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[PATCH 2/9] riscv: Fix riscv_online_cpu_vec

Andrew Jones posted 9 patches 1 year ago
There is a newer version of this series
[PATCH 2/9] riscv: Fix riscv_online_cpu_vec
Posted by Andrew Jones 1 year ago 
We shouldn't probe when we already know vector is unsupported and
we should probe when we see we don't yet know whether it's supported.
Furthermore, we should ensure we've set the access type to
unsupported when we don't have vector at all.

Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
 arch/riscv/kernel/unaligned_access_speed.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
index b7a8ff7ba6df..161964cf2abc 100644
--- a/arch/riscv/kernel/unaligned_access_speed.c
+++ b/arch/riscv/kernel/unaligned_access_speed.c
@@ -367,10 +367,12 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
 
 static int riscv_online_cpu_vec(unsigned int cpu)
 {
-	if (!has_vector())
+	if (!has_vector()) {
+		per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
 		return 0;
+	}
 
-	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED)
+	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN)
 		return 0;
 
 	check_vector_unaligned_access_emulated(NULL);
-- 
2.48.1
Re: [PATCH 2/9] riscv: Fix riscv_online_cpu_vec
Posted by Alexandre Ghiti 12 months ago 
On 07/02/2025 17:19, Andrew Jones wrote:
> We shouldn't probe when we already know vector is unsupported and
> we should probe when we see we don't yet know whether it's supported.
> Furthermore, we should ensure we've set the access type to
> unsupported when we don't have vector at all.
>
> Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>   arch/riscv/kernel/unaligned_access_speed.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
> index b7a8ff7ba6df..161964cf2abc 100644
> --- a/arch/riscv/kernel/unaligned_access_speed.c
> +++ b/arch/riscv/kernel/unaligned_access_speed.c
> @@ -367,10 +367,12 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
>   
>   static int riscv_online_cpu_vec(unsigned int cpu)
>   {
> -	if (!has_vector())
> +	if (!has_vector()) {
> +		per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
>   		return 0;
> +	}
>   
> -	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED)
> +	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN)
>   		return 0;
>   
>   	check_vector_unaligned_access_emulated(NULL);


Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>

Thanks,

Alex
Re: [PATCH 2/9] riscv: Fix riscv_online_cpu_vec
Posted by Clément Léger 1 year ago 

On 07/02/2025 17:19, Andrew Jones wrote:
> We shouldn't probe when we already know vector is unsupported and
> we should probe when we see we don't yet know whether it's supported.
> Furthermore, we should ensure we've set the access type to
> unsupported when we don't have vector at all.
> 
> Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  arch/riscv/kernel/unaligned_access_speed.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
> index b7a8ff7ba6df..161964cf2abc 100644
> --- a/arch/riscv/kernel/unaligned_access_speed.c
> +++ b/arch/riscv/kernel/unaligned_access_speed.c
> @@ -367,10 +367,12 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
>  
>  static int riscv_online_cpu_vec(unsigned int cpu)
>  {
> -	if (!has_vector())
> +	if (!has_vector()) {
> +		per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
>  		return 0;
> +	}
>  
> -	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED)
> +	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN)
>  		return 0;
>  
>  	check_vector_unaligned_access_emulated(NULL);

Hi Andrew,

Wouldn't it be easier just not to register the hotplug callback in case
!has_vector() ? In which case just set all possible cpus
vector_misaligned_access to RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED
at startup.

Thanks,

Clément
Re: [PATCH 2/9] riscv: Fix riscv_online_cpu_vec
Posted by Andrew Jones 1 year ago 
On Fri, Feb 07, 2025 at 05:47:28PM +0100, Clément Léger wrote:
> 
> 
> On 07/02/2025 17:19, Andrew Jones wrote:
> > We shouldn't probe when we already know vector is unsupported and
> > we should probe when we see we don't yet know whether it's supported.
> > Furthermore, we should ensure we've set the access type to
> > unsupported when we don't have vector at all.
> > 
> > Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
> > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> > ---
> >  arch/riscv/kernel/unaligned_access_speed.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
> > index b7a8ff7ba6df..161964cf2abc 100644
> > --- a/arch/riscv/kernel/unaligned_access_speed.c
> > +++ b/arch/riscv/kernel/unaligned_access_speed.c
> > @@ -367,10 +367,12 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
> >  
> >  static int riscv_online_cpu_vec(unsigned int cpu)
> >  {
> > -	if (!has_vector())
> > +	if (!has_vector()) {
> > +		per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
> >  		return 0;
> > +	}
> >  
> > -	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED)
> > +	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN)
> >  		return 0;
> >  
> >  	check_vector_unaligned_access_emulated(NULL);
> 
> Hi Andrew,
> 
> Wouldn't it be easier just not to register the hotplug callback in case
> !has_vector() ? In which case just set all possible cpus
> vector_misaligned_access to RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED
> at startup.

We could do that, but I have another use for the hotplug callback that
you'll see near the end of the series.

Thanks,
drew
Re: [PATCH 2/9] riscv: Fix riscv_online_cpu_vec
Posted by Clément Léger 1 year ago 

On 07/02/2025 18:08, Andrew Jones wrote:
> On Fri, Feb 07, 2025 at 05:47:28PM +0100, Clément Léger wrote:
>>
>>
>> On 07/02/2025 17:19, Andrew Jones wrote:
>>> We shouldn't probe when we already know vector is unsupported and
>>> we should probe when we see we don't yet know whether it's supported.
>>> Furthermore, we should ensure we've set the access type to
>>> unsupported when we don't have vector at all.
>>>
>>> Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
>>> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
>>> ---
>>>  arch/riscv/kernel/unaligned_access_speed.c | 6 ++++--
>>>  1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
>>> index b7a8ff7ba6df..161964cf2abc 100644
>>> --- a/arch/riscv/kernel/unaligned_access_speed.c
>>> +++ b/arch/riscv/kernel/unaligned_access_speed.c
>>> @@ -367,10 +367,12 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
>>>  
>>>  static int riscv_online_cpu_vec(unsigned int cpu)
>>>  {
>>> -	if (!has_vector())
>>> +	if (!has_vector()) {
>>> +		per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
>>>  		return 0;
>>> +	}
>>>  
>>> -	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED)
>>> +	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN)
>>>  		return 0;
>>>  
>>>  	check_vector_unaligned_access_emulated(NULL);
>>
>> Hi Andrew,
>>
>> Wouldn't it be easier just not to register the hotplug callback in case
>> !has_vector() ? In which case just set all possible cpus
>> vector_misaligned_access to RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED
>> at startup.
> 
> We could do that, but I have another use for the hotplug callback that
> you'll see near the end of the series.

Ok, I saw patch 7/9.

BTW, what happened to patch 8 ? I thought it was in my spam but even
lore.kernel.org does not have it:
https://lore.kernel.org/linux-riscv/20250207161939.46139-11-ajones@ventanamicro.com/T/#t

Thanks,

Clément

> 
> Thanks,
> drew
Re: [PATCH 2/9] riscv: Fix riscv_online_cpu_vec
Posted by Andrew Jones 1 year ago 
On Fri, Feb 07, 2025 at 06:43:26PM +0100, Clément Léger wrote:
> 
> 
> On 07/02/2025 18:08, Andrew Jones wrote:
> > On Fri, Feb 07, 2025 at 05:47:28PM +0100, Clément Léger wrote:
> >>
> >>
> >> On 07/02/2025 17:19, Andrew Jones wrote:
> >>> We shouldn't probe when we already know vector is unsupported and
> >>> we should probe when we see we don't yet know whether it's supported.
> >>> Furthermore, we should ensure we've set the access type to
> >>> unsupported when we don't have vector at all.
> >>>
> >>> Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
> >>> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> >>> ---
> >>>  arch/riscv/kernel/unaligned_access_speed.c | 6 ++++--
> >>>  1 file changed, 4 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
> >>> index b7a8ff7ba6df..161964cf2abc 100644
> >>> --- a/arch/riscv/kernel/unaligned_access_speed.c
> >>> +++ b/arch/riscv/kernel/unaligned_access_speed.c
> >>> @@ -367,10 +367,12 @@ static void check_vector_unaligned_access(struct work_struct *work __always_unus
> >>>  
> >>>  static int riscv_online_cpu_vec(unsigned int cpu)
> >>>  {
> >>> -	if (!has_vector())
> >>> +	if (!has_vector()) {
> >>> +		per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
> >>>  		return 0;
> >>> +	}
> >>>  
> >>> -	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED)
> >>> +	if (per_cpu(vector_misaligned_access, cpu) != RISCV_HWPROBE_MISALIGNED_VECTOR_UNKNOWN)
> >>>  		return 0;
> >>>  
> >>>  	check_vector_unaligned_access_emulated(NULL);
> >>
> >> Hi Andrew,
> >>
> >> Wouldn't it be easier just not to register the hotplug callback in case
> >> !has_vector() ? In which case just set all possible cpus
> >> vector_misaligned_access to RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED
> >> at startup.
> > 
> > We could do that, but I have another use for the hotplug callback that
> > you'll see near the end of the series.
> 
> Ok, I saw patch 7/9.
> 
> BTW, what happened to patch 8 ? I thought it was in my spam but even
> lore.kernel.org does not have it:
> https://lore.kernel.org/linux-riscv/20250207161939.46139-11-ajones@ventanamicro.com/T/#t

I see it on lore for lkml, so linux-riscv dropped it for no good reason...
I'll send patch 8 again (this time with feeling) just to linux-riscv and
we'll see if gets through.

https://lore.kernel.org/all/20250207161939.46139-19-ajones@ventanamicro.com/

Thanks,
drew

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