From patchwork Thu Jun 30 07:37:15 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 9206815 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 81E5B607D6 for ; Thu, 30 Jun 2016 07:38:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 745D428417 for ; Thu, 30 Jun 2016 07:38:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 67A02285C7; Thu, 30 Jun 2016 07:38:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id AA56628417 for ; Thu, 30 Jun 2016 07:38:15 +0000 (UTC) Received: from localhost ([::1]:47459 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIWYA-00080A-87 for patchwork-qemu-devel@patchwork.kernel.org; Thu, 30 Jun 2016 03:38:14 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58627) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIWXb-0007x7-TI for qemu-devel@nongnu.org; Thu, 30 Jun 2016 03:37:41 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bIWXW-0007tb-CS for qemu-devel@nongnu.org; Thu, 30 Jun 2016 03:37:38 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:35656 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIWXW-0007tG-2e for qemu-devel@nongnu.org; Thu, 30 Jun 2016 03:37:34 -0400 Received: (qmail 22624 invoked by uid 89); 30 Jun 2016 07:37:31 -0000 Received: from [195.62.97.28] by client-16-kamp (envelope-from , uid 89) with qmail-scanner-2010/03/19-MF (clamdscan: 0.99.2/21815. hbedv: 8.3.40.44/7.12.99.34. avast: 1.2.2/16062901. spamassassin: 3.4.1. Clear:RC:1(195.62.97.28):. Processed in 0.265399 secs); 30 Jun 2016 07:37:31 -0000 Received: from smtp.kamp.de (HELO submission.kamp.de) ([195.62.97.28]) by mx01.kamp.de with ESMTPS (DHE-RSA-AES256-GCM-SHA384 encrypted); 30 Jun 2016 07:37:28 -0000 X-GL_Whitelist: yes Received: (qmail 6026 invoked from network); 30 Jun 2016 07:37:27 -0000 Received: from lieven-pc.kamp-intra.net (HELO lieven-pc) (relay@kamp.de@::ffff:172.21.12.60) by submission.kamp.de with ESMTPS (DHE-RSA-AES256-GCM-SHA384 encrypted) ESMTPA; 30 Jun 2016 07:37:27 -0000 Received: by lieven-pc (Postfix, from userid 1000) id A72CF20434; Thu, 30 Jun 2016 09:37:23 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Date: Thu, 30 Jun 2016 09:37:15 +0200 Message-Id: <1467272240-32123-2-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1467272240-32123-1-git-send-email-pl@kamp.de> References: <1467272240-32123-1-git-send-email-pl@kamp.de> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2a02:248:0:51::16 Subject: [Qemu-devel] [PATCH 1/6] oslib-posix: add helpers for stack alloc and free X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, mst@redhat.com, Peter Lieven , dgilbert@redhat.com, mreitz@redhat.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Suggested-by: Peter Maydell Signed-off-by: Peter Lieven --- include/sysemu/os-posix.h | 24 ++++++++++++++++++++++++ util/oslib-posix.c | 22 ++++++++++++++++++++++ 2 files changed, 46 insertions(+) diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h index 9c7dfdf..34d102c 100644 --- a/include/sysemu/os-posix.h +++ b/include/sysemu/os-posix.h @@ -60,4 +60,28 @@ int qemu_utimens(const char *path, const qemu_timespec *times); bool is_daemonized(void); +/** + * qemu_alloc_stack: + * @sz: size of required stack in bytes + * + * Allocate memory that can be used as a stack, for instance for + * coroutines. If the memory cannot be allocated, this function + * will abort (like g_malloc()). The function will register a + * guard page right below the stack memory to catch stack overflows. + * + * The allocated stack must be freed with qemu_free_stack(). + * + * Returns: pointer to (the lowest address of) the stack memory. + */ +void *qemu_alloc_stack(size_t sz); + +/** + * qemu_free_stack: + * @stack: stack to free + * @sz: size of stack in bytes + * + * Free a stack allocated via qemu_alloc_stack(). + */ +void qemu_free_stack(void *stack, size_t sz); + #endif diff --git a/util/oslib-posix.c b/util/oslib-posix.c index e2e1d4d..a567a7d 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -497,3 +497,25 @@ pid_t qemu_fork(Error **errp) } return pid; } + +void *qemu_alloc_stack(size_t sz) +{ + /* allocate sz bytes plus one extra page for a guard + * page at the bottom of the stack */ + void *ptr = mmap(NULL, sz + getpagesize(), PROT_NONE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (ptr == MAP_FAILED) { + abort(); + } + if (mmap(ptr + getpagesize(), sz, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0) == MAP_FAILED) { + abort(); + } + return ptr + getpagesize(); +} + +void qemu_free_stack(void *stack, size_t sz) +{ + /* unmap the stack plus the extra guard page */ + munmap(stack - getpagesize(), sz + getpagesize()); +}