arm64: Clean up the initial page table creation in head.S

This patch adds a create_table_entry macro which is used to populate pgd
and pud entries, also reducing the number of arguments for
create_pgd_entry.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Jungseok Lee <jungseoklee85@gmail.com>

1 files changed, 27 insertions, 32 deletions

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 019f81d9f1d5..a6db505411bc 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -476,43 +476,38 @@ ENDPROC(__calc_phys_offset)
         .quad   PAGE_OFFSET
 
 /*
- * Macro to populate the PUD for the corresponding block entry in the next
- * level (tbl) for the given virtual address in case of 4 levels.
+ * Macro to create a table entry to the next page.
  *
- * Preserves:   pgd, virt
- * Corrupts:    tbl, tmp1, tmp2
- * Returns:     pud
+ *      tbl:    page table address
+ *      virt:   virtual address
+ *      shift:  #imm page table shift
+ *      ptrs:   #imm pointers per table page
+ *
+ * Preserves:   virt
+ * Corrupts:    tmp1, tmp2
+ * Returns:     tbl -> next level table page address
  */
-        .macro  create_pud_entry, pgd, tbl, virt, pud, tmp1, tmp2
-#if CONFIG_ARM64_PGTABLE_LEVELS == 4
-        add     \tbl, \tbl, #PAGE_SIZE          // bump tbl 1 page up.
-                                                // to make room for pud
-        add     \pud, \pgd, #PAGE_SIZE          // pgd points to pud which
-                                                // follows pgd
-        lsr     \tmp1, \virt, #PUD_SHIFT
-        and     \tmp1, \tmp1, #PTRS_PER_PUD - 1 // PUD index
-        orr     \tmp2, \tbl, #3                 // PUD entry table type
-        str     \tmp2, [\pud, \tmp1, lsl #3]
-#else
-        mov     \pud, \tbl
-#endif
+        .macro  create_table_entry, tbl, virt, shift, ptrs, tmp1, tmp2
+        lsr     \tmp1, \virt, #\shift
+        and     \tmp1, \tmp1, #\ptrs - 1        // table index
+        add     \tmp2, \tbl, #PAGE_SIZE
+        orr     \tmp2, \tmp2, #PMD_TYPE_TABLE   // address of next table and entry type
+        str     \tmp2, [\tbl, \tmp1, lsl #3]
+        add     \tbl, \tbl, #PAGE_SIZE          // next level table page
         .endm
 
 /*
  * Macro to populate the PGD (and possibily PUD) for the corresponding
  * block entry in the next level (tbl) for the given virtual address.
  *
- * Preserves:   pgd, virt
- * Corrupts:    tmp1, tmp2, tmp3
- * Returns:     tbl -> page where block mappings can be placed
- *      (changed to make room for pud with 4 levels, preserved otherwise)
+ * Preserves:   tbl, next, virt
+ * Corrupts:    tmp1, tmp2
  */
-        .macro  create_pgd_entry, pgd, tbl, virt, tmp1, tmp2, tmp3
-        create_pud_entry \pgd, \tbl, \virt, \tmp3, \tmp1, \tmp2
-        lsr     \tmp1, \virt, #PGDIR_SHIFT
-        and     \tmp1, \tmp1, #PTRS_PER_PGD - 1 // PGD index
-        orr     \tmp2, \tmp3, #3                // PGD entry table type
-        str     \tmp2, [\pgd, \tmp1, lsl #3]
+        .macro  create_pgd_entry, tbl, virt, tmp1, tmp2
+        create_table_entry \tbl, \virt, PGDIR_SHIFT, PTRS_PER_PGD, \tmp1, \tmp2
+#if CONFIG_ARM64_PGTABLE_LEVELS == 4
+        create_table_entry \tbl, \virt, PUD_SHIFT, PTRS_PER_PUD, \tmp1, \tmp2
+#endif
         .endm
 
 /*
@@ -573,10 +568,10 @@ __create_page_tables:
         /*
          * Create the identity mapping.
          */
-        add     x0, x25, #PAGE_SIZE             // section table address
+        mov     x0, x25                         // idmap_pg_dir
         ldr     x3, =KERNEL_START
         add     x3, x3, x28                     // __pa(KERNEL_START)
-        create_pgd_entry x25, x0, x3, x1, x5, x6
+        create_pgd_entry x0, x3, x5, x6
         ldr     x6, =KERNEL_END
         mov     x5, x3                          // __pa(KERNEL_START)
         add     x6, x6, x28                     // __pa(KERNEL_END)
@@ -585,9 +580,9 @@ __create_page_tables:
         /*
          * Map the kernel image (starting with PHYS_OFFSET).
          */
-        add     x0, x26, #PAGE_SIZE             // section table address
+        mov     x0, x26                         // swapper_pg_dir
         mov     x5, #PAGE_OFFSET
-        create_pgd_entry x26, x0, x5, x1, x3, x6
+        create_pgd_entry x0, x5, x3, x6
         ldr     x6, =KERNEL_END
         mov     x3, x24                         // phys offset
         create_block_map x0, x7, x3, x5, x6