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

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Message-ID: <032452c1-321a-486d-ae7b-46d7fb48578b@ghiti.fr>
Date: Thu, 1 Aug 2024 20:48:35 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Samuel Holland <samuel.holland@...ive.com>,
 Alexandre Ghiti <alexghiti@...osinc.com>, Palmer Dabbelt <palmer@...belt.com>
Cc: Paul Walmsley <paul.walmsley@...ive.com>,
 Albert Ou <aou@...s.berkeley.edu>, Andy Chiu <andy.chiu@...ive.com>,
 linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH -fixes] riscv: Re-introduce global icache flush in
 patch_text_XXX()

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@...ive.com>
>> Closes: https://lore.kernel.org/linux-riscv/CAHVXubh8Adb4=-vN4cSh0FrZ16TeOKJbLj4AF09QC241bRk1Jg@mail.gmail.com/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@...osinc.com>
>> ---
>>   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);
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv

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