From patchwork Thu Jul 7 11:37:21 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Lieven X-Patchwork-Id: 645838 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3rlbSx0r0vz9sBM for ; Thu, 7 Jul 2016 21:47:13 +1000 (AEST) Received: from localhost ([::1]:39049 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bL7lu-0003vW-QY for incoming@patchwork.ozlabs.org; Thu, 07 Jul 2016 07:47:10 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33577) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bL7cq-0000rr-A7 for qemu-devel@nongnu.org; Thu, 07 Jul 2016 07:37:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bL7cn-0005Jf-4y for qemu-devel@nongnu.org; Thu, 07 Jul 2016 07:37:48 -0400 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:49314 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bL7cm-0005Iy-SC for qemu-devel@nongnu.org; Thu, 07 Jul 2016 07:37:45 -0400 Received: (qmail 8043 invoked by uid 89); 7 Jul 2016 11:37:41 -0000 Received: from [195.62.97.28] by client-16-kamp (envelope-from , uid 89) with qmail-scanner-2010/03/19-MF (clamdscan: 0.99.2/21858. hbedv: 8.3.40.44/7.12.99.34. avast: 1.2.2/16070700. spamassassin: 3.4.1. 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Processed in 0.331296 secs); 07 Jul 2016 11:37:41 -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); 7 Jul 2016 11:37:38 -0000 X-GL_Whitelist: yes Received: (qmail 14705 invoked from network); 7 Jul 2016 11:37:37 -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; 7 Jul 2016 11:37:37 -0000 Received: by lieven-pc (Postfix, from userid 1000) id C0BD320675; Thu, 7 Jul 2016 13:37:36 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Date: Thu, 7 Jul 2016 13:37:21 +0200 Message-Id: <1467891446-22267-2-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1467891446-22267-1-git-send-email-pl@kamp.de> References: <1467891446-22267-1-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 V3 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+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" the allocated stack will be adjusted to the minimum supported stack size by the OS. Additionally an architecture dependent guard page is added to the stack to catch stack overflows. Suggested-by: Peter Maydell Signed-off-by: Peter Lieven --- include/sysemu/os-posix.h | 23 +++++++++++++++++++++++ util/oslib-posix.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+) diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h index 9c7dfdf..7630665 100644 --- a/include/sysemu/os-posix.h +++ b/include/sysemu/os-posix.h @@ -60,4 +60,27 @@ 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 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..1ce35ef 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -497,3 +497,42 @@ pid_t qemu_fork(Error **errp) } return pid; } + +void *qemu_alloc_stack(size_t sz) +{ + void *ptr, *guardpage; + size_t pagesz = getpagesize(); + + /* avoid stacks smaller than _SC_THREAD_STACK_MIN */ + sz = MAX(sz, sysconf(_SC_THREAD_STACK_MIN)); + /* assert that the stack size is a multiple of the page size */ + assert(!(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) +{ + sz = MAX(sz, sysconf(_SC_THREAD_STACK_MIN)); + munmap(stack, sz); +}