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path: root/arch/x86/boot/startup/map_kernel.c
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2025-05-17x86/mm/64: Make 5-level paging support unconditionalKirill A. Shutemov
Both Intel and AMD CPUs support 5-level paging, which is expected to become more widely adopted in the future. All major x86 Linux distributions have the feature enabled. Remove CONFIG_X86_5LEVEL and related #ifdeffery for it to make it more readable. Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250516123306.3812286-4-kirill.shutemov@linux.intel.com
2025-05-14x86/boot: Defer initialization of VM space related global variablesArd Biesheuvel
The global pseudo-constants 'page_offset_base', 'vmalloc_base' and 'vmemmap_base' are not used extremely early during the boot, and cannot be used safely until after the KASLR memory randomization code in kernel_randomize_memory() executes, which may update their values. So there is no point in setting these variables extremely early, and it can wait until after the kernel itself is mapped and running from its permanent virtual mapping. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20250513111157.717727-9-ardb+git@google.com
2025-05-04x86/boot: Disregard __supported_pte_mask in __startup_64()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 <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
2025-04-12x86/boot: Drop RIP_REL_REF() uses from early mapping codeArd Biesheuvel
Now that __startup_64() is built using -fPIC, RIP_REL_REF() has become a NOP and can be removed. Only some occurrences of rip_rel_ptr() will remain, to explicitly take the address of certain global structures in the 1:1 mapping of memory. While at it, update the code comment to describe why this is needed. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> 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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: linux-efi@vger.kernel.org Link: https://lore.kernel.org/r/20250410134117.3713574-17-ardb+git@google.com
2025-04-12x86/boot: Move early kernel mapping code into startup/Ard Biesheuvel
The startup code that constructs the kernel virtual mapping runs from the 1:1 mapping of memory itself, and therefore, cannot use absolute symbol references. Before making changes in subsequent patches, move this code into a separate source file under arch/x86/boot/startup/ where all such code will be kept from now on. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> 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: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: linux-efi@vger.kernel.org Link: https://lore.kernel.org/r/20250410134117.3713574-16-ardb+git@google.com