arm64: Extend the idmap to the whole kernel image

This patch changes the idmap page table creation during boot to cover
the whole kernel image, allowing functions like cpu_reset() to be safely
called with the physical address.

This patch also simplifies the create_block_map asm macro to no longer
take an idmap argument and always use the phys/virt/end parameters. For
the idmap case, phys == virt.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 8 insertions, 12 deletions

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 0b281fffda51..61035d6814cb 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -384,26 +384,18 @@ ENDPROC(__calc_phys_offset)
  * Preserves:   tbl, flags
  * Corrupts:    phys, start, end, pstate
  */
-        .macro  create_block_map, tbl, flags, phys, start, end, idmap=0
+        .macro  create_block_map, tbl, flags, phys, start, end
         lsr     \phys, \phys, #BLOCK_SHIFT
-        .if     \idmap
-        and     \start, \phys, #PTRS_PER_PTE - 1        // table index
-        .else
         lsr     \start, \start, #BLOCK_SHIFT
         and     \start, \start, #PTRS_PER_PTE - 1       // table index
-        .endif
         orr     \phys, \flags, \phys, lsl #BLOCK_SHIFT  // table entry
-        .ifnc   \start,\end
         lsr     \end, \end, #BLOCK_SHIFT
         and     \end, \end, #PTRS_PER_PTE - 1           // table end index
-        .endif
 9999:   str     \phys, [\tbl, \start, lsl #3]           // store the entry
-        .ifnc   \start,\end
         add     \start, \start, #1                      // next entry
         add     \phys, \phys, #BLOCK_SIZE               // next block
         cmp     \start, \end
         b.ls    9999b
-        .endif
         .endm
 
 /*
@@ -435,9 +427,13 @@ __create_page_tables:
          * Create the identity mapping.
          */
         add     x0, x25, #PAGE_SIZE             // section table address
-        adr     x3, __turn_mmu_on               // virtual/physical address
+        ldr     x3, =KERNEL_START
+        add     x3, x3, x28                     // __pa(KERNEL_START)
         create_pgd_entry x25, x0, x3, x5, x6
-        create_block_map x0, x7, x3, x5, x5, idmap=1
+        ldr     x6, =KERNEL_END
+        mov     x5, x3                          // __pa(KERNEL_START)
+        add     x6, x6, x28                     // __pa(KERNEL_END)
+        create_block_map x0, x7, x3, x5, x6
 
         /*
          * Map the kernel image (starting with PHYS_OFFSET).
@@ -445,7 +441,7 @@ __create_page_tables:
         add     x0, x26, #PAGE_SIZE             // section table address
         mov     x5, #PAGE_OFFSET
         create_pgd_entry x26, x0, x5, x3, x6
-        ldr     x6, =KERNEL_END - 1
+        ldr     x6, =KERNEL_END
         mov     x3, x24                         // phys offset
         create_block_map x0, x7, x3, x5, x6