powerpc/perf: Support to export MMCRA[TEC*] field to userspace

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.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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[]);

arch/powerpc/perf/core-book3s.c

@@ -2053,6 +2053,10 @@ 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);
 	}

arch/powerpc/perf/isa207-common.c

@@ -221,6 +221,14 @@ 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)
 {

arch/powerpc/perf/isa207-common.h

@@ -248,6 +248,15 @@
 #define MMCRA_SDAR_MODE_TLB		(1ull << MMCRA_SDAR_MODE_SHIFT)
 #define MMCRA_SDAR_MODE_NO_UPDATES	~(0x3ull << 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
@@ -282,5 +291,6 @@ 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