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arm: move gd handling outside of C code

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As of gcc 5.2.1 for Thumb-1, it is not possible any
more to assign gd from C code, as gd is mapped to r9,
and r9 may now be saved in the prolog sequence, and
restored in the epilog sequence, of any C functions.

Therefore arch_setup_gd(), which is supposed to set
r9, may actually have no effect, causing U-Boot to
use a bad address to access GD.

Fix this by never calling arch_setup_gd() for ARM,
and instead setting r9 in arch/arm/lib/crt0.S, to
the value returned by board_init_f_alloc_reserve().

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Albert ARIBAUD 2015-11-25 17:56:33 +01:00 committed by Tom Rini
parent ecc306639e
commit adc421e4ce
3 changed files with 22 additions and 15 deletions
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3
arch/arm/lib/crt0.S
View File

@ -85,6 +85,8 @@ ENTRY(_main)
mov r0, sp
bl board_init_f_alloc_reserve
mov sp, r0
/* set up gd here, outside any C code */
mov r9, r0
bl board_init_f_init_reserve
mov r0, #0
@ -134,6 +136,7 @@ here:
bl spl_relocate_stack_gd
cmp r0, #0
movne sp, r0
movne r9, r0
# endif
ldr r0, =__bss_start /* this is auto-relocated! */

8
common/init/board_init.c
View File

@ -21,13 +21,13 @@ DECLARE_GLOBAL_DATA_PTR;
#define _USE_MEMCPY
#endif
/* Unfortunately x86 can't compile this code as gd cannot be assigned */
#ifndef CONFIG_X86
/* Unfortunately x86 or ARM can't compile this code as gd cannot be assigned */
#if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
__weak void arch_setup_gd(struct global_data *gd_ptr)
{
gd = gd_ptr;
}
#endif /* !CONFIG_X86 */
#endif /* !CONFIG_X86 && !CONFIG_ARM */
/*
* Allocate reserved space for use as 'globals' from 'top' address and
@ -128,7 +128,7 @@ void board_init_f_init_reserve(ulong base)
*ptr++ = 0;
#endif
/* set GD unless architecture did it already */
#ifndef CONFIG_X86
#if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
arch_setup_gd(gd_ptr);
#endif
/* next alloc will be higher by one GD plus 16-byte alignment */

26
common/spl/spl.c
View File

@ -431,8 +431,13 @@ void preloader_console_init(void)
* more stack space for things like the MMC sub-system.
*
* This function calculates the stack position, copies the global_data into
* place and returns the new stack position. The caller is responsible for
* setting up the sp register.
* place, sets the new gd (except for ARM, for which setting GD within a C
* function may not always work) and returns the new stack position. The
* caller is responsible for setting up the sp register and, in the case
* of ARM, setting up gd.
*
* All of this is done using the same layout and alignments as done in
* board_init_f_init_reserve() / board_init_f_alloc_reserve().
*
* @return new stack location, or 0 to use the same stack
*/
@ -440,14 +445,7 @@ ulong spl_relocate_stack_gd(void)
{
#ifdef CONFIG_SPL_STACK_R
gd_t *new_gd;
ulong ptr;
/* Get stack position: use 8-byte alignment for ABI compliance */
ptr = CONFIG_SPL_STACK_R_ADDR - sizeof(gd_t);
ptr &= ~7;
new_gd = (gd_t *)ptr;
memcpy(new_gd, (void *)gd, sizeof(gd_t));
gd = new_gd;
ulong ptr = CONFIG_SPL_STACK_R_ADDR;
#ifdef CONFIG_SPL_SYS_MALLOC_SIMPLE
if (CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN) {
@ -460,7 +458,13 @@ ulong spl_relocate_stack_gd(void)
gd->malloc_ptr = 0;
}
#endif
/* Get stack position: use 8-byte alignment for ABI compliance */
ptr = CONFIG_SPL_STACK_R_ADDR - roundup(sizeof(gd_t),16);
new_gd = (gd_t *)ptr;
memcpy(new_gd, (void *)gd, sizeof(gd_t));
#if !defined(CONFIG_ARM)
gd = new_gd;
#endif
return ptr;
#else
return 0;