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From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Wed, 1 Mar 2023 11:07:05 -0800
Message-ID: <CAEf4BzbZogSTyvF4bPB8w_1KNrBOLOPKBWbo9na3_9JZSJnuAg@mail.gmail.com>
Subject: Re: [PATCH bpf-next v3] selftests/bpf: Set __BITS_PER_LONG if target
 is bpf for LoongArch
To:     Tiezhu Yang <yangtiezhu@loongson.cn>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>, bpf@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Feb 28, 2023 at 4:03=E2=80=AFAM Tiezhu Yang <yangtiezhu@loongson.cn=
> wrote:
>
> If target is bpf, there is no __loongarch__ definition, __BITS_PER_LONG
> defaults to 32, __NR_nanosleep is not defined:
>
>   #if defined(__ARCH_WANT_TIME32_SYSCALLS) || __BITS_PER_LONG !=3D 32
>   #define __NR_nanosleep 101
>   __SC_3264(__NR_nanosleep, sys_nanosleep_time32, sys_nanosleep)
>   #endif
>
> Work around this problem, by explicitly setting __BITS_PER_LONG to
> __loongarch_grlen which is defined by compiler as 64 for LA64, then
> __NR_nanosleep can also be defined to fix the following build errors:
>
>   clang  -g -Werror ... -target bpf -c progs/test_vmlinux.c ...
>   progs/test_vmlinux.c:24:18: error: use of undeclared identifier '__NR_n=
anosleep'
>           if (args->id !=3D __NR_nanosleep)
>                           ^
>   progs/test_vmlinux.c:42:12: error: use of undeclared identifier '__NR_n=
anosleep'
>           if (id !=3D __NR_nanosleep)
>                     ^
>   progs/test_vmlinux.c:60:12: error: use of undeclared identifier '__NR_n=
anosleep'
>           if (id !=3D __NR_nanosleep)
>                     ^
>   3 errors generated.

Not clear what __NR_nanosleep part has to do with this commit. I
dropped this part from the commit message. Applied to bpf-next.

>
> This is similar with commit 36e70b9b06bf ("selftests, bpf: Fix broken
> riscv build").
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
> ---
>  tools/testing/selftests/bpf/Makefile | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftes=
ts/bpf/Makefile
> index b677dcd..f40606a 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
> @@ -338,7 +338,8 @@ $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)=
/resolve_btfids        \
>  define get_sys_includes
>  $(shell $(1) $(2) -v -E - </dev/null 2>&1 \
>         | sed -n '/<...> search starts here:/,/End of search list./{ s| \=
(/.*\)|-idirafter \1|p }') \
> -$(shell $(1) $(2) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{pri=
ntf("-D__riscv_xlen=3D%d -D__BITS_PER_LONG=3D%d", $$3, $$3)}')
> +$(shell $(1) $(2) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{pri=
ntf("-D__riscv_xlen=3D%d -D__BITS_PER_LONG=3D%d", $$3, $$3)}') \
> +$(shell $(1) $(2) -dM -E - </dev/null | grep '__loongarch_grlen ' | awk =
'{printf("-D__BITS_PER_LONG=3D%d", $$3)}')
>  endef
>
>  # Determine target endianness.
> --
> 2.1.0
>