linux-kernel - [PATCH v3 2/7] MIPS: perf: More robustly probe for the presence of per-tc counters

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Date:   Fri, 20 Apr 2018 11:23:04 +0100
From:   Matt Redfearn <matt.redfearn@...s.com>
To:     James Hogan <jhogan@...nel.org>,
        Ralf Baechle <ralf@...ux-mips.org>,
        Florian Fainelli <f.fainelli@...il.com>
CC:     <linux-mips@...ux-mips.org>,
        Matt Redfearn <matt.redfearn@...s.com>,
        Namhyung Kim <namhyung@...nel.org>,
        "Maciej W. Rozycki" <macro@...s.com>,
        Peter Zijlstra <peterz@...radead.org>,
        <linux-kernel@...r.kernel.org>,
        "Paul Burton" <paul.burton@...s.com>,
        Robert Richter <rric@...nel.org>,
        Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...hat.com>,
        <oprofile-list@...ts.sf.net>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>
Subject: [PATCH v3 2/7] MIPS: perf: More robustly probe for the presence of per-tc counters

The presence of per TC performance counters is now detected by
cpu-probe.c and indicated by MIPS_CPU_MT_PER_TC_PERF_COUNTERS in
cpu_data. Switch detection of the feature to use this new flag rather
than blindly testing the implementation specific config7 register with a
magic number.

Signed-off-by: Matt Redfearn <matt.redfearn@...s.com>
---

Changes in v3:
Use flag in cpu_data set by cpu_probe.c to indicate feature presence.

Changes in v2: None

 arch/mips/include/asm/cpu-features.h | 7 +++++++
 arch/mips/kernel/perf_event_mipsxx.c | 3 ---
 arch/mips/oprofile/op_model_mipsxx.c | 2 --
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h
index 721b698bfe3c..69755d900c69 100644
--- a/arch/mips/include/asm/cpu-features.h
+++ b/arch/mips/include/asm/cpu-features.h
@@ -534,6 +534,13 @@
 # define cpu_has_shared_ftlb_entries 0
 #endif
 
+#ifdef CONFIG_MIPS_MT_SMP
+# define cpu_has_mipsmt_pertccounters \
+	(cpu_data[0].options & MIPS_CPU_MT_PER_TC_PERF_COUNTERS)
+#else
+# define cpu_has_mipsmt_pertccounters 0
+#endif /* CONFIG_MIPS_MT_SMP */
+
 /*
  * Guest capabilities
  */
diff --git a/arch/mips/kernel/perf_event_mipsxx.c b/arch/mips/kernel/perf_event_mipsxx.c
index 6668f67a61c3..0595a974bc81 100644
--- a/arch/mips/kernel/perf_event_mipsxx.c
+++ b/arch/mips/kernel/perf_event_mipsxx.c
@@ -129,8 +129,6 @@ static struct mips_pmu mipspmu;
 
 
 #ifdef CONFIG_MIPS_PERF_SHARED_TC_COUNTERS
-static int cpu_has_mipsmt_pertccounters;
-
 static DEFINE_RWLOCK(pmuint_rwlock);
 
 #if defined(CONFIG_CPU_BMIPS5000)
@@ -1723,7 +1721,6 @@ init_hw_perf_events(void)
 	}
 
 #ifdef CONFIG_MIPS_PERF_SHARED_TC_COUNTERS
-	cpu_has_mipsmt_pertccounters = read_c0_config7() & (1<<19);
 	if (!cpu_has_mipsmt_pertccounters)
 		counters = counters_total_to_per_cpu(counters);
 #endif
diff --git a/arch/mips/oprofile/op_model_mipsxx.c b/arch/mips/oprofile/op_model_mipsxx.c
index c3e4c18ef8d4..7c04b17f4a48 100644
--- a/arch/mips/oprofile/op_model_mipsxx.c
+++ b/arch/mips/oprofile/op_model_mipsxx.c
@@ -36,7 +36,6 @@ static int perfcount_irq;
 #endif
 
 #ifdef CONFIG_MIPS_MT_SMP
-static int cpu_has_mipsmt_pertccounters;
 #define WHAT		(MIPS_PERFCTRL_MT_EN_VPE | \
 			 M_PERFCTL_VPEID(cpu_vpe_id(&current_cpu_data)))
 #define vpe_id()	(cpu_has_mipsmt_pertccounters ? \
@@ -326,7 +325,6 @@ static int __init mipsxx_init(void)
 	}
 
 #ifdef CONFIG_MIPS_MT_SMP
-	cpu_has_mipsmt_pertccounters = read_c0_config7() & (1<<19);
 	if (!cpu_has_mipsmt_pertccounters)
 		counters = counters_total_to_per_cpu(counters);
 #endif
-- 
2.7.4