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[2620:137:e000::1:20]) by mx.google.com with ESMTP id l6-20020aa7c306000000b0052581143a06si2635578edq.365.2023.08.28.10.05.43; Mon, 28 Aug 2023 10:06:22 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232673AbjH1QAb (ORCPT + 99 others); Mon, 28 Aug 2023 12:00:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232645AbjH1QAF (ORCPT ); Mon, 28 Aug 2023 12:00:05 -0400 Received: from mail-yb1-f181.google.com (mail-yb1-f181.google.com [209.85.219.181]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43A2FCA; Mon, 28 Aug 2023 09:00:03 -0700 (PDT) Received: by mail-yb1-f181.google.com with SMTP id 3f1490d57ef6-d78328bc2abso3069388276.2; Mon, 28 Aug 2023 09:00:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693238402; x=1693843202; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=luyLmajpmSyQ8FebgnWKEdKBcRafu1L+AJoXX7hfZQI=; b=IvOALZMMuIfD0W8khI8mAte4s1jW9Pb09uKT3i6AQp+lLkJYlLfa1RjqJF1jZFqizX yUYHKBjy5/Pi2tf0f16XfvVxZ/meZE7fy0odIwYbB5zDECmaiF/ix5I1jkbFqbLA0OdV FFrAaCRWtQ8RIVxZs6EoNktPJK8TBs72qKRd4LbhwBWu6OH9gOJ9fQ8SoJ7nWmsfrXX7 dhwu5jZ4mWlC2YFh/t6RjgCJ0rwXxRuSkft65GRkicIZcv67ojfKojEfmOTM06lvmwZh 6jcrVRI+ORfIGhbsEJCg+s20O6St9APms7cewAKapWPRH9uq//S0kCozmFYEMIC0Hr2E TzWQ== X-Gm-Message-State: AOJu0YxNLTxZk3AVTgKLBtmTESmOgWWRy4u9ymdmw8bpn/g+i+hag1Lv pCFabqJyS6IR/GjSyAnrOQ5lujczF9GUTg== X-Received: by 2002:a25:a264:0:b0:d78:7e1:a715 with SMTP id b91-20020a25a264000000b00d7807e1a715mr10874158ybi.18.1693238402050; Mon, 28 Aug 2023 09:00:02 -0700 (PDT) Received: from localhost ([24.1.27.177]) by smtp.gmail.com with ESMTPSA id b19-20020a25cb13000000b00d20d4ffbbdbsm1747053ybg.0.2023.08.28.09.00.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Aug 2023 09:00:01 -0700 (PDT) From: David Vernet To: bpf@vger.kernel.org Cc: 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, linux-kernel@vger.kernel.org, kernel-team@meta.com, hch@infradead.org, hawkinsw@obs.cr, dthaler@microsoft.com, bpf@ietf.org Subject: [PATCH bpf-next 2/3] bpf,docs: Add abi.rst document to standardization subdirectory Date: Mon, 28 Aug 2023 10:59:47 -0500 Message-ID: <20230828155948.123405-3-void@manifault.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230828155948.123405-1-void@manifault.com> References: <20230828155948.123405-1-void@manifault.com> MIME-Version: 1.0 X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1775493324030347636 X-GMAIL-MSGID: 1775493324030347636 As specified in the IETF BPF charter, the BPF working group has plans to add one or more informational documents that recommend conventions and guidelines for producing portable BPF program binaries. The instruction-set.rst document currently contains a "Registers and calling convention" subsection which dictates a calling convention that belongs in an ABI document, rather than an instruction set document. Let's move it to a new abi.rst document so we can clean it up. The abi.rst document will of course be significantly changed and expanded upon over time. For now, it's really just a placeholder which will contain ABI-specific language that doesn't belong in other documents. Signed-off-by: David Vernet --- Documentation/bpf/standardization/abi.rst | 25 +++++++++++++++++++ Documentation/bpf/standardization/index.rst | 1 + .../bpf/standardization/instruction-set.rst | 16 ------------ 3 files changed, 26 insertions(+), 16 deletions(-) create mode 100644 Documentation/bpf/standardization/abi.rst diff --git a/Documentation/bpf/standardization/abi.rst b/Documentation/bpf/standardization/abi.rst new file mode 100644 index 000000000000..0c2e10eeb89a --- /dev/null +++ b/Documentation/bpf/standardization/abi.rst @@ -0,0 +1,25 @@ +.. contents:: +.. sectnum:: + +=================================================== +BPF ABI Recommended Conventions and Guidelines v1.0 +=================================================== + +This is version 1.0 of an informational document containing recommended +conventions and guidelines for producing portable BPF program binaries. + +Registers and calling convention +================================ + +BPF has 10 general purpose registers and a read-only frame pointer register, +all of which are 64-bits wide. + +The BPF calling convention is defined as: + +* R0: return value from function calls, and exit value for BPF programs +* R1 - R5: arguments for function calls +* R6 - R9: callee saved registers that function calls will preserve +* R10: read-only frame pointer to access stack + +R0 - R5 are scratch registers and BPF programs needs to spill/fill them if +necessary across calls. diff --git a/Documentation/bpf/standardization/index.rst b/Documentation/bpf/standardization/index.rst index d7b946f71261..a50c3baf6345 100644 --- a/Documentation/bpf/standardization/index.rst +++ b/Documentation/bpf/standardization/index.rst @@ -12,6 +12,7 @@ for the working group charter, documents, and more. :maxdepth: 1 instruction-set + abi .. Links: .. _IETF BPF Working Group: https://datatracker.ietf.org/wg/bpf/about/ diff --git a/Documentation/bpf/standardization/instruction-set.rst b/Documentation/bpf/standardization/instruction-set.rst index 4f73e9dc8d9e..cfe85129a303 100644 --- a/Documentation/bpf/standardization/instruction-set.rst +++ b/Documentation/bpf/standardization/instruction-set.rst @@ -97,22 +97,6 @@ Definitions A: 10000110 B: 11111111 10000110 -Registers and calling convention -================================ - -eBPF has 10 general purpose registers and a read-only frame pointer register, -all of which are 64-bits wide. - -The eBPF calling convention is defined as: - -* R0: return value from function calls, and exit value for eBPF programs -* R1 - R5: arguments for function calls -* R6 - R9: callee saved registers that function calls will preserve -* R10: read-only frame pointer to access stack - -R0 - R5 are scratch registers and eBPF programs needs to spill/fill them if -necessary across calls. - Instruction encoding ====================