[PATCH v3 14/16] powerpc/32: implement fast entry for syscalls on BOOKE

[Christophe Leroy]

On 05/28/2019 05:03 PM, Christophe Leroy wrote:
> Michael Ellerman <mpe at ellerman.id.au> a écrit :
> 
>> Christophe Leroy <christophe.leroy at c-s.fr> writes:
>>> Le 23/05/2019 à 09:00, Christophe Leroy a écrit :
>>>
>>> [...]
>>>
>>>>> arch/powerpc/kernel/head_fsl_booke.o: In function `SystemCall':
>>>>> arch/powerpc/kernel/head_fsl_booke.S:416: undefined reference to
>>>>> `kvmppc_handler_BOOKE_INTERRUPT_SYSCALL_SPRN_SRR1'
>>>>> Makefile:1052: recipe for target 'vmlinux' failed
>>>>>
>>>>>> +.macro SYSCALL_ENTRY trapno intno
>>>>>> +    mfspr    r10, SPRN_SPRG_THREAD
>>>>>> +#ifdef CONFIG_KVM_BOOKE_HV
>>>>>> +BEGIN_FTR_SECTION
>>>>>> +    mtspr    SPRN_SPRG_WSCRATCH0, r10
>>>>>> +    stw    r11, THREAD_NORMSAVE(0)(r10)
>>>>>> +    stw    r13, THREAD_NORMSAVE(2)(r10)
>>>>>> +    mfcr    r13            /* save CR in r13 for now       */
>>>>>> +    mfspr    r11, SPRN_SRR1
>>>>>> +    mtocrf    0x80, r11    /* check MSR[GS] without clobbering 
>>>>>> reg */
>>>>>> +    bf    3, 1975f
>>>>>> +    b    kvmppc_handler_BOOKE_INTERRUPT_\intno\()_SPRN_SRR1
>>>>>
>>>>> It seems to me that the "_SPRN_SRR1" on the end of this line
>>>>> isn't meant to be there...  However, it still fails to link with that
>>>>> removed.
>>>
>>> It looks like I missed the macro expansion.
>>>
>>> The called function should be kvmppc_handler_8_0x01B
>>>
>>> Seems like kisskb doesn't build any config like this.
>>
>> I thought we did, ie:
>>
>> http://kisskb.ellerman.id.au/kisskb/buildresult/13817941/
> 
> That's a ppc64 config it seems. The problem was on booke32.
> 
> Christophe
> 
>>
>> But clearly something is missing to trigger the bug.

I was able to trigger the bug with mpc85xx_defconfig + 
CONFIG_VIRTUALIZATION + CONFIG_PPC_E500MC

The bug pops up when CONFIG_KVM_BOOKE_HV is set.

Christophe

>>
>> cheers
> 
>