u-boot/env/embedded.c
Christophe Leroy 23ac79ff80 common: env_embedded: allow fine placement of environment object
Commit 7653942b10 ("common/env_embedded.c: drop support for
CONFIG_SYS_USE_PPCENV") dropped the .ppcenv section which was
used in linking scripts to allow fine placement of embedded
environment sections.

This implies that GCC randomly places objects from env/embedded.o
and environment is not guaranteed to be located at the correct address:

04003df8 g     F .text  00000038 mii_init
04004000 g     O .text  00000004 env_size
04004004 g     O .text  00002000 environment
04006004 g     F .text  00000040 .hidden __lshrdi3

This patch restores this capability by allocating each object marked
with __UBOOT_ENV_SECTION__ into a different section. Hence
'environment' will be alone in .text.environment, allowing a
fine placement in u-boot.lds with:

		. = DEFINED(env_offset) ? env_offset : .;
		env/embedded.o			(.text.environment)

Fixes: 7653942b10 ("common/env_embedded.c: drop support for CONFIG_SYS_USE_PPCENV")
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
2018-04-06 16:30:37 -04:00

97 lines
2.4 KiB
C

/*
* (C) Copyright 2001
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com.
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <linux/kconfig.h>
#ifndef __ASSEMBLY__
#define __ASSEMBLY__ /* Dirty trick to get only #defines */
#endif
#define __ASM_STUB_PROCESSOR_H__ /* don't include asm/processor. */
#include <config.h>
#undef __ASSEMBLY__
#include <environment.h>
#include <linux/stringify.h>
/* Handle HOSTS that have prepended crap on symbol names, not TARGETS. */
#if defined(__APPLE__)
/* Leading underscore on symbols */
# define SYM_CHAR "_"
#else /* No leading character on symbols */
# define SYM_CHAR
#endif
/*
* Generate embedded environment table
* inside U-Boot image, if needed.
*/
#if defined(ENV_IS_EMBEDDED) || defined(CONFIG_BUILD_ENVCRC)
/*
* Put the environment in the .text section when we are building
* U-Boot proper. The host based program "tools/envcrc" does not need
* a seperate section.
*/
#if defined(USE_HOSTCC) /* Native for 'tools/envcrc' */
# define __UBOOT_ENV_SECTION__(name) /*XXX DO_NOT_DEL_THIS_COMMENT*/
#else /* Environment is embedded in U-Boot's .text section */
/* XXX - This only works with GNU C */
# define __UBOOT_ENV_SECTION__(name) __attribute__ ((section(".text."#name)))
#endif
/*
* Macros to generate global absolutes.
*/
#if defined(__bfin__)
# define GEN_SET_VALUE(name, value) \
asm(".set " GEN_SYMNAME(name) ", " GEN_VALUE(value))
#else
# define GEN_SET_VALUE(name, value) \
asm(GEN_SYMNAME(name) " = " GEN_VALUE(value))
#endif
#define GEN_SYMNAME(str) SYM_CHAR #str
#define GEN_VALUE(str) #str
#define GEN_ABS(name, value) \
asm(".globl " GEN_SYMNAME(name)); \
GEN_SET_VALUE(name, value)
/*
* Check to see if we are building with a
* computed CRC. Otherwise define it as ~0.
*/
#if !defined(ENV_CRC)
# define ENV_CRC (~0)
#endif
#define DEFAULT_ENV_INSTANCE_EMBEDDED
#include <env_default.h>
#ifdef CONFIG_ENV_ADDR_REDUND
env_t redundand_environment __UBOOT_ENV_SECTION__(redundand_environment) = {
0, /* CRC Sum: invalid */
0, /* Flags: invalid */
{
"\0"
}
};
#endif /* CONFIG_ENV_ADDR_REDUND */
/*
* These will end up in the .text section
* if the environment strings are embedded
* in the image. When this is used for
* tools/envcrc, they are placed in the
* .data/.sdata section.
*
*/
unsigned long env_size __UBOOT_ENV_SECTION__(env_size) = sizeof(env_t);
/*
* Add in absolutes.
*/
GEN_ABS(env_offset, CONFIG_ENV_OFFSET);
#endif /* ENV_IS_EMBEDDED */