[v7] x86: strict separation of startup code

[PATCH v7 11/22] x86/boot: Provide PIC aliases for 5-level paging related constants

Posted by Ard Biesheuvel 1 week, 3 days ago

From: Ard Biesheuvel <ardb@kernel.org>

Provide PIC aliases for the global variables related to 5-level paging,
so that the startup code can access them in order to populate the kernel
page tables.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/x86/kernel/head64.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 533fcf5636fc..1bc40d0785ee 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -52,10 +52,13 @@ SYM_PIC_ALIAS(next_early_pgt);
 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
 
 unsigned int __pgtable_l5_enabled __ro_after_init;
+SYM_PIC_ALIAS(__pgtable_l5_enabled);
 unsigned int pgdir_shift __ro_after_init = 39;
 EXPORT_SYMBOL(pgdir_shift);
+SYM_PIC_ALIAS(pgdir_shift);
 unsigned int ptrs_per_p4d __ro_after_init = 1;
 EXPORT_SYMBOL(ptrs_per_p4d);
+SYM_PIC_ALIAS(ptrs_per_p4d);
 
 unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
 EXPORT_SYMBOL(page_offset_base);
-- 
2.51.0.268.g9569e192d0-goog

[tip: x86/sev] x86/boot: Provide PIC aliases for 5-level paging related constants

Posted by tip-bot2 for Ard Biesheuvel 3 days, 1 hour ago

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

Commit-ID:     f27906b287403af53be26341cf86d73798f15fe8
Gitweb:        https://git.kernel.org/tip/f27906b287403af53be26341cf86d73798f15fe8
Author:        Ard Biesheuvel <ardb@kernel.org>
AuthorDate:    Thu, 28 Aug 2025 12:22:14 +02:00
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Wed, 03 Sep 2025 17:59:40 +02:00

x86/boot: Provide PIC aliases for 5-level paging related constants

Provide PIC aliases for the global variables related to 5-level paging, so
that the startup code can access them in order to populate the kernel page
tables.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250828102202.1849035-35-ardb+git@google.com
---
 arch/x86/kernel/head64.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 533fcf5..1bc40d0 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -52,10 +52,13 @@ SYM_PIC_ALIAS(next_early_pgt);
 pmdval_t early_pmd_flags = __PAGE_KERNEL_LARGE & ~(_PAGE_GLOBAL | _PAGE_NX);
 
 unsigned int __pgtable_l5_enabled __ro_after_init;
+SYM_PIC_ALIAS(__pgtable_l5_enabled);
 unsigned int pgdir_shift __ro_after_init = 39;
 EXPORT_SYMBOL(pgdir_shift);
+SYM_PIC_ALIAS(pgdir_shift);
 unsigned int ptrs_per_p4d __ro_after_init = 1;
 EXPORT_SYMBOL(ptrs_per_p4d);
+SYM_PIC_ALIAS(ptrs_per_p4d);
 
 unsigned long page_offset_base __ro_after_init = __PAGE_OFFSET_BASE_L4;
 EXPORT_SYMBOL(page_offset_base);