perf_counter: powerpc: set sample enable bit for marked instruction events

Impact: enable access to hardware feature

POWER processors have the ability to "mark" a subset of the instructions
and provide more detailed information on what happens to the marked
instructions as they flow through the pipeline.  This marking is
enabled by the "sample enable" bit in MMCRA, and there are
synchronization requirements around setting and clearing the bit.

This adds logic to the processor-specific back-ends so that they know
which events relate to marked instructions and set the sampling enable
bit if any event that we want to put on the PMU is a marked instruction
event.  It also adds logic to the generic powerpc code to do the
necessary synchronization if that bit is set.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <18908.31930.1024.228867@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 69 insertions, 3 deletions

diff --git a/arch/powerpc/kernel/ppc970-pmu.c b/arch/powerpc/kernel/ppc970-pmu.c
index c3256580be1a..aed8ccd7c077 100644
--- a/arch/powerpc/kernel/ppc970-pmu.c
+++ b/arch/powerpc/kernel/ppc970-pmu.c
@@ -19,6 +19,8 @@
 #define PM_PMC_MSK      0xf
 #define PM_UNIT_SH      8       /* TTMMUX number and setting - unit select */
 #define PM_UNIT_MSK     0xf
+#define PM_SPCSEL_SH    6
+#define PM_SPCSEL_MSK   3
 #define PM_BYTE_SH      4       /* Byte number of event bus to use */
 #define PM_BYTE_MSK     3
 #define PM_PMCSEL_MSK   0xf
@@ -88,8 +90,11 @@ static short mmcr1_adder_bits[8] = {
  * Layout of constraint bits:
  * 6666555555555544444444443333333333222222222211111111110000000000
  * 3210987654321098765432109876543210987654321098765432109876543210
- *                 <><>[  >[  >[  ><  ><  ><  ><  ><><><><><><><><>
- *                 T0T1 UC  PS1 PS2 B0  B1  B2  B3 P1P2P3P4P5P6P7P8
+ *               <><><>[  >[  >[  ><  ><  ><  ><  ><><><><><><><><>
+ *               SPT0T1 UC  PS1 PS2 B0  B1  B2  B3 P1P2P3P4P5P6P7P8
+ *
+ * SP - SPCSEL constraint
+ *     48-49: SPCSEL value 0x3_0000_0000_0000
  *
  * T0 - TTM0 constraint
  *     46-47: TTM0SEL value (0=FPU, 2=IFU, 3=VPU) 0xC000_0000_0000
@@ -126,6 +131,57 @@ static short mmcr1_adder_bits[8] = {
  *     0-13: Count of events needing PMC2..PMC8
  */
 
+static unsigned char direct_marked_event[8] = {
+        (1<<2) | (1<<3),        /* PMC1: PM_MRK_GRP_DISP, PM_MRK_ST_CMPL */
+        (1<<3) | (1<<5),        /* PMC2: PM_THRESH_TIMEO, PM_MRK_BRU_FIN */
+        (1<<3) | (1<<5),        /* PMC3: PM_MRK_ST_CMPL_INT, PM_MRK_VMX_FIN */
+        (1<<4) | (1<<5),        /* PMC4: PM_MRK_GRP_CMPL, PM_MRK_CRU_FIN */
+        (1<<4) | (1<<5),        /* PMC5: PM_GRP_MRK, PM_MRK_GRP_TIMEO */
+        (1<<3) | (1<<4) | (1<<5),
+                /* PMC6: PM_MRK_ST_STS, PM_MRK_FXU_FIN, PM_MRK_GRP_ISSUED */
+        (1<<4) | (1<<5),        /* PMC7: PM_MRK_FPU_FIN, PM_MRK_INST_FIN */
+        (1<<4)                  /* PMC8: PM_MRK_LSU_FIN */
+};
+
+/*
+ * Returns 1 if event counts things relating to marked instructions
+ * and thus needs the MMCRA_SAMPLE_ENABLE bit set, or 0 if not.
+ */
+static int p970_marked_instr_event(unsigned int event)
+{
+        int pmc, psel, unit, byte, bit;
+        unsigned int mask;
+
+        pmc = (event >> PM_PMC_SH) & PM_PMC_MSK;
+        psel = event & PM_PMCSEL_MSK;
+        if (pmc) {
+                if (direct_marked_event[pmc - 1] & (1 << psel))
+                        return 1;
+                if (psel == 0)          /* add events */
+                        bit = (pmc <= 4)? pmc - 1: 8 - pmc;
+                else if (psel == 7 || psel == 13)       /* decode events */
+                        bit = 4;
+                else
+                        return 0;
+        } else
+                bit = psel;
+
+        byte = (event >> PM_BYTE_SH) & PM_BYTE_MSK;
+        unit = (event >> PM_UNIT_SH) & PM_UNIT_MSK;
+        mask = 0;
+        switch (unit) {
+        case PM_VPU:
+                mask = 0x4c;            /* byte 0 bits 2,3,6 */
+        case PM_LSU0:
+                /* byte 2 bits 0,2,3,4,6; all of byte 1 */
+                mask = 0x085dff00;
+        case PM_LSU1L:
+                mask = 0x50 << 24;      /* byte 3 bits 4,6 */
+                break;
+        }
+        return (mask >> (byte * 8 + bit)) & 1;
+}
+
 /* Masks and values for using events from the various units */
 static u64 unit_cons[PM_LASTUNIT+1][2] = {
         [PM_FPU] =   { 0xc80000000000ull, 0x040000000000ull },
@@ -138,7 +194,7 @@ static u64 unit_cons[PM_LASTUNIT+1][2] = {
 
 static int p970_get_constraint(unsigned int event, u64 *maskp, u64 *valp)
 {
-        int pmc, byte, unit, sh;
+        int pmc, byte, unit, sh, spcsel;
         u64 mask = 0, value = 0;
         int grp = -1;
 
@@ -177,6 +233,11 @@ static int p970_get_constraint(unsigned int event, u64 *maskp, u64 *valp)
                 mask  |= 0x800000000ull;
                 value |= 0x100000000ull;
         }
+        spcsel = (event >> PM_SPCSEL_SH) & PM_SPCSEL_MSK;
+        if (spcsel) {
+                mask  |= 3ull << 48;
+                value |= (u64)spcsel << 48;
+        }
         *maskp = mask;
         *valp = value;
         return 0;
@@ -209,6 +270,7 @@ static int p970_compute_mmcr(unsigned int event[], int n_ev,
         unsigned char ttmuse[2];
         unsigned char pmcsel[8];
         int i;
+        int spcsel;
 
         if (n_ev > 8)
                 return -1;
@@ -316,6 +378,10 @@ static int p970_compute_mmcr(unsigned int event[], int n_ev,
                 }
                 pmcsel[pmc] = psel;
                 hwc[i] = pmc;
+                spcsel = (event[i] >> PM_SPCSEL_SH) & PM_SPCSEL_MSK;
+                mmcr1 |= spcsel;
+                if (p970_marked_instr_event(event[i]))
+                        mmcra |= MMCRA_SAMPLE_ENABLE;
         }
         for (pmc = 0; pmc < 2; ++pmc)
                 mmcr0 |= pmcsel[pmc] << (MMCR0_PMC1SEL_SH - 7 * pmc);