Almost all thunks are already ARMv5 safe, so we can just require this
architecture on the gas command line, to enforce compatibility with the
F1Cx00 series. This prevents accidental changes in the future.
The RMR thunk uses the ARMv7 only DSB/ISB instructions, but this runs on
ARMv8 cores only anyway, so we just force ARMv7 for this file, and avoid
code changes.
Signed-off-by: Andre Przywara <osp@andrep.de>
Currently the thunk we upload into the SRAM is using DSB and ISB
instructions, which were introduced in ARMv7. Also it relies on
movw/movt pairs, which became available in ARMv6T2.
The Allwinner F1Cx00 SoCs are using an ARMv5TE compliant core, so they
do not know these instructions.
Change the code to be ARMv5TE compliant, so it can run on all relevant
Allwinner ARM cores:
- One movw is just used to compare two bits, replace that with a
tst/tsteq sequence to skip the load.
- The other movw/movt pairs get replaced with ldr's, that load from
literal storage at the end of the code (from Icenowy).
- The DSB and ISB get replaced with their CP15 MCR counterparts. Those
are deprecated in ARMv7, but still work, when the CP15BEN bit is set
in SCTLR. We check for this in fel.c (from Icenowy). ISB is not
implemented on the ARM926, so make this conditional. A simple branch
takes care of the desired pipeline flush for the old SoC.
Also remove the rather pointless Ruby prolog that generates the header
file. We have a less awkward version of this in the Makefile, and need
that for the other thunks there anyway, so it's just duplicated code.
Embedding a header generator in Ruby in an assembly file is a cute
gimmick, but serves no purpose anymore.
This is based on work by Icenowy, who put a similar solution in a
separate file.
Originally-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Andre Przywara <osp@andrep.de>
This patch moves the scan for an ARM gcc into a separate shell
script. To prevent against recursion issues, the new script adds
"-maxdepth 1" to the find invocation; and it now also correctly
handles directories in $PATH that contain spaces in their name.
Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
This function provides bitwise clear/set operations on 32-bit words
via FEL. It may help with implementing future functionality, where
ARM register manipulations often involve such bit level access.
Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
"make headers" (which in turn invokes "make -C thunks/" should now
build the include files via awk, avoiding the need for ruby.
Signed-off-by: Bernhard Nortmann <bernhard.nortmann@web.de>
