1 files changed, 55 insertions, 0 deletions
diff --git a/roms/skiboot/core/relocate.c b/roms/skiboot/core/relocate.c
new file mode 100644
index 000000000..6295927e2
--- /dev/null
+++ b/roms/skiboot/core/relocate.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+/*
+ * Relocate ourselves
+ *
+ * WARNING: This code is used to self-relocate, it cannot have any
+ * global reference nor TOC reference. It's also called before BSS
+ * is cleared.
+ *
+ * Copyright 2013-2015 IBM Corp.
+ */
+
+#include <stdbool.h>
+#include <elf.h>
+
+/* Called from head.S, thus no header. */
+int relocate(uint64_t offset, struct elf64_dyn *dyn, struct elf64_rela *rela);
+
+/* Note: This code is simplified according to the assumptions
+ *       that our link address is 0 and we are running at the
+ *       target address already.
+ */
+int relocate(uint64_t offset, struct elf64_dyn *dyn, struct elf64_rela *rela)
+{
+	uint64_t dt_rela	= 0;
+	uint64_t dt_relacount	= 0;
+	unsigned int i;
+
+	/* Look for relocation table */
+	for (; dyn->d_tag != DT_NULL; dyn++) {
+		if (dyn->d_tag == DT_RELA)
+			dt_rela = dyn->d_val;
+		else if (dyn->d_tag == DT_RELACOUNT)
+			dt_relacount = dyn->d_val;
+	}
+
+	/* If we miss either rela or relacount, bail */
+	if (!dt_rela || !dt_relacount)
+		return -1;
+
+	/* Check if the offset is consistent */
+	if ((offset + dt_rela) != (uint64_t)rela)
+		return -2;
+
+	/* Perform relocations */
+	for (i = 0; i < dt_relacount; i++, rela++) {
+		uint64_t *t;
+
+		if (ELF64_R_TYPE(rela->r_info) != R_PPC64_RELATIVE)
+			return -3;
+		t = (uint64_t *)(rela->r_offset + offset);
+		*t = rela->r_addend + offset;
+	}
+
+	return 0;
+}