// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2014, Michael Ellerman, IBM Corp. */ #include <stdbool.h> #include <stdio.h> #include <stdlib.h> #include "ebb.h" #define NUMBER_OF_EBBS 50 /* * Test that if we overflow the counter while in the EBB handler, we take * another EBB on exiting from the handler. * * We do this by counting with a stupidly low sample period, causing us to * overflow the PMU while we're still in the EBB handler, leading to another * EBB. * * We get out of what would otherwise be an infinite loop by leaving the * counter frozen once we've taken enough EBBs. */ static void ebb_callee(void) { uint64_t siar, val; val = mfspr(SPRN_BESCR); if (!(val & BESCR_PMEO)) { ebb_state.stats.spurious++; goto out; } ebb_state.stats.ebb_count++; trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count); /* Resets the PMC */ count_pmc(1, sample_period); out: if (ebb_state.stats.ebb_count == NUMBER_OF_EBBS) /* Reset but leave counters frozen */ reset_ebb_with_clear_mask(MMCR0_PMAO); else /* Unfreezes */ reset_ebb(); /* Do some stuff to chew some cycles and pop the counter */ siar = mfspr(SPRN_SIAR); trace_log_reg(ebb_state.trace, SPRN_SIAR, siar); val = mfspr(SPRN_PMC1); trace_log_reg(ebb_state.trace, SPRN_PMC1, val); val = mfspr(SPRN_MMCR0); trace_log_reg(ebb_state.trace, SPRN_MMCR0, val); } int back_to_back_ebbs(void) { struct event event; SKIP_IF(!ebb_is_supported()); event_init_named(&event, 0x1001e, "cycles"); event_leader_ebb_init(&event); event.attr.exclude_kernel = 1; event.attr.exclude_hv = 1; event.attr.exclude_idle = 1; FAIL_IF(event_open(&event)); setup_ebb_handler(ebb_callee); FAIL_IF(ebb_event_enable(&event)); sample_period = 5; ebb_freeze_pmcs(); mtspr(SPRN_PMC1, pmc_sample_period(sample_period)); ebb_global_enable(); ebb_unfreeze_pmcs(); while (ebb_state.stats.ebb_count < NUMBER_OF_EBBS) FAIL_IF(core_busy_loop()); ebb_global_disable(); ebb_freeze_pmcs(); dump_ebb_state(); event_close(&event); FAIL_IF(ebb_state.stats.ebb_count != NUMBER_OF_EBBS); return 0; } int main(void) { return test_harness(back_to_back_ebbs, "back_to_back_ebbs"); }