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

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Commit 63bed96604 ("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: 63bed96604 ("x86/startup_64: Defer assignment of 5-level paging global variables")
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/2ca419f4d0de719926fd82353f6751f717590a86.1711122067.git.thomas.lendacky@amd.com
This commit is contained in:
Tom Lendacky 2024-03-22 10:41:07 -05:00 committed by Ingo Molnar
parent 4d0d7e7852
commit 9843231c97
1 changed files with 7 additions and 9 deletions
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16
arch/x86/kernel/head64.c
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@ -81,6 +81,13 @@ static inline bool check_la57_support(void)
if (!(native_read_cr4() & X86_CR4_LA57))
return false;
RIP_REL_REF(__pgtable_l5_enabled) = 1;
RIP_REL_REF(pgdir_shift) = 48;
RIP_REL_REF(ptrs_per_p4d) = 512;
RIP_REL_REF(page_offset_base) = __PAGE_OFFSET_BASE_L5;
RIP_REL_REF(vmalloc_base) = __VMALLOC_BASE_L5;
RIP_REL_REF(vmemmap_base) = __VMEMMAP_BASE_L5;
return true;
}
@ -431,15 +438,6 @@ asmlinkage __visible void __init __noreturn x86_64_start_kernel(char * real_mode
(__START_KERNEL & PGDIR_MASK)));
BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
if (check_la57_support()) {
__pgtable_l5_enabled = 1;
pgdir_shift = 48;
ptrs_per_p4d = 512;
page_offset_base = __PAGE_OFFSET_BASE_L5;
vmalloc_base = __VMALLOC_BASE_L5;
vmemmap_base = __VMEMMAP_BASE_L5;
}
cr4_init_shadow();
/* Kill off the identity-map trampoline */