RFR: JDK-8158502: aarch32: detect QEMU user-mode emulation

[Andrey Petushkov]

Hi Alex,

Thank you! And you’re seem to be right, ARM1136 seem to be “pure” v6, without extensions brought by v6k. One problem though, it is soft-float as you say. And to my best knowledge our port is not ready for pure soft-float environment. It does not respect soft-float ABI. In addition, I’ve stumbled across one unpleasant problem of missing ldrexd/strext instruction in v6. So I might reconsider support of pure v6, at least for the time being. So please hold off from setting up this machine, until further notice.
At the same time support for v6k remains my first priority so keep your RPi B+ warmed :)
(I've finished the detection code and started battle against relocations)

Regards,
Andrey

> On 08 Jun 2016, at 17:27, Alex Kashchenko <akashche at redhat.com> wrote:
> 
> Hi Andrey,
> 
> On 06/07/2016 05:34 PM, Andrey Petushkov wrote:
>> Yes, I thought about “pure” v6, but in fact I only have RPI B+ as a test machine which is ARMv6K which is easier compared to plain old ARMv6. If by the chance you have anything with real v6 that would be very much appreciated if you could help with checking!
> 
> I setup an armel (softfp) version of Debian Wheezy in chroot on a Huawei u8150 phone. Its /proc/cpuinfo shows the following:
> 
> Processor       : ARMv6-compatible processor rev 2 (v6l)
> BogoMIPS        : 121.80
> Features        : swp half thumb fastmult edsp java
> CPU implementer : 0x41
> CPU architecture: 6TEJ
> CPU variant     : 0x1
> CPU part        : 0xb36
> CPU revision    : 2
> 
> It looks like it has ARM1136 (RPi B+/Zero has 1176) that should be the lowest model with ARMv6 support.
> 
> I haven't yet build jdk on it, but compilation of simple programs (tried detect.c mentioned before) works fine on it.
> 
> -- 
> -Alex