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Wed, 23 Apr 2025 04:10:41 -0700 (PDT) Date: Wed, 23 Apr 2025 13:09:52 +0200 In-Reply-To: <20250423110948.1103030-13-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250423110948.1103030-13-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=961; i=ardb@kernel.org; h=from:subject; bh=JADx/rxGDZiU/7QnFcGFPRIEIAFKDCf42sLIuHIBDFs=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIYPjVO/0SN3k1VX+rVe+Xlw/+/h/XhbP4pfP/CMuZ905/ mHigYvzO0pZGMQ4GGTFFFkEZv99t/P0RKla51myMHNYmUCGMHBxCsBEbsozMuyaINSpLWn0wOSZ NFNjR/iRwOjMucd2N9pcmhb1RtTw2i1GhhubucRe7Rde/8h5TkmVfovHS5fzvyvjG867bNkXoTs vgwkA X-Mailer: git-send-email 2.49.0.805.g082f7c87e0-goog Message-ID: <20250423110948.1103030-16-ardb+git@google.com> Subject: [RFC PATCH PoC 03/11] x86/boot: Disregard __supported_pte_mask in __startup_64() From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, mingo@kernel.org, Ard Biesheuvel Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ard Biesheuvel __supported_pte_mask is statically initialized to U64_MAX and never assigned until long after the startup code executes that creates the initial page tables. So applying the mask is unnecessary, and can be avoided. Signed-off-by: Ard Biesheuvel --- arch/x86/boot/startup/map_kernel.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/boot/startup/map_kernel.c b/arch/x86/boot/startup/map= _kernel.c index 0eac3f17dbd3..099ae2559336 100644 --- a/arch/x86/boot/startup/map_kernel.c +++ b/arch/x86/boot/startup/map_kernel.c @@ -179,8 +179,6 @@ unsigned long __head __startup_64(unsigned long p2v_off= set, pud[(i + 1) % PTRS_PER_PUD] =3D (pudval_t)pmd + pgtable_flags; =20 pmd_entry =3D __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL; - /* Filter out unsupported __PAGE_KERNEL_* bits: */ - pmd_entry &=3D __supported_pte_mask; pmd_entry +=3D sme_get_me_mask(); pmd_entry +=3D physaddr; =20 --=20 2.49.0.805.g082f7c87e0-goog