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* [PATCH kvm-unit-tests] arm64: Compile with -mno-outline-atomics
@ 2020-07-28 12:17 Andrew Jones
  2020-07-28 21:25 ` Paolo Bonzini
  0 siblings, 1 reply; 2+ messages in thread
From: Andrew Jones @ 2020-07-28 12:17 UTC (permalink / raw)
  To: kvm, kvmarm; +Cc: pbonzini

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)))
-- 
2.25.4

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^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH kvm-unit-tests] arm64: Compile with -mno-outline-atomics
  2020-07-28 12:17 [PATCH kvm-unit-tests] arm64: Compile with -mno-outline-atomics Andrew Jones
@ 2020-07-28 21:25 ` Paolo Bonzini
  0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2020-07-28 21:25 UTC (permalink / raw)
  To: Andrew Jones, kvm, kvmarm

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

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kvmarm@lists.cs.columbia.edu
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm

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2020-07-28 12:17 [PATCH kvm-unit-tests] arm64: Compile with -mno-outline-atomics Andrew Jones
2020-07-28 21:25 ` Paolo Bonzini

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