arm: ARMv4 assembly compatibility
There is currently a problem that U-Boot can not work on ARMv4
because assembly imlementations of memcpy() and some other functions
use "bx lr" instruction that is not available on ARMv4 ("mov pc, lr"
should be used instead).
A working preprocessor-based solution to this problem is found in
arch/arm/lib/relocate.S. Move it to the "ret" macro in
arch/arm/include/asm/assembler.h and change all "bx lr" code
to "ret lr" in functions that may run on ARMv4. Linux source code
deals with this problem in the same manner.
v1 -> v2:
Comment update. Pointed out by Andre Przywara.
Signed-off-by: Sergei Antonov <saproj@gmail.com>
CC: Samuel Holland <samuel@sholland.org>
CC: Ye Li <ye.li@nxp.com>
CC: Simon Glass <sjg@chromium.org>
CC: Andre Przywara <andre.przywara@arm.com>
CC: Marek Vasut <marex@denx.de>
CC: Sean Anderson <sean.anderson@seco.com>
CC: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S
index eee7a21..a1c996f 100644
--- a/arch/arm/lib/memcpy.S
+++ b/arch/arm/lib/memcpy.S
@@ -59,7 +59,7 @@
#endif
ENTRY(memcpy)
cmp r0, r1
- bxeq lr
+ reteq lr
enter r4, lr
@@ -148,7 +148,7 @@
str1b r0, ip, cs, abort=21f
exit r4, lr
- bx lr
+ ret lr
9: rsb ip, ip, #4
cmp ip, #2
@@ -258,7 +258,7 @@
.macro copy_abort_end
ldmfd sp!, {r4, lr}
- bx lr
+ ret lr
.endm
ENDPROC(memcpy)