target/arm: PMU: Set PMCR.N to 4

This both advertises that we support four counters and enables them
because the pmu_num_counters() reads this value from PMCR.

Signed-off-by: Aaron Lindsay <alindsay@codeaurora.org>
Signed-off-by: Aaron Lindsay <aaron@os.amperecomputing.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20181211151945.29137-13-aaron@os.amperecomputing.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 35c105a8618860bd366deb996dc534faf7c3a5c2..44f1340ee135f48f3e8eb4a77807bb26f2ae2e51 100644 (file)
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -1777,7 +1777,7 @@ static const ARMCPRegInfo v7_cp_reginfo[] = {
       .access = PL1_W, .type = ARM_CP_NOP },
     /* Performance monitors are implementation defined in v7,
      * but with an ARM recommended set of registers, which we
-     * follow (although we don't actually implement any counters)
+     * follow.
      *
      * Performance registers fall into three categories:
      *  (a) always UNDEF in PL0, RW in PL1 (PMINTENSET, PMINTENCLR)
@@ -5671,10 +5671,10 @@ void register_cp_regs_for_features(ARMCPU *cpu)
     }
     if (arm_feature(env, ARM_FEATURE_V7)) {
         /* v7 performance monitor control register: same implementor
-         * field as main ID register, and we implement only the cycle
-         * count register.
+         * field as main ID register, and we implement four counters in
+         * addition to the cycle count register.
          */
-        unsigned int i, pmcrn = 0;
+        unsigned int i, pmcrn = 4;
         ARMCPRegInfo pmcr = {
             .name = "PMCR", .cp = 15, .crn = 9, .crm = 12, .opc1 = 0, .opc2 = 0,
             .access = PL0_RW,
@@ -5689,7 +5689,7 @@ void register_cp_regs_for_features(ARMCPU *cpu)
             .access = PL0_RW, .accessfn = pmreg_access,
             .type = ARM_CP_IO,
             .fieldoffset = offsetof(CPUARMState, cp15.c9_pmcr),
-            .resetvalue = cpu->midr & 0xff000000,
+            .resetvalue = (cpu->midr & 0xff000000) | (pmcrn << PMCRN_SHIFT),
             .writefn = pmcr_write, .raw_writefn = raw_write,
         };
         define_one_arm_cp_reg(cpu, &pmcr);