From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Brendan Jackman <jackmanb@google.com>
Cc: bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
Yonghong Song <yhs@fb.com>,
Daniel Borkmann <daniel@iogearbox.net>,
KP Singh <kpsingh@chromium.org>,
Florent Revest <revest@chromium.org>,
open list <linux-kernel@vger.kernel.org>,
Jann Horn <jannh@google.com>
Subject: Re: [PATCH bpf-next v3 12/14] bpf: Pull tools/build/feature biz into selftests Makefile
Date: Tue, 8 Dec 2020 10:31:35 -0800 [thread overview]
Message-ID: <CAEf4BzYhCmahyXbG3mXgfGuSD8T3gvkXXYToTwAuG17MDZwwKQ@mail.gmail.com> (raw)
In-Reply-To: <X8+yHRxv2g7dXeNP@google.com>
On Tue, Dec 8, 2020 at 9:04 AM Brendan Jackman <jackmanb@google.com> wrote:
>
> On Mon, Dec 07, 2020 at 06:19:12PM -0800, Andrii Nakryiko wrote:
> > On Mon, Dec 7, 2020 at 3:00 AM Brendan Jackman <jackmanb@google.com> wrote:
> > >
> > > On Fri, Dec 04, 2020 at 11:00:24AM -0800, Andrii Nakryiko wrote:
> > > > On Fri, Dec 4, 2020 at 1:41 AM Brendan Jackman <jackmanb@google.com> wrote:
> > > > >
> > > > > On Thu, Dec 03, 2020 at 01:01:27PM -0800, Andrii Nakryiko wrote:
> > > > > > On Thu, Dec 3, 2020 at 8:07 AM Brendan Jackman <jackmanb@google.com> wrote:
> > > > > > >
> [...]
> > >
> > > Ah right gotcha. Then yeah I think we can do this:
> > >
> > > BPF_ATOMICS_SUPPORTED = $(shell \
> > > echo "int x = 0; int foo(void) { return __sync_val_compare_and_swap(&x, 1, 2); }" \
> > > | $(CLANG) -x cpp-output -S -target bpf -mcpu=v3 - -o /dev/null && echo 1 || echo 0)
> >
> > Looks like it would work, yes.
> /
> > Curious what "-x cpp-output" does?
>
> That's just to tell Clang what language to expect, since it can't infer
> it from a file extension:
>
> $ echo foo | clang -S -
> clang-10: error: -E or -x required when input is from standard input
>
> Yonghong pointed out that we can actually just use `-x c`.
yeah, that's what confused me, as we don't really write C++ for BPF
code :) All good.
next prev parent reply other threads:[~2020-12-08 18:32 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 16:02 [PATCH bpf-next v3 00/14] Atomics for eBPF Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 01/14] bpf: x86: Factor out emission of ModR/M for *(reg + off) Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 02/14] bpf: x86: Factor out emission of REX byte Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 03/14] bpf: x86: Factor out function to emit NEG Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 04/14] bpf: x86: Factor out a lookup table for some ALU opcodes Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 05/14] bpf: Rename BPF_XADD and prepare to encode other atomics in .imm Brendan Jackman
2020-12-04 4:49 ` Yonghong Song
2020-12-03 16:02 ` [PATCH bpf-next v3 06/14] bpf: Move BPF_STX reserved field check into BPF_STX verifier code Brendan Jackman
2020-12-04 4:51 ` Yonghong Song
2020-12-03 16:02 ` [PATCH bpf-next v3 07/14] bpf: Add BPF_FETCH field / create atomic_fetch_add instruction Brendan Jackman
2020-12-04 5:02 ` Yonghong Song
2020-12-04 5:27 ` Yonghong Song
2020-12-04 9:12 ` Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 08/14] bpf: Add instructions for atomic_[cmp]xchg Brendan Jackman
2020-12-04 5:34 ` Yonghong Song
2020-12-04 9:26 ` Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 09/14] bpf: Pull out a macro for interpreting atomic ALU operations Brendan Jackman
2020-12-04 6:30 ` Yonghong Song
2020-12-04 9:29 ` Brendan Jackman
2020-12-04 15:20 ` Yonghong Song
2020-12-03 16:02 ` [PATCH bpf-next v3 10/14] bpf: Add bitwise atomic instructions Brendan Jackman
2020-12-04 6:42 ` Yonghong Song
2020-12-04 9:36 ` Brendan Jackman
2020-12-04 15:21 ` Yonghong Song
2020-12-07 11:28 ` Brendan Jackman
2020-12-07 15:58 ` Yonghong Song
2020-12-07 16:14 ` Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 11/14] tools build: Implement feature check for BPF atomics in Clang Brendan Jackman
2020-12-03 21:02 ` Andrii Nakryiko
2020-12-03 16:02 ` [PATCH bpf-next v3 12/14] bpf: Pull tools/build/feature biz into selftests Makefile Brendan Jackman
2020-12-03 21:01 ` Andrii Nakryiko
2020-12-04 9:41 ` Brendan Jackman
2020-12-04 19:00 ` Andrii Nakryiko
2020-12-07 11:00 ` Brendan Jackman
2020-12-08 2:19 ` Andrii Nakryiko
2020-12-08 17:04 ` Brendan Jackman
2020-12-08 18:31 ` Andrii Nakryiko [this message]
2020-12-03 16:02 ` [PATCH bpf-next v3 13/14] bpf: Add tests for new BPF atomic operations Brendan Jackman
2020-12-04 7:06 ` Yonghong Song
2020-12-04 9:45 ` Brendan Jackman
2020-12-04 15:28 ` Yonghong Song
2020-12-04 19:49 ` Andrii Nakryiko
2020-12-07 15:48 ` Brendan Jackman
2020-12-03 16:02 ` [PATCH bpf-next v3 14/14] bpf: Document new atomic instructions Brendan Jackman
2020-12-03 16:10 ` [PATCH bpf-next v3 00/14] Atomics for eBPF Brendan Jackman
2020-12-04 4:46 ` Yonghong Song
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