From: Alex Richardson <alexrichard...@google.com> In the PMUv3, a new AArch32 64-bit (MCRR/MRRC) accessor for the PMCCNTR was added. In QEMU we forgot to implement this, so only provide the 32-bit accessor. Since we have a 64-bit PMCCNTR sysreg for AArch64, adding the 64-bit AArch32 version is easy.
We add the PMCCNTR to the v8_cp_reginfo because PMUv3 was added in the ARMv8 architecture. This is consistent with how we handle the existing PMCCNTR support, where we always implement it for all v7 CPUs. This is arguably something we should clean up so it is gated on ARM_FEATURE_PMU and/or an ID register check for the relevant PMU version, but we should do that as its own tidyup rather than being inconsistent between this PMCCNTR accessor and the others. Since the register name is the same as the 32-bit PMCCNTR, we set ARM_CP_NO_GDB on the 32-bit one to avoid generating an invalid GDB XML. See https://developer.arm.com/documentation/ddi0601/2024-06/AArch32-Registers/PMCCNTR--Performance-Monitors-Cycle-Count-Register?lang=en Note for potential backporting: * this code in cpregs-pmu.c will be in helper.c on stable branches that don't have commit ae2086426d37 Cc: qemu-sta...@nongnu.org Signed-off-by: Alex Richardson <alexrichard...@google.com> Message-id: 20250725170136.145116-1-alexrichard...@google.com Reviewed-by: Peter Maydell <peter.mayd...@linaro.org> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> --- target/arm/cpregs-pmu.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/target/arm/cpregs-pmu.c b/target/arm/cpregs-pmu.c index 0f295b1376c..9c4431c18ba 100644 --- a/target/arm/cpregs-pmu.c +++ b/target/arm/cpregs-pmu.c @@ -1067,11 +1067,6 @@ static const ARMCPRegInfo v7_pm_reginfo[] = { .fgt = FGT_PMSELR_EL0, .fieldoffset = offsetof(CPUARMState, cp15.c9_pmselr), .writefn = pmselr_write, .raw_writefn = raw_write, }, - { .name = "PMCCNTR", .cp = 15, .crn = 9, .crm = 13, .opc1 = 0, .opc2 = 0, - .access = PL0_RW, .resetvalue = 0, .type = ARM_CP_ALIAS | ARM_CP_IO, - .fgt = FGT_PMCCNTR_EL0, - .readfn = pmccntr_read, .writefn = pmccntr_write32, - .accessfn = pmreg_access_ccntr }, { .name = "PMCCNTR_EL0", .state = ARM_CP_STATE_AA64, .opc0 = 3, .opc1 = 3, .crn = 9, .crm = 13, .opc2 = 0, .access = PL0_RW, .accessfn = pmreg_access_ccntr, @@ -1211,6 +1206,23 @@ void define_pm_cpregs(ARMCPU *cpu) define_one_arm_cp_reg(cpu, &pmcr); define_one_arm_cp_reg(cpu, &pmcr64); define_arm_cp_regs(cpu, v7_pm_reginfo); + /* + * 32-bit AArch32 PMCCNTR. We don't expose this to GDB if the + * new-in-v8 PMUv3 64-bit AArch32 PMCCNTR register is implemented + * (as that will provide the GDB user's view of "PMCCNTR"). + */ + ARMCPRegInfo pmccntr = { + .name = "PMCCNTR", + .cp = 15, .crn = 9, .crm = 13, .opc1 = 0, .opc2 = 0, + .access = PL0_RW, .accessfn = pmreg_access_ccntr, + .resetvalue = 0, .type = ARM_CP_ALIAS | ARM_CP_IO, + .fgt = FGT_PMCCNTR_EL0, + .readfn = pmccntr_read, .writefn = pmccntr_write32, + }; + if (arm_feature(env, ARM_FEATURE_V8)) { + pmccntr.type |= ARM_CP_NO_GDB; + } + define_one_arm_cp_reg(cpu, &pmccntr); for (unsigned i = 0, pmcrn = pmu_num_counters(env); i < pmcrn; i++) { g_autofree char *pmevcntr_name = g_strdup_printf("PMEVCNTR%d", i); @@ -1276,6 +1288,13 @@ void define_pm_cpregs(ARMCPU *cpu) .access = PL0_R, .accessfn = pmreg_access, .type = ARM_CP_CONST, .fgt = FGT_PMCEIDN_EL0, .resetvalue = cpu->pmceid1 }, + /* AArch32 64-bit PMCCNTR view: added in PMUv3 with Armv8 */ + { .name = "PMCCNTR", .state = ARM_CP_STATE_AA32, + .cp = 15, .crm = 9, .opc1 = 0, + .access = PL0_RW, .accessfn = pmreg_access_ccntr, .resetvalue = 0, + .type = ARM_CP_ALIAS | ARM_CP_IO | ARM_CP_64BIT, + .fgt = FGT_PMCCNTR_EL0, .readfn = pmccntr_read, + .writefn = pmccntr_write, }, }; define_arm_cp_regs(cpu, v8_pm_reginfo); } -- 2.43.0
