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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1701474891; x=1702079691; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Pol7hI1Hy96E33miCesPUidUjW/JKgnpIaa4LePlFSs=; b=irbo1KS+OaMe3W6Vi27oankzerNHu6EeWcpfcNe+TxiSTM0XQDIJY91XGMV4EAYPAM XYnOZXi4E3d0LcN6ApVbtcxSVWkPzsWcRHQSdTc9tTHwbeV0Ncy79akOkPe17b6BLhUX YuGjcVGChujGYrmNkIJNlw0HNbpOggU/+DYNRtFQVPQ2TbSRo75/oeGizuWsN6/kCqS7 hCWn6roXowDOdFeY3LAsGCTwqBBwEIMg78rNx5A0ID/4yaBvA0/YpkOuXxpV12KQDuQC xz2QymBLP63N3t9Jjo/iHqQrkrWJ8BIt8IioZk2X0BsOEIk9sMwiXRNNcvzfeH6UuAMn pU5w== X-Gm-Message-State: AOJu0YywA3ZkKFS2rncJaBBKNvWGXllSU+jeQ1sethuh1qMc0Kcju5NT ejqaIDQwC6xyEFKtGez30VBeuIsSmTQ7fIQmvzkc8Q== X-Received: by 2002:a05:6122:319f:b0:4b2:c555:383 with SMTP id ch31-20020a056122319f00b004b2c5550383mr302268vkb.25.1701474891180; Fri, 01 Dec 2023 15:54:51 -0800 (PST) MIME-Version: 1.0 References: <20231120144642.591358648@infradead.org> <20231120154948.708762225@infradead.org> <20231122021817.ggym3biyfeksiplo@macbook-pro-49.dhcp.thefacebook.com> <20231122111517.GR8262@noisy.programming.kicks-ass.net> In-Reply-To: <20231122111517.GR8262@noisy.programming.kicks-ass.net> From: Sami Tolvanen Date: Fri, 1 Dec 2023 15:54:13 -0800 Message-ID: Subject: Re: [PATCH 2/2] x86/cfi,bpf: Fix BPF JIT call To: Peter Zijlstra Cc: Alexei Starovoitov , paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, davem@davemloft.net, dsahern@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, Arnd Bergmann , keescook@chromium.org, nathan@kernel.org, ndesaulniers@google.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, linux-arch@vger.kernel.org, llvm@lists.linux.dev, jpoimboe@kernel.org, joao@overdrivepizza.com, mark.rutland@arm.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-8.4 required=5.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Fri, 01 Dec 2023 15:55:17 -0800 (PST) On Wed, Nov 22, 2023 at 3:15=E2=80=AFAM Peter Zijlstra wrote: > > So the kCFI thing is 'new' but readily inspected by objdump or godbolt: > > https://godbolt.org/z/sGe18z3ca > > (@Sami, that .Ltmp15 thing, I don't see that in the kernel, what > compiler flag makes that go away?) Hmm, that looks like that's what we emit to .kcfi_traps. I suppose Godbolt just doesn't show the section directives? https://github.com/llvm/llvm-project/blob/main/llvm/test/CodeGen/X86/kcfi.l= l#L30 Sami