Re: [PATCH -fixes] riscv: Re-introduce global icache flush in patch_text_XXX()

[Alexandre Ghiti]

Hi Samuel,

On 01/08/2024 19:32, Samuel Holland wrote:
> Hi Alex,
>
> On 2024-07-30 8:59 AM, Alexandre Ghiti wrote:
> > commit edf2d546bfd6 ("riscv: patch: Flush the icache right after
> > patching to avoid illegal insns") mistakenly removed the global icache
> > flush in patch_text_nosync() and patch_text_set_nosync() functions, so
> > reintroduce them.
> >
> > Fixes: edf2d546bfd6 ("riscv: patch: Flush the icache right after patching to avoid illegal insns")
> > Reported-by: Samuel Holland <samuel.holland@xxxxxxxxxx>
> > Closes: https://lore.kernel.org/linux-riscv/CAHVXubh8Adb4=-vN4cSh0FrZ16TeOKJbLj4AF09QC241bRk1Jg@xxxxxxxxxxxxxx/T/#m800757c26f72a1d45c240cb815650430166c82ea
> Shouldn't this use the permalink for the specific message, not the thread?


I never paid attention to that, but the permalink is shorter so I'll 
change that, thanks


> > Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
> > ---
> >   arch/riscv/kernel/patch.c | 6 ++++++
> >   1 file changed, 6 insertions(+)
> >
> > diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
> > index ab03732d06c4..91edfd764ed9 100644
> > --- a/arch/riscv/kernel/patch.c
> > +++ b/arch/riscv/kernel/patch.c
> > @@ -205,6 +205,9 @@ int patch_text_set_nosync(void *addr, u8 c, size_t len)
> >   
> >   	ret = patch_insn_set(tp, c, len);
> >   
> > +	if (!ret)
> > +		flush_icache_range((uintptr_t)tp, (uintptr_t)tp + len);
> This patch was based on an old tree from before
> https://git.kernel.org/riscv/c/47742484ee16 removed the "tp" variable. While it
> still compiles because flush_icache_range() is a macro that discards its
> arguments, it will be confusing to anyone reading the code.


Hmmm not the first time I hear this :) Sorry, I prepared the patch a 
couple of weeks ago and the rebase on 6.11-rc1 did not complain, I do 
that right now and send a new version tomorrow.

Thanks,

Alex


> Regards,
> Samuel
>
> > +
> >   	return ret;
> >   }
> >   NOKPROBE_SYMBOL(patch_text_set_nosync);
> > @@ -237,6 +240,9 @@ int patch_text_nosync(void *addr, const void *insns, size_t len)
> >   
> >   	ret = patch_insn_write(tp, insns, len);
> >   
> > +	if (!ret)
> > +		flush_icache_range((uintptr_t) tp, (uintptr_t) tp + len);
> > +
> >   	return ret;
> >   }
> >   NOKPROBE_SYMBOL(patch_text_nosync);
>
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