xref: /openbmc/u-boot/arch/arm/lib/sections.c (revision b46694df)
1 /*
2  * Copyright 2013 Albert ARIBAUD <albert.u.boot@aribaud.net>
3  *
4  * See file CREDITS for list of people who contributed to this
5  * project.
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License as
9  * published by the Free Software Foundation; either version 2 of
10  * the License, or (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
20  * MA 02111-1307 USA
21  */
22 
23 /**
24  * These two symbols are declared in a C file so that the linker
25  * uses R_ARM_RELATIVE relocation, rather than the R_ARM_ABS32 one
26  * it would use if the symbols were defined in the linker file.
27  * Using only R_ARM_RELATIVE relocation ensures that references to
28  * the symbols are correct after as well as before relocation.
29  *
30  * We need a 0-byte-size type for these symbols, and the compiler
31  * does not allow defining objects of C type 'void'. Using an empty
32  * struct is allowed by the compiler, but causes gcc versions 4.4 and
33  * below to complain about aliasing. Therefore we use the next best
34  * thing: zero-sized arrays, which are both 0-byte-size and exempt from
35  * aliasing warnings.
36  */
37 
38 char __bss_start[0] __attribute__((section(".__bss_start")));
39 char __bss_end[0] __attribute__((section(".__bss_end")));
40 char __image_copy_start[0] __attribute__((section(".__image_copy_start")));
41 char __image_copy_end[0] __attribute__((section(".__image_copy_end")));
42 char __rel_dyn_start[0] __attribute__((section(".__rel_dyn_start")));
43 char __rel_dyn_end[0] __attribute__((section(".__rel_dyn_end")));
44