Messages in this thread | | | Date | Tue, 6 Jun 2017 19:39:04 +0200 | From | Karsten Merker <> | Subject | Re: [PATCH 1/7] RISC-V: Top-Level Makefile for riscv{32,64} |
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On Mon, Jun 05, 2017 at 09:56:33PM -0700, Palmer Dabbelt wrote: > On Mon, 29 May 2017 03:50:47 PDT (-0700), Arnd Bergmann wrote: > > On Sat, May 27, 2017 at 2:57 AM, Palmer Dabbelt <palmer@dabbelt.com> wrote: > >> On Tue, 23 May 2017 04:30:50 PDT (-0700), Arnd Bergmann wrote: > >>> On Tue, May 23, 2017 at 2:41 AM, Palmer Dabbelt <palmer@dabbelt.com> 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. > > > > Right, but my point is that a new architecture should not rely on 'ARCH=' > > to pick the defconfig, we only do that on a couple of architectures for > > backwards compatibility with old scripts. > > > >> 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 ($(ARCH),sparc32) > >> SRCARCH := sparc > >> > >> then I'll end up with "uname -m" as "riscv" -- I haven't tried it, but that's > >> why we ended up with this diff in the first place. > > > > Do you mean the "uname -m" output comes from "${SRCARCH}" at > > the time of the kernel build? That would be easy enough to change > > by simply hardcoding it depending on CONFIG_64BIT. > > OK, I didn't know about COMPAT_UTS_MACHINE. That's a much better solution, > I'll use that.
Hello Palmer,
I suppose the commit:
https://github.com/riscv/riscv-linux/commit/8c826930d2a19ecd4f1036f10a380dc4fddd0da5
aims to address this, but it appears to be incomplete. It lacks the first fragment of the patch above, i.e. the conversion from the "uname -m" output (i.e. "riscv{64,32}") to the canonical arch string (i.e. "riscv"). As a result, a native build (which normally doesn't explicitly pass ARCH=riscv to make and therefore relies on the output of "uname -m") would fail.
Regards, Karsten -- Gem. Par. 28 Abs. 4 Bundesdatenschutzgesetz widerspreche ich der Nutzung sowie der Weitergabe meiner personenbezogenen Daten für Zwecke der Werbung sowie der Markt- oder Meinungsforschung.
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