Received: by 2002:a25:6193:0:0:0:0:0 with SMTP id v141csp775094ybb; Sat, 28 Mar 2020 09:46:18 -0700 (PDT) X-Google-Smtp-Source: ADFU+vvvaRtgIOa04jofOwHkQuuMK6m9njx6QhgQKmDD8TylJS8y+7m14hYnPVu6Am799ECz9ded X-Received: by 2002:a54:478a:: with SMTP id o10mr2863711oic.45.1585413977904; Sat, 28 Mar 2020 09:46:17 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1585413977; cv=none; d=google.com; s=arc-20160816; b=cc26r0MW27I16SwiRv0FqTb1hms1r9PxTLK47p/yuGQRCyU3DoLdgy2W6RouQqN8Gj njJUsyz5kCGAXkAjTxAyO6HQZA94w1mYRZe8UBjvlcOlffKV0bgx5AeWvNnkZ5OSsaEd QU6d41f1iC2/OZhe9L5F0ZKrfaUxmgaBG2X95dFMmj9Qudt3pirMspudfjGCa3XjvTAx iMKGyt9SuMHkA24A0w5r6AE7ZtXHztiMcUvBDf8YIjUtXUu5xLPo8dWujCoCUmF0/ChH bYWSbVfaZ3BF0WHmuZ2lTmzp+VB49m1zib+pMChx/gJ1VxIJpIaTtfse2MRwTvQvz36O fZcA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:date:from:message-id; bh=eAPDL2ox8quDpFi1Ah37ovr4Llb58W24kaGarJ0B5gc=; b=jnsY54IJTJQWyW5htN31g9L1MU2E9/FQrpfJqDGgawsWuIy/XsKx8DPj85UAW7mr9s 7Jch89WhTON1dPkPqNqu6UubAoE8ccby6vyZl9An4GiAmgdTWdIYM4xqLN0tIe5Nfvwm QwTuUTfzctIxgwPt5LtW8MRgpTE4g9Aci/SK0eidJyEn/EObNSfrQ6pOi9kGQ/T4UVkY NrwpVfKjLy1hYN5+HehmqaJzyzf4ioVH1SIi27xKxEN+cfmqAThsRzsN8ghIV9LrsFLi zWqSjcn2EnH/EnejIzQxSQzEX1Hgfph26WT8DAF83UNT0EHUU0DwcFJYfyDGF8WbRQDB ZIAA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id g1si4198636otp.268.2020.03.28.09.46.05; Sat, 28 Mar 2020 09:46:17 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727772AbgC1QpI (ORCPT + 99 others); Sat, 28 Mar 2020 12:45:08 -0400 Received: from mx.sdf.org ([205.166.94.20]:49937 "EHLO mx.sdf.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727829AbgC1Qno (ORCPT ); Sat, 28 Mar 2020 12:43:44 -0400 Received: from sdf.org (IDENT:lkml@sdf.lonestar.org [205.166.94.16]) by mx.sdf.org (8.15.2/8.14.5) with ESMTPS id 02SGhPra027632 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits) verified NO); Sat, 28 Mar 2020 16:43:25 GMT Received: (from lkml@localhost) by sdf.org (8.15.2/8.12.8/Submit) id 02SGhPH7029961; Sat, 28 Mar 2020 16:43:25 GMT Message-Id: <202003281643.02SGhPH7029961@sdf.org> From: George Spelvin Date: Fri, 29 Nov 2019 17:16:39 -0500 Subject: [RFC PATCH v1 47/50] kernel/bpf/core.c: Use get_random_max32() To: linux-kernel@vger.kernel.org, lkml@sdf.org Cc: Daniel Borkmann , Alexei Starovoitov , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , bpf@vger.kernel.org, netdev@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Smaller, faster, and a smidge more uniform than %. Signed-off-by: George Spelvin Cc: Daniel Borkmann Cc: Alexei Starovoitov Cc: Martin KaFai Lau Cc: Song Liu Cc: Yonghong Song Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: netdev@vger.kernel.org --- kernel/bpf/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index af6b738cf435c..61713a7f73d85 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -874,7 +874,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, hdr->pages = pages; hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), PAGE_SIZE - sizeof(*hdr)); - start = (get_random_int() % hole) & ~(alignment - 1); + start = get_random_max32(hole) & ~(alignment - 1); /* Leave a random number of instructions before BPF code. */ *image_ptr = &hdr->image[start]; @@ -947,7 +947,7 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, bool emit_zext) { struct bpf_insn *to = to_buff; - u32 imm_rnd = get_random_int(); + u32 imm_rnd = get_random_u32(); s16 off; BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); -- 2.26.0