[PATCH] riscv: Ensure isa-ext static keys are writable

[PATCH] riscv: Ensure isa-ext static keys are writable

[Andrew Jones]

riscv_isa_ext_keys[] is an array of static keys used in the unified
ISA extension framework. The keys added to this array may be used
anywhere, including in modules. Ensure the keys remain writable by
placing them in the data section.

The need to change riscv_isa_ext_keys[]'s section was found when the
kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
add Zihintpause support") adds a static branch check for a newly
added isa-ext key to cpu_relax(), which kvm uses.

Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
---
 arch/riscv/kernel/cpufeature.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 553d755483ed..3b5583db9d80 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
 /* Host ISA bitmap */
 static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
 
-__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
+DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
 EXPORT_SYMBOL(riscv_isa_ext_keys);
 
 /**
-- 
2.37.1

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Conor.Dooley]

On 16/08/2022 17:30, Andrew Jones wrote:
> riscv_isa_ext_keys[] is an array of static keys used in the unified
> ISA extension framework. The keys added to this array may be used
> anywhere, including in modules. Ensure the keys remain writable by
> placing them in the data section.
> 
> The need to change riscv_isa_ext_keys[]'s section was found when the
> kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> add Zihintpause support") adds a static branch check for a newly
> added isa-ext key to cpu_relax(), which kvm uses.
> 
> Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")

Hey Drew,
How about adding:

Reported-by: Ron Economos <re@w6rz.net>
Reported-by: Anup Patel <apatel@ventanamicro.com>
Reported-by: Conor Dooley <conor.dooley@microchip.com>

Thanks,
Conor.

> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  arch/riscv/kernel/cpufeature.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 553d755483ed..3b5583db9d80 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
>  /* Host ISA bitmap */
>  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
>  
> -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>  EXPORT_SYMBOL(riscv_isa_ext_keys);
>  
>  /**

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Andrew Jones]

On Tue, Aug 16, 2022 at 04:36:55PM +0000, Conor.Dooley@microchip.com wrote:
> On 16/08/2022 17:30, Andrew Jones wrote:
> > riscv_isa_ext_keys[] is an array of static keys used in the unified
> > ISA extension framework. The keys added to this array may be used
> > anywhere, including in modules. Ensure the keys remain writable by
> > placing them in the data section.
> > 
> > The need to change riscv_isa_ext_keys[]'s section was found when the
> > kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> > add Zihintpause support") adds a static branch check for a newly
> > added isa-ext key to cpu_relax(), which kvm uses.
> > 
> > Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
> 
> Hey Drew,
> How about adding:
> 
> Reported-by: Ron Economos <re@w6rz.net>
> Reported-by: Anup Patel <apatel@ventanamicro.com>
> Reported-by: Conor Dooley <conor.dooley@microchip.com>

Sure, should I repost or can those be picked up when/if the patch is
picked up?

Thanks,
drew

> 
> Thanks,
> Conor.
> 
> > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> > ---
> >  arch/riscv/kernel/cpufeature.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > index 553d755483ed..3b5583db9d80 100644
> > --- a/arch/riscv/kernel/cpufeature.c
> > +++ b/arch/riscv/kernel/cpufeature.c
> > @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
> >  /* Host ISA bitmap */
> >  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> >  
> > -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> > +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> >  EXPORT_SYMBOL(riscv_isa_ext_keys);
> >  
> >  /**

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Conor.Dooley]

On 16/08/2022 17:49, Andrew Jones wrote:
> On Tue, Aug 16, 2022 at 04:36:55PM +0000, Conor.Dooley@microchip.com wrote:
>> On 16/08/2022 17:30, Andrew Jones wrote:
>>> riscv_isa_ext_keys[] is an array of static keys used in the unified
>>> ISA extension framework. The keys added to this array may be used
>>> anywhere, including in modules. Ensure the keys remain writable by
>>> placing them in the data section.
>>>
>>> The need to change riscv_isa_ext_keys[]'s section was found when the
>>> kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
>>> add Zihintpause support") adds a static branch check for a newly
>>> added isa-ext key to cpu_relax(), which kvm uses.
>>>
>>> Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
>>
>> Hey Drew,
>> How about adding:
>>
>> Reported-by: Ron Economos <re@w6rz.net>
>> Reported-by: Anup Patel <apatel@ventanamicro.com>
>> Reported-by: Conor Dooley <conor.dooley@microchip.com>
> 
> Sure, should I repost or can those be picked up when/if the patch is
> picked up?

Oh god no, don't repost for that alone.
Sorry, should've specified.
Conor.

> 
> Thanks,
> drew
> 
>>
>> Thanks,
>> Conor.
>>
>>> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
>>> ---
>>>  arch/riscv/kernel/cpufeature.c | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
>>> index 553d755483ed..3b5583db9d80 100644
>>> --- a/arch/riscv/kernel/cpufeature.c
>>> +++ b/arch/riscv/kernel/cpufeature.c
>>> @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
>>>  /* Host ISA bitmap */
>>>  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
>>>  
>>> -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>>> +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>>>  EXPORT_SYMBOL(riscv_isa_ext_keys);
>>>  
>>>  /**
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Conor.Dooley]

On 16/08/2022 17:30, Andrew Jones wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> riscv_isa_ext_keys[] is an array of static keys used in the unified
> ISA extension framework. The keys added to this array may be used
> anywhere, including in modules. Ensure the keys remain writable by
> placing them in the data section.
> 
> The need to change riscv_isa_ext_keys[]'s section was found when the
> kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> add Zihintpause support") adds a static branch check for a newly
> added isa-ext key to cpu_relax(), which kvm uses.
> 
> Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>

Tested-by: Conor Dooley <conor.dooley@microchip.com>

Thanks for the fix!

Still got issues booting mainline on my D1, but this is
no longer one of them :)

> ---
>  arch/riscv/kernel/cpufeature.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 553d755483ed..3b5583db9d80 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
>  /* Host ISA bitmap */
>  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> 
> -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>  EXPORT_SYMBOL(riscv_isa_ext_keys);
> 
>  /**
> --
> 2.37.1
> 

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Ron Economos]

On 8/16/22 9:30 AM, Andrew Jones wrote:
> riscv_isa_ext_keys[] is an array of static keys used in the unified
> ISA extension framework. The keys added to this array may be used
> anywhere, including in modules. Ensure the keys remain writable by
> placing them in the data section.
>
> The need to change riscv_isa_ext_keys[]'s section was found when the
> kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> add Zihintpause support") adds a static branch check for a newly
> added isa-ext key to cpu_relax(), which kvm uses.
>
> Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>   arch/riscv/kernel/cpufeature.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 553d755483ed..3b5583db9d80 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
>   /* Host ISA bitmap */
>   static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
>   
> -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>   EXPORT_SYMBOL(riscv_isa_ext_keys);
>   
>   /**

Works good on HiFive Unmatched.

Tested-by: Ron Economos <re@w6rz.net>

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Atish Patra]

On Tue, Aug 16, 2022 at 9:31 AM Andrew Jones <ajones@ventanamicro.com> wrote:
>
> riscv_isa_ext_keys[] is an array of static keys used in the unified
> ISA extension framework. The keys added to this array may be used
> anywhere, including in modules. Ensure the keys remain writable by
> placing them in the data section.
>
> The need to change riscv_isa_ext_keys[]'s section was found when the
> kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> add Zihintpause support") adds a static branch check for a newly
> added isa-ext key to cpu_relax(), which kvm uses.
>
> Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> ---
>  arch/riscv/kernel/cpufeature.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> index 553d755483ed..3b5583db9d80 100644
> --- a/arch/riscv/kernel/cpufeature.c
> +++ b/arch/riscv/kernel/cpufeature.c
> @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
>  /* Host ISA bitmap */
>  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
>
> -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>  EXPORT_SYMBOL(riscv_isa_ext_keys);
>
>  /**
> --
> 2.37.1
>
>
> --
> kvm-riscv mailing list
> kvm-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kvm-riscv

Thanks for the quick fix. Tested with kvm guests booting in Qemu.

Tested-by: Atish Patra <atishp@rivosinc.com>

-- 
Regards,
Atish

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Palmer Dabbelt]

On Tue, 16 Aug 2022 16:41:46 PDT (-0700), atishp@atishpatra.org wrote:
> On Tue, Aug 16, 2022 at 9:31 AM Andrew Jones <ajones@ventanamicro.com> wrote:
>>
>> riscv_isa_ext_keys[] is an array of static keys used in the unified
>> ISA extension framework. The keys added to this array may be used
>> anywhere, including in modules. Ensure the keys remain writable by
>> placing them in the data section.
>>
>> The need to change riscv_isa_ext_keys[]'s section was found when the
>> kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
>> add Zihintpause support") adds a static branch check for a newly
>> added isa-ext key to cpu_relax(), which kvm uses.
>>
>> Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
>> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
>> ---
>>  arch/riscv/kernel/cpufeature.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
>> index 553d755483ed..3b5583db9d80 100644
>> --- a/arch/riscv/kernel/cpufeature.c
>> +++ b/arch/riscv/kernel/cpufeature.c
>> @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
>>  /* Host ISA bitmap */
>>  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
>>
>> -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>> +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
>>  EXPORT_SYMBOL(riscv_isa_ext_keys);
>>
>>  /**
>> --
>> 2.37.1
>>
>>
>> --
>> kvm-riscv mailing list
>> kvm-riscv@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kvm-riscv
>
> Thanks for the quick fix. Tested with kvm guests booting in Qemu.
>
> Tested-by: Atish Patra <atishp@rivosinc.com>

Thanks, I hadn't realized how static keys work but looks like having them as
__ro_after_init was always bogus.  Sorry to break stuff, looks like I should be
loading some module (probably KVM, as it's in the defconfig) during testing.

This is on fixes, I'm planning on sending it up later this week.

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Jisheng Zhang]

On Tue, Aug 16, 2022 at 09:29:36PM -0700, Palmer Dabbelt wrote:
> On Tue, 16 Aug 2022 16:41:46 PDT (-0700), atishp@atishpatra.org wrote:
> > On Tue, Aug 16, 2022 at 9:31 AM Andrew Jones <ajones@ventanamicro.com> wrote:
> > > 
> > > riscv_isa_ext_keys[] is an array of static keys used in the unified
> > > ISA extension framework. The keys added to this array may be used
> > > anywhere, including in modules. Ensure the keys remain writable by
> > > placing them in the data section.
> > > 
> > > The need to change riscv_isa_ext_keys[]'s section was found when the
> > > kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> > > add Zihintpause support") adds a static branch check for a newly
> > > added isa-ext key to cpu_relax(), which kvm uses.
> >> > > 
> > > Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
> > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> > > > > ---
> > >  arch/riscv/kernel/cpufeature.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > 
> > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > > index 553d755483ed..3b5583db9d80 100644
> > > --- a/arch/riscv/kernel/cpufeature.c
> > > +++ b/arch/riscv/kernel/cpufeature.c
> > > @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
> > >  /* Host ISA bitmap */
> > >  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> > > 
> > > -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> > > +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> > >  EXPORT_SYMBOL(riscv_isa_ext_keys);
> > > 
> > >  /**
> > > --
> > > 2.37.1
> > > 
> > > 
> > > --
> > > kvm-riscv mailing list
> > > kvm-riscv@lists.infradead.org
> > > http://lists.infradead.org/mailman/listinfo/kvm-riscv
> > 
> > Thanks for the quick fix. Tested with kvm guests booting in Qemu.
> > 
> > Tested-by: Atish Patra <atishp@rivosinc.com>

Reviewed-by: Jisheng Zhang <jszhang@kernel.org>

Thanks for catching the bug in my code.

> 
> Thanks, I hadn't realized how static keys work but looks like having them as
> __ro_after_init was always bogus.  Sorry to break stuff, looks like I should be

Sorry for breaking the static isa extension key usage in modules.
It's a good idea to make them readonly, but need to cope with the usage
in module properly. This may be a good improvement item.

> loading some module (probably KVM, as it's in the defconfig) during testing.
> 
> This is on fixes, I'm planning on sending it up later this week.

Re: [PATCH] riscv: Ensure isa-ext static keys are writable

[Andrew Jones]

On Wed, Aug 17, 2022 at 10:30:07PM +0800, Jisheng Zhang wrote:
> On Tue, Aug 16, 2022 at 09:29:36PM -0700, Palmer Dabbelt wrote:
> > On Tue, 16 Aug 2022 16:41:46 PDT (-0700), atishp@atishpatra.org wrote:
> > > On Tue, Aug 16, 2022 at 9:31 AM Andrew Jones <ajones@ventanamicro.com> wrote:
> > > > 
> > > > riscv_isa_ext_keys[] is an array of static keys used in the unified
> > > > ISA extension framework. The keys added to this array may be used
> > > > anywhere, including in modules. Ensure the keys remain writable by
> > > > placing them in the data section.
> > > > 
> > > > The need to change riscv_isa_ext_keys[]'s section was found when the
> > > > kvm module started failing to load. Commit 8eb060e10185 ("arch/riscv:
> > > > add Zihintpause support") adds a static branch check for a newly
> > > > added isa-ext key to cpu_relax(), which kvm uses.
> > >> > > 
> > > > Fixes: c360cbec3511 ("riscv: introduce unified static key mechanism for ISA extensions")
> > > > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> > > > > > ---
> > > >  arch/riscv/kernel/cpufeature.c | 2 +-
> > > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
> > > > index 553d755483ed..3b5583db9d80 100644
> > > > --- a/arch/riscv/kernel/cpufeature.c
> > > > +++ b/arch/riscv/kernel/cpufeature.c
> > > > @@ -28,7 +28,7 @@ unsigned long elf_hwcap __read_mostly;
> > > >  /* Host ISA bitmap */
> > > >  static DECLARE_BITMAP(riscv_isa, RISCV_ISA_EXT_MAX) __read_mostly;
> > > > 
> > > > -__ro_after_init DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> > > > +DEFINE_STATIC_KEY_ARRAY_FALSE(riscv_isa_ext_keys, RISCV_ISA_EXT_KEY_MAX);
> > > >  EXPORT_SYMBOL(riscv_isa_ext_keys);
> > > > 
> > > >  /**
> > > > --
> > > > 2.37.1
> > > > 
> > > > 
> > > > --
> > > > kvm-riscv mailing list
> > > > kvm-riscv@lists.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/kvm-riscv
> > > 
> > > Thanks for the quick fix. Tested with kvm guests booting in Qemu.
> > > 
> > > Tested-by: Atish Patra <atishp@rivosinc.com>
> 
> Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
> 
> Thanks for catching the bug in my code.
> 
> > 
> > Thanks, I hadn't realized how static keys work but looks like having them as
> > __ro_after_init was always bogus.  Sorry to break stuff, looks like I should be
> 
> Sorry for breaking the static isa extension key usage in modules.
> It's a good idea to make them readonly, but need to cope with the usage
> in module properly. This may be a good improvement item.

While some static keys do use __ro_after_init, they're almost all locally
defined (static __ro_after_init). I see a few instances of __read_mostly
global static key definitions, though. That may make sense for
riscv_isa_ext_keys[] as well.

Thanks,
drew