From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 13608ECAAD3 for ; Fri, 9 Sep 2022 11:41:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229494AbiIILlM (ORCPT ); Fri, 9 Sep 2022 07:41:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231251AbiIILk4 (ORCPT ); Fri, 9 Sep 2022 07:40:56 -0400 Received: from mail-wr1-x436.google.com (mail-wr1-x436.google.com [IPv6:2a00:1450:4864:20::436]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B3DE1AF22 for ; Fri, 9 Sep 2022 04:40:53 -0700 (PDT) Received: by mail-wr1-x436.google.com with SMTP id bj14so2232182wrb.12 for ; Fri, 09 Sep 2022 04:40:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date; bh=RQdyheQEdBwlN5AUWD/28exptj6FeXRUMRGwNcf0Gu8=; b=NlaafQm9MBfBztbM7RNeZ/X2mpfcfsiZxj58YjxfzfknlWNr/XVnh32PBBBkj49SO2 ABelvnBU/O7wmcUE/+iF+xrbSkMr/HMJyFcNL4U+vQLYCZhCxCvUCelowYkh67UIfWwH G4J70LLuXhMLtNZwa6kV8Jt/tvBzLExVQYVXii48ELqwaIc1ozxwbHN2pDX5TIeu9ywr KaK8TeYliCL8+Uvpbv39Obr4KsYRhO51/d/e9UjXpw9lkU2fGJzH0XYryoklx3bl5u4y CevvUpUlxtjpADEZyUrMBe6hihtAktuIRNTfPQMz7CisvK4AoRRhGDP7dgk08iYV70lO lv/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date; bh=RQdyheQEdBwlN5AUWD/28exptj6FeXRUMRGwNcf0Gu8=; b=n11dbNeNTElzjWwdKyUT7KlOQvrK85zsf0yQNKKAJobNPSGIbbmglgtOgAtNkpTzcs WZiuOxYNvJ7/D5Ux5USmEXe2/bh+7ClQwJQ7Vsqb8eZ/GVF1vJgXKytJ+xBRbHW0SAI8 8RJfmBbL/kiaDjoPVnqDNAxyBFSyzG2AdvHOwZ0NWXxZ9u6NTk7EM9mOy5ZsBhD82OKX NUX1WJjLvrZAm5oi4C5BcGi4TraCh1670RaEhlrmX17UdZs+PTpooqUEzIuFvb4CLXgW 5N6T5wq+Ua5tcsDaZVf70vsWFJY3v3CpDq9Di32CD9FoJpHeLQQwdTJxfNwELvFOAtg/ LQDg== X-Gm-Message-State: ACgBeo0Ms2YCDGcCNq4KQKFntr9pfFSBQKTrrxBfgWDxg3Hsch294kGx WXGsNvwgCYVGqHqvIxIr1Hd2sgIBA3pD1g== X-Google-Smtp-Source: AA6agR5n2aBP/3nayTabsL1HTxLoRhn9LTfOISgPrGj85Doz/FXXfu7iJ6euwk2/1pcZ6ADYOyzJZw== X-Received: by 2002:a05:6000:2c1:b0:226:e7d0:f098 with SMTP id o1-20020a05600002c100b00226e7d0f098mr7913195wry.578.1662723651676; Fri, 09 Sep 2022 04:40:51 -0700 (PDT) Received: from krava ([193.85.244.190]) by smtp.gmail.com with ESMTPSA id h14-20020a05600c414e00b003b3180551c8sm345301wmm.40.2022.09.09.04.40.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Sep 2022 04:40:51 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Fri, 9 Sep 2022 13:40:49 +0200 To: Peter Zijlstra Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , "Masami Hiramatsu (Google)" , Martynas Pumputis Subject: Re: [PATCHv3 bpf-next 3/6] bpf: Use given function address for trampoline ip arg Message-ID: References: <20220909101245.347173-1-jolsa@kernel.org> <20220909101245.347173-4-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Fri, Sep 09, 2022 at 01:30:52PM +0200, Peter Zijlstra wrote: > On Fri, Sep 09, 2022 at 12:12:42PM +0200, Jiri Olsa wrote: > > Using function address given at the generation time as the trampoline > > ip argument. This way we get directly the function address that we > > need, so we don't need to: > > - read the ip from the stack > > - subtract X86_PATCH_SIZE > > - subtract ENDBR_INSN_SIZE if CONFIG_X86_KERNEL_IBT is enabled > > which is not even implemented yet ;-) > > > > Signed-off-by: Jiri Olsa > > --- > > arch/x86/net/bpf_jit_comp.c | 9 ++++----- > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c > > index ae89f4143eb4..1047686cc545 100644 > > --- a/arch/x86/net/bpf_jit_comp.c > > +++ b/arch/x86/net/bpf_jit_comp.c > > @@ -2039,13 +2039,14 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog, > > int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *image_end, > > const struct btf_func_model *m, u32 flags, > > struct bpf_tramp_links *tlinks, > > - void *orig_call) > > + void *func_addr) > > { > > int ret, i, nr_args = m->nr_args, extra_nregs = 0; > > int regs_off, ip_off, args_off, stack_size = nr_args * 8, run_ctx_off; > > struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; > > struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; > > struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; > > + void *orig_call = func_addr; > > u8 **branches = NULL; > > u8 *prog; > > bool save_ret; > > @@ -2126,12 +2127,10 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i > > > > 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 rax, func_addr > > Shouldn't that be: movabs? Regular mov can't do 64bit immediates. right, will change jirka > > Also curse Intel syntax, this is bloody unreadable. > > > * mov QWORD PTR [rbp - ip_off], rax > > */ > > - emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, 8); > > - EMIT4(0x48, 0x83, 0xe8, X86_PATCH_SIZE); > > + emit_mov_imm64(&prog, BPF_REG_0, (long) func_addr >> 32, (u32) (long) func_addr); > > emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -ip_off); > > } > > > > -- > > 2.37.3 > >