linux-kernel - [tip: x86/boot] x86/boot/64: Use RIP_REL_REF() to access '__supported_pte

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Date: Mon, 26 Feb 2024 12:12:45 -0000
From: "tip-bot2 for Ard Biesheuvel" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Ard Biesheuvel <ardb@...nel.org>, Ingo Molnar <mingo@...nel.org>,
 x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [tip: x86/boot] x86/boot/64: Use RIP_REL_REF() to access
 '__supported_pte_mask'

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

Commit-ID:     4f8b6cf25f5c119b117cb2a4bacb604a6cd00ff1
Gitweb:        https://git.kernel.org/tip/4f8b6cf25f5c119b117cb2a4bacb604a6cd00ff1
Author:        Ard Biesheuvel <ardb@...nel.org>
AuthorDate:    Wed, 21 Feb 2024 12:35:11 +01:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Mon, 26 Feb 2024 12:58:35 +01:00

x86/boot/64: Use RIP_REL_REF() to access '__supported_pte_mask'

'__supported_pte_mask' is accessed from code that executes from a 1:1
mapping so it cannot use a plain access from C. Replace the use of
fixup_pointer() with RIP_REL_REF(), which is better and simpler.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Link: https://lore.kernel.org/r/20240221113506.2565718-22-ardb+git@google.com
---
 arch/x86/kernel/head64.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 2ac9041..e2573dd 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -177,7 +177,6 @@ unsigned long __head __startup_64(unsigned long physaddr,
 	p4dval_t *p4d;
 	pudval_t *pud;
 	pmdval_t *pmd, pmd_entry;
-	pteval_t *mask_ptr;
 	bool la57;
 	int i;
 
@@ -259,8 +258,7 @@ unsigned long __head __startup_64(unsigned long physaddr,
 
 	pmd_entry = __PAGE_KERNEL_LARGE_EXEC & ~_PAGE_GLOBAL;
 	/* Filter out unsupported __PAGE_KERNEL_* bits: */
-	mask_ptr = fixup_pointer(&__supported_pte_mask, physaddr);
-	pmd_entry &= *mask_ptr;
+	pmd_entry &= RIP_REL_REF(__supported_pte_mask);
 	pmd_entry += sme_get_me_mask();
 	pmd_entry +=  physaddr;