From: "Björn Töpel" <bjorn@kernel.org>
To: Pu Lehui <pulehui@huaweicloud.com>,
bpf@vger.kernel.org, linux-riscv@lists.infradead.org,
netdev@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@kernel.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Jiri Olsa <jolsa@kernel.org>, Palmer Dabbelt <palmer@dabbelt.com>,
Conor Dooley <conor@kernel.org>,
Luke Nelson <luke.r.nels@gmail.com>,
Pu Lehui <pulehui@huawei.com>, Pu Lehui <pulehui@huaweicloud.com>
Subject: Re: [PATCH bpf-next 0/4] Mixing bpf2bpf and tailcalls for RV64
Date: Tue, 26 Sep 2023 15:30:14 +0200 [thread overview]
Message-ID: <877codoye1.fsf@all.your.base.are.belong.to.us> (raw)
In-Reply-To: <20230919035711.3297256-1-pulehui@huaweicloud.com>
Pu Lehui <pulehui@huaweicloud.com> writes:
> In the current RV64 JIT, if we just don't initialize the TCC in subprog,
> the TCC can be propagated from the parent process to the subprocess, but
> the TCC of the parent process cannot be restored when the subprocess
> exits. Since the RV64 TCC is initialized before saving the callee saved
> registers into the stack, we cannot use the callee saved register to
> pass the TCC, otherwise the original value of the callee saved register
> will be destroyed. So we implemented mixing bpf2bpf and tailcalls
> similar to x86_64, i.e. using a non-callee saved register to transfer
> the TCC between functions, and saving that register to the stack to
> protect the TCC value. At the same time, we also consider the scenario
> of mixing trampoline.
>
> In addition, some code cleans are also attached to this patchset.
>
> Tests test_bpf.ko and test_verifier have passed, as well as the relative
> testcases of test_progs*.
Apologies for the review delay. I'm travelling, and will pick it up ASAP
when I'm back.
Björn
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prev parent reply other threads:[~2023-09-26 13:30 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-19 3:57 [PATCH bpf-next 0/4] Mixing bpf2bpf and tailcalls for RV64 Pu Lehui
2023-09-19 3:57 ` [PATCH bpf-next 1/4] riscv, bpf: Remove redundant ctx->offset initialization Pu Lehui
2023-09-19 3:57 ` [PATCH bpf-next 2/4] riscv, bpf: Using kvcalloc to allocate cache buffer Pu Lehui
2023-09-19 3:57 ` [PATCH bpf-next 3/4] riscv, bpf: Add RV_TAILCALL_OFFSET macro to format tailcall offset Pu Lehui
2023-09-19 3:57 ` [PATCH bpf-next 4/4] riscv, bpf: Mixing bpf2bpf and tailcalls Pu Lehui
2023-09-19 10:04 ` Conor Dooley
2023-09-19 10:54 ` Conor Dooley
2023-09-19 11:23 ` Pu Lehui
2023-09-19 11:50 ` Conor Dooley
2023-09-19 12:01 ` Pu Lehui
2023-09-28 9:59 ` Björn Töpel
2023-09-28 10:39 ` Pu Lehui
2024-01-16 14:21 ` Pu Lehui
2024-01-30 8:29 ` Björn Töpel
2024-01-30 9:14 ` Pu Lehui
2024-01-30 13:28 ` Björn Töpel
2024-01-30 14:10 ` Pu Lehui
2024-01-30 16:03 ` Björn Töpel
2024-01-31 9:18 ` Pu Lehui
2024-01-30 3:26 ` Pu Lehui
2023-09-26 13:30 ` Björn Töpel [this message]
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