From e3feeaa73b8056c3565139cefb959c33a5e68541 Mon Sep 17 00:00:00 2001
From: matt <matt@NetBSD.org>
Date: Wed, 24 Apr 2013 22:32:29 +0000
Subject: [PATCH] Add a ld.elf_so internals version of __gnu_Unwind_Find_exidx
 for that the libgcc EHABI can find the exception tables for a supplied PC.

---
 libexec/ld.elf_so/arch/arm/find_exidx.c | 86 +++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 libexec/ld.elf_so/arch/arm/find_exidx.c

diff --git a/libexec/ld.elf_so/arch/arm/find_exidx.c b/libexec/ld.elf_so/arch/arm/find_exidx.c
new file mode 100644
index 000000000000..ea162dac1af9
--- /dev/null
+++ b/libexec/ld.elf_so/arch/arm/find_exidx.c
@@ -0,0 +1,86 @@
+/*-
+ * Copyright (c) 2013 The NetBSD Foundation, Inc.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Matt Thomas of 3am Software Foundry.
+ *
+ * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+__RCSID("$NetBSD: find_exidx.c,v 1.1 2013/04/24 22:32:29 matt Exp $");
+#endif /* not lint */
+
+#include "debug.h"
+#include "rtld.h"
+
+_Unwind_Ptr
+__gnu_Unwind_Find_exidx(_Unwind_Ptr pc, int * pcount)
+{
+	const Obj_Entry *obj;
+	_Unwind_Ptr start = NULL;
+	int count = 0;
+
+	dbg(("__gnu_Unwind_Find_exidx"));
+
+	_rtld_shared_enter();
+
+	vaddr_t va = (vaddr_t)pc; 
+	for (obj = _rtld_objlist; obj != NULL; obj = obj->next) {
+		/*
+		 * If the address we are looking for is inside this object,
+		 * we've found the object to inspect.
+		 */
+		if ((vaddr_t)obj->mapbase <= va
+		    && va < (vaddr_t)obj->mapbase + obj->mapsize)
+			break;
+	}
+
+	/*
+	 * If we found an object and it has some exception data, we 
+	 * need to see if the address matches a PT_LOAD section.
+	 */
+	if (obj != NULL && obj->exidx_start != NULL) {
+		va -= (vaddr_t)obj->mapbase;
+		const Elf_Phdr *ph = obj->phdr;
+		const Elf_Phdr * const phlimit = ph + obj->phsize / sizeof(*ph);
+		for (; ph < phlimit; ph++) {
+			if (ph->p_type == PT_LOAD
+			    && ph->p_vaddr <= va
+			    && va < ph->p_vaddr + ph->p_memsz) {
+				count = obj->exidx_sz / 8;
+				start = obj->exidx_start;
+				break;
+			}
+		}
+	}
+
+	_rtld_shared_exit();
+
+	/*
+	 * deal with the return values.
+	 */
+	*pcount = count;
+	return start;
+}