target/linux/ipq40xx/patches-6.1/301-arm-compressed-add-appended-DTB-section.patch

   1 From 0843a61d6913bdac8889eb048ed89f7903059787 Mon Sep 17 00:00:00 2001
   2 From: Robert Marko <robimarko@gmail.com>
   3 Date: Fri, 30 Oct 2020 13:36:31 +0100
   4 Subject: [PATCH] arm: compressed: add appended DTB section
   5
   6 This adds a appended_dtb section to the ARM decompressor
   7 linker script.
   8
   9 This allows using the existing ARM zImage appended DTB support for
  10 appending a DTB to the raw ELF kernel.
  11
  12 Its size is set to 1MB max to match the zImage appended DTB size limit.
  13
  14 To use it to pass the DTB to the kernel, objcopy is used:
  15
  16 objcopy --set-section-flags=.appended_dtb=alloc,contents \
  17         --update-section=.appended_dtb=<target>.dtb vmlinux
  18
  19 This is based off the following patch:
  20 https://github.com/openwrt/openwrt/commit/c063e27e02a9dcac0e7f5877fb154e58fa3e1a69
  21
  22 Signed-off-by: Robert Marko <robimarko@gmail.com>
  23 ---
  24  arch/arm/boot/compressed/vmlinux.lds.S | 9 ++++++++-
  25  1 file changed, 8 insertions(+), 1 deletion(-)
  26
  27 --- a/arch/arm/boot/compressed/vmlinux.lds.S
  28 +++ b/arch/arm/boot/compressed/vmlinux.lds.S
  29 @@ -103,6 +103,13 @@ SECTIONS
  30
  31    _edata = .;
  32
  33 +  .appended_dtb : {
  34 +    /* leave space for appended DTB */
  35 +    . += 0x100000;
  36 +  }
  37 +
  38 +  _edata_dtb = .;
  39 +
  40    /*
  41     * The image_end section appears after any additional loadable sections
  42     * that the linker may decide to insert in the binary image.  Having
  43 @@ -140,4 +147,4 @@ SECTIONS
  44
  45    ARM_ASSERTS
  46  }
  47 -ASSERT(_edata_real == _edata, "error: zImage file size is incorrect");
  48 +ASSERT(_edata_real == _edata_dtb, "error: zImage file size is incorrect");