diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index f9f7be9588..5168eb4588 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -459,7 +459,6 @@ ENDPROC(cpu_init) create_page_tables: /* Prepare the page-tables for mapping Xen */ mov_w r0, XEN_VIRT_START - create_table_entry boot_pgtable, boot_second, r0, 1 create_table_entry boot_second, boot_third, r0, 2 /* Setup boot_third: */ @@ -479,70 +478,37 @@ create_page_tables: cmp r1, #(XEN_PT_LPAE_ENTRIES<<3) /* 512*8-byte entries per page */ blo 1b - /* - * If Xen is loaded at exactly XEN_VIRT_START then we don't - * need an additional 1:1 mapping, the virtual mapping will - * suffice. - */ - cmp r9, #XEN_VIRT_START - moveq pc, lr - /* * Setup the 1:1 mapping so we can turn the MMU on. Note that * only the first page of Xen will be part of the 1:1 mapping. - * - * In all the cases, we will link boot_third_id. So create the - * mapping in advance. */ + create_table_entry boot_pgtable, boot_second_id, r9, 1 + create_table_entry boot_second_id, boot_third_id, r9, 2 create_mapping_entry boot_third_id, r9, r9 /* - * Find the first slot used. If the slot is not XEN_FIRST_SLOT, - * then the 1:1 mapping will use its own set of page-tables from - * the second level. + * Find the first slot used. If the slot is not the same + * as TEMPORARY_AREA_FIRST_SLOT, then we will want to switch + * to the temporary mapping before jumping to the runtime + * virtual mapping. */ get_table_slot r1, r9, 1 /* r1 := first slot */ - cmp r1, #XEN_FIRST_SLOT - beq 1f - create_table_entry boot_pgtable, boot_second_id, r9, 1 - b link_from_second_id + cmp r1, #TEMPORARY_AREA_FIRST_SLOT + bne use_temporary_mapping -1: - /* - * Find the second slot used. If the slot is XEN_SECOND_SLOT, then the - * 1:1 mapping will use its own set of page-tables from the - * third level. - */ - get_table_slot r1, r9, 2 /* r1 := second slot */ - cmp r1, #XEN_SECOND_SLOT - beq virtphys_clash - create_table_entry boot_second, boot_third_id, r9, 2 - b link_from_third_id - -link_from_second_id: - create_table_entry boot_second_id, boot_third_id, r9, 2 -link_from_third_id: - /* Good news, we are not clashing with Xen virtual mapping */ + mov_w r0, XEN_VIRT_START + create_table_entry boot_pgtable, boot_second, r0, 1 mov r12, #0 /* r12 := temporary mapping not created */ mov pc, lr -virtphys_clash: +use_temporary_mapping: /* - * The identity map clashes with boot_third. Link boot_first_id and - * map Xen to a temporary mapping. See switch_to_runtime_mapping - * for more details. + * The identity mapping is not using the first slot + * TEMPORARY_AREA_FIRST_SLOT. Create a temporary mapping. + * See switch_to_runtime_mapping for more details. */ - PRINT("- Virt and Phys addresses clash -\r\n") PRINT("- Create temporary mapping -\r\n") - /* - * This will override the link to boot_second in XEN_FIRST_SLOT. - * The page-tables are not live yet. So no need to use - * break-before-make. - */ - create_table_entry boot_pgtable, boot_second_id, r9, 1 - create_table_entry boot_second_id, boot_third_id, r9, 2 - /* Map boot_second (cover Xen mappings) to the temporary 1st slot */ mov_w r0, TEMPORARY_XEN_VIRT_START create_table_entry boot_pgtable, boot_second, r0, 1 @@ -675,33 +641,13 @@ remove_identity_mapping: /* r2:r3 := invalid page-table entry */ mov r2, #0x0 mov r3, #0x0 - /* - * Find the first slot used. Remove the entry for the first - * table if the slot is not XEN_FIRST_SLOT. - */ + + /* Find the first slot used and remove it */ get_table_slot r1, r9, 1 /* r1 := first slot */ - cmp r1, #XEN_FIRST_SLOT - beq 1f - /* It is not in slot 0, remove the entry */ mov_w r0, boot_pgtable /* r0 := root table */ lsl r1, r1, #3 /* r1 := Slot offset */ strd r2, r3, [r0, r1] - b identity_mapping_removed -1: - /* - * Find the second slot used. Remove the entry for the first - * table if the slot is not XEN_SECOND_SLOT. - */ - get_table_slot r1, r9, 2 /* r1 := second slot */ - cmp r1, #XEN_SECOND_SLOT - beq identity_mapping_removed - /* It is not in slot 1, remove the entry */ - mov_w r0, boot_second /* r0 := second table */ - lsl r1, r1, #3 /* r1 := Slot offset */ - strd r2, r3, [r0, r1] - -identity_mapping_removed: flush_xen_tlb_local r0 mov pc, lr ENDPROC(remove_identity_mapping)