On 3/4/26 15:25, Daniel Kiper wrote:
On Tue, Mar 03, 2026 at 09:41:12PM -0500, Nicholas Vinson wrote:
Starting with ld.llvm-21, any attempt create a non-relocatable binary and set
one more secton addresses below 0x400000 results in a linker error. Furthermore,
the differences between ld.bfd and ld.lld made finding a proper set of
command-line flags tht worked with both linkers and bypass the image base
address restriction difficult. Therefore, the approach of using a custom linker
script was adopted to solve the issue.

This approach was tested using:

../configure CC=clang CXX=clang++ LDFLAGS="-fuse-ld=lld" 
TARGET_LDFLAGS="-fuse-ld=lld" --with-platform=pc
../configure CC=clang CXX=clang++ --with-platform=pc (both with ld.lld as the 
default and ld.bfd as the default)
../configure CC=gcc CXX=g++ --with-platform=pc

and a VM was used for testing. To build the disk images the VM was booted with,
the following scripts were used:

EFI disk:
--- /dev/null   2026-01-18 13:24:44.262332704 -0500
+++ efi_disk_image.sh   2026-01-25 11:17:33.554420324 -0500
@@ -0,0 +1,23 @@
+#!/bin/sh
+
+set -xe
+
+dd if=/dev/zero of=grub.img bs=1M count=100 status=progress
+
+sfdisk --force --no-reread --no-tell-kernel grub.img <<EOF
+label: gpt
+label-id: ABEB6772-65C7-4391-BF21-B616916286B9
+size=1M, type=21686148-6449-6E6F-744E-656564454649, 
uuid=9892A604-439E-4401-A372-AAD5E99EADBB
+type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, 
uuid=FCE5EBB3-C887-4FDE-93C5-7670CC3914BF
+EOF
+
+LOOP_DEV=$(losetup --show -fP grub.img)
+sleep 1
+
+mkfs.ext4 -F "${LOOP_DEV}p2"
+
+mount "${LOOP_DEV}p2" /mnt/gentoo
+./grub-install -v --directory ./grub-core --locale-directory /usr/share/locale 
--boot-directory=/mnt/gentoo "${LOOP_DEV}"
+
+umount "${LOOP_DEV}p2"
+losetup -d "${LOOP_DEV}"
--

MBR image:
--- /dev/null   2026-01-18 13:24:44.262332704 -0500
+++ mbr_disk_image.sh   2026-01-25 11:17:24.129208591 -0500
@@ -0,0 +1,22 @@
+#!/bin/sh
+
+set -xe
+
+dd if=/dev/zero of=grub.img bs=1M count=100 status=progress
+
+sfdisk --force --no-reread --no-tell-kernel grub.img <<EOF
+label: dos
+label-id: 0x12345678
+type=83, bootable
+EOF
+
+LOOP_DEV=$(losetup --show -fP grub.img)
+sleep 1
+
+mkfs.ext4 -F -O ^has_journal "${LOOP_DEV}p1"
+
+mount "${LOOP_DEV}p1" /mnt/gentoo
+./grub-install -v --directory ./grub-core --locale-directory /usr/share/locale 
--boot-directory=/mnt/gentoo "${LOOP_DEV}"
+
+umount "${LOOP_DEV}p1"
+losetup -d "${LOOP_DEV}"
--

In all cases, the VM successfully booted to the standard GRUB prompt.

Nicholas Vinson (9):
   i386/pc/int.h: move GRUB_MACHINE_PCBIOS ifdef
   grub-core: Update kernel image generation
   Revert "configure: Print a more helpful error if autoconf-archive is
     not installed"
   Revert "configure: Check linker for --image-base support"
   Revert "INSTALL: Add note that the GNU Autoconf Archive may be needed"
   configure: drop -Ttext checks for i386-pc
   configure.ac: Add --image-base check for non-i386
   i386-cygwin-img-ld.sc -> i386-cygwin-img.lds
   conf/i386-cygwin-img.lds: Update to use _grub_text_base symbol

In general Reviewed-by: Daniel Kiper <[email protected]> but...

diff --git a/configure.ac b/configure.ac
index 560c8a320..d19fb625d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1462,8 +1462,8 @@ elif test x$grub_cv_target_cc_link_format = x-mi386pe || 
test x$grub_cv_target_c
    TARGET_IMG_LDSCRIPT='$(top_srcdir)'"/conf/i386-cygwin-img.lds"
    TARGET_IMG_LDFLAGS="-Wl,-T${TARGET_IMG_LDSCRIPT}"
    TARGET_IMG_LDFLAGS_AC="-Wl,-T${srcdir}/conf/i386-cygwin-img.lds"
-  TARGET_IMG_BASE_LDOPT="-Wl,--defsym,_grub_text_base"
-  TARGET_IMG_BASE_LDOPT_ARG_SEP=","
+  TARGET_IMG_BASE_LDOPT="-Wl,--defsym=_grub_text_base"
+  TARGET_IMG_BASE_LDOPT_ARG_SEP="="
    TARGET_IMG_CFLAGS=
  else
    TARGET_APPLE_LINKER=0
@@ -1486,7 +1486,7 @@ else
          ])])
      TARGET_IMG_BASE_LDOPT_ARG_SEP=","
    else
-    TARGET_IMG_BASE_LDOPT="-Wl,--defsym,_grub_text_base"
+    TARGET_IMG_BASE_LDOPT="-Wl,--defsym=_grub_text_base"
      TARGET_IMG_BASE_LDOPT_ARG_SEP="="
      TARGET_IMG_LDSCRIPT='$(top_srcdir)'"/conf/i386-pc-kernel.lds"
      TARGET_IMG_LDFLAGS="${TARGET_IMG_LDFLAGS} -Wl,-T${TARGET_IMG_LDSCRIPT}"

The ld man is clear: --defsym=symbol=expression

If you are OK with proposed changes I will make them for you.

I am OK with those changes.

Thank you!
Nicholas Vinson


Daniel


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