From patchwork Wed Jul 7 19:46:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 471134 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EF9DC07E9B for ; Wed, 7 Jul 2021 19:46:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 05CFA61CC2 for ; Wed, 7 Jul 2021 19:46:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232930AbhGGTtN (ORCPT ); Wed, 7 Jul 2021 15:49:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:39268 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232660AbhGGTtN (ORCPT ); Wed, 7 Jul 2021 15:49:13 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625687192; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QgBr4LV9SR6/Qelufj3zindVEajUhYS2+l3zjx7rHSU=; b=LnVMXQFH5pgY3ojaN0hM8HLv970Zpb82XHV+zT1gXHIwUuO8Om/4c/NiWUKOlBAIQ6MLmf iVUh+YdUKT6dQeQjT+pIZJzqBvafPFR0JnAaqUtcQo1iI0J5D25R5u1nNnOk7DWQ8Y0+Gv mMwfn45MpGDr3HJ7Y1Qc/OD8v9MLjVE= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-228-SArVoU4cOF68W-dbU_wvBg-1; Wed, 07 Jul 2021 15:46:31 -0400 X-MC-Unique: SArVoU4cOF68W-dbU_wvBg-1 Received: by mail-wm1-f71.google.com with SMTP id p4-20020a05600c3584b0290210725ac6bcso2555458wmq.2 for ; Wed, 07 Jul 2021 12:46:31 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=QgBr4LV9SR6/Qelufj3zindVEajUhYS2+l3zjx7rHSU=; b=g9WpF5HdG3Jd4+7xSNNtW4J5X1bQT69iUwqvG7IrCSsUe9tugMyz0vRwbwH/DSRtjM YxxZMJq+d5+OaRnckuKkNPtsOQpPyqJTxIZLF7rV1Olh20yCRMveALDrX2I7m/z99PxV OwAGCJmXxfOWLxckbNfYJ9o/6BzA85Rbhmyba1kBVZwkV34ol/zBFs75xqRsMRJN0Z4J OgYALfmWgZhHT5jF59dAMRjE3TwJlNlWPsUKfWNRe3qL16f3F2CoOpI29ntPLlFs85vw PEIQYBcHxn3tbdVzc1LlrFlrLv8ZZnBOZ8UYP/+fuRoXt8KTXCed7OyHjRRweBdG5hGX Iz8w== X-Gm-Message-State: AOAM531qFV1nM7OA6V8wZ93MfqC9RrlNm6i+t0Cx543Mkpm/Tcj0VAay G4u6eUA/yfWxpmdKXRbdqZ0L/cZWa+NrYIlA0viMcLA7Q2g6pAPlLOkofEsGV8glpTuwCHnvzRc qA7lqEjNEa0myKeab X-Received: by 2002:adf:9084:: with SMTP id i4mr30099347wri.23.1625687190057; Wed, 07 Jul 2021 12:46:30 -0700 (PDT) X-Google-Smtp-Source: ABdhPJxLO79EMn3rV783LaMxncMKtw60ZojKfQRrfALZnttyQBWpER13DmAyWOA56j8/XujiSgM20A== X-Received: by 2002:adf:9084:: with SMTP id i4mr30099335wri.23.1625687189932; Wed, 07 Jul 2021 12:46:29 -0700 (PDT) Received: from krava.redhat.com ([185.153.78.55]) by smtp.gmail.com with ESMTPSA id b7sm17543795wri.96.2021.07.07.12.46.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Jul 2021 12:46:29 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Alan Maguire Subject: [PATCH 1/7] bpf, x86: Store caller's ip in trampoline stack Date: Wed, 7 Jul 2021 21:46:13 +0200 Message-Id: <20210707194619.151676-2-jolsa@kernel.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210707194619.151676-1-jolsa@kernel.org> References: <20210707194619.151676-1-jolsa@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Storing caller's ip in trampoline's stack. Trampoline programs can reach the IP in (ctx - 8) address, so there's no change in program's arguments interface. The IP address is takes from [fp + 8], which is return address from the initial 'call fentry' call to trampoline. This IP address will be returned via bpf_get_func_ip helper helper, which is added in following patches. Signed-off-by: Jiri Olsa --- arch/x86/net/bpf_jit_comp.c | 19 +++++++++++++++++++ include/linux/bpf.h | 5 +++++ 2 files changed, 24 insertions(+) diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index e835164189f1..c320b3ce7b58 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1951,6 +1951,9 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i if (flags & BPF_TRAMP_F_CALL_ORIG) stack_size += 8; /* room for return value of orig_call */ + if (flags & BPF_TRAMP_F_IP_ARG) + stack_size += 8; /* room for IP address argument */ + if (flags & BPF_TRAMP_F_SKIP_FRAME) /* skip patched call instruction and point orig_call to actual * body of the kernel function. @@ -1964,6 +1967,22 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i EMIT4(0x48, 0x83, 0xEC, stack_size); /* sub rsp, stack_size */ EMIT1(0x53); /* push rbx */ + if (flags & BPF_TRAMP_F_IP_ARG) { + /* Store IP address of the traced function: + * mov rax, QWORD PTR [rbp + 8] + * sub rax, X86_PATCH_SIZE + * mov QWORD PTR [rbp - stack_size], rax + */ + emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, 8); + EMIT4(0x48, 0x83, 0xe8, X86_PATCH_SIZE); + emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -stack_size); + + /* Continue with stack_size for regs storage, stack will + * be correctly restored with 'leave' instruction. + */ + stack_size -= 8; + } + save_regs(m, &prog, nr_args, stack_size); if (flags & BPF_TRAMP_F_CALL_ORIG) { diff --git a/include/linux/bpf.h b/include/linux/bpf.h index f309fc1509f2..6b3da9bc3d16 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -554,6 +554,11 @@ struct btf_func_model { */ #define BPF_TRAMP_F_SKIP_FRAME BIT(2) +/* Store IP address of the caller on the trampoline stack, + * so it's available for trampoline's programs. + */ +#define BPF_TRAMP_F_IP_ARG BIT(3) + /* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50 * bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2 */