Add MD relocation support for amd64 and i386 platforms. The no-op

relocation is not sufficient for ELF relocatable object format
modules, since accessing the module metadata involves following
pointers between different ELF sections.

This allows kldxref to correctly build linker.hints on the amd64
platform.

2 files changed, 207 insertions, 0 deletions

diff --git a/usr.sbin/kldxref/ef_amd64.c b/usr.sbin/kldxref/ef_amd64.c
new file mode 100644
index 0000000..f0acba8
--- /dev/null
+++ b/usr.sbin/kldxref/ef_amd64.c
@@ -0,0 +1,114 @@
+/*-
+ * Copyright (c) 2003 Jake Burkholder.
+ * Copyright 1996-1998 John D. Polstra.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+#include <machine/elf.h>
+
+#include <err.h>
+#include <errno.h>
+#include <string.h>
+
+#include "ef.h"
+
+/*
+ * Apply relocations to the values we got from the file.
+ */
+int
+ef_reloc(struct elf_file *ef, const void *data, int type, Elf_Off offset,
+    size_t len, void *dest)
+{
+	Elf64_Addr *where, val;
+	Elf32_Addr *where32, val32;
+	Elf_Addr addend, addr;
+	Elf_Word rtype, symidx;
+	const Elf_Rel *rel;
+	const Elf_Rela *rela;
+
+	switch (type) {
+	case EF_RELOC_REL:
+		rel = (const Elf_Rel *)data;
+		where = (Elf_Addr *)(dest + rel->r_offset - offset);
+		rtype = ELF_R_TYPE(rel->r_info);
+		symidx = ELF_R_SYM(rel->r_info);
+		break;
+	case EF_RELOC_RELA:
+		rela = (const Elf_Rela *)data;
+		where = (Elf_Addr *)(dest + rela->r_offset - offset);
+		addend = rela->r_addend;
+		rtype = ELF_R_TYPE(rela->r_info);
+		symidx = ELF_R_SYM(rela->r_info);
+		break;
+	default:
+		return (EINVAL);
+	}
+
+	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
+		return (0);
+
+	if (type == EF_RELOC_REL) {
+		/* Addend is 32 bit on 32 bit relocs */
+		switch (rtype) {
+		case R_X86_64_PC32:
+		case R_X86_64_32S:
+			addend = *(Elf32_Addr *)where;
+			break;
+		default:
+			addend = *where;
+			break;
+		}
+	}
+
+	switch (rtype) {
+	case R_X86_64_NONE:	/* none */
+		break;
+	case R_X86_64_64:	/* S + A */
+		addr = EF_SYMADDR(ef, symidx);
+		val = addr + addend;
+		*where = val;
+		break;
+	case R_X86_64_32S:	/* S + A sign extend */
+		addr = EF_SYMADDR(ef, symidx);
+		val32 = (Elf32_Addr)(addr + addend);
+		where32 = (Elf32_Addr *)where;
+		*where32 = val32;
+		break;
+	case R_X86_64_GLOB_DAT:	/* S */
+		addr = EF_SYMADDR(ef, symidx);
+		*where = addr;
+		break;
+	case R_X86_64_RELATIVE:	/* B + A */
+		addr = (Elf_Addr)addend;
+		val = addr;
+		*where = val;
+		break;
+	default:
+		warnx("unhandled relocation type %d", (int)rtype);
+	}
+	return (0);
+}
diff --git a/usr.sbin/kldxref/ef_i386.c b/usr.sbin/kldxref/ef_i386.c
new file mode 100644
index 0000000..9735900
--- /dev/null
+++ b/usr.sbin/kldxref/ef_i386.c
@@ -0,0 +1,93 @@
+/*-
+ * Copyright (c) 2003 Jake Burkholder.
+ * Copyright 1996-1998 John D. Polstra.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/types.h>
+#include <machine/elf.h>
+
+#include <err.h>
+#include <errno.h>
+#include <string.h>
+
+#include "ef.h"
+
+/*
+ * Apply relocations to the values we got from the file.
+ */
+int
+ef_reloc(struct elf_file *ef, const void *data, int type, Elf_Off offset,
+    size_t len, void *dest)
+{
+	Elf_Addr *where, addr, addend;
+	Elf_Word rtype, symidx;
+	const Elf_Rel *rel;
+	const Elf_Rela *rela;
+
+	switch (type) {
+	case EF_RELOC_REL:
+		rel = (const Elf_Rel *)data;
+		where = (Elf_Addr *)(dest + rel->r_offset - offset);
+		rtype = ELF_R_TYPE(rel->r_info);
+		symidx = ELF_R_SYM(rel->r_info);
+		break;
+	case EF_RELOC_RELA:
+		rela = (const Elf_Rela *)data;
+		where = (Elf_Addr *)(dest + rela->r_offset - offset);
+		addend = rela->r_addend;
+		rtype = ELF_R_TYPE(rela->r_info);
+		symidx = ELF_R_SYM(rela->r_info);
+		break;
+	default:
+		return (EINVAL);
+	}
+
+	if ((char *)where < (char *)dest || (char *)where >= (char *)dest + len)
+		return (0);
+
+	if (type == EF_RELOC_REL)
+		addend = *where;
+
+	switch (rtype) {
+	case R_386_RELATIVE:	/* A + B */
+		addr = (Elf_Addr)addend;
+		*where = addr;
+		break;
+	case R_386_32:	/* S + A - P */
+		addr = EF_SYMADDR(ef, symidx);
+		addr += addend;
+		*where = addr;
+		break;
+	case R_386_GLOB_DAT:	/* S */
+		addr = EF_SYMADDR(ef, symidx);
+		*where = addr;
+		break;
+	default:
+		warnx("unhandled relocation type %d", (int)rtype);
+	}
+	return (0);
+}