On 03/02/2017 12:33 AM, Michael Ellerman wrote:
Paul Clarke <p...@us.ibm.com> writes:
On 02/02/2017 12:22 AM, Benjamin Herrenschmidt wrote:
This adds AUX vectors for the L1I,D, L2 and L3 cache levels
providing for each cache level the size of the cache in bytes
and the geometry (line size and number of ways).
We chose to not use the existing alpha/sh definition which
packs all the information in a single entry per cache level as
it is too restricted to represent some of the geometries used
on POWER.
Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
---
v2. Remove some leftovers and fix 32-bit build
Paul, can you test & ack this please ? It replaces the last patch of
my previous series (the rest is identical).
Sorry for the delay on this, I totally missed this e-mail until this week.
I tested this with the Power Functional Simulator (a.k.a. Mambo), with
a fairly recent 4.9 kernel from the powerpc git tree.
You mean 4.9 plus this patch?
Using Mambo-P8, I see what I expect for cache line size, but associativity is 0:
AT_L1I_CACHESIZE: 32768 (0x8000)
AT_L1I_CACHEGEOMETRY: associativity 0; line size 128
AT_L1D_CACHESIZE: 32768 (0x8000)
AT_L1D_CACHEGEOMETRY: associativity 0; line size 128
AT_L2_CACHESIZE: 524288 (0x80000)
AT_L2_CACHEGEOMETRY: associativity 0; line size 128
AT_L3_CACHESIZE: 8388608 (0x800000)
AT_L3_CACHEGEOMETRY: associativity 0; line size 128
...shouldn't associativity be 8 for all levels?
Yes.
I fixed it in v3: http://patchwork.ozlabs.org/patch/723576/
Which is now merged in Linus tree, so please test that.
It's not working for me, but it's also very likely that I could be doing something stupid. Just pulling from
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git, it built (without the "systemsim"
patches"), but wouldn't boot in Mambo (not because it couldn't find root...something else not fully
explored). I checked out tag "v4.10", and that built (with the "systemsim" patches, Ben's 1-8
and your 9v3) and booted. On Mambo-P8, the device tree looks correct (to me), but the associativity is still 0.
On P9, the device tree isn't correct, so I'm not sure what to expect.
I added a bit more debug to my test:
AT_L1I_CACHESIZE: 32768 (0x8000)
getauxval(AT_L1I_CACHEGEOMETRY) = 0x0000000000000080
AT_L1I_CACHEGEOMETRY: associativity 0; line size 128
AT_L1D_CACHESIZE: 32768 (0x8000)
getauxval(AT_L1D_CACHEGEOMETRY) = 0x0000000000000080
AT_L1D_CACHEGEOMETRY: associativity 0; line size 128
AT_L2_CACHESIZE: 524288 (0x80000)
getauxval(AT_L2_CACHEGEOMETRY) = 0x0000000000000080
AT_L2_CACHEGEOMETRY: associativity 0; line size 128
AT_L3_CACHESIZE: 8388608 (0x800000)
getauxval(AT_L2_CACHEGEOMETRY) = 0x0000000000000080
AT_L3_CACHEGEOMETRY: associativity 0; line size 128
When I use gdb, and break at main:
(gdb) x/60gx ($r6)
0x3ffffffffca0: 0x0000000000000016 0x0000000000000016
0x3ffffffffcb0: 0x0000000000000016 0x0000000000000016
0x3ffffffffcc0: 0x0000000000000013 0x0000000000000080
0x3ffffffffcd0: 0x0000000000000014 0x0000000000000080
0x3ffffffffce0: 0x0000000000000015 0x0000000000000000
0x3ffffffffcf0: 0x0000000000000021 0x00003fffb7fa0000
0x3ffffffffd00: 0x0000000000000028 0x0000000000008000
0x3ffffffffd10: 0x0000000000000029 0x0000000000000080
0x3ffffffffd20: 0x000000000000002a 0x0000000000008000
0x3ffffffffd30: 0x000000000000002b 0x0000000000000080
0x3ffffffffd40: 0x000000000000002c 0x0000000000080000
0x3ffffffffd50: 0x000000000000002d 0x0000000000000080
0x3ffffffffd60: 0x000000000000002e 0x0000000000800000
0x3ffffffffd70: 0x000000000000002f 0x0000000000000080
and, looking at the device-tree:
# for i in /proc/device-tree/cpus/PowerPC@0/*cache*; do echo $i;
od -tx1 $i; done
/proc/device-tree/cpus/PowerPC@0/d-cache-block-size
0000000 00 00 00 80
/proc/device-tree/cpus/PowerPC@0/d-cache-line-size
0000000 00 00 00 80
/proc/device-tree/cpus/PowerPC@0/d-cache-sets
0000000 00 00 00 04
/proc/device-tree/cpus/PowerPC@0/d-cache-size
0000000 00 00 80 00
/proc/device-tree/cpus/PowerPC@0/i-cache-block-size
0000000 00 00 00 80
/proc/device-tree/cpus/PowerPC@0/i-cache-line-size
0000000 00 00 00 80
/proc/device-tree/cpus/PowerPC@0/i-cache-sets
0000000 00 00 00 02
/proc/device-tree/cpus/PowerPC@0/i-cache-size
0000000 00 00 80 00
/proc/device-tree/cpus/PowerPC@0/l2-cache-size
0000000 00 0a 00 00
Can you try the test program I wrote (which may also have bugs):
http://patchwork.ozlabs.org/patch/724418/
I couldn't get this working, either, so I'm probably doing something stupid.
PC
