[v3,bpf-next,05/14] samples: bpf: makefile: use __LINUX_ARM_ARCH__ selector for arm
diff mbox series

Message ID 20190916105433.11404-6-ivan.khoronzhuk@linaro.org
State Superseded
Headers show
Series
  • samples: bpf: improve/fix cross-compilation
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Commit Message

Ivan Khoronzhuk Sept. 16, 2019, 10:54 a.m. UTC
For arm, -D__LINUX_ARM_ARCH__=X is min version used as instruction
set selector and is absolutely required while parsing some parts of
headers. It's present in KBUILD_CFLAGS but not in autoconf.h, so let's
retrieve it from and add to programs cflags. In another case errors
like "SMP is not supported" for armv7 and bunch of other errors are
issued resulting to incorrect final object.
---
 samples/bpf/Makefile | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

Andrii Nakryiko Sept. 16, 2019, 8:44 p.m. UTC | #1
On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
<ivan.khoronzhuk@linaro.org> wrote:
>
> For arm, -D__LINUX_ARM_ARCH__=X is min version used as instruction
> set selector and is absolutely required while parsing some parts of
> headers. It's present in KBUILD_CFLAGS but not in autoconf.h, so let's
> retrieve it from and add to programs cflags. In another case errors
> like "SMP is not supported" for armv7 and bunch of other errors are
> issued resulting to incorrect final object.
> ---
>  samples/bpf/Makefile | 10 ++++++++++
>  1 file changed, 10 insertions(+)
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 8ecc5d0c2d5b..d3c8db3df560 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -185,6 +185,16 @@ HOSTLDLIBS_map_perf_test   += -lrt
>  HOSTLDLIBS_test_overhead       += -lrt
>  HOSTLDLIBS_xdpsock             += -pthread
>
> +ifeq ($(ARCH), arm)
> +# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
> +# headers when arm instruction set identification is requested.
> +ARM_ARCH_SELECTOR = $(shell echo "$(KBUILD_CFLAGS) " | \
> +                   sed 's/[[:blank:]]/\n/g' | sed '/^-D__LINUX_ARM_ARCH__/!d')

Does the following work exactly like that without shelling out (and
being arguably simpler)?

ARM_ARCH_SELECTOR = $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS))

> +
> +CLANG_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
> +KBUILD_HOSTCFLAGS := $(ARM_ARCH_SELECTOR)

Isn't this clearing out previous value of KBUILD_HOSTCFLAGS? Is that
intentional, or it was supposed to be += here?

> +endif
> +
>  # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
>  #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
>  LLC ?= llc
> --
> 2.17.1
>
Ivan Khoronzhuk Sept. 16, 2019, 10:04 p.m. UTC | #2
On Mon, Sep 16, 2019 at 01:44:23PM -0700, Andrii Nakryiko wrote:
>On Mon, Sep 16, 2019 at 3:59 AM Ivan Khoronzhuk
><ivan.khoronzhuk@linaro.org> wrote:
>>
>> For arm, -D__LINUX_ARM_ARCH__=X is min version used as instruction
>> set selector and is absolutely required while parsing some parts of
>> headers. It's present in KBUILD_CFLAGS but not in autoconf.h, so let's
>> retrieve it from and add to programs cflags. In another case errors
>> like "SMP is not supported" for armv7 and bunch of other errors are
>> issued resulting to incorrect final object.
>> ---
>>  samples/bpf/Makefile | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 8ecc5d0c2d5b..d3c8db3df560 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -185,6 +185,16 @@ HOSTLDLIBS_map_perf_test   += -lrt
>>  HOSTLDLIBS_test_overhead       += -lrt
>>  HOSTLDLIBS_xdpsock             += -pthread
>>
>> +ifeq ($(ARCH), arm)
>> +# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
>> +# headers when arm instruction set identification is requested.
>> +ARM_ARCH_SELECTOR = $(shell echo "$(KBUILD_CFLAGS) " | \
>> +                   sed 's/[[:blank:]]/\n/g' | sed '/^-D__LINUX_ARM_ARCH__/!d')
>
>Does the following work exactly like that without shelling out (and
>being arguably simpler)?
>
>ARM_ARCH_SELECTOR = $(filter -D__LINUX_ARM_ARCH__%, $(KBUILD_CFLAGS))
>
>> +
>> +CLANG_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
>> +KBUILD_HOSTCFLAGS := $(ARM_ARCH_SELECTOR)
>
>Isn't this clearing out previous value of KBUILD_HOSTCFLAGS? Is that
>intentional, or it was supposed to be += here?
>
>> +endif
>> +
>>  # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
>>  #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
>>  LLC ?= llc
>> --
>> 2.17.1
>>

Just left from previous version filtering all -D options.
Will update in next v., SELECTOR also.

Patch
diff mbox series

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 8ecc5d0c2d5b..d3c8db3df560 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -185,6 +185,16 @@  HOSTLDLIBS_map_perf_test	+= -lrt
 HOSTLDLIBS_test_overhead	+= -lrt
 HOSTLDLIBS_xdpsock		+= -pthread
 
+ifeq ($(ARCH), arm)
+# Strip all except -D__LINUX_ARM_ARCH__ option needed to handle linux
+# headers when arm instruction set identification is requested.
+ARM_ARCH_SELECTOR = $(shell echo "$(KBUILD_CFLAGS) " | \
+		    sed 's/[[:blank:]]/\n/g' | sed '/^-D__LINUX_ARM_ARCH__/!d')
+
+CLANG_EXTRA_CFLAGS := $(ARM_ARCH_SELECTOR)
+KBUILD_HOSTCFLAGS := $(ARM_ARCH_SELECTOR)
+endif
+
 # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
 #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
 LLC ?= llc