Messages in this thread | | | Subject | Re: linux-parisc compile failure in current git | From | Helge Deller <> | Date | Thu, 10 Jun 2021 09:03:34 +0200 |
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Hi Masahiro,
On 6/10/21 4:03 AM, Masahiro Yamada wrote: > On Thu, Jun 10, 2021 at 7:50 AM Helge Deller <deller@gmx.de> wrote: >> >> On 6/1/21 12:21 PM, Meelis Roos wrote: >>> Upstream Linux git fails to compile on gentoo hppa - .config below. >>> I have 2 gcc-s as always: >>> $ gcc-config -l >>> [1] hppa2.0-unknown-linux-gnu-9.3.0 >>> [2] hppa2.0-unknown-linux-gnu-10.2.0 * >>> >>> [3] hppa64-unknown-linux-gnu-10.2.0 * >> >> >> I see the same issue too, but only when compiling natively on a parisc machine. >> Cross-compiling on a x86 box works nicely. >> >> First I thought it's a problem with setting the "cross_compiling" flag in ./Makefile. >> But that's not sufficient. >> >> On a x86 machine (which builds fine) I get >> SRCARCH=parisc SUBARCH=x86 UTS_MACHINE=parisc >> The arch/parisc/kernel/asm-offsets.c file gets preprocessed via: >> hppa64-linux-gnu-gcc >> >> On a native 32bit parisc machine I have: >> SRCARCH=parisc SUBARCH=parisc UTS_MACHINE=parisc >> Here the arch/parisc/kernel/asm-offsets.c file gets preprocessed via: >> gcc >> Instead here the native hppa64-linux-gnu-gcc (cross compiler) should have been used too, since >> we build a 64-bit hppa kernel (CONFIG_64BIT is set). >> Note, on hppa we don't have an "-m64" compiler flag as on x86. > > I see. > hppa is not a bi-arch compiler, in other words, > http- and hppa64- are separate compilers.
Yes.
>> Mashahiro, do you maybe have an idea what gets wrong here, or which >> patch has changed the behaviour how the asm-offsets.c file gets preprocessed? > > Presumably, commit 23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3 > > Prior to that commit, arch/parisc/Makefile was like this: > > ifneq ($(SUBARCH),$(UTS_MACHINE)) > ifeq ($(CROSS_COMPILE),) > ... > > Now I understand why arch/parisc/Makefile was written this way. > > Reverting the change in arch/parisc/Makefile will restore the original behavior.
Sadly, reverting this change (23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3) does not restore the original behavior.
> But, please keep in mind that there is an issue remaining. > > Please see this code: > > ifdef CONFIG_64BIT > UTS_MACHINE := parisc64 > CHECKFLAGS += -D__LP64__=1 > CC_ARCHES = hppa64 > LD_BFD := elf64-hppa-linux > else # 32-bit > CC_ARCHES = hppa hppa2.0 hppa1.1 > LD_BFD := elf32-hppa-linux > endif > > > UTS_MACHINE is determined by CONFIG_64BIT. > > CONFIG_64BIT is defined only after Kconfig is finished. > When you are trying to configure the .config, > CONFIG_64BIT is not defined yet. > So UTS_MACHINE is always 'parisc'.
Yes. See above, but it worked when I had SUBARCH=x86 (when running my laptop).
> As you know, Kconfig files now have a bunch of 'cc-option' syntax > to check the compiler capability in Kconfig time. > Hence, you need to provide a proper compiler in Kconfig time too. > > When you build a 64-bit parisc kernel on a 32-bit parisc machine,
Please note, that we don't have a 64-bit parisc userspace yet (just kernel). This means, that all builds on parisc machines are 32bit and do a cross-compilation to a parisc64 kernel if requested in the .config.
> Kconfig is passed with CC=gcc since SUBARCH==UTS_MACHINE==parisc. > After Kconfig, CROSS_COMPILE=hppa64-* is set, > and the kernel is built by CC=hppa64-*-gcc.
Right. That is the old behaviour. Based on the CONFIG_64BIT option the hppa64 compiler is choosen for CROSS_COMPILE.
> So, Kconfig evaluated a compiletely different compiler. This is pointless.
Yes, probably.
> There are some options > > [option 1] > revert the parisc bit of 23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3 > This will restore the functionality you may want, but > as I said above, Kconfig is doing pointless things.
as mentioned above: Doesn't solve the issue.
> [option 2] > Stop using cc-cross-prefix, and pass CROSS_COMPILE explicitly. > This is what many architectures including arm, arm64 do. > You need to explicitly pass CROSS_COMPILE=aarch64-linux-gnu- etc. > if you are cross-compiling arm64.
Might be an option, but it's not as handy as simply choosing CONFIG_64BIT and then things are done automatically.
> [option 3] > Introduce ARCH=parisc64. > > When you are building 64-bit kernel, you can pass ARCH=parisc64 > A patch attached. (but not tested much)
Tried it, but doesn't work. asm-offsets.c is still preprocessed with 32bit compiler (gcc, not hppa20-gcc).
Thanks for your help so far! If you like I'm happy to give you an account on a hppa64 machine to reproduce yourself. I'll now try to bisect where it goes wrong. There must be something else before commit 23243c1ace9fb4eae2f75e0fe0ece8e3219fb4f3.
Helge
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