From patchwork Tue Jun 29 19:29:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Olsa X-Patchwork-Id: 12350679 X-Patchwork-Delegate: bpf@iogearbox.net 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=-19.2 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 3B6CAC11F67 for ; Tue, 29 Jun 2021 19:29:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 114D561DE6 for ; Tue, 29 Jun 2021 19:29:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234186AbhF2TcW (ORCPT ); Tue, 29 Jun 2021 15:32:22 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:24460 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234171AbhF2TcV (ORCPT ); Tue, 29 Jun 2021 15:32:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1624994993; 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=jN8Mb9waVl6aEdlN2rQLLeHjomuDBp9x8ciwcANSFVFpozF/uqAb6xfNq7F9MUZn59D6eb y2ZRJUlXJt68i2qwTAH33bGCiI4jv1iapnKYGhosqK8MSAfED3yh1SvW3YbolvTYhqzFm2 tcLB+SQ9KTqQ47ZBo4uMBCjR2WlmvAk= Received: from mail-ed1-f71.google.com (mail-ed1-f71.google.com [209.85.208.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-97-Vxx7jdzFOOOXDqgx8g9TZA-1; Tue, 29 Jun 2021 15:29:51 -0400 X-MC-Unique: Vxx7jdzFOOOXDqgx8g9TZA-1 Received: by mail-ed1-f71.google.com with SMTP id j15-20020a05640211cfb0290394f9de5750so11368172edw.16 for ; Tue, 29 Jun 2021 12:29:51 -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=pKy0F901A8IgaurZYhAdYW699Nhp/DzR9FbNY4F6PU54hUXOg9MJFJQ096LWGrZ8xr nv4AP+IvWJaGuyHZZ1EMgejSOSBc7x+fXaDpNxZCEzhSv0XUTfu8o7jzX3XOcypyfY7w vWp5EjnPMOjYCdNV6ttGg3BXhjwHcoKCqJkNqJ+gtmW21Yvg9+j9Hw/n4wIpa/rKXvpD DmpQtgje6v5B5etWDRFFRRDVOZUdx+0asAjCrbvj31w9l/44hnhom9o+1rlaT36pIhbH M2sDuduciEpP3H8DdDNY++xeztXQkrDwvI57N47fho3xO4s2bbR+7QO/Vq9mvoBxjlk7 qcUA== X-Gm-Message-State: AOAM530t19hitjViRFUxrOy4HrhX+987L+me0X+3Q8R6tbg5iocD0UK9 Wxsogc96JapudIZA4GxkASTGVOZBHc/9SMTZq0iqkO1hP1WWW9nyKIPI6gz6Sh/lxf9lbFJuLhb odKkZPZHXy/Sb X-Received: by 2002:a05:6402:1c11:: with SMTP id ck17mr29205326edb.370.1624994990334; Tue, 29 Jun 2021 12:29:50 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwXHlbTwtU81vylTCzW77E+j+DPUwj3/0W67M0b+va71aRhfz4ja1tt1bjornX+DBMxs/e2RA== X-Received: by 2002:a05:6402:1c11:: with SMTP id ck17mr29205314edb.370.1624994990153; Tue, 29 Jun 2021 12:29:50 -0700 (PDT) Received: from krava.redhat.com ([185.153.78.55]) by smtp.gmail.com with ESMTPSA id n22sm472559eje.3.2021.06.29.12.29.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Jun 2021 12:29:49 -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 , Masami Hiramatsu Subject: [PATCH bpf-next 1/5] bpf, x86: Store caller's ip in trampoline stack Date: Tue, 29 Jun 2021 21:29:41 +0200 Message-Id: <20210629192945.1071862-2-jolsa@kernel.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210629192945.1071862-1-jolsa@kernel.org> References: <20210629192945.1071862-1-jolsa@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net 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 */