Hi, As I mentioned yeaterday, I ran into some toolchain issues yesterday. When attempting my first build on Fedora 22, which uses GCC5.1, the build fails. First with an internal compiler error, and with a workaround for that, it simply refuses to go past.
Basically, AArch64 (arm64) does not define a soft-float ABI. Recent versions of GCC now (presumably correctly) bails out when encountering floating-point if +nofp has been specified in -march flags. Also, the UEFI specification mandates that for aarch64 the cpu is configured such that floating-point exceptions are not generated - so it should be safe to generate floating-point instructions. So would it be possible to do something like the below?: >From a1821c9222bab447b2d3faccf69e518c65e0f638 Mon Sep 17 00:00:00 2001 From: Leif Lindholm <[email protected]> Date: Mon, 1 Jun 2015 23:58:44 +0100 Subject: [PATCH] arm64: do not force-enable soft-float AArch64 (arm64) does not define a soft-float ABI. GCC5.1 now (presumably correctly) bails out when encountering floating-point if +nofp has been specified in -march flags. Also, the UEFI specification mandates that the cpu is configured such that floating-point exceptions are not generated - so it should be safe to generate floating-point instructions. So drop +nofp and +nosimd from configure.ac for arm64. Signed-off-by: Leif Lindholm <[email protected]> --- configure.ac | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) diff --git a/configure.ac b/configure.ac index 891c14f..0a6d2e9 100644 --- a/configure.ac +++ b/configure.ac @@ -686,9 +686,8 @@ if test x"$platform" != xemu ; then AC_CACHE_CHECK([for options to get soft-float], grub_cv_target_cc_soft_float, [ grub_cv_target_cc_soft_float=no if test "x$target_cpu" = xarm64; then - CFLAGS="$TARGET_CFLAGS -march=armv8-a+nofp+nosimd -Werror" - AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[]])], - [grub_cv_target_cc_soft_float="-march=armv8-a+nofp+nosimd"], []) + CFLAGS="$TARGET_CFLAGS -Werror" + grub_cv_target_cc_soft_float="" fi if test "x$target_cpu" = xia64; then CFLAGS="$TARGET_CFLAGS -mno-inline-float-divide -mno-inline-sqrt -Werror" @@ -720,15 +719,7 @@ if test x"$platform" != xemu ; then TARGET_CFLAGS="$TARGET_CFLAGS $grub_cv_target_cc_soft_float" ;; esac - case x"$grub_cv_target_cc_soft_float" in - x"-march=armv8-a+nofp+nosimd") - # +nosimd disables also the cache opcodes that we need in asm. - TARGET_CCASFLAGS="$TARGET_CCASFLAGS -march=armv8-a+nofp" - ;; - *) - TARGET_CCASFLAGS="$TARGET_CCASFLAGS $grub_cv_target_cc_soft_float" - ;; - esac + TARGET_CCASFLAGS="$TARGET_CCASFLAGS $grub_cv_target_cc_soft_float" fi -- 2.1.4 _______________________________________________ Grub-devel mailing list [email protected] https://lists.gnu.org/mailman/listinfo/grub-devel
