[aarch64-port-dev ] RFR: 8079203: aarch64: need to cater for different partner implementations

[Mark Rutland]

Hi,

> The following webrev addresses issue
> http://bugs.openjdk.java.net/browse/JDK-8079203
> 
> http://cr.openjdk.java.net/~enevill/8079203/webrev
> 
> The patch parses /proc/cpuinfo to obtain cpu, model, variant and revision
> information.

>From a look at the proposed patch, I guess this assumes a uniform SMP
system (i.e. no big.LITTLE)?

A while back [1] the /proc/cpuinfo format was fixed to show information per-cpu
(example form a Juno system below), and it looks like the CPU information
parsed will only refer to ther final CPU listed, and may not be representative
of the system as a whole.

That format has been packported to the various stable kernels too.

Thanks,
Mark.

[1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/kernel/setup.c?id=44b82b7700d05a52cd983799d3ecde1a976b3bed

---->8----
$ cat /proc/cpuinfo 
processor       : 0
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 0

processor       : 1
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd07
CPU revision    : 0

processor       : 2
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd07
CPU revision    : 0

processor       : 3
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 0

processor       : 4
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 0

processor       : 5
Features        : fp asimd evtstrm aes pmull sha1 sha2 crc32
CPU implementer : 0x41
CPU architecture: 8
CPU variant     : 0x0
CPU part        : 0xd03
CPU revision    : 0