Re[2]: PS3 platform is broken on Linux 3.7.0

[Phileas Fogg]

 Hi,

i found where the problem lies.
I also printed some values in ps3_hpte_insert with and without 64TB support, i used OpenWRT with Linux 3.7.6 for testing.

Some values without 64TB support:
-------------------------------------------------

[    0.060487] RPC: Registered named UNIX socket transport module.
[    0.060511] RPC: Registered udp transport module.
[    0.060672] RPC: Registered tcp transport module.
[    0.060873] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    0.061080] initcall .init_sunrpc+0x0/0xbc returned 0 after 784 usecs
[    0.061280] calling  .populate_rootfs+0x0/0x120 @ 1
[    0.061683] ps3_hpte_insert:result=0 vpn=f09b89af50101 pa=d4e0000 ix=dfa0 v=f09b89af5001 r=6c005d4e0194 psize=0 ssize=0 lpar=6c005d4e0000
[    0.061733] ps3_hpte_insert:result=0 vpn=f09b89af50102 pa=d4e1000 ix=dfb8 v=f09b89af5001 r=6c005d4e1194 psize=0 ssize=0 lpar=6c005d4e1000
[    0.061895] ps3_hpte_insert:result=0 vpn=f09b89af50103 pa=d4e2000 ix=dfb0 v=f09b89af5001 r=6c005d4e2194 psize=0 ssize=0 lpar=6c005d4e2000


Some values with 64TB support:
-------------------------------------------------

[    0.076477] calling  .init_sunrpc+0x0/0xbc @ 1
[    0.076992] RPC: Registered named UNIX socket transport module.
[    0.077017] RPC: Registered udp transport module.
[    0.077076] RPC: Registered tcp transport module.
[    0.077277] RPC: Registered tcp NFSv4.1 backchannel transport module.
[    0.077484] initcall .init_sunrpc+0x0/0xbc returned 0 after 784 usecs
[    0.077684] calling  .populate_rootfs+0x0/0x120 @ 1
[    0.078126] ps3_hpte_insert:result=-17 vpn=25008684d80101 pa=d567000 ix=2ec8 v=25008684d8001 r=6c005d567194 psize=0 ssize=0 lpar=6c005d567000
[    0.078164] ps3_hpte_insert:result=-17 vpn=25008684d80101 pa=d567000 ix=2ec8 v=25008684d8001 r=6c005d567194 psize=0 ssize=0 lpar=6c005d567000
[    0.078287] ------------[ cut here ]------------
[    0.078482] Kernel BUG at c00000000002cb3c [verbose debug info unavailable]
[    0.078686] Oops: Exception in kernel mode, sig: 5 [#1]
[    0.078883] SMP NR_CPUS=2 PS3
[    0.079084] Modules linked in:
[    0.079287] NIP: c00000000002cb3c LR: c00000000002cb38 CTR: 00000000002ffc38
[    0.079489] REGS: c00000000d04f0e0 TRAP: 0700   Not tainted  (3.7.6)
[    0.079687] MSR: 8000000000020032 <SF,IR,DR,RI>  CR: 22000022  XER: 00000000
[    0.079888] SOFTE: 0
[    0.080090] TASK = c00000000d049060[1] 'swapper/1' THREAD: c00000000d04c000 CPU: 1
GPR00: c00000000002cb38 c00000000d04f360 c0000000012ec8d0 0000000000000081 
GPR04: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
GPR08: 0000000000000000 c00000000124ce10 0000000000000000 c00000000002bcf0 
GPR12: 0000000022000022 c000000007ffe280 c000000000008c94 c0000000005cba00 



And now take a look at 'v' values in both cases.

Without 64TB support:   v=f09b89af5001
With 64TB support: v=25008684d8001

Number of leading zeros in f09b89af5001 is 16.
Number of leading zeros in 25008684d8001 is 14.

And that's why lv1_insert_htab_entry fails with -17 which means LV1_ILLEGAL_PARAMETER_VALUE because
the Hypervisor of PS3 checks 'AVPN' values for number of leading zeros and allows at least 15 bits which in case
of 'v' value 25008684d8001 is too small of course.

Not sure how to fix it in current Linux kernel. You guys know it better than me.

Regards




Понедельник, 14 января 2013, 15:37 -08:00 от Geoff Levand <geoff at infradead.org>:
>Hi,
>
>On Fri, 2013-01-11 at 18:12 -0800, Geoff Levand wrote:
>> I checked these, and Michael's 407821a34fce89b4f0b031dbab5cec7d059f46bc
>> does indeed cause the LV1 hypervisor to panic early, and if that is
>> reverted, Aneesh's 048ee0993ec8360abb0b51bdf8f8721e9ed62ec4 hits a BUG.
>
>Just to give an update, I did a little more work on it and found that
>the call to lv1_insert_htab_entry() inside ps3_hpte_insert() is
>failing.
>
>    http://git.kernel.org/?p=linux/kernel/git/geoff/ps3-linux.git;a=blob;f=arch/powerpc/platforms/ps3/htab.c;hb=HEAD#l70
>
>The values of the variables printed all look strange compared with
>commit 048ee0993 reverted.  I'll try do some more work on it this
>week.
>
>-Geoff
>
>
>
>
>
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