Subject: Re: next: Build errors due to 'MIPS: Add probing & defs for VZ & guest features'

From: James Hogan <[email-masked]>
Date: Sat, 14 May 2016 16:52:06 +0100

On Sat, May 14, 2016 at 08:19:50AM -0700, Guenter Roeck wrote:
> James,
> 
> your patch 'MIPS: Add probing & defs for VZ & guest features' causes build errors
> in -next when using gcc 4.7.4 / binutils 2.24. This affects almost all mips builds.

Thanks Guenter. Hmm, I thought virt extensions were supported since
binutils 2.24, odd.

I'll look into implementing a workaround for toolchains that don't
support it.

Cheers
James

> 
> {standard input}: Assembler messages:
> {standard input}:3306: Warning: Tried to set unrecognized symbol: virt
> {standard input}:3307: Error: Unrecognized opcode `mfgc0 $3,$16,0'
> 
> and lots of similar messages when building arch/mips/kernel/cpu-probe.o.
> 
> Build is fine with gcc 5.2.0 and binutils 2.5.
> 
> Bisect log is attached.
> 
> Guenter
> 
> ---
> Bisect log:
> 
> # bad: [7fd1a8676b7f573be6aa8072e8fa1d4f1bbf8ea7] Add linux-next specific files for 20160513
> # good: [44549e8f5eea4e0a41b487b63e616cb089922b99] Linux 4.6-rc7
> git bisect start 'HEAD' 'v4.6-rc7'
> # bad: [d573c57f72f32687ed2d11ba60ee5e6f5746ccde] Merge remote-tracking branch 'crypto/master'
> git bisect bad d573c57f72f32687ed2d11ba60ee5e6f5746ccde
> # bad: [cea0bc891cbcb9cd57a95c0fe03cb16ce3716125] Merge branch 'jdelvare-hwmon/master'
> git bisect bad cea0bc891cbcb9cd57a95c0fe03cb16ce3716125
> # good: [ffa24f116d6f3925e0eebcd4d4ae30d9ac237459] Merge remote-tracking branch 'tegra/for-next'
> git bisect good ffa24f116d6f3925e0eebcd4d4ae30d9ac237459
> # bad: [cb4699056080a4a094be6080e10c692af0794d93] Merge remote-tracking branch 'btrfs-kdave/for-next'
> git bisect bad cb4699056080a4a094be6080e10c692af0794d93
> # bad: [9f2e34d4ff5756624948fe7976866749664793c7] Merge remote-tracking branch 'mips/mips-for-linux-next'
> git bisect bad 9f2e34d4ff5756624948fe7976866749664793c7
> # good: [fe33223366b2c02394274395f4ac43e48c453654] MIPS: Separate XPA CPU feature into LPA and MVH
> git bisect good fe33223366b2c02394274395f4ac43e48c453654
> # good: [5eae0ba2589f767b5c9c14e662f972084b4a46d7] Merge remote-tracking branch 'arm64/for-next/core'
> git bisect good 5eae0ba2589f767b5c9c14e662f972084b4a46d7
> # bad: [9ca0b767b011347402eb083f887629b27c8eda54] Merge branch '4.6-fixes' into mips-for-linux-next
> git bisect bad 9ca0b767b011347402eb083f887629b27c8eda54
> # good: [128639395b2ceacc6a56a0141d0261012bfe04d3] MIPS: Adjust set_pte() SMP fix to handle R10000_LLSC_WAR
> git bisect good 128639395b2ceacc6a56a0141d0261012bfe04d3
> # good: [6768a2c2e1310acb3e8e8e63a6e2caa146d19d0e] MIPS: BMIPS: BMIPS4380 and BMIPS5000 support RIXI
> git bisect good 6768a2c2e1310acb3e8e8e63a6e2caa146d19d0e
> # good: [c1b01a9f21daaf269d77683a4f91f423254f0c3e] MIPS: Add perf counter feature
> git bisect good c1b01a9f21daaf269d77683a4f91f423254f0c3e
> # bad: [354d36f4304a14aced7e4ffb0d27038cd19b532f] MIPS: Add probing & defs for VZ & guest features
> git bisect bad 354d36f4304a14aced7e4ffb0d27038cd19b532f
> # good: [b7c0199bf7404e87839ad633e699370ed397d548] MIPS: Add register definitions for VZ ASE registers
> git bisect good b7c0199bf7404e87839ad633e699370ed397d548
> # good: [cf5c5ac39a33127caa3e4e97f52754a6feede8fd] MIPS: Add guest CP0 accessors
> git bisect good cf5c5ac39a33127caa3e4e97f52754a6feede8fd
> # first bad commit: [354d36f4304a14aced7e4ffb0d27038cd19b532f] MIPS: Add probing & defs for VZ & guest features
>