perfcounters/powerpc: Add support for POWER5 processors

This adds the back-end for the PMU on the POWER5 processor.  This knows
how to use the fixed-function PMC5 and PMC6 (instructions completed and
run cycles).  Unlike POWER6, PMC5/6 obey the freeze conditions and can
generate interrupts, so their use doesn't impose any extra restrictions.

POWER5+ is different and is not supported by this patch.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 475 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/power5-pmu.c b/arch/powerpc/kernel/power5-pmu.c
new file mode 100644
index 000000000000..379ed1087cca
--- /dev/null
+++ b/arch/powerpc/kernel/power5-pmu.c
@@ -0,0 +1,475 @@
+/*
+ * Performance counter support for POWER5 (not POWER5++) processors.
+ *
+ * Copyright 2009 Paul Mackerras, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/kernel.h>
+#include <linux/perf_counter.h>
+#include <asm/reg.h>
+
+/*
+ * Bits in event code for POWER5 (not POWER5++)
+ */
+#define PM_PMC_SH       20      /* PMC number (1-based) for direct events */
+#define PM_PMC_MSK      0xf
+#define PM_PMC_MSKS     (PM_PMC_MSK << PM_PMC_SH)
+#define PM_UNIT_SH      16      /* TTMMUX number and setting - unit select */
+#define PM_UNIT_MSK     0xf
+#define PM_BYTE_SH      12      /* Byte number of event bus to use */
+#define PM_BYTE_MSK     7
+#define PM_GRS_SH       8       /* Storage subsystem mux select */
+#define PM_GRS_MSK      7
+#define PM_BUSEVENT_MSK 0x80    /* Set if event uses event bus */
+#define PM_PMCSEL_MSK   0x7f
+
+/* Values in PM_UNIT field */
+#define PM_FPU          0
+#define PM_ISU0         1
+#define PM_IFU          2
+#define PM_ISU1         3
+#define PM_IDU          4
+#define PM_ISU0_ALT     6
+#define PM_GRS          7
+#define PM_LSU0         8
+#define PM_LSU1         0xc
+#define PM_LASTUNIT     0xc
+
+/*
+ * Bits in MMCR1 for POWER5
+ */
+#define MMCR1_TTM0SEL_SH        62
+#define MMCR1_TTM1SEL_SH        60
+#define MMCR1_TTM2SEL_SH        58
+#define MMCR1_TTM3SEL_SH        56
+#define MMCR1_TTMSEL_MSK        3
+#define MMCR1_TD_CP_DBG0SEL_SH  54
+#define MMCR1_TD_CP_DBG1SEL_SH  52
+#define MMCR1_TD_CP_DBG2SEL_SH  50
+#define MMCR1_TD_CP_DBG3SEL_SH  48
+#define MMCR1_GRS_L2SEL_SH      46
+#define MMCR1_GRS_L2SEL_MSK     3
+#define MMCR1_GRS_L3SEL_SH      44
+#define MMCR1_GRS_L3SEL_MSK     3
+#define MMCR1_GRS_MCSEL_SH      41
+#define MMCR1_GRS_MCSEL_MSK     7
+#define MMCR1_GRS_FABSEL_SH     39
+#define MMCR1_GRS_FABSEL_MSK    3
+#define MMCR1_PMC1_ADDER_SEL_SH 35
+#define MMCR1_PMC2_ADDER_SEL_SH 34
+#define MMCR1_PMC3_ADDER_SEL_SH 33
+#define MMCR1_PMC4_ADDER_SEL_SH 32
+#define MMCR1_PMC1SEL_SH        25
+#define MMCR1_PMC2SEL_SH        17
+#define MMCR1_PMC3SEL_SH        9
+#define MMCR1_PMC4SEL_SH        1
+#define MMCR1_PMCSEL_SH(n)      (MMCR1_PMC1SEL_SH - (n) * 8)
+#define MMCR1_PMCSEL_MSK        0x7f
+
+/*
+ * Bits in MMCRA
+ */
+
+/*
+ * Layout of constraint bits:
+ * 6666555555555544444444443333333333222222222211111111110000000000
+ * 3210987654321098765432109876543210987654321098765432109876543210
+ *         <><>[  ><><>< ><> [  >[ >[ ><  ><  ><  ><  ><><><><><><>
+ *         T0T1 NC G0G1G2 G3  UC PS1PS2 B0  B1  B2  B3 P6P5P4P3P2P1
+ *
+ * T0 - TTM0 constraint
+ *     54-55: TTM0SEL value (0=FPU, 2=IFU, 3=ISU1) 0xc0_0000_0000_0000
+ *
+ * T1 - TTM1 constraint
+ *     52-53: TTM1SEL value (0=IDU, 3=GRS) 0x30_0000_0000_0000
+ *
+ * NC - number of counters
+ *     51: NC error 0x0008_0000_0000_0000
+ *     48-50: number of events needing PMC1-4 0x0007_0000_0000_0000
+ *
+ * G0..G3 - GRS mux constraints
+ *     46-47: GRS_L2SEL value
+ *     44-45: GRS_L3SEL value
+ *     41-44: GRS_MCSEL value
+ *     39-40: GRS_FABSEL value
+ *      Note that these match up with their bit positions in MMCR1
+ *
+ * UC - unit constraint: can't have all three of FPU|IFU|ISU1, ISU0, IDU|GRS
+ *     37: UC3 error 0x20_0000_0000
+ *     36: FPU|IFU|ISU1 events needed 0x10_0000_0000
+ *     35: ISU0 events needed 0x08_0000_0000
+ *     34: IDU|GRS events needed 0x04_0000_0000
+ *
+ * PS1
+ *     33: PS1 error 0x2_0000_0000
+ *     31-32: count of events needing PMC1/2 0x1_8000_0000
+ *
+ * PS2
+ *     30: PS2 error 0x4000_0000
+ *     28-29: count of events needing PMC3/4 0x3000_0000
+ *
+ * B0
+ *     24-27: Byte 0 event source 0x0f00_0000
+ *            Encoding as for the event code
+ *
+ * B1, B2, B3
+ *     20-23, 16-19, 12-15: Byte 1, 2, 3 event sources
+ *
+ * P1..P6
+ *     0-11: Count of events needing PMC1..PMC6
+ */
+
+static const int grsel_shift[8] = {
+        MMCR1_GRS_L2SEL_SH, MMCR1_GRS_L2SEL_SH, MMCR1_GRS_L2SEL_SH,
+        MMCR1_GRS_L3SEL_SH, MMCR1_GRS_L3SEL_SH, MMCR1_GRS_L3SEL_SH,
+        MMCR1_GRS_MCSEL_SH, MMCR1_GRS_FABSEL_SH
+};
+
+/* Masks and values for using events from the various units */
+static u64 unit_cons[PM_LASTUNIT+1][2] = {
+        [PM_FPU] =   { 0xc0002000000000ull, 0x00001000000000ull },
+        [PM_ISU0] =  { 0x00002000000000ull, 0x00000800000000ull },
+        [PM_ISU1] =  { 0xc0002000000000ull, 0xc0001000000000ull },
+        [PM_IFU] =   { 0xc0002000000000ull, 0x80001000000000ull },
+        [PM_IDU] =   { 0x30002000000000ull, 0x00000400000000ull },
+        [PM_GRS] =   { 0x30002000000000ull, 0x30000400000000ull },
+};
+
+static int power5_get_constraint(unsigned int event, u64 *maskp, u64 *valp)
+{
+        int pmc, byte, unit, sh;
+        int bit, fmask;
+        u64 mask = 0, value = 0;
+        int grp = -1;
+
+        pmc = (event >> PM_PMC_SH) & PM_PMC_MSK;
+        if (pmc) {
+                if (pmc > 6)
+                        return -1;
+                sh = (pmc - 1) * 2;
+                mask |= 2 << sh;
+                value |= 1 << sh;
+                if (pmc <= 4)
+                        grp = (pmc - 1) >> 1;
+                else if (event != 0x500009 && event != 0x600005)
+                        return -1;
+        }
+        if (event & PM_BUSEVENT_MSK) {
+                unit = (event >> PM_UNIT_SH) & PM_UNIT_MSK;
+                if (unit > PM_LASTUNIT)
+                        return -1;
+                if (unit == PM_ISU0_ALT)
+                        unit = PM_ISU0;
+                mask |= unit_cons[unit][0];
+                value |= unit_cons[unit][1];
+                byte = (event >> PM_BYTE_SH) & PM_BYTE_MSK;
+                if (byte >= 4) {
+                        if (unit != PM_LSU1)
+                                return -1;
+                        /* Map LSU1 low word (bytes 4-7) to unit LSU1+1 */
+                        ++unit;
+                        byte &= 3;
+                }
+                if (unit == PM_GRS) {
+                        bit = event & 7;
+                        fmask = (bit == 6)? 7: 3;
+                        sh = grsel_shift[bit];
+                        mask |= (u64)fmask << sh;
+                        value |= (u64)((event >> PM_GRS_SH) & fmask) << sh;
+                }
+                /*
+                 * Bus events on bytes 0 and 2 can be counted
+                 * on PMC1/2; bytes 1 and 3 on PMC3/4.
+                 */
+                if (!pmc)
+                        grp = byte & 1;
+                /* Set byte lane select field */
+                mask  |= 0xfULL << (24 - 4 * byte);
+                value |= (u64)unit << (24 - 4 * byte);
+        }
+        if (grp == 0) {
+                /* increment PMC1/2 field */
+                mask  |= 0x200000000ull;
+                value |= 0x080000000ull;
+        } else if (grp == 1) {
+                /* increment PMC3/4 field */
+                mask  |= 0x40000000ull;
+                value |= 0x10000000ull;
+        }
+        if (pmc < 5) {
+                /* need a counter from PMC1-4 set */
+                mask  |= 0x8000000000000ull;
+                value |= 0x1000000000000ull;
+        }
+        *maskp = mask;
+        *valp = value;
+        return 0;
+}
+
+#define MAX_ALT 3       /* at most 3 alternatives for any event */
+
+static const unsigned int event_alternatives[][MAX_ALT] = {
+        { 0x120e4,  0x400002 },                 /* PM_GRP_DISP_REJECT */
+        { 0x410c7,  0x441084 },                 /* PM_THRD_L2MISS_BOTH_CYC */
+        { 0x100005, 0x600005 },                 /* PM_RUN_CYC */
+        { 0x100009, 0x200009, 0x500009 },       /* PM_INST_CMPL */
+        { 0x300009, 0x400009 },                 /* PM_INST_DISP */
+};
+
+/*
+ * Scan the alternatives table for a match and return the
+ * index into the alternatives table if found, else -1.
+ */
+static int find_alternative(unsigned int event)
+{
+        int i, j;
+
+        for (i = 0; i < ARRAY_SIZE(event_alternatives); ++i) {
+                if (event < event_alternatives[i][0])
+                        break;
+                for (j = 0; j < MAX_ALT && event_alternatives[i][j]; ++j)
+                        if (event == event_alternatives[i][j])
+                                return i;
+        }
+        return -1;
+}
+
+static const unsigned char bytedecode_alternatives[4][4] = {
+        /* PMC 1 */     { 0x21, 0x23, 0x25, 0x27 },
+        /* PMC 2 */     { 0x07, 0x17, 0x0e, 0x1e },
+        /* PMC 3 */     { 0x20, 0x22, 0x24, 0x26 },
+        /* PMC 4 */     { 0x07, 0x17, 0x0e, 0x1e }
+};
+
+/*
+ * Some direct events for decodes of event bus byte 3 have alternative
+ * PMCSEL values on other counters.  This returns the alternative
+ * event code for those that do, or -1 otherwise.
+ */
+static int find_alternative_bdecode(unsigned int event)
+{
+        int pmc, altpmc, pp, j;
+
+        pmc = (event >> PM_PMC_SH) & PM_PMC_MSK;
+        if (pmc == 0 || pmc > 4)
+                return -1;
+        altpmc = 5 - pmc;       /* 1 <-> 4, 2 <-> 3 */
+        pp = event & PM_PMCSEL_MSK;
+        for (j = 0; j < 4; ++j) {
+                if (bytedecode_alternatives[pmc - 1][j] == pp) {
+                        return (event & ~(PM_PMC_MSKS | PM_PMCSEL_MSK)) |
+                                (altpmc << PM_PMC_SH) |
+                                bytedecode_alternatives[altpmc - 1][j];
+                }
+        }
+        return -1;
+}
+
+static int power5_get_alternatives(unsigned int event, unsigned int alt[])
+{
+        int i, j, ae, nalt = 1;
+
+        alt[0] = event;
+        nalt = 1;
+        i = find_alternative(event);
+        if (i >= 0) {
+                for (j = 0; j < MAX_ALT; ++j) {
+                        ae = event_alternatives[i][j];
+                        if (ae && ae != event)
+                                alt[nalt++] = ae;
+                }
+        } else {
+                ae = find_alternative_bdecode(event);
+                if (ae > 0)
+                        alt[nalt++] = ae;
+        }
+        return nalt;
+}
+
+static int power5_compute_mmcr(unsigned int event[], int n_ev,
+                               unsigned int hwc[], u64 mmcr[])
+{
+        u64 mmcr1 = 0;
+        unsigned int pmc, unit, byte, psel;
+        unsigned int ttm, grp;
+        int i, isbus, bit, grsel;
+        unsigned int pmc_inuse = 0;
+        unsigned int pmc_grp_use[2];
+        unsigned char busbyte[4];
+        unsigned char unituse[16];
+        int ttmuse;
+
+        if (n_ev > 6)
+                return -1;
+
+        /* First pass to count resource use */
+        pmc_grp_use[0] = pmc_grp_use[1] = 0;
+        memset(busbyte, 0, sizeof(busbyte));
+        memset(unituse, 0, sizeof(unituse));
+        for (i = 0; i < n_ev; ++i) {
+                pmc = (event[i] >> PM_PMC_SH) & PM_PMC_MSK;
+                if (pmc) {
+                        if (pmc > 6)
+                                return -1;
+                        if (pmc_inuse & (1 << (pmc - 1)))
+                                return -1;
+                        pmc_inuse |= 1 << (pmc - 1);
+                        /* count 1/2 vs 3/4 use */
+                        if (pmc <= 4)
+                                ++pmc_grp_use[(pmc - 1) >> 1];
+                }
+                if (event[i] & PM_BUSEVENT_MSK) {
+                        unit = (event[i] >> PM_UNIT_SH) & PM_UNIT_MSK;
+                        byte = (event[i] >> PM_BYTE_SH) & PM_BYTE_MSK;
+                        if (unit > PM_LASTUNIT)
+                                return -1;
+                        if (unit == PM_ISU0_ALT)
+                                unit = PM_ISU0;
+                        if (byte >= 4) {
+                                if (unit != PM_LSU1)
+                                        return -1;
+                                ++unit;
+                                byte &= 3;
+                        }
+                        if (!pmc)
+                                ++pmc_grp_use[byte & 1];
+                        if (busbyte[byte] && busbyte[byte] != unit)
+                                return -1;
+                        busbyte[byte] = unit;
+                        unituse[unit] = 1;
+                }
+        }
+        if (pmc_grp_use[0] > 2 || pmc_grp_use[1] > 2)
+                return -1;
+
+        /*
+         * Assign resources and set multiplexer selects.
+         *
+         * PM_ISU0 can go either on TTM0 or TTM1, but that's the only
+         * choice we have to deal with.
+         */
+        if (unituse[PM_ISU0] &
+            (unituse[PM_FPU] | unituse[PM_IFU] | unituse[PM_ISU1])) {
+                unituse[PM_ISU0_ALT] = 1;       /* move ISU to TTM1 */
+                unituse[PM_ISU0] = 0;
+        }
+        /* Set TTM[01]SEL fields. */
+        ttmuse = 0;
+        for (i = PM_FPU; i <= PM_ISU1; ++i) {
+                if (!unituse[i])
+                        continue;
+                if (ttmuse++)
+                        return -1;
+                mmcr1 |= (u64)i << MMCR1_TTM0SEL_SH;
+        }
+        ttmuse = 0;
+        for (; i <= PM_GRS; ++i) {
+                if (!unituse[i])
+                        continue;
+                if (ttmuse++)
+                        return -1;
+                mmcr1 |= (u64)(i & 3) << MMCR1_TTM1SEL_SH;
+        }
+        if (ttmuse > 1)
+                return -1;
+
+        /* Set byte lane select fields, TTM[23]SEL and GRS_*SEL. */
+        for (byte = 0; byte < 4; ++byte) {
+                unit = busbyte[byte];
+                if (!unit)
+                        continue;
+                if (unit == PM_ISU0 && unituse[PM_ISU0_ALT]) {
+                        /* get ISU0 through TTM1 rather than TTM0 */
+                        unit = PM_ISU0_ALT;
+                } else if (unit == PM_LSU1 + 1) {
+                        /* select lower word of LSU1 for this byte */
+                        mmcr1 |= 1ull << (MMCR1_TTM3SEL_SH + 3 - byte);
+                }
+                ttm = unit >> 2;
+                mmcr1 |= (u64)ttm << (MMCR1_TD_CP_DBG0SEL_SH - 2 * byte);
+        }
+
+        /* Second pass: assign PMCs, set PMCxSEL and PMCx_ADDER_SEL fields */
+        for (i = 0; i < n_ev; ++i) {
+                pmc = (event[i] >> PM_PMC_SH) & PM_PMC_MSK;
+                unit = (event[i] >> PM_UNIT_SH) & PM_UNIT_MSK;
+                byte = (event[i] >> PM_BYTE_SH) & PM_BYTE_MSK;
+                psel = event[i] & PM_PMCSEL_MSK;
+                isbus = event[i] & PM_BUSEVENT_MSK;
+                if (!pmc) {
+                        /* Bus event or any-PMC direct event */
+                        for (pmc = 0; pmc < 4; ++pmc) {
+                                if (pmc_inuse & (1 << pmc))
+                                        continue;
+                                grp = (pmc >> 1) & 1;
+                                if (isbus) {
+                                        if (grp == (byte & 1))
+                                                break;
+                                } else if (pmc_grp_use[grp] < 2) {
+                                        ++pmc_grp_use[grp];
+                                        break;
+                                }
+                        }
+                        pmc_inuse |= 1 << pmc;
+                } else if (pmc <= 4) {
+                        /* Direct event */
+                        --pmc;
+                        if ((psel == 8 || psel == 0x10) && isbus && (byte & 2))
+                                /* add events on higher-numbered bus */
+                                mmcr1 |= 1ull << (MMCR1_PMC1_ADDER_SEL_SH - pmc);
+                } else {
+                        /* Instructions or run cycles on PMC5/6 */
+                        --pmc;
+                }
+                if (isbus && unit == PM_GRS) {
+                        bit = psel & 7;
+                        grsel = (event[i] >> PM_GRS_SH) & PM_GRS_MSK;
+                        mmcr1 |= (u64)grsel << grsel_shift[bit];
+                }
+                if (pmc <= 3)
+                        mmcr1 |= psel << MMCR1_PMCSEL_SH(pmc);
+                hwc[i] = pmc;
+        }
+
+        /* Return MMCRx values */
+        mmcr[0] = 0;
+        if (pmc_inuse & 1)
+                mmcr[0] = MMCR0_PMC1CE;
+        if (pmc_inuse & 0x3e)
+                mmcr[0] |= MMCR0_PMCjCE;
+        mmcr[1] = mmcr1;
+        mmcr[2] = 0;
+        return 0;
+}
+
+static void power5_disable_pmc(unsigned int pmc, u64 mmcr[])
+{
+        if (pmc <= 3)
+                mmcr[1] &= ~(0x7fUL << MMCR1_PMCSEL_SH(pmc));
+}
+
+static int power5_generic_events[] = {
+        [PERF_COUNT_CPU_CYCLES] = 0xf,
+        [PERF_COUNT_INSTRUCTIONS] = 0x100009,
+        [PERF_COUNT_CACHE_REFERENCES] = 0x4c1090,       /* LD_REF_L1 */
+        [PERF_COUNT_CACHE_MISSES] = 0x3c1088,           /* LD_MISS_L1 */
+        [PERF_COUNT_BRANCH_INSTRUCTIONS] = 0x230e4,     /* BR_ISSUED */ 
+        [PERF_COUNT_BRANCH_MISSES] = 0x230e5,           /* BR_MPRED_CR */
+};
+
+struct power_pmu power5_pmu = {
+        .n_counter = 6,
+        .max_alternatives = MAX_ALT,
+        .add_fields = 0x7000090000555ull,
+        .test_adder = 0x3000490000000ull,
+        .compute_mmcr = power5_compute_mmcr,
+        .get_constraint = power5_get_constraint,
+        .get_alternatives = power5_get_alternatives,
+        .disable_pmc = power5_disable_pmc,
+        .n_generic = ARRAY_SIZE(power5_generic_events),
+        .generic_events = power5_generic_events,
+};