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>

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 019f81d9f1d552b18d13ba934babb839748995f0..a6db505411bcc14665e650b13a3a72464fefe10d 100644 (file)
--- 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