From patchwork Sun Aug 6 03:36:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 1817427 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256 header.s=google header.b=YhRjrWag; dkim-atps=neutral Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RJQF75s2vz1yYl for ; Sun, 6 Aug 2023 13:39:55 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qSUa7-0003eY-Bz; Sat, 05 Aug 2023 23:37:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qSUa5-0003dj-Rr for qemu-devel@nongnu.org; Sat, 05 Aug 2023 23:37:25 -0400 Received: from mail-pf1-x435.google.com ([2607:f8b0:4864:20::435]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qSUa4-0007Xa-7n for qemu-devel@nongnu.org; Sat, 05 Aug 2023 23:37:25 -0400 Received: by mail-pf1-x435.google.com with SMTP id d2e1a72fcca58-686ea67195dso2458964b3a.2 for ; Sat, 05 Aug 2023 20:37:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1691293043; x=1691897843; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=U8M/sECGKblXQECxwhiXY/mNUP2fHciHERdH2OiT8nA=; b=YhRjrWagjbp13SDviaVcq4SUcJqN8fFgf1kOTYRE5xGpALC0SXlo4yKQhBZT4RwFhd vPuXFP/fLW0Od+P3O7xl0j+H/OD0k5QaFEHqWjsfTxdBuPmx5MDfS6m89RgZ70/Emvza jrxbhtQaaRsXqia8xXY/ai24XnVOMHfDWM53mDmcws8obe15lffBBp5TgBp0s2wpyRit JWOPuFL1yZXe0yctgcRjswZUbYOKsdkgnvugCUKi7lQveUV83nOt04+w+eIagYiPxlXo YXSbMTXQBg2MlryX+UGwpJhPYRS40bJAsbiOkOngTAnIDqm6GtEm3CQM6R4n9g+6fTsX nvAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691293043; x=1691897843; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=U8M/sECGKblXQECxwhiXY/mNUP2fHciHERdH2OiT8nA=; b=fi5BmKlbNCrd/AAWJLgTJVOLJ/jMD5xpHj/ljuyWykla7RkAdN4JKDn1sg5gDNeisN 8OK41czmgFtFXRUThlExUg+oBUSjPqwV0gIKh2Ar9YdrroxNFxaa+H8G2IBzL6GPJedX gf4SNsadkTWDOg/9EuqzJYwx4zTRwYpBZA+KCs6fEHE5/T4XLCxI+SXhAPzrXFmY2caR LIK/QdZF8/10AdUw/Z/Vl7p0fXenraV2U6Vq+tGqxh05UlIbkiv/0XiACAmnEhW74l6M dPeYAgwN+czME238tSX7aUflipUQgWHNl0CJLfITvDiizBO+KXEXZwHUdmmPk+0+hWDR 7f2g== X-Gm-Message-State: AOJu0Yw5Z4hPWquzQYwnYrdAxjuf2RYIRUlHTp5d6qhLmuaCh0gTeKNh 2nW7YJf8Mak/om/7tke0/iQ8Mp5FZSV3KgJmhps= X-Google-Smtp-Source: AGHT+IEcVvz/QQf1HsxJAMkAA4SK992SrhyNjQyKk0WHgmlU5YjGBwhzbsnm+RY750+LRyRZC/DoKQ== X-Received: by 2002:a17:903:2587:b0:1b8:b564:b531 with SMTP id jb7-20020a170903258700b001b8b564b531mr5870990plb.60.1691293042786; Sat, 05 Aug 2023 20:37:22 -0700 (PDT) Received: from stoup.. ([2602:47:d490:6901:9454:a46f:1c22:a7c6]) by smtp.gmail.com with ESMTPSA id a5-20020a17090a740500b00262e604724dsm6306451pjg.50.2023.08.05.20.37.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Aug 2023 20:37:22 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: Akihiko Odaki Subject: [PULL 08/24] linux-user: Use MAP_FIXED_NOREPLACE for do_brk() Date: Sat, 5 Aug 2023 20:36:59 -0700 Message-Id: <20230806033715.244648-9-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230806033715.244648-1-richard.henderson@linaro.org> References: <20230806033715.244648-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::435; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x435.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Akihiko Odaki MAP_FIXED_NOREPLACE can ensure the mapped address is fixed without concerning that the new mapping overwrites something else. Signed-off-by: Akihiko Odaki Message-Id: <20230802071754.14876-5-akihiko.odaki@daynix.com> [rth: Pass -1 as fd for MAP_ANON] Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- linux-user/syscall.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index b9d2ec02f9..f64024273f 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -854,17 +854,12 @@ abi_long do_brk(abi_ulong brk_val) return target_brk; } - /* We need to allocate more memory after the brk... Note that - * we don't use MAP_FIXED because that will map over the top of - * any existing mapping (like the one with the host libc or qemu - * itself); instead we treat "mapped but at wrong address" as - * a failure and unmap again. - */ if (new_host_brk_page > brk_page) { new_alloc_size = new_host_brk_page - brk_page; mapped_addr = target_mmap(brk_page, new_alloc_size, - PROT_READ|PROT_WRITE, - MAP_ANON|MAP_PRIVATE, 0, 0); + PROT_READ | PROT_WRITE, + MAP_FIXED_NOREPLACE | MAP_ANON | MAP_PRIVATE, + -1, 0); } else { new_alloc_size = 0; mapped_addr = brk_page; @@ -883,12 +878,6 @@ abi_long do_brk(abi_ulong brk_val) target_brk = brk_val; brk_page = new_host_brk_page; return target_brk; - } else if (mapped_addr != -1) { - /* Mapped but at wrong address, meaning there wasn't actually - * enough space for this brk. - */ - target_munmap(mapped_addr, new_alloc_size); - mapped_addr = -1; } #if defined(TARGET_ALPHA)