arc: Introduce a possibility to not relocate U-boot
Disabling relocation might be useful on ARC for 2 reasons:
a) For advanced debugging with Synopsys proprietary MetaWare debugger
which is capable of accessing much more specific hardware resources
compared to gdb. For example it may show contents of L1 and L2 caches,
internal states of some hardware blocks etc.
But on the downside MetaWare debugger still cannot work with PIE.
Even though that limitation could be work-arounded with change of ELF's
header and stripping down all debug info but with it we won't have
debug info for source-level debugging which is quite inconvenient.
b) Some platforms which might benefit from usage of U-Boot basically
don't have enough RAM to accommodate relocation of U-Boot so we
keep code in flash and use as much of RAM as possible for more
interesting things.
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: York Sun <york.sun@nxp.com>
Cc: Stefan Roese <sr@denx.de>
diff --git a/arch/arc/lib/start.S b/arch/arc/lib/start.S
index ac9944c..c78dd00 100644
--- a/arch/arc/lib/start.S
+++ b/arch/arc/lib/start.S
@@ -78,7 +78,13 @@
/* Zero the one and only argument of "board_init_f" */
mov_s %r0, 0
- j board_init_f
+ bl board_init_f
+
+ /* We only get here if relocation is disabled by GD_FLG_SKIP_RELOC */
+ /* Make sure we don't lose GD overwritten by zero new GD */
+ mov %r0, %r25
+ mov %r1, 0
+ bl board_init_r
ENDPROC(_start)
/*