From patchwork Tue Aug 23 14:21:40 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 9295745 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 4A6A2608A7 for ; Tue, 23 Aug 2016 14:22:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 38CF428BCA for ; Tue, 23 Aug 2016 14:22:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2DC6528C0C; Tue, 23 Aug 2016 14:22:46 +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 BEDEF28C05 for ; Tue, 23 Aug 2016 14:22:45 +0000 (UTC) Received: from localhost ([::1]:46829 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bcCbE-0002yF-Q6 for patchwork-qemu-devel@patchwork.kernel.org; Tue, 23 Aug 2016 10:22:44 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40603) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bcCab-0002s6-TP for qemu-devel@nongnu.org; Tue, 23 Aug 2016 10:22:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bcCaV-0002f3-Cv for qemu-devel@nongnu.org; Tue, 23 Aug 2016 10:22:04 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:34497 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bcCaV-0002ea-3L for qemu-devel@nongnu.org; Tue, 23 Aug 2016 10:21:59 -0400 Received: (qmail 3511 invoked by uid 89); 23 Aug 2016 14:21:54 -0000 Received: from [195.62.97.28] by client-16-kamp (envelope-from , uid 89) with qmail-scanner-2010/03/19-MF (clamdscan: 0.99.2/22129. avast: 1.2.2/16082300. spamassassin: 3.4.1. 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Processed in 0.309513 secs); 23 Aug 2016 14:21:54 -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); 23 Aug 2016 14:21:51 -0000 X-GL_Whitelist: yes Received: (qmail 4789 invoked from network); 23 Aug 2016 14:21:50 -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; 23 Aug 2016 14:21:50 -0000 Received: by lieven-pc (Postfix, from userid 1000) id 7BC9A20850; Tue, 23 Aug 2016 16:21:48 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Date: Tue, 23 Aug 2016 16:21:40 +0200 Message-Id: <1471962105-31267-2-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1471962105-31267-1-git-send-email-pl@kamp.de> References: <1471962105-31267-1-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 V7 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, 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. The memory for the guard page is deductated from stack memory so that the usable stack size is effectively reduced by the size of one page. This is equivalent to how the glibc stack allocation routines behave. Signed-off-by: Peter Lieven Reviewed-by: Richard Henderson --- include/sysemu/os-posix.h | 27 ++++++++++++++++++++++++++ util/oslib-posix.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 75 insertions(+) diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h index 9c7dfdf..87e60fe 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: 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()). This function also inserts a + * guard page to catch a potential stack overflow. The memory + * for the guard page is deductated from stack memory so that + * the usable stack size is effectively sz bytes minus the size + * of one page. + * + * 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 f2d4e9e..74dbe1c 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -499,3 +499,51 @@ pid_t qemu_fork(Error **errp) } return pid; } + +static size_t adjust_stack_size(size_t sz, size_t pagesz) +{ +#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); + return sz; +} + +void *qemu_alloc_stack(size_t sz) +{ + void *ptr, *guardpage; + size_t pagesz = getpagesize(); + sz = adjust_stack_size(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) +{ + size_t pagesz = getpagesize(); + sz = adjust_stack_size(sz, pagesz); + munmap(stack, sz); +}