wireguard-linux/arch/x86/kernel/head64.c, branch update-toolchain

x86/boot/64: Move 5-level paging global variable assignments back

2024-03-24T04:00:36Z

Commit 63bed9660420 ("x86/startup_64: Defer assignment of 5-level paging global variables") moved assignment of 5-level global variables to later in the boot in order to avoid having to use RIP relative addressing in order to set them. However, when running with 5-level paging and SME active (mem_encrypt=on), the variables are needed as part of the page table setup needed to encrypt the kernel (using pgd_none(), p4d_offset(), etc.). Since the variables haven't been set, the page table manipulation is done as if 4-level paging is active, causing the system to crash on boot. While only a subset of the assignments that were moved need to be set early, move all of the assignments back into check_la57_support() so that these assignments aren't spread between two locations. Instead of just reverting the fix, this uses the new RIP_REL_REF() macro when assigning the variables. Fixes: 63bed9660420 ("x86/startup_64: Defer assignment of 5-level paging global variables") Signed-off-by: Tom Lendacky Signed-off-by: Ingo Molnar Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/2ca419f4d0de719926fd82353f6751f717590a86.1711122067.git.thomas.lendacky@amd.com

x86/boot/64: Apply encryption mask to 5-level pagetable update

2024-03-24T04:00:35Z

When running with 5-level page tables, the kernel mapping PGD entry is updated to point to the P4D table. The assignment uses _PAGE_TABLE_NOENC, which, when SME is active (mem_encrypt=on), results in a page table entry without the encryption mask set, causing the system to crash on boot. Change the assignment to use _PAGE_TABLE instead of _PAGE_TABLE_NOENC so that the encryption mask is set for the PGD entry. Fixes: 533568e06b15 ("x86/boot/64: Use RIP_REL_REF() to access early_top_pgt[]") Signed-off-by: Tom Lendacky Signed-off-by: Ingo Molnar Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/8f20345cda7dbba2cf748b286e1bc00816fe649a.1711122067.git.thomas.lendacky@amd.com

x86/startup_64: Defer assignment of 5-level paging global variables

2024-03-04T17:12:06Z

Assigning the 5-level paging related global variables from the earliest C code using explicit references that use the 1:1 translation of memory is unnecessary, as the startup code itself does not rely on them to create the initial page tables, and this is all it should be doing. So defer these assignments to the primary C entry code that executes via the ordinary kernel virtual mapping. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Tested-by: Tom Lendacky Link: https://lore.kernel.org/r/20240227151907.387873-13-ardb+git@google.com

x86/boot/64: Load the final kernel GDT during early boot directly, remove startup_gdt[]

2024-02-28T10:02:16Z

Instead of loading a duplicate GDT just for early boot, load the kernel GDT from its physical address. Signed-off-by: Brian Gerst Signed-off-by: Ingo Molnar Acked-by: Ard Biesheuvel Cc: Kees Cook Cc: Andy Lutomirski Cc: Linus Torvalds Cc: "H. Peter Anvin" Cc: Josh Poimboeuf Link: https://lore.kernel.org/r/20240226220544.70769-1-brgerst@gmail.com

x86/boot/64: Use RIP_REL_REF() to access early_top_pgt[]

2024-02-26T11:58:35Z

early_top_pgt[] is assigned 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. For legibility and to align with the code that populates the lower page table levels, statically initialize the root level page table with an entry pointing to level3_kernel_pgt[], and overwrite it when needed to enable 5-level paging. Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240221113506.2565718-24-ardb+git@google.com

x86/boot/64: Use RIP_REL_REF() to access early page tables

2024-02-26T11:58:35Z

The early statically allocated page tables are populated from code that executes from a 1:1 mapping so it cannot use plain accesses from C. Replace the use of fixup_pointer() with RIP_REL_REF(), which is better and simpler. Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240221113506.2565718-23-ardb+git@google.com

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

2024-02-26T11:58:35Z

'__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 Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240221113506.2565718-22-ardb+git@google.com

x86/boot/64: Use RIP_REL_REF() to access early_dynamic_pgts[]

2024-02-26T11:58:35Z

early_dynamic_pgts[] and next_early_pgt are 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 Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240221113506.2565718-21-ardb+git@google.com

x86/boot/64: Use RIP_REL_REF() to assign 'phys_base'

2024-02-26T11:58:35Z

'phys_base' is assigned 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. While at it, move the assignment to before the addition of the SME mask so there is no need to subtract it again, and drop the unnecessary addition ('phys_base' is statically initialized to 0x0) Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240221113506.2565718-20-ardb+git@google.com

x86/boot/64: Simplify global variable accesses in GDT/IDT programming

2024-02-26T11:58:11Z

There are two code paths in the startup code to program an IDT: one that runs from the 1:1 mapping and one that runs from the virtual kernel mapping. Currently, these are strictly separate because fixup_pointer() is used on the 1:1 path, which will produce the wrong value when used while executing from the virtual kernel mapping. Switch to RIP_REL_REF() so that the two code paths can be merged. Also, move the GDT and IDT descriptors to the stack so that they can be referenced directly, rather than via RIP_REL_REF(). Rename startup_64_setup_env() to startup_64_setup_gdt_idt() while at it, to make the call from assembler self-documenting. Signed-off-by: Ard Biesheuvel Signed-off-by: Borislav Petkov (AMD) Signed-off-by: Ard Biesheuvel Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20240221113506.2565718-19-ardb+git@google.com