From patchwork Wed Jul 25 22:10:34 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 173304 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 56D962C0085 for ; Thu, 26 Jul 2012 08:58:18 +1000 (EST) Received: from localhost ([::1]:52342 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Su9nq-0001DI-IM for incoming@patchwork.ozlabs.org; Wed, 25 Jul 2012 18:11:34 -0400 Received: from eggs.gnu.org ([208.118.235.92]:42408) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Su9nC-0007nt-Nj for qemu-devel@nongnu.org; Wed, 25 Jul 2012 18:10:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Su9nA-00012y-UG for qemu-devel@nongnu.org; Wed, 25 Jul 2012 18:10:54 -0400 Received: from mail-gh0-f173.google.com ([209.85.160.173]:59558) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Su9nA-00012p-QR for qemu-devel@nongnu.org; Wed, 25 Jul 2012 18:10:52 -0400 Received: by ghrr14 with SMTP id r14so1286355ghr.4 for ; Wed, 25 Jul 2012 15:10:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; bh=1brU2RWSZY/nnob3Hl1Ue3LooEatPmYFkeHWE8/dJcY=; b=enrIDj14F39nZ3HGswFx0wgjIrP5nxlEjmnWPs8OR3OwyenVADLThwTKrA4yDnnqqF HzyfcQaB4E7j0cnTSt8rMp+8ocMnyKrWhFFMbqdnOKOwYpXfMoXRlAqeIG8iktB4Tdx5 VVb0KpdrUEiLWrp2ZpIKc3f4IgLkIX4WNNrVQW5fB0lberocpO2WrxXZX5EbX/oUdaxv IYK6RSBUy36ZCS9CbkNANuPxBmN+6ODhYODo1sJqmY8icVMioT1lucECTJX8W59SFa4G kf+a9UnChfuKQ4EmS3pJkSX+qB9jH6yKjoFze/Jkj1STrqvTB0hCO+IhmoUE+OA3zPKq XVhA== Received: by 10.66.78.42 with SMTP id y10mr15754070paw.31.1343254252160; Wed, 25 Jul 2012 15:10:52 -0700 (PDT) Received: from anchor.twiddle.home.com ([173.160.232.49]) by mx.google.com with ESMTPS id oo6sm15136761pbc.22.2012.07.25.15.10.51 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 25 Jul 2012 15:10:51 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Date: Wed, 25 Jul 2012 15:10:34 -0700 Message-Id: <1343254238-4727-7-git-send-email-rth@twiddle.net> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1343254238-4727-1-git-send-email-rth@twiddle.net> References: <1343254238-4727-1-git-send-email-rth@twiddle.net> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 209.85.160.173 Cc: riku.voipio@iki.fi Subject: [Qemu-devel] [PATCH 06/10] linux-user: Allocate the right amount of space for non-fixed file maps X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 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 If we let the kernel handle the implementation of mmap_find_vma, via an anon mmap, we must use the size as indicated by the user and not the size truncated to the filesize. This happens often in ld.so, where we initially mmap the file to the size of the text+data+bss to reserve an area, then mmap+fixed over the top to properly handle data and bss. Signed-off-by: Richard Henderson --- linux-user/mmap.c | 30 +++++++++++++++++++----------- 1 files changed, 19 insertions(+), 11 deletions(-) diff --git a/linux-user/mmap.c b/linux-user/mmap.c index d9468fe..b412e3f 100644 --- a/linux-user/mmap.c +++ b/linux-user/mmap.c @@ -382,7 +382,6 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, int flags, int fd, abi_ulong offset) { abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len; - unsigned long host_start; mmap_lock(); #ifdef DEBUG_MMAP @@ -421,6 +420,19 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, if (len == 0) goto the_end; real_start = start & qemu_host_page_mask; + host_offset = offset & qemu_host_page_mask; + + /* If the user is asking for the kernel to find a location, do that + before we truncate the length for mapping files below. */ + if (!(flags & MAP_FIXED)) { + host_len = len + offset - host_offset; + host_len = HOST_PAGE_ALIGN(host_len); + start = mmap_find_vma(real_start, host_len); + if (start == (abi_ulong)-1) { + errno = ENOMEM; + goto fail; + } + } /* When mapping files into a memory area larger than the file, accesses to pages beyond the file size will cause a SIGBUS. @@ -453,27 +465,23 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot, } if (!(flags & MAP_FIXED)) { - abi_ulong mmap_start; + unsigned long host_start; void *p; - host_offset = offset & qemu_host_page_mask; + host_len = len + offset - host_offset; host_len = HOST_PAGE_ALIGN(host_len); - mmap_start = mmap_find_vma(real_start, host_len); - if (mmap_start == (abi_ulong)-1) { - errno = ENOMEM; - goto fail; - } + /* Note: we prefer to control the mapping address. It is especially important if qemu_host_page_size > qemu_real_host_page_size */ - p = mmap(g2h(mmap_start), - host_len, prot, flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0); + p = mmap(g2h(start), host_len, prot, + flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0); if (p == MAP_FAILED) goto fail; /* update start so that it points to the file position at 'offset' */ host_start = (unsigned long)p; if (!(flags & MAP_ANONYMOUS)) { - p = mmap(g2h(mmap_start), len, prot, + p = mmap(g2h(start), len, prot, flags | MAP_FIXED, fd, host_offset); host_start += offset - host_offset; }