From 3ebd1cbc49f0005092d69cf0d9a6e64d7a1c300b Mon Sep 17 00:00:00 2001 From: Albert ARIBAUD Date: Mon, 25 Feb 2013 00:58:59 +0000 Subject: arm: make __bss_start and __bss_end__ compiler-generated Turn __bss_start and __bss_end__ from linker-generated to compiler-generated symbols, causing relocations for these symbols to change type, from R_ARM_ABS32 to R_ARM_RELATIVE. This should have no functional impact, as it affects references to __bss_start and __bss_end__ only before relocation, and no such references are done. Signed-off-by: Albert ARIBAUD --- arch/arm/lib/Makefile | 1 + arch/arm/lib/bss.c | 39 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 40 insertions(+) create mode 100644 arch/arm/lib/bss.c (limited to 'arch/arm/lib') diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 57111af..11c2674 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -39,6 +39,7 @@ GLCOBJS += div0.o SOBJS-y += crt0.o ifndef CONFIG_SPL_BUILD +COBJS-y += bss.o COBJS-y += board.o COBJS-y += bootm.o COBJS-$(CONFIG_SYS_L2_PL310) += cache-pl310.o diff --git a/arch/arm/lib/bss.c b/arch/arm/lib/bss.c new file mode 100644 index 0000000..7c0b154 --- /dev/null +++ b/arch/arm/lib/bss.c @@ -0,0 +1,39 @@ +/* + * Copyright 2013 Albert ARIBAUD + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ + +/** + * These two symbols are declared in a C file so that the linker + * uses R_ARM_RELATIVE relocation, rather than the R_ARM_ABS32 one + * it would use if the symbols were defined in the linker file. + * Using only R_ARM_RELATIVE relocation ensures that references to + * the symbols are correct after as well as before relocation. + * + * We need a 0-byte-size type for these symbols, and the compiler + * does not allow defining objects of C type 'void'. Using an empty + * struct is allowed by the compiler, but causes gcc versions 4.4 and + * below to complain about aliasing. Therefore we use the next best + * thing: zero-sized arrays, which are both 0-byte-size and exempt from + * aliasing warnings. + */ + +char __bss_start[0] __attribute__((used, section(".__bss_start"))); +char __bss_end__[0] __attribute__((used, section(".__bss_end__"))); -- cgit v1.1