[tip: x86/boot] x86/boot: Disregard __supported_pte_mask in __startup_64()

tip-bot2 for Ard Biesheuvel
2025-05-04T14:20:31Z

The following commit has been merged into the x86/boot branch of tip:

Commit-ID: b3464a36f7f2499d517e8334e07ddd6eefcd67c1
Gitweb: https://git.kernel.org/tip/b3464a36f7f2499d517e8334e07ddd6eefcd67c1
Author: Ard Biesheuvel <ardb@kernel.org>
AuthorDate: Sun, 04 May 2025 11:52:32 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Sun, 04 May 2025 15:27:23 +02:00

x86/boot: Disregard __supported_pte_mask in __startup_64()

__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 <ardb@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Cc: Dionna Amalie Glaze <dionnaglaze@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kevin Loughlin <kevinloughlin@google.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-efi@vger.kernel.org
Link: https://lore.kernel.org/r/20250504095230.2932860-27-ardb+git@google.com
---
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 0eac3f1..099ae25 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_offset,
pud[(i + 1) % PTRS_PER_PUD] = (pudval_t)pmd + pgtable_flags;

pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
- /* Filter out unsupported __PAGE_KERNEL_* bits: */
- pmd_entry &= __supported_pte_mask;
pmd_entry += sme_get_me_mask();
pmd_entry += physaddr;