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Message-ID: <295ea2ef-3480-856b-b93a-9ae36f7b2286@cs.kuleuven.be>
Date:   Fri, 11 Aug 2023 16:27:17 -0700
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Subject: Re: [PATCH 1/1] x86/pti: Fix kernel warnings for pti= and nopti
 cmdline options.
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To:     linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com,
        luto@kernel.org, peterz@infradead.org, mingo@redhat.com,
        sohil.mehta@intel.com
Cc:     x86@kernel.org, bp@alien8.de, tglx@linutronix.de, hpa@zytor.com
References: <20230811213628.40428-1-jo.vanbulck@cs.kuleuven.be>
 <20230811213628.40428-2-jo.vanbulck@cs.kuleuven.be>
From:   Jo Van Bulck <jo.vanbulck@cs.kuleuven.be>
In-Reply-To: <20230811213628.40428-2-jo.vanbulck@cs.kuleuven.be>
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On 11.08.23 14:36, Jo Van Bulck wrote:>   static enum pti_mode {
>   	PTI_AUTO = 0,
> +	PTI_FORCE_AUTO,
>   	PTI_FORCE_OFF,
>   	PTI_FORCE_ON
>   } pti_mode;

I introduced a new PTI_FORCE_AUTO value here to make pti=auto override 
any mitigations=off parameter. However, I realize now that this may 
inadvertently affect other functions that test for pti_mode == PTI_AUTO 
(eg in pti_kernel_image_global_ok()).

Having 2 constants PTI_AUTO and PTI_FORCE_AUTO is arguably not very 
neat, so we should better get rid of this. I see several options:

- not have pti=auto override mitigations=off
- have a global var to indicate pti= argument was passed
- set pti_mode = PTI_AUTO in the pti_mode == PTI_FORCE_AUTO if branch

Not sure which option would best match kernel coding guidelines?

Best,
Jo