.gz
>
> Great work! I tested FALCON kernel and I can now boot with RELOC_KERNEL 
> (and
> with 68060 :). However I can't test RELOC_KERNEL with 68030 because 68060
> accelerator has TT-RAM.
>
> Thanks!
>
> -Tuomo
>