On Tue, 23 May 2017 04:30:50 PDT (-0700), Arnd Bergmann wrote:
> On Tue, May 23, 2017 at 2:41 AM, Palmer Dabbelt <[email protected]> wrote:
>> RISC-V has both 32-bit and 64-bit base ISAs, but they are very similar.
>> Like some other platforms, we'd like to share one arch directory between
>> the two of them.
>
> I think we mainly do the others for backwards-compatibility with ancient
> build scripts, and we don't need that here. Instead, you could add one more
> line to the 'SUBARCH:=' statement that interprets the uname output.
I don't think that does the same thing. The desired effect of this diff is:
* "uname -m" when running on a RISC-V machine returns either riscv32 or
riscv64, as that's what tools like autoconf expect when trying to find
tuples.
* I can cross compile for riscv32 and riscv64. That's currently controlled by
a Kconfig setting, but ARCH=riscv32 vs ARCH=riscv64 controlls what defconfig
sets.
* I can natively compile for riscv32 and riscv64. That uses the same Kconfig
setting, and the same ARCH=riscv32 vs ARCH=riscv64 switch for defconfig.
Neither of the two Kconfig issues is a big deal, but we de need "uname -m" to
return "riscv64" or "riscv32" not "riscv". I think the only way to do that is
to set SRCARCH, but I'd be happy to change it if there's a better way. I think
if I just do this
diff --git a/Makefile b/Makefile
index 0606f28..4adc609 100644
--- a/Makefile
+++ b/Makefile
@@ -232,7 +232,8 @@ SUBARCH := $(shell uname -m | sed -e s/i.86/x86/ -e
s/x86_64/x86/ \
-e s/arm.*/arm/ -e s/sa110/arm/ \
-e s/s390x/s390/ -e s/parisc64/parisc/ \
-e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
- -e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ )
+ -e s/sh[234].*/sh/ -e s/aarch64.*/arm64/ \
+ -e s/riscv.*/riscv/ )
# Cross compiling and selecting different set of gcc/bin-utils
# ---------------------------------------------------------------------------
@@ -269,14 +270,6 @@ ifeq ($(ARCH),x86_64)
SRCARCH := x86
endif
-# Additional ARCH settings for RISC-V
-ifeq ($(ARCH),riscv32)
- SRCARCH := riscv
-endif
-ifeq ($(ARCH),riscv64)
- SRCARCH := riscv
-endif
-
# Additional ARCH settings for sparc
ifeq ($(ARCH),sparc32)
SRCARCH := sparc
then I'll end up with "uname -m" as "riscv" -- I haven't tried it, but that's
why we ended up with this diff in the first place.
