// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2014, Michael Ellerman, IBM Corp.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include "ebb.h"
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/*
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* Test of counting cycles while using MMCR0_FC (freeze counters) to only count
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* parts of the code. This is complicated by the fact that FC is set by the
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* hardware when the event overflows. We may take the EBB after we have set FC,
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* so we have to be careful about whether we clear FC at the end of the EBB
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* handler or not.
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*/
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static bool counters_frozen = false;
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static int ebbs_while_frozen = 0;
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static void ebb_callee(void)
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{
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uint64_t mask, val;
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mask = MMCR0_PMAO | MMCR0_FC;
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val = mfspr(SPRN_BESCR);
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if (!(val & BESCR_PMEO)) {
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ebb_state.stats.spurious++;
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goto out;
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}
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ebb_state.stats.ebb_count++;
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trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count);
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val = mfspr(SPRN_MMCR0);
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trace_log_reg(ebb_state.trace, SPRN_MMCR0, val);
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if (counters_frozen) {
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trace_log_string(ebb_state.trace, "frozen");
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ebbs_while_frozen++;
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mask &= ~MMCR0_FC;
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}
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count_pmc(1, sample_period);
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out:
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reset_ebb_with_clear_mask(mask);
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}
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int cycles_with_freeze(void)
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{
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struct event event;
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uint64_t val;
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bool fc_cleared;
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SKIP_IF(!ebb_is_supported());
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event_init_named(&event, 0x1001e, "cycles");
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event_leader_ebb_init(&event);
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event.attr.exclude_kernel = 1;
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event.attr.exclude_hv = 1;
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event.attr.exclude_idle = 1;
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FAIL_IF(event_open(&event));
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setup_ebb_handler(ebb_callee);
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ebb_global_enable();
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FAIL_IF(ebb_event_enable(&event));
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mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
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fc_cleared = false;
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/* Make sure we loop until we take at least one EBB */
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while ((ebb_state.stats.ebb_count < 20 && !fc_cleared) ||
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ebb_state.stats.ebb_count < 1)
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{
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counters_frozen = false;
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mb();
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mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC);
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FAIL_IF(core_busy_loop());
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counters_frozen = true;
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mb();
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mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC);
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val = mfspr(SPRN_MMCR0);
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if (! (val & MMCR0_FC)) {
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printf("Outside of loop, FC NOT set MMCR0 0x%lx\n", val);
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fc_cleared = true;
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}
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}
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ebb_global_disable();
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ebb_freeze_pmcs();
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dump_ebb_state();
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printf("EBBs while frozen %d\n", ebbs_while_frozen);
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event_close(&event);
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FAIL_IF(ebb_state.stats.ebb_count == 0);
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FAIL_IF(fc_cleared);
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return 0;
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}
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int main(void)
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{
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return test_harness(cycles_with_freeze, "cycles_with_freeze");
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}
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