Re: AMD Geode i686

[Matteo Croce <technoboy85@gmail.com>]

On Thu, Apr 15, 2010 at 7:11 PM, Lennart Sorensen
<lsorense@csclub.uwaterloo.ca> wrote:
> On Mon, Mar 01, 2010 at 11:03:09PM +0100, Matteo Croce wrote:
>> Hi,
>> I have refreshed my AMD Geode i686 patch with NOPL and I have added a
>> new nice feature.
>> When a NOPL is found the parser looks for any NOPL after the current
>> one, so they are emulated in bulk.
>> Tested ok on a Pcengines Alix.
>>
>> Signed-off-by: Matteo Croce <technoboy85@gmail.com>
>>
>> --- a/arch/x86/kernel/Makefile        2010-03-01 01:18:51.697166322 +0100
>> +++ b/arch/x86/kernel/Makefile        2010-03-01 01:19:45.727095700 +0100
>> @@ -89,6 +89,8 @@
>>  obj-$(CONFIG_HPET_TIMER)     += hpet.o
>>
>>  obj-$(CONFIG_K8_NB)          += k8.o
>> +obj-$(CONFIG_MGEODEGX1)              += nopl_emu.o
>> +obj-$(CONFIG_MGEODE_LX)              += nopl_emu.o
>>  obj-$(CONFIG_DEBUG_RODATA_TEST)      += test_rodata.o
>>  obj-$(CONFIG_DEBUG_NX_TEST)  += test_nx.o
>>
>> --- a/arch/x86/kernel/cpu/amd.c       2010-03-01 01:18:51.737097341 +0100
>> +++ b/arch/x86/kernel/cpu/amd.c       2010-03-01 01:19:27.867865836 +0100
>> @@ -138,8 +138,10 @@
>>       }
>>
>>       if (c->x86_model == 10) {
>> -             /Index: linux-2.6.33/arch/x86/kernel/Makefile
>> ===================================================================
>> * AMD Geode LX is model 10 */
>> -             /* placeholder for any needed mods */
>> +             /* Geode only lacks the NOPL instruction to be i686,
>> +                but we can emulate it in the exception handler
>> +                and promote it to a class 6 cpu */
>> +             boot_cpu_data.x86 = 6;
>>               return;
>>       }
>>  }
>> --- a/arch/x86/kernel/entry_32.S      2010-03-01 01:18:51.717096708 +0100
>> +++ b/arch/x86/kernel/entry_32.S      2010-03-01 01:19:27.867865836 +0100
>> @@ -960,7 +960,11 @@
>>       RING0_INT_FRAME
>>       pushl $0
>>       CFI_ADJUST_CFA_OFFSET 4
>> +#ifdef CONFIG_MGEODE_LX
>> +     pushl $do_nopl_emu
>> +#else
>>       pushl $do_invalid_op
>> +#endif
>
> How does this work for MGEODEGX1 when it looks for MGEODE_LX?  It seems
> you made both link against the code above after all.  Is this wrong or
> the above?
>
> Can it not work if you want to run a generic kernel on your Geode rather
> than one built explicitly for the LX?  I build one kernel to run on
> Geode SC1200 and Geode LX.
>
> --
> Len Sorensen
>

This code should work for Geode GX too.
Try it and report success please

-- 
Matteo Croce
OpenWrt developer
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