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Processed in 0.216839 secs); 04 Jul 2016 12:31:46 -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); 4 Jul 2016 12:31:43 -0000 X-GL_Whitelist: yes Received: (qmail 21764 invoked from network); 4 Jul 2016 12:31:42 -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; 4 Jul 2016 12:31:42 -0000 Received: by lieven-pc (Postfix, from userid 1000) id 18BFD2086C; Mon, 4 Jul 2016 14:31:33 +0200 (CEST) From: Peter Lieven To: qemu-devel@nongnu.org Date: Mon, 4 Jul 2016 14:31:22 +0200 Message-Id: <1467635487-9329-2-git-send-email-pl@kamp.de> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1467635487-9329-1-git-send-email-pl@kamp.de> References: <1467635487-9329-1-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 V2 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, 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 Suggested-by: Peter Maydell Signed-off-by: Peter Lieven Reviewed-by: Richard Henderson --- 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); +}