On 2023/6/13 17:06, Xiaotian Wu wrote:
Because the binutils of the loongarch architecture adds relaxation support [1],
the next version of binutils will not be able to build grub.
We can simplify the sentence a bit, like "A working grub cannot be built
with upcoming binutils and gcc, because linker relaxation was added [1]
causing new unsupported relocations to appear in modules".
So we use the -mno-relax cflags to disable gcc to generate relaxation
relocations to enhance the compatibility of grub.
Better mention the justification for not enabling relaxation, i.e.
because bootloaders are not exactly performance-sensitive code.
Also we can make the sentence more natural, like "So we pass -mno-relax
to gcc if it is supported, to disable relaxation and make grub
forward-compatible with new toolchains".
[1]:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=56576f4a722b7398d35802ecf7d4185c27d6d69b
Signed-off-by: Xiaotian Wu <wuxiaot...@loongson.cn>
---
configure.ac | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/configure.ac b/configure.ac
index d9f088d12..cd3cc6ba8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -874,6 +874,18 @@ if test "x$target_cpu" = xloongarch64; then
TARGET_CFLAGS="$TARGET_CFLAGS -mno-explicit-relocs -fno-plt"
TARGET_CCASFLAGS="$TARGET_CCASFLAGS -mno-explicit-relocs -fno-plt"
fi
+
+ AC_CACHE_CHECK([whether _mno_relax works], [grub_cv_cc_mno_relax], [
I don't have a strong opinion as to whether a justification should be
put here above the check though.
+ CFLAGS="$TARGET_CFLAGS -mno-relax -Werror"
+ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])],
+ [grub_cv_cc_mno_relax=yes],
+ [grub_cv_cc_mno_relax=no])
+ ])
+ if test "x$grub_cv_cc_mno_relax" = xyes; then
+ TARGET_CFLAGS="$TARGET_CFLAGS -mno-relax"
+ TARGET_CCASFLAGS="$TARGET_CCASFLAGS -mno-relax"
+ fi
+
TARGET_CFLAGS="$TARGET_CFLAGS -Wa,-mla-global-with-abs"
TARGET_CCASFLAGS="$TARGET_CCASFLAGS -Wa,-mla-global-with-abs"
fi
_______________________________________________
Grub-devel mailing list
Grub-devel@gnu.org
https://lists.gnu.org/mailman/listinfo/grub-devel
