From: Alexey Dobriyan <adobriyan@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Florian Weimer <fweimer@redhat.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-api@vger.kernel.org, x86@kernel.org,
Eric Biederman <ebiederm@xmission.com>,
linux-mm@kvack.org
Subject: Re: [PATCH v4] ELF: AT_PAGE_SHIFT_MASK -- supply userspace with available page shifts
Date: Fri, 9 Feb 2024 15:30:37 +0300 [thread overview]
Message-ID: <acd02481-ca2e-412a-8c6b-d9dff1345139@p183> (raw)
In-Reply-To: <202402050445.0331B94A73@keescook>
On Mon, Feb 05, 2024 at 04:48:08AM -0800, Kees Cook wrote:
> On Mon, Feb 05, 2024 at 12:51:43PM +0300, Alexey Dobriyan wrote:
> > +#define ARCH_AT_PAGE_SHIFT_MASK \
> > + do { \
> > + u32 val = 1 << 12; \
> > + if (boot_cpu_has(X86_FEATURE_PSE)) { \
> > + val |= 1 << 21; \
> > + } \
> > + if (boot_cpu_has(X86_FEATURE_GBPAGES)) { \
> > + val |= 1 << 30; \
> > + } \
>
> Can we use something besides literal "12", "21", and "30" values here?
Ehh, no, why? Inside x86_64 the page shifts are very specific numbers,
they won't change.
next prev parent reply other threads:[~2024-02-09 12:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-05 9:51 [PATCH v4] ELF: AT_PAGE_SHIFT_MASK -- supply userspace with available page shifts Alexey Dobriyan
2024-02-05 12:48 ` Kees Cook
2024-02-09 12:30 ` Alexey Dobriyan [this message]
2024-02-10 0:41 ` Kees Cook
2024-02-13 18:51 ` Alexey Dobriyan
2024-02-13 19:39 ` Kees Cook
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