Suggested-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Peter Lieven <p...@kamp.de>
---
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());
+}
--
1.9.1
