From: Guenter Roeck <linux@roeck-us.net>
To: Dave Hansen <dave.hansen@intel.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Darren Hart <dvhart@infradead.org>,
Andy Shevchenko <andy@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, linux-efi@vger.kernel.org,
"H. Peter Anvin" <hpa@zytor.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH] x86/mm: Disable W^X detection and enforcement on 32-bit
Date: Fri, 23 Sep 2022 21:38:04 -0700 [thread overview]
Message-ID: <a3970db3-1ded-da2e-84a0-754810c15183@roeck-us.net> (raw)
In-Reply-To: <ca72bdfb-9868-162f-63d5-f778dd03db22@intel.com>
On 9/23/22 17:12, Dave Hansen wrote:
> On 9/23/22 17:09, Kirill A. Shutemov wrote:
>> On Fri, Sep 23, 2022 at 03:17:30PM -0700, Dave Hansen wrote:
>>> The 32-bit code is in a weird spot. Some 32-bit builds (non-PAE) do not
>>> even have NX support. Even PAE builds that support NX have to contend
>>> with things like EFI data and code mixed in the same pages where W+X
>>> is unavoidable.
>>>
>>> The folks still running X86_32=y kernels are unlikely to care much about
>>> NX. That combined with the fundamental inability fix _all_ of the W+X
>>> things means this code had little value on X86_32=y. Disable the checks.
>> Maybe downgrade the check to a warning for X86_32=y?
>
> But for this EFI case, we really don't want the warning. It's unfixable.
>
> I'm also not sure we want to go to the trouble to properly silence the
> warning in these unfixable cases. There was an argument elsewhere in
> the thread that we really shouldn't be warning on things that we don't
> have full intentions to fix. I buy that argument.
Yes, there are already way too many such useless warnings around.
Please don't add more of them.
Guenter
next prev parent reply other threads:[~2022-09-24 4:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-23 22:17 [PATCH] x86/mm: Disable W^X detection and enforcement on 32-bit Dave Hansen
2022-09-24 0:09 ` Kirill A. Shutemov
2022-09-24 0:12 ` Dave Hansen
2022-09-24 4:38 ` Guenter Roeck [this message]
2022-09-24 4:26 ` Kees Cook
2022-09-24 6:52 ` Guenter Roeck
2022-09-24 7:26 ` Ard Biesheuvel
2022-10-02 10:33 ` Pavel Machek
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