[PATCH v2 3/6] powerpc/perf: Support to export MMCRA[TEC*] field to userspace

[Madhavan Srinivasan <maddy@linux.vnet.ibm.com>]

Threshold feature when used with MMCRA [Threshold Event Counter Event],
MMCRA[Threshold Start event] and MMCRA[Threshold End event] will update
MMCRA[Threashold Event Counter Exponent] and MMCRA[Threshold Event
Counter Multiplier] with the corresponding threshold event count values.
Patch to export MMCRA[TECX/TECM] to userspace in 'weight' field of
struct perf_sample_data.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/perf_event_server.h |  1 +
 arch/powerpc/perf/core-book3s.c              |  4 ++++
 arch/powerpc/perf/isa207-common.c            |  8 ++++++++
 arch/powerpc/perf/isa207-common.h            | 10 ++++++++++
 4 files changed, 23 insertions(+)

diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h
index 446cdcd9b7f5..723bf48e7494 100644
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -40,6 +40,7 @@ struct power_pmu {
 				u64 alt[]);
 	void		(*get_mem_data_src)(union perf_mem_data_src *dsrc,
 				u32 flags, struct pt_regs *regs);
+	void		(*get_mem_weight)(u64 *weight);
 	u64             (*bhrb_filter_map)(u64 branch_sample_type);
 	void            (*config_bhrb)(u64 pmu_bhrb_filter);
 	void		(*disable_pmc)(unsigned int pmc, unsigned long mmcr[]);
diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index d644c5ab4d2f..a6b265e31663 100644
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -2051,6 +2051,10 @@ static void record_and_restart(struct perf_event *event, unsigned long val,
 						ppmu->get_mem_data_src)
 			ppmu->get_mem_data_src(&data.data_src, ppmu->flags, regs);
 
+		if (event->attr.sample_type & PERF_SAMPLE_WEIGHT &&
+						ppmu->get_mem_weight)
+			ppmu->get_mem_weight(&data.weight);
+
 		if (perf_event_overflow(event, &data, regs))
 			power_pmu_stop(event, 0);
 	}
diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index 08bb62454a2e..42e999da934e 100644
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -196,6 +196,14 @@ void isa207_get_mem_data_src(union perf_mem_data_src *dsrc, u32 flags,
 	}
 }
 
+void isa207_get_mem_weight(u64 *weight)
+{
+	u64 mmcra = mfspr(SPRN_MMCRA);
+	u64 exp = MMCRA_THR_CTR_EXP(mmcra);
+	u64 mantissa = MMCRA_THR_CTR_MANT(mmcra);
+
+	*weight = mantissa << (2 * exp);
+}
 
 int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp)
 {
diff --git a/arch/powerpc/perf/isa207-common.h b/arch/powerpc/perf/isa207-common.h
index 982542cce991..b4d02ae3a6e0 100644
--- a/arch/powerpc/perf/isa207-common.h
+++ b/arch/powerpc/perf/isa207-common.h
@@ -247,6 +247,15 @@
 #define MMCRA_SDAR_MODE_SHIFT		42
 #define MMCRA_SDAR_MODE_TLB		(1ull << MMCRA_SDAR_MODE_SHIFT)
 #define MMCRA_IFM_SHIFT			30
+#define MMCRA_THR_CTR_MANT_SHIFT	19
+#define MMCRA_THR_CTR_MANT_MASK		0x7Ful
+#define MMCRA_THR_CTR_MANT(v)		(((v) >> MMCRA_THR_CTR_MANT_SHIFT) &\
+						MMCRA_THR_CTR_MANT_MASK)
+
+#define MMCRA_THR_CTR_EXP_SHIFT		27
+#define MMCRA_THR_CTR_EXP_MASK		0x7ul
+#define MMCRA_THR_CTR_EXP(v)		(((v) >> MMCRA_THR_CTR_EXP_SHIFT) &\
+						MMCRA_THR_CTR_EXP_MASK)
 
 /* MMCR1 Threshold Compare bit constant for power9 */
 #define p9_MMCRA_THR_CMP_SHIFT	45
@@ -281,5 +290,6 @@ int isa207_get_alternatives(u64 event, u64 alt[],
 				const unsigned int ev_alt[][MAX_ALT], int size);
 void isa207_get_mem_data_src(union perf_mem_data_src *dsrc, u32 flags,
 							struct pt_regs *regs);
+void isa207_get_mem_weight(u64 *weight);
 
 #endif
-- 
2.7.4