From c2bf2ccb266dc9ae4a6da75b845f54535417e109 Mon Sep 17 00:00:00 2001 From: Artyom Kunakovsky Date: Thu, 23 May 2024 08:11:18 +0300 Subject: [PATCH] configure: move -mcx16 flag out of CPU_CFLAGS The point of CPU_CFLAGS is really just to select the appropriate multilib, for example for library linking tests, and -mcx16 is not needed for that purpose. Furthermore, if -mcx16 is part of QEMU's choice of a basic x86_64 instruction set, it should be applied to cross-compiled x86_64 code too; it is plausible that tests/tcg would want to cover cmpxchg16b as well, for example. In the end this makes just as much sense as a per sub-build tweak, so move the flag to meson.build and cross_cc_cflags_x86_64. This leaves out contrib/plugins, which would fail when attempting to use __sync_val_compare_and_swap_16 (note it does not do yet); while minor, this *is* a disadvantage of this change. But building contrib/plugins with a Makefile instead of meson.build is something self-inflicted just for the sake of showing that it can be done, and if this kind of papercut started becoming a problem we could make the directory part of the meson build. Until then, we can live with the limitation. Signed-off-by: Artyom Kunakovsky Message-ID: <20240523051118.29367-1-artyomkunakovsky@gmail.com> [rewrite commit message, remove from configure. - Paolo] Signed-off-by: Paolo Bonzini --- configure | 7 ++----- meson.build | 7 +++++++ 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/configure b/configure index 38ee257701..4d01a42ba6 100755 --- a/configure +++ b/configure @@ -512,10 +512,7 @@ case "$cpu" in cpu="x86_64" host_arch=x86_64 linux_arch=x86 - # ??? Only extremely old AMD cpus do not have cmpxchg16b. - # If we truly care, we should simply detect this case at - # runtime and generate the fallback to serial emulation. - CPU_CFLAGS="-m64 -mcx16" + CPU_CFLAGS="-m64" ;; esac @@ -1203,7 +1200,7 @@ fi : ${cross_cc_cflags_sparc64="-m64 -mcpu=ultrasparc"} : ${cross_cc_sparc="$cross_cc_sparc64"} : ${cross_cc_cflags_sparc="-m32 -mcpu=supersparc"} -: ${cross_cc_cflags_x86_64="-m64"} +: ${cross_cc_cflags_x86_64="-m64 -mcx16"} compute_target_variable() { eval "$2=" diff --git a/meson.build b/meson.build index a9de71d450..7fd82b5f48 100644 --- a/meson.build +++ b/meson.build @@ -336,6 +336,13 @@ if host_arch == 'i386' and not cc.links(''' qemu_common_flags = ['-march=i486'] + qemu_common_flags endif +# ??? Only extremely old AMD cpus do not have cmpxchg16b. +# If we truly care, we should simply detect this case at +# runtime and generate the fallback to serial emulation. +if host_arch == 'x86_64' + qemu_common_flags = ['-mcx16'] + qemu_common_flags +endif + if get_option('prefer_static') qemu_ldflags += get_option('b_pie') ? '-static-pie' : '-static' endif