Message ID | 20200717164727.75580-1-alexandru.elisei@arm.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | [kvm-unit-tests] arm64: Compile with -mno-outline-atomics for GCC >= 10 | expand |
On Fri, Jul 17, 2020 at 05:47:27PM +0100, Alexandru Elisei wrote: > GCC 10.1.0 introduced the -m{,no-}outline-atomics flags which, according to > man 1 gcc: > > "Enable or disable calls to out-of-line helpers to implement atomic > operations. These helpers will, at runtime, determine if the LSE > instructions from ARMv8.1-A can be used; if not, they will use the > load/store-exclusive instructions that are present in the base ARMv8.0 ISA. > [..] This option is on by default." > > Unfortunately the option causes the following error at compile time: > > aarch64-linux-gnu-ld -nostdlib -pie -n -o arm/spinlock-test.elf -T /path/to/kvm-unit-tests/arm/flat.lds \ > arm/spinlock-test.o arm/cstart64.o lib/libcflat.a lib/libfdt/libfdt.a /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a lib/arm/libeabi.a arm/spinlock-test.aux.o > 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 if we detect a GCC version greater than 10. > > Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> > --- > > Tested with gcc versions 10.1.0 and 5.4.0 (cross-compilation), 9.3.0 > (native). > > I've been able to suss out the reason for the build failure from this > rejected gcc patch [1]. > > [1] https://patches.openembedded.org/patch/172460/ > > arm/Makefile.arm64 | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64 > index dfd0c56fe8fb..3223cb966789 100644 > --- a/arm/Makefile.arm64 > +++ b/arm/Makefile.arm64 > @@ -9,6 +9,12 @@ ldarch = elf64-littleaarch64 > arch_LDFLAGS = -pie -n > CFLAGS += -mstrict-align > > +# The -mno-outline-atomics flag is only valid for GCC versions 10 and greater. > +GCC_MAJOR_VERSION=$(shell $(CC) -dumpversion 2> /dev/null | cut -f1 -d.) > +ifeq ($(shell expr "$(GCC_MAJOR_VERSION)" ">=" "10"), 1) > +CFLAGS += -mno-outline-atomics > +endif How about this patch instead? 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))) Thanks, drew > + > define arch_elf_check = > $(if $(shell ! $(OBJDUMP) -R $(1) >&/dev/null && echo "nok"), > $(error $(shell $(OBJDUMP) -R $(1) 2>&1))) > -- > 2.27.0 >
Hi, On 7/18/20 10:11 AM, Andrew Jones wrote: > On Fri, Jul 17, 2020 at 05:47:27PM +0100, Alexandru Elisei wrote: >> GCC 10.1.0 introduced the -m{,no-}outline-atomics flags which, according to >> man 1 gcc: >> >> "Enable or disable calls to out-of-line helpers to implement atomic >> operations. These helpers will, at runtime, determine if the LSE >> instructions from ARMv8.1-A can be used; if not, they will use the >> load/store-exclusive instructions that are present in the base ARMv8.0 ISA. >> [..] This option is on by default." >> >> Unfortunately the option causes the following error at compile time: >> >> aarch64-linux-gnu-ld -nostdlib -pie -n -o arm/spinlock-test.elf -T /path/to/kvm-unit-tests/arm/flat.lds \ >> arm/spinlock-test.o arm/cstart64.o lib/libcflat.a lib/libfdt/libfdt.a /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a lib/arm/libeabi.a arm/spinlock-test.aux.o >> 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 if we detect a GCC version greater than 10. >> >> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> >> --- >> >> Tested with gcc versions 10.1.0 and 5.4.0 (cross-compilation), 9.3.0 >> (native). >> >> I've been able to suss out the reason for the build failure from this >> rejected gcc patch [1]. >> >> [1] https://patches.openembedded.org/patch/172460/ >> >> arm/Makefile.arm64 | 6 ++++++ >> 1 file changed, 6 insertions(+) >> >> diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64 >> index dfd0c56fe8fb..3223cb966789 100644 >> --- a/arm/Makefile.arm64 >> +++ b/arm/Makefile.arm64 >> @@ -9,6 +9,12 @@ ldarch = elf64-littleaarch64 >> arch_LDFLAGS = -pie -n >> CFLAGS += -mstrict-align >> >> +# The -mno-outline-atomics flag is only valid for GCC versions 10 and greater. >> +GCC_MAJOR_VERSION=$(shell $(CC) -dumpversion 2> /dev/null | cut -f1 -d.) >> +ifeq ($(shell expr "$(GCC_MAJOR_VERSION)" ">=" "10"), 1) >> +CFLAGS += -mno-outline-atomics >> +endif > How about this patch instead? > > 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))) > > > Thanks, > drew Looks much better than my version. Do you want me to spin a v2 or do you want to send it as a separate patch? If that's the case, I tested the same way I did my patch (gcc 10.1.0 and 5.4.0 for cross-compiling, 9.3.0 native): Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> Thanks, Alex
Hi Drew, On 7/18/20 2:50 PM, Alexandru Elisei wrote: > Hi, > > On 7/18/20 10:11 AM, Andrew Jones wrote: >> On Fri, Jul 17, 2020 at 05:47:27PM +0100, Alexandru Elisei wrote: >>> GCC 10.1.0 introduced the -m{,no-}outline-atomics flags which, according to >>> man 1 gcc: >>> >>> "Enable or disable calls to out-of-line helpers to implement atomic >>> operations. These helpers will, at runtime, determine if the LSE >>> instructions from ARMv8.1-A can be used; if not, they will use the >>> load/store-exclusive instructions that are present in the base ARMv8.0 ISA. >>> [..] This option is on by default." >>> >>> Unfortunately the option causes the following error at compile time: >>> >>> aarch64-linux-gnu-ld -nostdlib -pie -n -o arm/spinlock-test.elf -T /path/to/kvm-unit-tests/arm/flat.lds \ >>> arm/spinlock-test.o arm/cstart64.o lib/libcflat.a lib/libfdt/libfdt.a /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a lib/arm/libeabi.a arm/spinlock-test.aux.o >>> 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 if we detect a GCC version greater than 10. >>> >>> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> >>> --- >>> >>> Tested with gcc versions 10.1.0 and 5.4.0 (cross-compilation), 9.3.0 >>> (native). >>> >>> I've been able to suss out the reason for the build failure from this >>> rejected gcc patch [1]. >>> >>> [1] https://patches.openembedded.org/patch/172460/ >>> >>> arm/Makefile.arm64 | 6 ++++++ >>> 1 file changed, 6 insertions(+) >>> >>> diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64 >>> index dfd0c56fe8fb..3223cb966789 100644 >>> --- a/arm/Makefile.arm64 >>> +++ b/arm/Makefile.arm64 >>> @@ -9,6 +9,12 @@ ldarch = elf64-littleaarch64 >>> arch_LDFLAGS = -pie -n >>> CFLAGS += -mstrict-align >>> >>> +# The -mno-outline-atomics flag is only valid for GCC versions 10 and greater. >>> +GCC_MAJOR_VERSION=$(shell $(CC) -dumpversion 2> /dev/null | cut -f1 -d.) >>> +ifeq ($(shell expr "$(GCC_MAJOR_VERSION)" ">=" "10"), 1) >>> +CFLAGS += -mno-outline-atomics >>> +endif >> How about this patch instead? >> >> 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))) >> >> >> Thanks, >> drew > Looks much better than my version. Do you want me to spin a v2 or do you want to > send it as a separate patch? If that's the case, I tested the same way I did my > patch (gcc 10.1.0 and 5.4.0 for cross-compiling, 9.3.0 native): > > Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> Gentle ping regarding this. Thanks, Alex
On Mon, Jul 27, 2020 at 01:21:03PM +0100, Alexandru Elisei wrote: > Hi Drew, > > On 7/18/20 2:50 PM, Alexandru Elisei wrote: > > Hi, > > > > On 7/18/20 10:11 AM, Andrew Jones wrote: > >> On Fri, Jul 17, 2020 at 05:47:27PM +0100, Alexandru Elisei wrote: > >>> GCC 10.1.0 introduced the -m{,no-}outline-atomics flags which, according to > >>> man 1 gcc: > >>> > >>> "Enable or disable calls to out-of-line helpers to implement atomic > >>> operations. These helpers will, at runtime, determine if the LSE > >>> instructions from ARMv8.1-A can be used; if not, they will use the > >>> load/store-exclusive instructions that are present in the base ARMv8.0 ISA. > >>> [..] This option is on by default." > >>> > >>> Unfortunately the option causes the following error at compile time: > >>> > >>> aarch64-linux-gnu-ld -nostdlib -pie -n -o arm/spinlock-test.elf -T /path/to/kvm-unit-tests/arm/flat.lds \ > >>> arm/spinlock-test.o arm/cstart64.o lib/libcflat.a lib/libfdt/libfdt.a /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a lib/arm/libeabi.a arm/spinlock-test.aux.o > >>> 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 if we detect a GCC version greater than 10. > >>> > >>> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> > >>> --- > >>> > >>> Tested with gcc versions 10.1.0 and 5.4.0 (cross-compilation), 9.3.0 > >>> (native). > >>> > >>> I've been able to suss out the reason for the build failure from this > >>> rejected gcc patch [1]. > >>> > >>> [1] https://patches.openembedded.org/patch/172460/ > >>> > >>> arm/Makefile.arm64 | 6 ++++++ > >>> 1 file changed, 6 insertions(+) > >>> > >>> diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64 > >>> index dfd0c56fe8fb..3223cb966789 100644 > >>> --- a/arm/Makefile.arm64 > >>> +++ b/arm/Makefile.arm64 > >>> @@ -9,6 +9,12 @@ ldarch = elf64-littleaarch64 > >>> arch_LDFLAGS = -pie -n > >>> CFLAGS += -mstrict-align > >>> > >>> +# The -mno-outline-atomics flag is only valid for GCC versions 10 and greater. > >>> +GCC_MAJOR_VERSION=$(shell $(CC) -dumpversion 2> /dev/null | cut -f1 -d.) > >>> +ifeq ($(shell expr "$(GCC_MAJOR_VERSION)" ">=" "10"), 1) > >>> +CFLAGS += -mno-outline-atomics > >>> +endif > >> How about this patch instead? > >> > >> 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))) > >> > >> > >> Thanks, > >> drew > > Looks much better than my version. Do you want me to spin a v2 or do you want to > > send it as a separate patch? If that's the case, I tested the same way I did my > > patch (gcc 10.1.0 and 5.4.0 for cross-compiling, 9.3.0 native): > > > > Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> > > Gentle ping regarding this. > Hi Alexandru, I was on vacation all last week and have been digging myself out of email today. I'll send this as a proper patch with your T-b later today or tomorrow. Thanks, drew
Hi Drew, On 7/27/20 1:30 PM, Andrew Jones wrote: > On Mon, Jul 27, 2020 at 01:21:03PM +0100, Alexandru Elisei wrote: >> Hi Drew, >> >> On 7/18/20 2:50 PM, Alexandru Elisei wrote: >>> Hi, >>> >>> On 7/18/20 10:11 AM, Andrew Jones wrote: >>>> On Fri, Jul 17, 2020 at 05:47:27PM +0100, Alexandru Elisei wrote: >>>>> GCC 10.1.0 introduced the -m{,no-}outline-atomics flags which, according to >>>>> man 1 gcc: >>>>> >>>>> "Enable or disable calls to out-of-line helpers to implement atomic >>>>> operations. These helpers will, at runtime, determine if the LSE >>>>> instructions from ARMv8.1-A can be used; if not, they will use the >>>>> load/store-exclusive instructions that are present in the base ARMv8.0 ISA. >>>>> [..] This option is on by default." >>>>> >>>>> Unfortunately the option causes the following error at compile time: >>>>> >>>>> aarch64-linux-gnu-ld -nostdlib -pie -n -o arm/spinlock-test.elf -T /path/to/kvm-unit-tests/arm/flat.lds \ >>>>> arm/spinlock-test.o arm/cstart64.o lib/libcflat.a lib/libfdt/libfdt.a /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a lib/arm/libeabi.a arm/spinlock-test.aux.o >>>>> 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 if we detect a GCC version greater than 10. >>>>> >>>>> Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> >>>>> --- >>>>> >>>>> Tested with gcc versions 10.1.0 and 5.4.0 (cross-compilation), 9.3.0 >>>>> (native). >>>>> >>>>> I've been able to suss out the reason for the build failure from this >>>>> rejected gcc patch [1]. >>>>> >>>>> [1] https://patches.openembedded.org/patch/172460/ >>>>> >>>>> arm/Makefile.arm64 | 6 ++++++ >>>>> 1 file changed, 6 insertions(+) >>>>> >>>>> diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64 >>>>> index dfd0c56fe8fb..3223cb966789 100644 >>>>> --- a/arm/Makefile.arm64 >>>>> +++ b/arm/Makefile.arm64 >>>>> @@ -9,6 +9,12 @@ ldarch = elf64-littleaarch64 >>>>> arch_LDFLAGS = -pie -n >>>>> CFLAGS += -mstrict-align >>>>> >>>>> +# The -mno-outline-atomics flag is only valid for GCC versions 10 and greater. >>>>> +GCC_MAJOR_VERSION=$(shell $(CC) -dumpversion 2> /dev/null | cut -f1 -d.) >>>>> +ifeq ($(shell expr "$(GCC_MAJOR_VERSION)" ">=" "10"), 1) >>>>> +CFLAGS += -mno-outline-atomics >>>>> +endif >>>> How about this patch instead? >>>> >>>> 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 $(1) 2>&1))) >>>> >>>> >>>> Thanks, >>>> drew >>> Looks much better than my version. Do you want me to spin a v2 or do you want to >>> send it as a separate patch? If that's the case, I tested the same way I did my >>> patch (gcc 10.1.0 and 5.4.0 for cross-compiling, 9.3.0 native): >>> >>> Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> >> Gentle ping regarding this. >> > Hi Alexandru, > > I was on vacation all last week and have been digging myself out of email > today. I'll send this as a proper patch with your T-b later today or > tomorrow. Great, thanks, I was worried my reply might have slipped by unnoticed. Thanks, Alex > > Thanks, > drew >
On 27/07/20 14:30, Andrew Jones wrote: >>> Looks much better than my version. Do you want me to spin a v2 or do you want to >>> send it as a separate patch? If that's the case, I tested the same way I did my >>> patch (gcc 10.1.0 and 5.4.0 for cross-compiling, 9.3.0 native): >>> >>> Tested-by: Alexandru Elisei <alexandru.elisei@arm.com> >> Gentle ping regarding this. >> > Hi Alexandru, > > I was on vacation all last week and have been digging myself out of email > today. I'll send this as a proper patch with your T-b later today or > tomorrow. Same here; will wait for Andrew's patch. Paolo
diff --git a/arm/Makefile.arm64 b/arm/Makefile.arm64 index dfd0c56fe8fb..3223cb966789 100644 --- a/arm/Makefile.arm64 +++ b/arm/Makefile.arm64 @@ -9,6 +9,12 @@ ldarch = elf64-littleaarch64 arch_LDFLAGS = -pie -n CFLAGS += -mstrict-align +# The -mno-outline-atomics flag is only valid for GCC versions 10 and greater. +GCC_MAJOR_VERSION=$(shell $(CC) -dumpversion 2> /dev/null | cut -f1 -d.) +ifeq ($(shell expr "$(GCC_MAJOR_VERSION)" ">=" "10"), 1) +CFLAGS += -mno-outline-atomics +endif + define arch_elf_check = $(if $(shell ! $(OBJDUMP) -R $(1) >&/dev/null && echo "nok"), $(error $(shell $(OBJDUMP) -R $(1) 2>&1)))
GCC 10.1.0 introduced the -m{,no-}outline-atomics flags which, according to man 1 gcc: "Enable or disable calls to out-of-line helpers to implement atomic operations. These helpers will, at runtime, determine if the LSE instructions from ARMv8.1-A can be used; if not, they will use the load/store-exclusive instructions that are present in the base ARMv8.0 ISA. [..] This option is on by default." Unfortunately the option causes the following error at compile time: aarch64-linux-gnu-ld -nostdlib -pie -n -o arm/spinlock-test.elf -T /path/to/kvm-unit-tests/arm/flat.lds \ arm/spinlock-test.o arm/cstart64.o lib/libcflat.a lib/libfdt/libfdt.a /usr/lib/gcc/aarch64-linux-gnu/10.1.0/libgcc.a lib/arm/libeabi.a arm/spinlock-test.aux.o 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 if we detect a GCC version greater than 10. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> --- Tested with gcc versions 10.1.0 and 5.4.0 (cross-compilation), 9.3.0 (native). I've been able to suss out the reason for the build failure from this rejected gcc patch [1]. [1] https://patches.openembedded.org/patch/172460/ arm/Makefile.arm64 | 6 ++++++ 1 file changed, 6 insertions(+)