s390/cpum_cf: use perf software context for hardware counters
authorHendrik Brueckner <brueckner@linux.vnet.ibm.com>
Thu, 9 Jun 2016 10:28:13 +0000 (12:28 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Thu, 16 Jun 2016 10:08:49 +0000 (12:08 +0200)
commit9254e70c4ef1fee2e5c43feded4433d19cbb6177
treebce8fe2f460659b40f87e99522c9f85ea613abcf
parent1c343f7b0e177e8ca7f4d4a5dd1fa790f85abbcc
s390/cpum_cf: use perf software context for hardware counters

On s390, there are two different hardware PMUs for counting and
sampling.  Previously, both PMUs have shared the perf_hw_context
which is not correct and, recently, results in this warning:

    ------------[ cut here ]------------
    WARNING: CPU: 5 PID: 1 at kernel/events/core.c:8485 perf_pmu_register+0x420/0x428
    Modules linked in:
    CPU: 5 PID: 1 Comm: swapper/0 Not tainted 4.7.0-rc1+ #2
    task: 00000009c5240000 ti: 00000009c5234000 task.ti: 00000009c5234000
    Krnl PSW : 0704c00180000000 0000000000220c50 (perf_pmu_register+0x420/0x428)
               R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
    Krnl GPRS: ffffffffffffffff 0000000000b15ac6 0000000000000000 00000009cb440000
               000000000022087a 0000000000000000 0000000000b78fa0 0000000000000000
               0000000000a9aa90 0000000000000084 0000000000000005 000000000088a97a
               0000000000000004 0000000000749dd0 000000000022087a 00000009c5237cc0
    Krnl Code: 0000000000220c44a7f4ff54            brc     15,220aec
               0000000000220c4892011000           mvi     0(%r1),1
              #0000000000220c4ca7f40001           brc     15,220c4e
              >0000000000220c50a7f4ff12           brc     15,220a74
               0000000000220c54: 0707               bcr     0,%r7
               0000000000220c56: 0707               bcr     0,%r7
               0000000000220c58ebdff0800024       stmg    %r13,%r15,128(%r15)
               0000000000220c5ea7f13fe0           tmll    %r15,16352
    Call Trace:
    ([<000000000022087a>] perf_pmu_register+0x4a/0x428)
    ([<0000000000b2c25c>] init_cpum_sampling_pmu+0x14c/0x1f8)
    ([<0000000000100248>] do_one_initcall+0x48/0x140)
    ([<0000000000b25d26>] kernel_init_freeable+0x1e6/0x2a0)
    ([<000000000072bda4>] kernel_init+0x24/0x138)
    ([<000000000073495e>] kernel_thread_starter+0x6/0xc)
    ([<0000000000734958>] kernel_thread_starter+0x0/0xc)
    Last Breaking-Event-Address:
     [<0000000000220c4c>] perf_pmu_register+0x41c/0x428
    ---[ end trace 0c6ef9f5b771ad97 ]---

Using the perf_sw_context is an option because the cpum_cf PMU does
not use interrupts.  To make this more clear, initialize the
capabilities in the PMU structure.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
arch/s390/kernel/perf_cpum_cf.c