arm: move gd handling outside of C code
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>
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 4f2a712..2f4c14e 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -85,6 +85,8 @@
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 @@
bl spl_relocate_stack_gd
cmp r0, #0
movne sp, r0
+ movne r9, r0
# endif
ldr r0, =__bss_start /* this is auto-relocated! */