u-boot/lib/asm-offsets.c
Kunihiko Hayashi 534f0fbd65 arm64: Fix relocation of env_addr if POSITION_INDEPENDENT=y
If both POSITION_INDEPENDENT and SYS_RELOC_GD_ENV_ADDR are enabled,
wherever original env is placed anywhere, it should be relocated to
the right address.

Relocation offset gd->reloc_off is calculated with SYS_TEXT_BASE in
setup_reloc() and env address gd->env_addr is relocated by the offset in
initr_reloc_global_data().

gd->env_addr
  = (orig env) + gd->reloc_off
  = (orig env) + (gd->relocaddr - SYS_TEXT_BASE)

However, SYS_TEXT_BASE isn't always runtime base address when
POSITION_INDEPENDENT is enabled. So the relocated env_addr might point to
wrong address. For example, if SYS_TEXT_BASE is zero, gd->env_addr is
out of memory location and memory exception will occur.

There is a difference between linked address such as SYS_TEXT_BASE and
runtime base address. In _main, the difference is calculated as
"run-vs-link" offset. The env_addr should also be added to the offset
to fix the address.

gd->env_addr
  = (orig env) + ("run-vs-link" offset)   + gd->reloc_off
  = (orig env) + (SYS_TEXT_BASE - _start) + (gd->relocaddr - SYS_TEXT_BASE)
  = (orig env) + (gd->relocaddr - _start)

Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Acked-by: Marek Vasut <marex@denx.de>
Tested-by: Marek Vasut <marex@denx.de>
2021-06-28 14:47:10 -04:00

47 lines
1.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Adapted from Linux v2.6.36 kernel: arch/powerpc/kernel/asm-offsets.c
*
* This program is used to generate definitions needed by
* assembly language modules.
*
* We use the technique used in the OSF Mach kernel code:
* generate asm statements containing #defines,
* compile this file to assembler, and then extract the
* #defines from the assembly-language output.
*/
#include <common.h>
#include <asm-offsets.h>
#include <asm/global_data.h>
#include <linux/kbuild.h>
int main(void)
{
/* Round up to make sure size gives nice stack alignment */
DEFINE(GENERATED_GBL_DATA_SIZE,
(sizeof(struct global_data) + 15) & ~15);
DEFINE(GENERATED_BD_INFO_SIZE,
(sizeof(struct bd_info) + 15) & ~15);
DEFINE(GD_SIZE, sizeof(struct global_data));
DEFINE(GD_BD, offsetof(struct global_data, bd));
#if CONFIG_VAL(SYS_MALLOC_F_LEN)
DEFINE(GD_MALLOC_BASE, offsetof(struct global_data, malloc_base));
#endif
DEFINE(GD_RELOCADDR, offsetof(struct global_data, relocaddr));
DEFINE(GD_RELOC_OFF, offsetof(struct global_data, reloc_off));
DEFINE(GD_START_ADDR_SP, offsetof(struct global_data, start_addr_sp));
DEFINE(GD_NEW_GD, offsetof(struct global_data, new_gd));
DEFINE(GD_ENV_ADDR, offsetof(struct global_data, env_addr));
return 0;
}