* Does SMP work at all on 40x ?
@ 2019-01-30 7:16 Christophe Leroy
2019-01-30 11:43 ` Michael Ellerman
2019-02-01 7:42 ` Benjamin Herrenschmidt
0 siblings, 2 replies; 4+ messages in thread
From: Christophe Leroy @ 2019-01-30 7:16 UTC (permalink / raw)
To: Paul Mackerras, Benjamin Herrenschmidt, Michael Ellerman, linuxppc-dev
In transfer_to_handler() (entry_32.S), we have:
#if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
...
#ifdef CONFIG_SMP
CURRENT_THREAD_INFO(r9, r1)
lwz r9,TI_CPU(r9)
slwi r9,r9,3
add r11,r11,r9
#endif
#endif
When running this piece of code, MMU translation is off. But r9 contains
the virtual addr of current_thread_info, so unless I miss something,
this cannot work on the 40x, can it ?
On CONFIG_BOOKE it works because phys addr = virt addr
Christophe
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Does SMP work at all on 40x ?
2019-01-30 7:16 Does SMP work at all on 40x ? Christophe Leroy
@ 2019-01-30 11:43 ` Michael Ellerman
2019-01-31 10:53 ` Christophe Leroy
2019-02-01 7:42 ` Benjamin Herrenschmidt
1 sibling, 1 reply; 4+ messages in thread
From: Michael Ellerman @ 2019-01-30 11:43 UTC (permalink / raw)
To: Christophe Leroy, Paul Mackerras, Benjamin Herrenschmidt, linuxppc-dev
Christophe Leroy <christophe.leroy@c-s.fr> writes:
> In transfer_to_handler() (entry_32.S), we have:
>
> #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
> ...
> #ifdef CONFIG_SMP
> CURRENT_THREAD_INFO(r9, r1)
> lwz r9,TI_CPU(r9)
> slwi r9,r9,3
> add r11,r11,r9
> #endif
> #endif
>
> When running this piece of code, MMU translation is off. But r9 contains
> the virtual addr of current_thread_info, so unless I miss something,
> this cannot work on the 40x, can it ?
>
> On CONFIG_BOOKE it works because phys addr = virt addr
AFAIK 40x can't be SMP:
config SMP
depends on PPC_BOOK3S || PPC_BOOK3E || FSL_BOOKE || PPC_47x
But this stuff is all before my time.
The commit that added the SMP block was clearly only meant for BookE:
4eaddb4d7ec3 ("[POWERPC] Make Book-E debug handling SMP safe")
cheers
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Does SMP work at all on 40x ?
2019-01-30 11:43 ` Michael Ellerman
@ 2019-01-31 10:53 ` Christophe Leroy
0 siblings, 0 replies; 4+ messages in thread
From: Christophe Leroy @ 2019-01-31 10:53 UTC (permalink / raw)
To: Michael Ellerman, Paul Mackerras, Benjamin Herrenschmidt, linuxppc-dev
Le 30/01/2019 à 12:43, Michael Ellerman a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>
>> In transfer_to_handler() (entry_32.S), we have:
>>
>> #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
>> ...
>> #ifdef CONFIG_SMP
>> CURRENT_THREAD_INFO(r9, r1)
>> lwz r9,TI_CPU(r9)
>> slwi r9,r9,3
>> add r11,r11,r9
>> #endif
>> #endif
>>
>> When running this piece of code, MMU translation is off. But r9 contains
>> the virtual addr of current_thread_info, so unless I miss something,
>> this cannot work on the 40x, can it ?
>>
>> On CONFIG_BOOKE it works because phys addr = virt addr
>
> AFAIK 40x can't be SMP:
>
> config SMP
> depends on PPC_BOOK3S || PPC_BOOK3E || FSL_BOOKE || PPC_47x
>
>
> But this stuff is all before my time.
>
> The commit that added the SMP block was clearly only meant for BookE:
>
> 4eaddb4d7ec3 ("[POWERPC] Make Book-E debug handling SMP safe")
Ok, then no need to worry about it. It will implicitely get fixed with
the THREAD_INFO_IN_TASK_STRUCT series.
Christophe
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Does SMP work at all on 40x ?
2019-01-30 7:16 Does SMP work at all on 40x ? Christophe Leroy
2019-01-30 11:43 ` Michael Ellerman
@ 2019-02-01 7:42 ` Benjamin Herrenschmidt
1 sibling, 0 replies; 4+ messages in thread
From: Benjamin Herrenschmidt @ 2019-02-01 7:42 UTC (permalink / raw)
To: Christophe Leroy, Paul Mackerras, Michael Ellerman, linuxppc-dev
On Wed, 2019-01-30 at 08:16 +0100, Christophe Leroy wrote:
> In transfer_to_handler() (entry_32.S), we have:
>
> #if defined(CONFIG_40x) || defined(CONFIG_BOOKE)
> ...
> #ifdef CONFIG_SMP
> CURRENT_THREAD_INFO(r9, r1)
> lwz r9,TI_CPU(r9)
> slwi r9,r9,3
> add r11,r11,r9
> #endif
> #endif
>
> When running this piece of code, MMU translation is off. But r9 contains
> the virtual addr of current_thread_info, so unless I miss something,
> this cannot work on the 40x, can it ?
>
> On CONFIG_BOOKE it works because phys addr = virt addr
There is no 40x SMP that I am aware of.
Cheers,
Ben.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-02-01 7:44 UTC | newest]
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2019-01-30 7:16 Does SMP work at all on 40x ? Christophe Leroy
2019-01-30 11:43 ` Michael Ellerman
2019-01-31 10:53 ` Christophe Leroy
2019-02-01 7:42 ` Benjamin Herrenschmidt
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