Add arm64 ifunc support in static binaries

Add support for the R_AARCH64_IRELATIVE relocation type in static
binaries on arm64. This is based on the powerpc code, updating it to
use the arm64 resolver ABI, and use the arm64 relocation type.

Tested by:	brd
Reviewed by:	kib
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D31641

3 files changed, 51 insertions, 2 deletions

diff --git a/lib/csu/aarch64/Makefile b/lib/csu/aarch64/Makefile
index 666bf569b786..e4c9029fcacc 100644
--- a/lib/csu/aarch64/Makefile
+++ b/lib/csu/aarch64/Makefile
@@ -2,7 +2,8 @@
 
 .PATH: ${.CURDIR:H}/common
 
-CFLAGS+=	-DCRT_IRELOC_SUPPRESS
+CFLAGS+=	-I${.CURDIR}
+CFLAGS+=	-DCRT_IRELOC_RELA
 
 CRT1OBJS+=	crt1_s.o
 
diff --git a/lib/csu/aarch64/crt1_c.c b/lib/csu/aarch64/crt1_c.c
index d8c2156ffc21..9b3ffbff22d0 100644
--- a/lib/csu/aarch64/crt1_c.c
+++ b/lib/csu/aarch64/crt1_c.c
@@ -57,8 +57,10 @@ __start(int argc, char *argv[], char *env[], void (*cleanup)(void))
 
 	if (&_DYNAMIC != NULL)
 		atexit(cleanup);
-	else
+	else {
+		process_irelocs();
 		_init_tls();
+	}
 
 #ifdef GCRT
 	atexit(_mcleanup);
diff --git a/lib/csu/aarch64/reloc.c b/lib/csu/aarch64/reloc.c
new file mode 100644
index 000000000000..f3dbf3e3b570
--- /dev/null
+++ b/lib/csu/aarch64/reloc.c
@@ -0,0 +1,46 @@
+/*-
+ * Copyright (c) 2019 Leandro Lupori
+ * Copyright (c) 2021 The FreeBSD Foundation
+ *
+ * Portions of this software were developed by Andrew Turner
+ * under sponsorship from the FreeBSD Foundation.
+ *
+ * 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.
+ *
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+static void
+crt1_handle_rela(const Elf_Rela *r)
+{
+	typedef Elf_Addr (*ifunc_resolver_t)(
+	    uint64_t, uint64_t, uint64_t, uint64_t,
+	    uint64_t, uint64_t, uint64_t, uint64_t);
+	Elf_Addr *ptr, *where, target;
+
+	switch (ELF_R_TYPE(r->r_info)) {
+	case R_AARCH64_IRELATIVE:
+		ptr = (Elf_Addr *)r->r_addend;
+		where = (Elf_Addr *)r->r_offset;
+		target = ((ifunc_resolver_t)ptr)(0, 0, 0, 0, 0, 0, 0, 0);
+		*where = target;
+		break;
+	}
+}