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, 339 insertions, 0 deletions

diff --git a/lib/libfdt/fdt.c b/lib/libfdt/fdt.c
new file mode 100644
index 0000000..95f644c
--- /dev/null
+++ b/lib/libfdt/fdt.c
@@ -0,0 +1,339 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * libfdt - Flat Device Tree manipulation
+ * Copyright (C) 2006 David Gibson, IBM Corporation.
+ */
+#include "libfdt_env.h"
+
+#include <fdt.h>
+#include <libfdt.h>
+
+#include "libfdt_internal.h"
+
+/*
+ * Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
+ * that the given buffer contains what appears to be a flattened
+ * device tree with sane information in its header.
+ */
+int32_t fdt_ro_probe_(const void *fdt)
+{
+	uint32_t totalsize = fdt_totalsize(fdt);
+
+	if (can_assume(VALID_DTB))
+		return totalsize;
+
+	/* The device tree must be at an 8-byte aligned address */
+	if ((uintptr_t)fdt & 7)
+		return -FDT_ERR_ALIGNMENT;
+
+	if (fdt_magic(fdt) == FDT_MAGIC) {
+		/* Complete tree */
+		if (!can_assume(LATEST)) {
+			if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
+				return -FDT_ERR_BADVERSION;
+			if (fdt_last_comp_version(fdt) >
+					FDT_LAST_SUPPORTED_VERSION)
+				return -FDT_ERR_BADVERSION;
+		}
+	} else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
+		/* Unfinished sequential-write blob */
+		if (!can_assume(VALID_INPUT) && fdt_size_dt_struct(fdt) == 0)
+			return -FDT_ERR_BADSTATE;
+	} else {
+		return -FDT_ERR_BADMAGIC;
+	}
+
+	if (totalsize < INT32_MAX)
+		return totalsize;
+	else
+		return -FDT_ERR_TRUNCATED;
+}
+
+static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
+{
+	return (off >= hdrsize) && (off <= totalsize);
+}
+
+static int check_block_(uint32_t hdrsize, uint32_t totalsize,
+			uint32_t base, uint32_t size)
+{
+	if (!check_off_(hdrsize, totalsize, base))
+		return 0; /* block start out of bounds */
+	if ((base + size) < base)
+		return 0; /* overflow */
+	if (!check_off_(hdrsize, totalsize, base + size))
+		return 0; /* block end out of bounds */
+	return 1;
+}
+
+size_t fdt_header_size_(uint32_t version)
+{
+	if (version <= 1)
+		return FDT_V1_SIZE;
+	else if (version <= 2)
+		return FDT_V2_SIZE;
+	else if (version <= 3)
+		return FDT_V3_SIZE;
+	else if (version <= 16)
+		return FDT_V16_SIZE;
+	else
+		return FDT_V17_SIZE;
+}
+
+size_t fdt_header_size(const void *fdt)
+{
+	return can_assume(LATEST) ? FDT_V17_SIZE :
+		fdt_header_size_(fdt_version(fdt));
+}
+
+int fdt_check_header(const void *fdt)
+{
+	size_t hdrsize;
+
+	/* The device tree must be at an 8-byte aligned address */
+	if ((uintptr_t)fdt & 7)
+		return -FDT_ERR_ALIGNMENT;
+
+	if (fdt_magic(fdt) != FDT_MAGIC)
+		return -FDT_ERR_BADMAGIC;
+	if (!can_assume(LATEST)) {
+		if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
+		    || (fdt_last_comp_version(fdt) >
+			FDT_LAST_SUPPORTED_VERSION))
+			return -FDT_ERR_BADVERSION;
+		if (fdt_version(fdt) < fdt_last_comp_version(fdt))
+			return -FDT_ERR_BADVERSION;
+	}
+	hdrsize = fdt_header_size(fdt);
+	if (!can_assume(VALID_DTB)) {
+		if ((fdt_totalsize(fdt) < hdrsize)
+		    || (fdt_totalsize(fdt) > INT_MAX))
+			return -FDT_ERR_TRUNCATED;
+
+		/* Bounds check memrsv block */
+		if (!check_off_(hdrsize, fdt_totalsize(fdt),
+				fdt_off_mem_rsvmap(fdt)))
+			return -FDT_ERR_TRUNCATED;
+
+		/* Bounds check structure block */
+		if (!can_assume(LATEST) && fdt_version(fdt) < 17) {
+			if (!check_off_(hdrsize, fdt_totalsize(fdt),
+					fdt_off_dt_struct(fdt)))
+				return -FDT_ERR_TRUNCATED;
+		} else {
+			if (!check_block_(hdrsize, fdt_totalsize(fdt),
+					  fdt_off_dt_struct(fdt),
+					  fdt_size_dt_struct(fdt)))
+				return -FDT_ERR_TRUNCATED;
+		}
+
+		/* Bounds check strings block */
+		if (!check_block_(hdrsize, fdt_totalsize(fdt),
+				  fdt_off_dt_strings(fdt),
+				  fdt_size_dt_strings(fdt)))
+			return -FDT_ERR_TRUNCATED;
+	}
+
+	return 0;
+}
+
+const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
+{
+	unsigned int uoffset = offset;
+	unsigned int absoffset = offset + fdt_off_dt_struct(fdt);
+
+	if (offset < 0)
+		return NULL;
+
+	if (!can_assume(VALID_INPUT))
+		if ((absoffset < uoffset)
+		    || ((absoffset + len) < absoffset)
+		    || (absoffset + len) > fdt_totalsize(fdt))
+			return NULL;
+
+	if (can_assume(LATEST) || fdt_version(fdt) >= 0x11)
+		if (((uoffset + len) < uoffset)
+		    || ((offset + len) > fdt_size_dt_struct(fdt)))
+			return NULL;
+
+	return fdt_offset_ptr_(fdt, offset);
+}
+
+uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
+{
+	const fdt32_t *tagp, *lenp;
+	uint32_t tag, len, sum;
+	int offset = startoffset;
+	const char *p;
+
+	*nextoffset = -FDT_ERR_TRUNCATED;
+	tagp = fdt_offset_ptr(fdt, offset, FDT_TAGSIZE);
+	if (!can_assume(VALID_DTB) && !tagp)
+		return FDT_END; /* premature end */
+	tag = fdt32_to_cpu(*tagp);
+	offset += FDT_TAGSIZE;
+
+	*nextoffset = -FDT_ERR_BADSTRUCTURE;
+	switch (tag) {
+	case FDT_BEGIN_NODE:
+		/* skip name */
+		do {
+			p = fdt_offset_ptr(fdt, offset++, 1);
+		} while (p && (*p != '\0'));
+		if (!can_assume(VALID_DTB) && !p)
+			return FDT_END; /* premature end */
+		break;
+
+	case FDT_PROP:
+		lenp = fdt_offset_ptr(fdt, offset, sizeof(*lenp));
+		if (!can_assume(VALID_DTB) && !lenp)
+			return FDT_END; /* premature end */
+
+		len = fdt32_to_cpu(*lenp);
+		sum = len + offset;
+		if (!can_assume(VALID_DTB) &&
+		    (INT_MAX <= sum || sum < (uint32_t) offset))
+			return FDT_END; /* premature end */
+
+		/* skip-name offset, length and value */
+		offset += sizeof(struct fdt_property) - FDT_TAGSIZE + len;
+
+		if (!can_assume(LATEST) &&
+		    fdt_version(fdt) < 0x10 && len >= 8 &&
+		    ((offset - len) % 8) != 0)
+			offset += 4;
+		break;
+
+	case FDT_END:
+	case FDT_END_NODE:
+	case FDT_NOP:
+		break;
+
+	default:
+		return FDT_END;
+	}
+
+	if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
+		return FDT_END; /* premature end */
+
+	*nextoffset = FDT_TAGALIGN(offset);
+	return tag;
+}
+
+int fdt_check_node_offset_(const void *fdt, int offset)
+{
+	if (!can_assume(VALID_INPUT)
+	    && ((offset < 0) || (offset % FDT_TAGSIZE)))
+		return -FDT_ERR_BADOFFSET;
+
+	if (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE)
+		return -FDT_ERR_BADOFFSET;
+
+	return offset;
+}
+
+int fdt_check_prop_offset_(const void *fdt, int offset)
+{
+	if (!can_assume(VALID_INPUT)
+	    && ((offset < 0) || (offset % FDT_TAGSIZE)))
+		return -FDT_ERR_BADOFFSET;
+
+	if (fdt_next_tag(fdt, offset, &offset) != FDT_PROP)
+		return -FDT_ERR_BADOFFSET;
+
+	return offset;
+}
+
+int fdt_next_node(const void *fdt, int offset, int *depth)
+{
+	int nextoffset = 0;
+	uint32_t tag;
+
+	if (offset >= 0)
+		if ((nextoffset = fdt_check_node_offset_(fdt, offset)) < 0)
+			return nextoffset;
+
+	do {
+		offset = nextoffset;
+		tag = fdt_next_tag(fdt, offset, &nextoffset);
+
+		switch (tag) {
+		case FDT_PROP:
+		case FDT_NOP:
+			break;
+
+		case FDT_BEGIN_NODE:
+			if (depth)
+				(*depth)++;
+			break;
+
+		case FDT_END_NODE:
+			if (depth && ((--(*depth)) < 0))
+				return nextoffset;
+			break;
+
+		case FDT_END:
+			if ((nextoffset >= 0)
+			    || ((nextoffset == -FDT_ERR_TRUNCATED) && !depth))
+				return -FDT_ERR_NOTFOUND;
+			else
+				return nextoffset;
+		}
+	} while (tag != FDT_BEGIN_NODE);
+
+	return offset;
+}
+
+int fdt_first_subnode(const void *fdt, int offset)
+{
+	int depth = 0;
+
+	offset = fdt_next_node(fdt, offset, &depth);
+	if (offset < 0 || depth != 1)
+		return -FDT_ERR_NOTFOUND;
+
+	return offset;
+}
+
+int fdt_next_subnode(const void *fdt, int offset)
+{
+	int depth = 1;
+
+	/*
+	 * With respect to the parent, the depth of the next subnode will be
+	 * the same as the last.
+	 */
+	do {
+		offset = fdt_next_node(fdt, offset, &depth);
+		if (offset < 0 || depth < 1)
+			return -FDT_ERR_NOTFOUND;
+	} while (depth > 1);
+
+	return offset;
+}
+
+const char *fdt_find_string_len_(const char *strtab, int tabsize, const char *s,
+				 int slen)
+{
+	const char *last = strtab + tabsize - (slen + 1);
+	const char *p;
+
+	for (p = strtab; p <= last; p++)
+		if (memcmp(p, s, slen) == 0 && p[slen] == '\0')
+			return p;
+	return NULL;
+}
+
+int fdt_move(const void *fdt, void *buf, int bufsize)
+{
+	if (!can_assume(VALID_INPUT) && bufsize < 0)
+		return -FDT_ERR_NOSPACE;
+
+	FDT_RO_PROBE(fdt);
+
+	if (fdt_totalsize(fdt) > (unsigned int)bufsize)
+		return -FDT_ERR_NOSPACE;
+
+	memmove(buf, fdt, fdt_totalsize(fdt));
+	return 0;
+}