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 138A0C00144 for ; Fri, 29 Jul 2022 11:10:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235045AbiG2LKm (ORCPT ); Fri, 29 Jul 2022 07:10:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235460AbiG2LKm (ORCPT ); Fri, 29 Jul 2022 07:10:42 -0400 Received: from mail-wr1-x42e.google.com (mail-wr1-x42e.google.com [IPv6:2a00:1450:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60F8C54679 for ; Fri, 29 Jul 2022 04:10:41 -0700 (PDT) Received: by mail-wr1-x42e.google.com with SMTP id m13so1627059wrq.6 for ; Fri, 29 Jul 2022 04:10:41 -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; bh=Giw/1gk04NH25KunnIqIMkXWxed0rc1D0pJw4ex8yC8=; b=PjmTjRTXIhXGjDWixoZB5nIjNwTE+B/OVhQQ2Yc7DYlCDnth2sDTT8d9tu5CFHeWmR 5c07QjC2JBaqmNRk92ZwWOEifhLLsE206elBkuygRBPHPNx6ZPijZorJhzb2JX9UsEuQ bkqTlUQ5dDIRJRpFQlHoH6bBkLRJVHt36MhH8HO3SE1VIH9jBSAYg5S7mOlyVZ2oHQ55 U9XpniPt5d/EYx4Uczh0GGm2+I6CQmaZiHo9VFtUY24UYGytHfzjAjPMNRBOt6aDRl3Q xxfoLrrAqvTZMpZ71e9McWL0epennp3sFOCKOok4e/jqKYpAUwlrGPX++DmAfMVvxUyQ q9cQ== 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; bh=Giw/1gk04NH25KunnIqIMkXWxed0rc1D0pJw4ex8yC8=; b=uSQb0P/FDVXIBHpux0bs617VsbWuAclT/qDmZkb9CkaTJ1Sk9TkHnahwJGqX4rhtif DGAKDccWVMFbL+pZlHowyOTlYSwTNq9zFx72w2n/1rTp0c3T33TwgrsTS/97bjZF8piB g/VvSQY2MNaBJ+uHbEEDMbvu0aTUPDCvmDRP8u38AVNcUJDF5dHXyDJpoOzUDAva4JGx I4xYHtEZFoDpMjKAeFeK/q+AeDnzvBVmov5a0tWo+o0klKdk0sefnee91rtEDyK0RD9h 6WJzLgPb5sWKIdfgY+rppZzMchlQqwPps9+QIgATNR5HwvsmctVELJ9GUFNiv9FD2xoG /5bQ== X-Gm-Message-State: ACgBeo3eDOmbCFjfcqBGxHqnPwyyNPcyXyRtTyCirVuBVochBqMm+zFV D8XhlDjlfau7qHTk8uslcCU= X-Google-Smtp-Source: AA6agR7IWLLZCkn7+93KTNjSBMUq3dHEOz0d4nRC0t+5wlCyRuplsL48n4trREfDlzg7fhJZTayqaQ== X-Received: by 2002:a5d:5244:0:b0:21d:866e:2409 with SMTP id k4-20020a5d5244000000b0021d866e2409mr2019603wrc.400.1659093039621; Fri, 29 Jul 2022 04:10:39 -0700 (PDT) Received: from krava ([193.85.244.190]) by smtp.gmail.com with ESMTPSA id be4-20020a05600c1e8400b0039c454067ddsm4330624wmb.15.2022.07.29.04.10.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Jul 2022 04:10:39 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Fri, 29 Jul 2022 13:10:37 +0200 To: Yonghong Song Cc: bpf@vger.kernel.org, Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com Subject: Re: [RFC PATCH bpf-next 4/7] bpf: x86: Support in-register struct arguments Message-ID: References: <20220726171129.708371-1-yhs@fb.com> <20220726171151.712242-1-yhs@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220726171151.712242-1-yhs@fb.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Tue, Jul 26, 2022 at 10:11:51AM -0700, Yonghong Song wrote: SNIP > > -static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args, > - int regs_off) > +static void __save_struct_arg_regs(u8 **prog, int curr_reg_idx, int nr_regs, > + int struct_val_off, int stack_start_idx) > { > - int i; > + int i, reg_idx; > + > + /* Save struct registers to stack. > + * For example, argument 1 (second argument) size is 16 which occupies two > + * registers, these two register values will be saved in stack. > + * mov QWORD PTR [rbp-0x40],rsi > + * mov QWORD PTR [rbp-0x38],rdx > + */ > + for (i = 0; i < nr_regs; i++) { > + reg_idx = curr_reg_idx + i; > + emit_stx(prog, bytes_to_bpf_size(8), > + BPF_REG_FP, > + reg_idx == 5 ? X86_REG_R9 : BPF_REG_1 + reg_idx, > + -(struct_val_off - stack_start_idx * 8)); > + stack_start_idx++; > + } > +} > + > +static void save_regs(const struct btf_func_model *m, u8 **prog, int nr_args, > + int regs_off, int struct_val_off) > +{ > + int curr_arg_idx, curr_reg_idx, curr_s_stack_off; > + int s_size, s_arg_idx, s_arg_nregs; > + > + curr_arg_idx = curr_reg_idx = curr_s_stack_off = 0; > + for (int i = 0; i < MAX_BPF_FUNC_STRUCT_ARGS; i++) { > + s_size = m->struct_arg_bsize[i]; > + if (!s_size) > + return __save_normal_arg_regs(m, prog, curr_arg_idx, nr_args - curr_arg_idx, > + curr_reg_idx, regs_off); could we just do break in here instead? SNIP > + > +static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args, > + int regs_off, int struct_val_off) > +{ > + int curr_arg_idx, curr_reg_idx, curr_s_stack_off; > + int s_size, s_arg_idx, s_arg_nregs; > + > + curr_arg_idx = curr_reg_idx = curr_s_stack_off = 0; > + for (int i = 0; i < MAX_BPF_FUNC_STRUCT_ARGS; i++) { > + s_size = m->struct_arg_bsize[i]; > + if (!s_size) > + return __restore_normal_arg_regs(m, prog, curr_arg_idx, > + nr_args - curr_arg_idx, > + curr_reg_idx, regs_off); same here jirka > + > + s_arg_idx = m->struct_arg_idx[i]; > + s_arg_nregs = (s_size + 7) / 8; > + > + __restore_normal_arg_regs(m, prog, curr_arg_idx, s_arg_idx - curr_arg_idx, > + curr_reg_idx, regs_off); > + __restore_struct_arg_regs(prog, curr_reg_idx + s_arg_idx - curr_arg_idx, > + s_arg_nregs, struct_val_off, curr_s_stack_off); > + curr_reg_idx += s_arg_idx - curr_arg_idx + s_arg_nregs; > + curr_s_stack_off += s_arg_nregs; > + curr_arg_idx = s_arg_idx + 1; > + } > + > + __restore_normal_arg_regs(m, prog, curr_arg_idx, nr_args - curr_arg_idx, curr_reg_idx, > + regs_off); > } > SNIP