firmware: Remove the unhelpful alignment codes before fdt relocation

If the device tree is at an address that is not __SIZEOF_POINTER__
aligned, the fdt relocation code tries to align both source and
destination address to __SIZEOF_POINTER__ before the memory copy.
But such alignment can lead to unexpected results if either source
or destination address is not aligned.

In fact libfdt requires that the device tree must be at an 8-byte
aligned address. Hence remove the unhelpful alignment codes.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index 928ca91..6baf6ab 100644 (file)
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -349,8 +349,7 @@ _scratch_init:
         * previous booting stage.
         */
        beqz    a1, _fdt_reloc_done
-       /* Mask values in a3 and a4 */
-       li      a3, ~(__SIZEOF_POINTER__ - 1)
+       /* Mask values in a4 */
        li      a4, 0xff
        /* t1 = destination FDT start address */
        MOV_3R  s0, a0, s1, a1, s2, a2
@@ -359,10 +358,8 @@ _scratch_init:
        MOV_3R  a0, s0, a1, s1, a2, s2
        beqz    t1, _fdt_reloc_done
        beq     t1, a1, _fdt_reloc_done
-       and     t1, t1, a3
        /* t0 = source FDT start address */
        add     t0, a1, zero
-       and     t0, t0, a3
        /* t2 = source FDT size in big-endian */
 #if __riscv_xlen == 64
        lwu     t2, 4(t0)