Toggle page table writability when copying page tables in efi_sync_low_kernel_mappings(). These page tables will not be protected until after init, but later on they will not be writable. Signed-off-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx> --- arch/x86/platform/efi/efi_64.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index 7515e78ef898..7a5c81450fa4 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -116,7 +116,9 @@ void efi_sync_low_kernel_mappings(void) pgd_k = pgd_offset_k(PAGE_OFFSET); num_entries = pgd_index(EFI_VA_END) - pgd_index(PAGE_OFFSET); + enable_pgtable_write(); memcpy(pgd_efi, pgd_k, sizeof(pgd_t) * num_entries); + disable_pgtable_write(); pgd_efi = efi_pgd + pgd_index(EFI_VA_END); pgd_k = pgd_offset_k(EFI_VA_END); @@ -124,7 +126,9 @@ void efi_sync_low_kernel_mappings(void) p4d_k = p4d_offset(pgd_k, 0); num_entries = p4d_index(EFI_VA_END); + enable_pgtable_write(); memcpy(p4d_efi, p4d_k, sizeof(p4d_t) * num_entries); + disable_pgtable_write(); /* * We share all the PUD entries apart from those that map the @@ -139,13 +143,17 @@ void efi_sync_low_kernel_mappings(void) pud_k = pud_offset(p4d_k, 0); num_entries = pud_index(EFI_VA_END); + enable_pgtable_write(); memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries); + disable_pgtable_write(); pud_efi = pud_offset(p4d_efi, EFI_VA_START); pud_k = pud_offset(p4d_k, EFI_VA_START); num_entries = PTRS_PER_PUD - pud_index(EFI_VA_START); + enable_pgtable_write(); memcpy(pud_efi, pud_k, sizeof(pud_t) * num_entries); + disable_pgtable_write(); } /* -- 2.17.1
