tashaboot: arm64 bringup, semihosting payload loader

consoles on the pl011 the dtb points at, walks the memory node and
chosen, loads an arm64 kernel Image over semihosting and jumps to it
with the documented register state. string functions, printf and
libfdt are vendored from lk (lk2nd) and u-boot so the libc surface is
the one those projects already proved. built and booted on qemu virt,
payload exits clean through semihosting.

1 files changed, 50 insertions, 0 deletions

diff --git a/lib/string/strlcpy.c b/lib/string/strlcpy.c
new file mode 100644
index 0000000..2fa498c
--- /dev/null
+++ b/lib/string/strlcpy.c
@@ -0,0 +1,50 @@
+/*	$OpenBSD: strlcpy.c,v 1.16 2019/01/25 00:19:25 millert Exp $	*/
+
+/*
+ * Copyright (c) 1998, 2015 Todd C. Miller <millert@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+#include <string.h>
+
+/*
+ * Copy string src to buffer dst of size dsize.  At most dsize-1
+ * chars will be copied.  Always NUL terminates (unless dsize == 0).
+ * Returns strlen(src); if retval >= dsize, truncation occurred.
+ */
+size_t
+strlcpy(char *dst, const char *src, size_t dsize)
+{
+	const char *osrc = src;
+	size_t nleft = dsize;
+
+	/* Copy as many bytes as will fit. */
+	if (nleft != 0) {
+		while (--nleft != 0) {
+			if ((*dst++ = *src++) == '\0')
+				break;
+		}
+	}
+
+	/* Not enough room in dst, add NUL and traverse rest of src. */
+	if (nleft == 0) {
+		if (dsize != 0)
+			*dst = '\0';		/* NUL-terminate dst */
+		while (*src++)
+			;
+	}
+
+	return(src - osrc - 1);	/* count does not include NUL */
+}