From patchwork Tue Sep 27 09:58:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 9351637 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 699BE6077A for ; Tue, 27 Sep 2016 09:59:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5A425291A3 for ; Tue, 27 Sep 2016 09:59:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4EC91291AB; Tue, 27 Sep 2016 09:59:42 +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 508F2291A3 for ; Tue, 27 Sep 2016 09:59:40 +0000 (UTC) Received: from localhost ([::1]:49207 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bopAp-0007mI-GX for patchwork-qemu-devel@patchwork.kernel.org; Tue, 27 Sep 2016 05:59:39 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50178) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bopAL-0007kY-Aj for qemu-devel@nongnu.org; Tue, 27 Sep 2016 05:59:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bopAH-00073z-6g for qemu-devel@nongnu.org; Tue, 27 Sep 2016 05:59:08 -0400 Received: from mx01.kamp.de ([82.141.2.16]:43339) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bopAG-00073D-TI for qemu-devel@nongnu.org; Tue, 27 Sep 2016 05:59:05 -0400 Received: (qmail 18466 invoked by uid 89); 27 Sep 2016 09:59:02 -0000 Received: from [195.62.97.28] by client-16-kamp (envelope-from , uid 89) with qmail-scanner-2010/03/19-MF (clamdscan: 0.99.2/22259. avast: 1.2.2/16092600. spamassassin: 3.4.1. 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Processed in 0.320876 secs); 27 Sep 2016 09:59:02 -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); 27 Sep 2016 09:58:59 -0000 X-GL_Whitelist: yes Received: (qmail 12438 invoked from network); 27 Sep 2016 09:58:58 -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; 27 Sep 2016 09:58:58 -0000 Received: by lieven-pc (Postfix, from userid 1000) id 8C287203CB; Tue, 27 Sep 2016 11:58:58 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Date: Tue, 27 Sep 2016 11:58:40 +0200 Message-Id: <1474970326-10271-2-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1474970326-10271-1-git-send-email-pl@kamp.de> References: <1474970326-10271-1-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: 82.141.2.16 Subject: [Qemu-devel] [PATCH V9 1/7] 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, armbru@redhat.com, Peter Lieven , dgilbert@redhat.com, mreitz@redhat.com, pbonzini@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP the allocated stack will be adjusted to the minimum supported stack size by the OS and rounded up to be a multiple of the system pagesize. Additionally an architecture dependent guard page is added to the stack to catch stack overflows. Signed-off-by: Peter Lieven --- include/sysemu/os-posix.h | 27 +++++++++++++++++++++++++++ util/oslib-posix.c | 42 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 69 insertions(+) diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h index 9c7dfdf..3cfedbc 100644 --- a/include/sysemu/os-posix.h +++ b/include/sysemu/os-posix.h @@ -60,4 +60,31 @@ int qemu_utimens(const char *path, const qemu_timespec *times); bool is_daemonized(void); +/** + * qemu_alloc_stack: + * @sz: pointer to a size_t holding the requested usable stack size + * + * 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()). This function also inserts an + * additional guard page to catch a potential stack overflow. + * Note that the memory required for the guard page and alignment + * and minimal stack size restrictions will increase the value of sz. + * + * 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(). Note that sz must + * be exactly the adjusted stack size returned by 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 f2d4e9e..5745229 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -499,3 +499,45 @@ pid_t qemu_fork(Error **errp) } return pid; } + +void *qemu_alloc_stack(size_t *sz) +{ + void *ptr, *guardpage; + size_t pagesz = getpagesize(); +#ifdef _SC_THREAD_STACK_MIN + /* avoid stacks smaller than _SC_THREAD_STACK_MIN */ + long min_stack_sz = sysconf(_SC_THREAD_STACK_MIN); + *sz = MAX(MAX(min_stack_sz, 0), *sz); +#endif + /* adjust stack size to a multiple of the page size */ + *sz = ROUND_UP(*sz, pagesz); + /* allocate one extra page for the guard page */ + *sz += pagesz; + + ptr = mmap(NULL, *sz, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (ptr == MAP_FAILED) { + abort(); + } + +#if defined(HOST_IA64) + /* separate register stack */ + guardpage = ptr + (((sz - pagesz) / 2) & ~pagesz); +#elif defined(HOST_HPPA) + /* stack grows up */ + guardpage = ptr + sz - pagesz; +#else + /* stack grows down */ + guardpage = ptr; +#endif + if (mprotect(guardpage, pagesz, PROT_NONE) != 0) { + abort(); + } + + return ptr; +} + +void qemu_free_stack(void *stack, size_t sz) +{ + munmap(stack, sz); +}