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From: "Erhard F." <erhard_f@mailbox.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Benjamin Gray <bgray@linux.ibm.com>
Subject: Re: Bug: Write fault blocked by KUAP! (kernel 6.2-rc6, Talos II)
Date: Thu, 16 Feb 2023 16:20:20 +0100	[thread overview]
Message-ID: <20230216162020.0b90ed66@yea> (raw)
In-Reply-To: <65f1c4b4-a1f0-9eac-0ce3-70196a331052@csgroup.eu>

On Thu, 9 Feb 2023 07:21:55 +0000
Christophe Leroy <christophe.leroy@csgroup.eu> wrote:

> An easy fix would probably be to also check the suffix as a prefixed 
> instruction with 0 as suffix is not valid :
> 
> diff --git a/arch/powerpc/include/asm/inst.h 
> b/arch/powerpc/include/asm/inst.h
> index 684d3f453282..87084a52598b 100644
> --- a/arch/powerpc/include/asm/inst.h
> +++ b/arch/powerpc/include/asm/inst.h
> @@ -86,7 +86,7 @@ static inline ppc_inst_t ppc_inst_read(const u32 *ptr)
> 
>   static inline bool ppc_inst_prefixed(ppc_inst_t x)
>   {
> -	return IS_ENABLED(CONFIG_PPC64) && ppc_inst_primary_opcode(x) == 
> OP_PREFIX;
> +	return IS_ENABLED(CONFIG_PPC64) && ppc_inst_primary_opcode(x) == 
> OP_PREFIX && ppc_inst_suffix(x);
>   }
> 
>   static inline ppc_inst_t ppc_inst_swab(ppc_inst_t x)

Your patch works fine for me! Applied on top of v6.2-rc7 and in the resulting kernel the Write fault is gone. Thanks!

Regards,
Erhard

  reply	other threads:[~2023-02-16 15:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-02 23:46 Bug: Write fault blocked by KUAP! (kernel 6.2-rc6, Talos II) Erhard F.
2023-02-03  2:02 ` Benjamin Gray
2023-02-03  2:45   ` Nicholas Piggin
2023-02-09  7:21     ` Christophe Leroy
2023-02-16 15:20       ` Erhard F. [this message]
2023-02-03 10:46   ` Erhard F.

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