Re: [Patch][gas][arm] Make .fpu reset the FPU/Coprocessor feature bits

[Mihail Ionescu <mihail dot ionescu at foss dot arm dot com>]

Hi,


On 11/21/2019 10:05 AM, Mihail Ionescu wrote:
> Hi Nathan,
>
> On 11/20/2019 03:19 AM, Nathan Chancellor wrote:
> > On Tue, Nov 12, 2019 at 12:22:47PM +0000, Nick Clifton wrote:
> > > Hi Mihail,
> > >
> > > > gas/ChangeLog:
> > > >
> > > > 2019-11-11  Mihail Ionescu  <mihail.ionescu@arm.com>
> > > >
> > > >     * config/tc-arm.c (s_arm_fpu): Clear selected_cpu fpu bits.
> > > >     (fpu_any): Remove OBJ_ELF guards.
> > > >     * gas/testsuite/gas/arm/fpu-rst.s: New.
> > > >     * gas/testsuite/gas/arm/fpu-rst.d: New.
> > > >     * gas/testsuite/gas/arm/fpu-rst.l: New.
> > >
> > > Approved - please apply.
> > >
> > > Cheers
> > >    Nick
> >
> > For what it's worth, this commit breaks building the Linux kernel for me:
> >
> > $ make -j$(nproc) -s ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- 
> > O=out.arm32 distclean defconfig arch/arm/crypto/
> > ../arch/arm/crypto/crc32-ce-core.S: Assembler messages:
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32w r0,r0,r2' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32w r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32w r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32h r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32b r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32b r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:300: Error: selected processor does 
> > not support `crc32h r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32cw r0,r0,r2' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32cw r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32cw r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32ch r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32cb r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32cb r0,r0,r3' in ARM mode
> > ../arch/arm/crypto/crc32-ce-core.S:305: Error: selected processor does 
> > not support `crc32ch r0,r0,r3' in ARM mode
> > ../scripts/Makefile.build:357: recipe for target 
> > 'arch/arm/crypto/crc32-ce-core.o' failed
> > make[3]: *** [arch/arm/crypto/crc32-ce-core.o] Error 1
> > make[3]: *** Waiting for unfinished jobs....
> > ../Makefile:1652: recipe for target 'arch/arm/crypto' failed
> > make[2]: *** [arch/arm/crypto] Error 2
> > make[2]: *** Waiting for unfinished jobs....
> > /home/nathan/src/linux/Makefile:326: recipe for target 
> > '__build_one_by_one' failed
> > make[1]: *** [__build_one_by_one] Error 2
> > Makefile:179: recipe for target 'sub-make' failed
> > make: *** [sub-make] Error 2
> >
> > $ git bisect log
> > # bad: [fa4dea24454e132e677b98c21d23e87e5041e1af] Automatic date 
> > update in version.in
> > # good: [e264b5b7a57dab997776ae845f9e0b3e5f20c713] Allow the --output 
> > option of the "ar" prorgam to extract files to locations outside of 
> > the current directory.
> > git bisect start 'origin/master' 'e264b5b7a5'
> > # bad: [31175a0d7167ab7f98878076be02dc4330b825bb] Automatic date 
> > update in version.in
> > git bisect bad 31175a0d7167ab7f98878076be02dc4330b825bb
> > # good: [cf57ad6d61771f608079f31db10a93872a4553c5] gdb_vecs.h: Avoid 
> > self move assign
> > git bisect good cf57ad6d61771f608079f31db10a93872a4553c5
> > # good: [aa16be3993e2b29d4f6a774fca82c67a43956864] Automatic date 
> > update in version.in
> > git bisect good aa16be3993e2b29d4f6a774fca82c67a43956864
> > # bad: [ef8f595f73a6b42f745bc76a716f45079eae1075] [gas][arm] Enable 
> > VLDM, VSTM, VPUSH, VPOP for MVE
> > git bisect bad ef8f595f73a6b42f745bc76a716f45079eae1075
> > # good: [51c8edf68bf1e16c6d05fbb31a36e0cc436a9750] x86: fold EsSeg 
> > into IsString
> > git bisect good 51c8edf68bf1e16c6d05fbb31a36e0cc436a9750
> > # bad: [ce760a762093d59a3faab07fff895b484071977c] [binutils][arm] 
> > Update the decoding of MVE VMOV, VMVN
> > git bisect bad ce760a762093d59a3faab07fff895b484071977c
> > # bad: [f439988037a589de3798f44e7268301adaec21a9] [gas][arm] Make .fpu 
> > reset the FPU/Coprocessor feature bits
> > git bisect bad f439988037a589de3798f44e7268301adaec21a9
> > # first bad commit: [f439988037a589de3798f44e7268301adaec21a9] 
> > [gas][arm] Make .fpu reset the FPU/Coprocessor feature bits
> >
> > Let me know if there is anything I can do to test a fix (either on the
> > binutils or kernel side).
>
> I'm looking into the failure.

The issue was causes by crc using the fpu feature bits instead of the 
core feature bits. I've got a fix for it here:
https://sourceware.org/ml/binutils/2019-11/msg00286.html

> > Cheers,
> > Nathan
>
> Regards,
> Mihail

Regards,
Mihail