Re: [PATCH kvm-unit-tests] arm64: Compile with -mno-outline-atomics

[Paolo Bonzini <pbonzini@redhat.com>]

On 28/07/20 14:17, Andrew Jones wrote:
> GCC 10.1.0 introduced the -moutline-atomics option which, when
> enabled, use LSE instructions when the processor provides them.
> The option is enabled by default and unfortunately causes the
> following error at compile time:
> 
>  aarch64-linux-gnu-ld: /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a(lse-init.o): in function `init_have_lse_atomics':
>  lse-init.c:(.text.startup+0xc): undefined reference to `__getauxval'
> 
> This is happening because we are linking against our own libcflat which
> doesn't implement the function __getauxval().
> 
> Disable the use of the out-of-line functions by compiling with
> -mno-outline-atomics.
> 
> Reported-by: Alexandru Elisei <alexandru.elisei@arm.com>
> Tested-by: Alexandru Elisei <alexandru.elisei@arm.com>
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  Makefile           | 11 +++++------
>  arm/Makefile.arm64 |  3 +++
>  2 files changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/Makefile b/Makefile
> index 3ff2f91600f6..0e21a49096ba 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -17,6 +17,11 @@ DESTDIR := $(PREFIX)/share/kvm-unit-tests/
>  
>  .PHONY: arch_clean clean distclean cscope
>  
> +# cc-option
> +# Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
> +cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
> +              > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
> +
>  #make sure env CFLAGS variable is not used
>  CFLAGS =
>  
> @@ -43,12 +48,6 @@ OBJDIRS += $(LIBFDT_objdir)
>  #include architecture specific make rules
>  include $(SRCDIR)/$(TEST_DIR)/Makefile
>  
> -# cc-option
> -# Usage: OP_CFLAGS+=$(call cc-option, -falign-functions=0, -malign-functions=0)
> -
> -cc-option = $(shell if $(CC) -Werror $(1) -S -o /dev/null -xc /dev/null \
> -              > /dev/null 2>&1; then echo "$(1)"; else echo "$(2)"; fi ;)
> -
>  COMMON_CFLAGS += -g $(autodepend-flags) -fno-strict-aliasing -fno-common
>  COMMON_CFLAGS += -Wall -Wwrite-strings -Wempty-body -Wuninitialized
>  COMMON_CFLAGS += -Wignored-qualifiers -Werror
> diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64
> index dfd0c56fe8fb..dbc7524d3070 100644
> --- a/arm/Makefile.arm64
> +++ b/arm/Makefile.arm64
> @@ -9,6 +9,9 @@ ldarch = elf64-littleaarch64
>  arch_LDFLAGS = -pie -n
>  CFLAGS += -mstrict-align
>  
> +mno_outline_atomics := $(call cc-option, -mno-outline-atomics, "")
> +CFLAGS += $(mno_outline_atomics)
> +
>  define arch_elf_check =
>  	$(if $(shell ! $(OBJDUMP) -R $(1) >&/dev/null && echo "nok"),
>  		$(error $(shell $(OBJDUMP) -R $(1) 2>&1)))
> 

Queued, thanks.

Paolo