[PATCH 1/1] powerpc: fix missing L2 cache size in /sys/devices/system/cpu

[Michael Ellerman]

On Tue, 2015-02-10 at 11:12 +1100, Benjamin Herrenschmidt wrote:
> On Mon, 2015-02-09 at 15:43 -0800, Dave Olson wrote:
> > Michael Ellerman <mpe at ellerman.id.au> wrote:
> > 
> > > On Mon, 2015-02-09 at 14:14 -0800, Dave Olson wrote:
> > > > From: Dave Olson <olson at cumulusnetworks.com>
> > > > 
> > > > Fix missing L2 cache size in /sys/devices/system/cpu/cpu0/cache/index2/size
> > > > This bug appears to be introduced in 2.6.29 by 93197a36a9c16a85fb24cf5a8639f7bf9af838a3.
> > > > The missing entry caused lscpu to error out on e500v2 devices, and probably others
> > > >  error: cannot open /sys/devices/system/cpu/cpu0/cache/index2/size: No such file or directory
> > > > The DTS files we see use cache-size for the unified L2 cache size, not d-cache-size
> > > 
> > > Can you convince me that this is not going to break other machines that have
> > > "d-cache-size" but not "cache-size"?
> > 
> > I'm unable to find any dts file that uses d-cache-size for the L2
> > unified cache.  All in the powerpc tree in arch/powerpc/boot/dts/*
> > are using cache-size in the L2 description for the cache size.
> > 
> > As best as I can tell from looking around, this is universal.
>
> 
> It may be universal for embedded machines using DTS in the kernel tree
> but it's definitely not true of any Mac or server machine (from which
> there is no DTS in the kernel as we get the DT from the firmware).

Right.

$ grep machine /proc/cpuinfo 
machine		: PowerNV 8247-22L

$ lsprop /proc/device-tree/cpus/l2-cache at 20000020
name             "l2-cache"
status           "okay"
reg              20000020 (536870944)
phandle          00000005
linux,phandle    00000005
l2-cache         00000006
i-cache-size     00080000 (524288)
i-cache-sets     00000008
device_type      "cache"
d-cache-size     00080000 (524288)
d-cache-sets     00000008
cache-unified   


cheers