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

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 <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

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7d2eb035b6a3647190d38ccd541fe6b3802d4f78..a817ed0724d1e76bb110c7fa8ff7239e4bfa72d2 100644 (file)
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -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 */