powerpc/perf: Adds support for programming of Thresholding in P10

Thresholding, a performance monitoring unit feature, can be
used to identify marked instructions which take more than
expected cycles between start event and end event.
Threshold compare (thresh_cmp) bits are programmed in MMCRA
register. In Power9, thresh_cmp bits were part of the
event code. But in case of P10, thresh_cmp are not part of
event code due to inclusion of MMCR3 bits.

Patch here adds an option to use attr.config1 variable
to be used to pass thresh_cmp value to be programmed in
MMCRA register. A new ppmu flag called PPMU_HAS_ATTR_CONFIG1
has been added and this flag is used to notify the use of
attr.config1 variable.

Patch has extended the parameter list of 'compute_mmcr',
to include power_pmu's 'flags' element and parameter list of
get_constraint to include attr.config1 value. It also extend
parameter list of power_check_constraints inorder to pass
perf_event list.

As stated by commit ef0e3b650f8d ("powerpc/perf: Fix Threshold
Event Counter Multiplier width for P10"), constraint bits for
thresh_cmp is also needed to be increased to 11 bits, which is
handled as part of this patch. We added bit number 53 as part
of constraint bits of thresh_cmp for power10 to make it an
11 bit field.

Updated layout for p10:

/*
 * Layout of constraint bits:
 *
 *        60        56        52        48        44        40        36        32
 * | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - |
 *   [   fab_match   ]         [       thresh_cmp      ] [   thresh_ctl    ] [   ]
 *                                          |                                  |
 *                           [  thresh_cmp bits for p10]           thresh_sel -*
 *
 *        28        24        20        16        12         8         4         0
 * | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - |
 *               [ ] |   [ ] |  [  sample ]   [     ]   [6] [5]   [4] [3]   [2] [1]
 *                |  |    |  |                  |
 *      BHRB IFM -*  |    |  |*radix_scope      |      Count of events for each PMC.
 *              EBB -*    |                     |        p1, p2, p3, p4, p5, p6.
 *      L1 I/D qualifier -*                     |
 *                     nc - number of counters -*
 *
 * The PMC fields P1..P6, and NC, are adder fields. As we accumulate constraints
 * we want the low bit of each field to be added to any existing value.
 *
 * Everything else is a value field.
 */

Result:
command#: cat /sys/devices/cpu/format/thresh_cmp
config1:0-17

ex. usage:

command#: perf record -I --weight -d  -e
	 cpu/event=0x67340101EC,thresh_cmp=500/ ./ebizzy -S 2 -t 1 -s 4096
1826636 records/s
real  2.00 s
user  2.00 s
sys   0.00 s
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.038 MB perf.data (61 samples) ]

Signed-off-by: Kajol Jain <kjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210209095234.837356-1-kjain@linux.ibm.com

diff --git a/arch/powerpc/include/asm/perf_event_server.h b/arch/powerpc/include/asm/perf_event_server.h
index 3b7baba..00e7e67 100644 (file)
--- a/arch/powerpc/include/asm/perf_event_server.h
+++ b/arch/powerpc/include/asm/perf_event_server.h
@@ -36,9 +36,9 @@ struct power_pmu {
        unsigned long   test_adder;
        int             (*compute_mmcr)(u64 events[], int n_ev,
                                unsigned int hwc[], struct mmcr_regs *mmcr,
-                               struct perf_event *pevents[]);
+                               struct perf_event *pevents[], u32 flags);
        int             (*get_constraint)(u64 event_id, unsigned long *mskp,
-                               unsigned long *valp);
+                               unsigned long *valp, u64 event_config1);
        int             (*get_alternatives)(u64 event_id, unsigned int flags,
                                u64 alt[]);
        void            (*get_mem_data_src)(union perf_mem_data_src *dsrc,
@@ -83,6 +83,7 @@ struct power_pmu {
 #define PPMU_NO_SIAR           0x00000100 /* Do not use SIAR */
 #define PPMU_ARCH_31           0x00000200 /* Has MMCR3, SIER2 and SIER3 */
 #define PPMU_P10_DD1           0x00000400 /* Is power10 DD1 processor version */
+#define PPMU_HAS_ATTR_CONFIG1  0x00000800 /* Using config1 attribute */
 
 /*
  * Values for flags to get_alternatives()

diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c
index 0e31aaa..4b4319d 100644 (file)
--- a/arch/powerpc/perf/core-book3s.c
+++ b/arch/powerpc/perf/core-book3s.c
@@ -916,7 +916,7 @@ void perf_event_print_debug(void)
  */
 static int power_check_constraints(struct cpu_hw_events *cpuhw,
                                   u64 event_id[], unsigned int cflags[],
-                                  int n_ev)
+                                  int n_ev, struct perf_event **event)
 {
        unsigned long mask, value, nv;
        unsigned long smasks[MAX_HWEVENTS], svalues[MAX_HWEVENTS];
@@ -939,7 +939,7 @@ static int power_check_constraints(struct cpu_hw_events *cpuhw,
                        event_id[i] = cpuhw->alternatives[i][0];
                }
                if (ppmu->get_constraint(event_id[i], &cpuhw->amasks[i][0],
-                                        &cpuhw->avalues[i][0]))
+                                        &cpuhw->avalues[i][0], event[i]->attr.config1))
                        return -1;
        }
        value = mask = 0;
@@ -974,7 +974,8 @@ static int power_check_constraints(struct cpu_hw_events *cpuhw,
                for (j = 1; j < n_alt[i]; ++j)
                        ppmu->get_constraint(cpuhw->alternatives[i][j],
                                             &cpuhw->amasks[i][j],
-                                            &cpuhw->avalues[i][j]);
+                                            &cpuhw->avalues[i][j],
+                                            event[i]->attr.config1);
        }
 
        /* enumerate all possibilities and see if any will work */
@@ -1392,7 +1393,7 @@ static void power_pmu_enable(struct pmu *pmu)
        memset(&cpuhw->mmcr, 0, sizeof(cpuhw->mmcr));
 
        if (ppmu->compute_mmcr(cpuhw->events, cpuhw->n_events, hwc_index,
-                              &cpuhw->mmcr, cpuhw->event)) {
+                              &cpuhw->mmcr, cpuhw->event, ppmu->flags)) {
                /* shouldn't ever get here */
                printk(KERN_ERR "oops compute_mmcr failed\n");
                goto out;
@@ -1580,7 +1581,7 @@ static int power_pmu_add(struct perf_event *event, int ef_flags)
 
        if (check_excludes(cpuhw->event, cpuhw->flags, n0, 1))
                goto out;
-       if (power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n0 + 1))
+       if (power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n0 + 1, cpuhw->event))
                goto out;
        event->hw.config = cpuhw->events[n0];
 
@@ -1790,7 +1791,7 @@ static int power_pmu_commit_txn(struct pmu *pmu)
        n = cpuhw->n_events;
        if (check_excludes(cpuhw->event, cpuhw->flags, 0, n))
                return -EAGAIN;
-       i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n);
+       i = power_check_constraints(cpuhw, cpuhw->events, cpuhw->flags, n, cpuhw->event);
        if (i < 0)
                return -EAGAIN;
 
@@ -2028,7 +2029,7 @@ static int power_pmu_event_init(struct perf_event *event)
        local_irq_save(irq_flags);
        cpuhw = this_cpu_ptr(&cpu_hw_events);
 
-       err = power_check_constraints(cpuhw, events, cflags, n + 1);
+       err = power_check_constraints(cpuhw, events, cflags, n + 1, ctrs);
 
        if (has_branch_stack(event)) {
                u64 bhrb_filter = -1;

diff --git a/arch/powerpc/perf/isa207-common.c b/arch/powerpc/perf/isa207-common.c
index 6ab5b27..e4f577d 100644 (file)
--- a/arch/powerpc/perf/isa207-common.c
+++ b/arch/powerpc/perf/isa207-common.c
@@ -108,12 +108,57 @@ static void mmcra_sdar_mode(u64 event, unsigned long *mmcra)
                *mmcra |= MMCRA_SDAR_MODE_TLB;
 }
 
+static u64 p10_thresh_cmp_val(u64 value)
+{
+       int exp = 0;
+       u64 result = value;
+
+       if (!value)
+               return value;
+
+       /*
+        * Incase of P10, thresh_cmp value is not part of raw event code
+        * and provided via attr.config1 parameter. To program threshold in MMCRA,
+        * take a 18 bit number N and shift right 2 places and increment
+        * the exponent E by 1 until the upper 10 bits of N are zero.
+        * Write E to the threshold exponent and write the lower 8 bits of N
+        * to the threshold mantissa.
+        * The max threshold that can be written is 261120.
+        */
+       if (cpu_has_feature(CPU_FTR_ARCH_31)) {
+               if (value > 261120)
+                       value = 261120;
+               while ((64 - __builtin_clzl(value)) > 8) {
+                       exp++;
+                       value >>= 2;
+               }
+
+               /*
+                * Note that it is invalid to write a mantissa with the
+                * upper 2 bits of mantissa being zero, unless the
+                * exponent is also zero.
+                */
+               if (!(value & 0xC0) && exp)
+                       result = 0;
+               else
+                       result = (exp << 8) | value;
+       }
+       return result;
+}
+
 static u64 thresh_cmp_val(u64 value)
 {
+       if (cpu_has_feature(CPU_FTR_ARCH_31))
+               value = p10_thresh_cmp_val(value);
+
+       /*
+        * Since location of threshold compare bits in MMCRA
+        * is different for p8, using different shift value.
+        */
        if (cpu_has_feature(CPU_FTR_ARCH_300))
                return value << p9_MMCRA_THR_CMP_SHIFT;
-
-       return value << MMCRA_THR_CMP_SHIFT;
+       else
+               return value << MMCRA_THR_CMP_SHIFT;
 }
 
 static unsigned long combine_from_event(u64 event)
@@ -141,13 +186,13 @@ static bool is_thresh_cmp_valid(u64 event)
 {
        unsigned int cmp, exp;
 
+       if (cpu_has_feature(CPU_FTR_ARCH_31))
+               return p10_thresh_cmp_val(event) != 0;
+
        /*
         * Check the mantissa upper two bits are not zero, unless the
         * exponent is also zero. See the THRESH_CMP_MANTISSA doc.
-        * Power10: thresh_cmp is replaced by l2_l3 event select.
         */
-       if (cpu_has_feature(CPU_FTR_ARCH_31))
-               return false;
 
        cmp = (event >> EVENT_THR_CMP_SHIFT) & EVENT_THR_CMP_MASK;
        exp = cmp >> 7;
@@ -256,7 +301,7 @@ void isa207_get_mem_weight(u64 *weight)
                *weight = mantissa << (2 * exp);
 }
 
-int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp)
+int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp, u64 event_config1)
 {
        unsigned int unit, pmc, cache, ebb;
        unsigned long mask, value;
@@ -355,9 +400,11 @@ int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp)
        }
 
        if (cpu_has_feature(CPU_FTR_ARCH_31)) {
-               if (event_is_threshold(event)) {
+               if (event_is_threshold(event) && is_thresh_cmp_valid(event_config1)) {
                        mask  |= CNST_THRESH_CTL_SEL_MASK;
                        value |= CNST_THRESH_CTL_SEL_VAL(event >> EVENT_THRESH_SHIFT);
+                       mask  |= p10_CNST_THRESH_CMP_MASK;
+                       value |= p10_CNST_THRESH_CMP_VAL(p10_thresh_cmp_val(event_config1));
                }
        } else if (cpu_has_feature(CPU_FTR_ARCH_300))  {
                if (event_is_threshold(event) && is_thresh_cmp_valid(event)) {
@@ -411,7 +458,7 @@ ebb_bhrb:
 
 int isa207_compute_mmcr(u64 event[], int n_ev,
                               unsigned int hwc[], struct mmcr_regs *mmcr,
-                              struct perf_event *pevents[])
+                              struct perf_event *pevents[], u32 flags)
 {
        unsigned long mmcra, mmcr1, mmcr2, unit, combine, psel, cache, val;
        unsigned long mmcr3;
@@ -504,6 +551,10 @@ int isa207_compute_mmcr(u64 event[], int n_ev,
                                val = (event[i] >> EVENT_THR_CMP_SHIFT) &
                                        EVENT_THR_CMP_MASK;
                                mmcra |= thresh_cmp_val(val);
+                       } else if (flags & PPMU_HAS_ATTR_CONFIG1) {
+                               val = (pevents[i]->attr.config1 >> p10_EVENT_THR_CMP_SHIFT) &
+                                       p10_EVENT_THR_CMP_MASK;
+                               mmcra |= thresh_cmp_val(val);
                        }
                }
 

diff --git a/arch/powerpc/perf/isa207-common.h b/arch/powerpc/perf/isa207-common.h
index 454b32c..1af0e8c 100644 (file)
--- a/arch/powerpc/perf/isa207-common.h
+++ b/arch/powerpc/perf/isa207-common.h
@@ -105,6 +105,10 @@
 #define p10_EVENT_RADIX_SCOPE_QUAL_MASK        0x1
 #define p10_MMCR1_RADIX_SCOPE_QUAL_SHIFT       45
 
+/* Event Threshold Compare bit constant for power10 in config1 attribute */
+#define p10_EVENT_THR_CMP_SHIFT        0
+#define p10_EVENT_THR_CMP_MASK 0x3FFFFull
+
 #define p10_EVENT_VALID_MASK           \
        ((p10_SDAR_MODE_MASK   << p10_SDAR_MODE_SHIFT           |       \
        (p10_EVENT_THRESH_MASK  << EVENT_THRESH_SHIFT)          |       \
@@ -124,8 +128,8 @@
  *        60        56        52        48        44        40        36        32
  * | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - |
  *   [   fab_match   ]         [       thresh_cmp      ] [   thresh_ctl    ] [   ]
- *                                                                             |
- *                                                                 thresh_sel -*
+ *                                          |                                  |
+ *                           [  thresh_cmp bits for p10]           thresh_sel -*
  *
  *        28        24        20        16        12         8         4         0
  * | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - | - - - - |
@@ -152,6 +156,9 @@
 #define CNST_THRESH_CTL_SEL_VAL(v)     (((v) & 0x7ffull) << 32)
 #define CNST_THRESH_CTL_SEL_MASK       CNST_THRESH_CTL_SEL_VAL(0x7ff)
 
+#define p10_CNST_THRESH_CMP_VAL(v) (((v) & 0x7ffull) << 43)
+#define p10_CNST_THRESH_CMP_MASK   p10_CNST_THRESH_CMP_VAL(0x7ff)
+
 #define CNST_EBB_VAL(v)                (((v) & EVENT_EBB_MASK) << 24)
 #define CNST_EBB_MASK          CNST_EBB_VAL(EVENT_EBB_MASK)
 
@@ -262,10 +269,10 @@
 #define PH(a, b)                       (P(LVL, HIT) | P(a, b))
 #define PM(a, b)                       (P(LVL, MISS) | P(a, b))
 
-int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp);
+int isa207_get_constraint(u64 event, unsigned long *maskp, unsigned long *valp, u64 event_config1);
 int isa207_compute_mmcr(u64 event[], int n_ev,
                                unsigned int hwc[], struct mmcr_regs *mmcr,
-                               struct perf_event *pevents[]);
+                               struct perf_event *pevents[], u32 flags);
 void isa207_disable_pmc(unsigned int pmc, struct mmcr_regs *mmcr);
 int isa207_get_alternatives(u64 event, u64 alt[], int size, unsigned int flags,
                                        const unsigned int ev_alt[][MAX_ALT]);

diff --git a/arch/powerpc/perf/mpc7450-pmu.c b/arch/powerpc/perf/mpc7450-pmu.c
index 1919e9d..e39b15b 100644 (file)
--- a/arch/powerpc/perf/mpc7450-pmu.c
+++ b/arch/powerpc/perf/mpc7450-pmu.c
@@ -148,7 +148,7 @@ static u32 classbits[N_CLASSES - 1][2] = {
 };
 
 static int mpc7450_get_constraint(u64 event, unsigned long *maskp,
-                                 unsigned long *valp)
+                                 unsigned long *valp, u64 event_config1 __maybe_unused)
 {
        int pmc, class;
        u32 mask, value;
@@ -258,7 +258,8 @@ static const u32 pmcsel_mask[N_COUNTER] = {
  */
 static int mpc7450_compute_mmcr(u64 event[], int n_ev, unsigned int hwc[],
                                struct mmcr_regs *mmcr,
-                               struct perf_event *pevents[])
+                               struct perf_event *pevents[],
+                               u32 flags __maybe_unused)
 {
        u8 event_index[N_CLASSES][N_COUNTER];
        int n_classevent[N_CLASSES];

diff --git a/arch/powerpc/perf/power10-pmu.c b/arch/powerpc/perf/power10-pmu.c
index 79e0206..a901c13 100644 (file)
--- a/arch/powerpc/perf/power10-pmu.c
+++ b/arch/powerpc/perf/power10-pmu.c
@@ -216,6 +216,7 @@ PMU_FORMAT_ATTR(invert_bit,     "config:47");
 PMU_FORMAT_ATTR(src_mask,       "config:48-53");
 PMU_FORMAT_ATTR(src_match,      "config:54-59");
 PMU_FORMAT_ATTR(radix_scope,   "config:9");
+PMU_FORMAT_ATTR(thresh_cmp,     "config1:0-17");
 
 static struct attribute *power10_pmu_format_attr[] = {
        &format_attr_event.attr,
@@ -236,6 +237,7 @@ static struct attribute *power10_pmu_format_attr[] = {
        &format_attr_src_mask.attr,
        &format_attr_src_match.attr,
        &format_attr_radix_scope.attr,
+       &format_attr_thresh_cmp.attr,
        NULL,
 };
 
@@ -550,7 +552,7 @@ static struct power_pmu power10_pmu = {
        .get_mem_weight         = isa207_get_mem_weight,
        .disable_pmc            = isa207_disable_pmc,
        .flags                  = PPMU_HAS_SIER | PPMU_ARCH_207S |
-                                 PPMU_ARCH_31,
+                                 PPMU_ARCH_31 | PPMU_HAS_ATTR_CONFIG1,
        .n_generic              = ARRAY_SIZE(power10_generic_events),
        .generic_events         = power10_generic_events,
        .cache_events           = &power10_cache_events,

diff --git a/arch/powerpc/perf/power5+-pmu.c b/arch/powerpc/perf/power5+-pmu.c
index 3e64b4a..1873226 100644 (file)
--- a/arch/powerpc/perf/power5+-pmu.c
+++ b/arch/powerpc/perf/power5+-pmu.c
@@ -132,7 +132,7 @@ static unsigned long unit_cons[PM_LASTUNIT+1][2] = {
 };
 
 static int power5p_get_constraint(u64 event, unsigned long *maskp,
-                                 unsigned long *valp)
+                                 unsigned long *valp, u64 event_config1 __maybe_unused)
 {
        int pmc, byte, unit, sh;
        int bit, fmask;
@@ -451,7 +451,8 @@ static int power5p_marked_instr_event(u64 event)
 
 static int power5p_compute_mmcr(u64 event[], int n_ev,
                                unsigned int hwc[], struct mmcr_regs *mmcr,
-                               struct perf_event *pevents[])
+                               struct perf_event *pevents[],
+                               u32 flags __maybe_unused)
 {
        unsigned long mmcr1 = 0;
        unsigned long mmcra = 0;

diff --git a/arch/powerpc/perf/power5-pmu.c b/arch/powerpc/perf/power5-pmu.c
index 017bb19..cb611c1 100644 (file)
--- a/arch/powerpc/perf/power5-pmu.c
+++ b/arch/powerpc/perf/power5-pmu.c
@@ -136,7 +136,7 @@ static unsigned long unit_cons[PM_LASTUNIT+1][2] = {
 };
 
 static int power5_get_constraint(u64 event, unsigned long *maskp,
-                                unsigned long *valp)
+                                unsigned long *valp, u64 event_config1 __maybe_unused)
 {
        int pmc, byte, unit, sh;
        int bit, fmask;
@@ -382,7 +382,8 @@ static int power5_marked_instr_event(u64 event)
 
 static int power5_compute_mmcr(u64 event[], int n_ev,
                               unsigned int hwc[], struct mmcr_regs *mmcr,
-                              struct perf_event *pevents[])
+                              struct perf_event *pevents[],
+                              u32 flags __maybe_unused)
 {
        unsigned long mmcr1 = 0;
        unsigned long mmcra = MMCRA_SDAR_DCACHE_MISS | MMCRA_SDAR_ERAT_MISS;

diff --git a/arch/powerpc/perf/power6-pmu.c b/arch/powerpc/perf/power6-pmu.c
index 1899744..69ef382 100644 (file)
--- a/arch/powerpc/perf/power6-pmu.c
+++ b/arch/powerpc/perf/power6-pmu.c
@@ -173,7 +173,8 @@ static int power6_marked_instr_event(u64 event)
  * Assign PMC numbers and compute MMCR1 value for a set of events
  */
 static int p6_compute_mmcr(u64 event[], int n_ev,
-                          unsigned int hwc[], struct mmcr_regs *mmcr, struct perf_event *pevents[])
+                          unsigned int hwc[], struct mmcr_regs *mmcr, struct perf_event *pevents[],
+                          u32 flags __maybe_unused)
 {
        unsigned long mmcr1 = 0;
        unsigned long mmcra = MMCRA_SDAR_DCACHE_MISS | MMCRA_SDAR_ERAT_MISS;
@@ -266,7 +267,7 @@ static int p6_compute_mmcr(u64 event[], int n_ev,
  *     32-34   select field: nest (subunit) event selector
  */
 static int p6_get_constraint(u64 event, unsigned long *maskp,
-                            unsigned long *valp)
+                            unsigned long *valp, u64 event_config1 __maybe_unused)
 {
        int pmc, byte, sh, subunit;
        unsigned long mask = 0, value = 0;

diff --git a/arch/powerpc/perf/power7-pmu.c b/arch/powerpc/perf/power7-pmu.c
index bacfab1..894c17f 100644 (file)
--- a/arch/powerpc/perf/power7-pmu.c
+++ b/arch/powerpc/perf/power7-pmu.c
@@ -81,7 +81,7 @@ enum {
  */
 
 static int power7_get_constraint(u64 event, unsigned long *maskp,
-                                unsigned long *valp)
+                                unsigned long *valp, u64 event_config1 __maybe_unused)
 {
        int pmc, sh, unit;
        unsigned long mask = 0, value = 0;
@@ -245,7 +245,8 @@ static int power7_marked_instr_event(u64 event)
 
 static int power7_compute_mmcr(u64 event[], int n_ev,
                               unsigned int hwc[], struct mmcr_regs *mmcr,
-                              struct perf_event *pevents[])
+                              struct perf_event *pevents[],
+                              u32 flags __maybe_unused)
 {
        unsigned long mmcr1 = 0;
        unsigned long mmcra = MMCRA_SDAR_DCACHE_MISS | MMCRA_SDAR_ERAT_MISS;

diff --git a/arch/powerpc/perf/ppc970-pmu.c b/arch/powerpc/perf/ppc970-pmu.c
index 7d78df9..1f82637 100644 (file)
--- a/arch/powerpc/perf/ppc970-pmu.c
+++ b/arch/powerpc/perf/ppc970-pmu.c
@@ -190,7 +190,7 @@ static unsigned long unit_cons[PM_LASTUNIT+1][2] = {
 };
 
 static int p970_get_constraint(u64 event, unsigned long *maskp,
-                              unsigned long *valp)
+                              unsigned long *valp, u64 event_config1 __maybe_unused)
 {
        int pmc, byte, unit, sh, spcsel;
        unsigned long mask = 0, value = 0;
@@ -256,7 +256,8 @@ static int p970_get_alternatives(u64 event, unsigned int flags, u64 alt[])
 
 static int p970_compute_mmcr(u64 event[], int n_ev,
                             unsigned int hwc[], struct mmcr_regs *mmcr,
-                            struct perf_event *pevents[])
+                            struct perf_event *pevents[],
+                            u32 flags __maybe_unused)
 {
        unsigned long mmcr0 = 0, mmcr1 = 0, mmcra = 0;
        unsigned int pmc, unit, byte, psel;