From 9254e70c4ef1fee2e5c43feded4433d19cbb6177 Mon Sep 17 00:00:00 2001 From: Hendrik Brueckner Date: Thu, 9 Jun 2016 12:28:13 +0200 Subject: [PATCH] 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: 0000000000220c44: a7f4ff54 brc 15,220aec 0000000000220c48: 92011000 mvi 0(%r1),1 #0000000000220c4c: a7f40001 brc 15,220c4e >0000000000220c50: a7f4ff12 brc 15,220a74 0000000000220c54: 0707 bcr 0,%r7 0000000000220c56: 0707 bcr 0,%r7 0000000000220c58: ebdff0800024 stmg %r13,%r15,128(%r15) 0000000000220c5e: a7f13fe0 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 Suggested-by: Peter Zijlstra Acked-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/perf_cpum_cf.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff --git a/arch/s390/kernel/perf_cpum_cf.c b/arch/s390/kernel/perf_cpum_cf.c index 59215c518f37..7ec63b1d920d 100644 --- a/arch/s390/kernel/perf_cpum_cf.c +++ b/arch/s390/kernel/perf_cpum_cf.c @@ -649,6 +649,8 @@ static int cpumf_pmu_commit_txn(struct pmu *pmu) /* Performance monitoring unit for s390x */ static struct pmu cpumf_pmu = { + .task_ctx_nr = perf_sw_context, + .capabilities = PERF_PMU_CAP_NO_INTERRUPT, .pmu_enable = cpumf_pmu_enable, .pmu_disable = cpumf_pmu_disable, .event_init = cpumf_pmu_event_init, @@ -708,12 +710,6 @@ static int __init cpumf_pmu_init(void) goto out; } - /* The CPU measurement counter facility does not have overflow - * interrupts to do sampling. Sampling must be provided by - * external means, for example, by timers. - */ - cpumf_pmu.capabilities |= PERF_PMU_CAP_NO_INTERRUPT; - cpumf_pmu.attr_groups = cpumf_cf_event_group(); rc = perf_pmu_register(&cpumf_pmu, "cpum_cf", PERF_TYPE_RAW); if (rc) { -- 2.20.1