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

From: Andrew Jones
Date: Tue Aug 16 2022 - 12:49:58 EST


On Tue, Aug 16, 2022 at 04:36:55PM +0000, Conor.Dooley@xxxxxxxxxxxxx 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@xxxxxxxx>
> Reported-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> Reported-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxx>
> > ---
> > 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);
> >
> > /**