+
+#ifdef __OpenBSD__
+
+int openbsd_use_fxsave = 0;
+
+void
+openbsd_init()
+{
+#ifdef LISP_FEATURE_X86
+ int mib[2];
+ size_t size;
+#endif
+ /*
+ * Show a warning if it looks like the memory available after
+ * allocating the spaces won't be at least this much.
+ */
+#ifdef LISP_FEATURE_X86_64
+ const int wantfree = 64 * 1024 * 1024;
+#else
+ const int wantfree = 32 * 1024 * 1024;
+#endif
+ struct rlimit rl;
+
+#ifdef LISP_FEATURE_X86
+ /* Save the machdep.osfxsr sysctl for use by os_restore_fp_control() */
+ mib[0] = CTL_MACHDEP;
+ mib[1] = CPU_OSFXSR;
+ size = sizeof (openbsd_use_fxsave);
+ sysctl(mib, 2, &openbsd_use_fxsave, &size, NULL, 0);
+#endif
+
+ /* OpenBSD, like NetBSD, counts mmap()ed space against the
+ * process's data size limit. If the soft limit is lower than the
+ * hard limit then try to yank it up, this lets users in the
+ * "staff" or "daemon" login classes run sbcl with larger dynamic
+ * space sizes.
+ */
+ getrlimit (RLIMIT_DATA, &rl);
+ if (rl.rlim_cur < rl.rlim_max) {
+ rl.rlim_cur = rl.rlim_max;
+ if (setrlimit (RLIMIT_DATA, &rl) < 0) {
+ fprintf (stderr,
+ "RUNTIME WARNING: unable to raise process data size limit:\n\
+ %s.\n\
+The system may fail to start.\n",
+ strerror(errno));
+ }
+ }
+
+ /*
+ * Display a (hopefully) helpful warning if it looks like we won't
+ * be able to allocate enough memory.
+ */
+ getrlimit (RLIMIT_DATA, &rl);
+ if (dynamic_space_size + READ_ONLY_SPACE_SIZE + STATIC_SPACE_SIZE +
+ LINKAGE_TABLE_SPACE_SIZE + wantfree > rl.rlim_cur)
+ fprintf (stderr,
+ "RUNTIME WARNING: data size resource limit may be too low,\n"
+ " try decreasing the dynamic space size with --dynamic-space-size\n"
+ " or raising the datasize or datasize-max limits in /etc/login.conf\n");
+}
+
+/* OpenBSD's dlsym() relies on the gcc bulitin
+ * __builtin_return_address(0) returning an address in the
+ * executable's text segment, but when called from lisp it will return
+ * an address in the dynamic space. Work around this by calling this
+ * wrapper function instead. Note that tail-call optimization will
+ * defeat this, disable it by saving the dlsym() return value in a
+ * volatile variable.
+*/
+void *
+os_dlsym(void *handle, const char *symbol)
+{
+ void * volatile ret = dlsym(handle, symbol);
+ return ret;
+}
+
+#endif