Re: [Qemu-ppc] [Qemu-devel] [PATCH] (RFC) target-ppc: Remove vestigial PowerPC 620 support

[Alexander Graf]

On 11.02.2013, at 16:13, Andreas Färber wrote:

> Am 11.02.2013 05:50, schrieb David Gibson:
>> The PowerPC 620 was the very first 64-bit PowerPC implementation, but
>> hardly anyone ever actually used the chips.  qemu notionally supports the
>> 620, but since we don't actually have code to implement the segment table,
>> the support is broken (quite likely in other ways too).
>> 
>> This partch, therefore, removes all remaining pieces of 620 support, to
>> stop it cluttering up the platforms we actually care about.
>> 
>> Signed-off-by: David Gibson <address@hidden>
>> ---
>> monitor.c                   |    4 -
>> target-ppc/cpu.h            |   29 -----
>> target-ppc/helper.h         |    1 -
>> target-ppc/machine.c        |    4 +-
>> target-ppc/misc_helper.c    |    6 --
>> target-ppc/mmu_helper.c     |   44 +-------
>> target-ppc/translate.c      |    1 -
>> target-ppc/translate_init.c |  251 
>> -------------------------------------------
>> 8 files changed, 7 insertions(+), 333 deletions(-)
>> 
>> Andreas,
>> 
>> I know Alex Graf is happy to remove the PPC620 stuff, but he suggested
>> I talk to you since prep is the only existing ppc machine which would
>> ever have supported a PPC620 CPU.  Any objections?
> [...]
>> diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
>> index f038850..7dc1b9b 100644
>> --- a/target-ppc/translate_init.c
>> +++ b/target-ppc/translate_init.c
> [...]
>> @@ -9244,10 +9000,6 @@ static const ppc_def_t ppc_defs[] = {
>>     POWERPC_DEF("7457A_v1.2",    CPU_POWERPC_74x7A_v12,              7455),
>>     /* 64 bits PowerPC                                                       
>> */
>> #if defined (TARGET_PPC64)
>> -    /* PowerPC 620                                                          
>>  */
>> -    POWERPC_DEF("620",           CPU_POWERPC_620,                    620),
>> -    /* Code name for PowerPC 620                                            
>>  */
>> -    POWERPC_DEF("Trident",       CPU_POWERPC_620,                    620),
>> #if defined (TODO)
>>     /* PowerPC 630 (POWER3)                                                  
>> */
>>     POWERPC_DEF("630",           CPU_POWERPC_630,                    630),
> [snip]
> 
> Are you sure this is what Alex asked you to do? Because he specifically
> instructed me NOT to remove any of these model definitions or their PVR
> values, even if guarded by defined(TODO), about a week ago.

Correct. The only thing he asked me about was the MMU bits. Removing those is 
safe and a good idea. Having a full table of PVRs and aliases available is 
still a good idea IMHO and we should preserve that.

Whether we're able to run such a CPU should be orthogonal information 
(currently indicated by #ifdef TODO).


Alex

> 
> I'll polish what I have cooking for the CPU models later today; the MMU
> code itself has not been touched by my refactorings so far.
> We do have a conflict here in that I have moved all code name aliases
> from the above definitions array to another array (here: "Trident").
> https://github.com/afaerber/qemu-cpu/commits/qom-cpu-ppc-types (WIP)
> 
> We were hoping to refactor the current macro mess into a set of
> self-contained abstract parent classes, and I was hoping that we might
> be able to move them out of translate_init.c afterwards, to speed up
> compilation.
> Would isolating 620 code in a, say, cpu-620.c help you or is this about
> some ifs in disas or whatever code? Or what exactly is your motivation?
> 
> The BeBox had a 604e iirc and so far all my PReP testing has been
> 32-bit. CC'ing Hervé on whether any of his 40P emulations need the 620.
> 
> Regards,
> Andreas
> 
> P.S. Still waiting on your feedback on sPAPR hypercall testing and CPU
> hot-plug btw. :-)
> 
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