// 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 <signal.h>
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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 <sys/types.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <setjmp.h>
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#include "ebb.h"
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/*
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* Test that a fork clears the PMU state of the child. eg. BESCR/EBBHR/EBBRR
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* are cleared, and MMCR0_PMCC is reset, preventing the child from accessing
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* the PMU.
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*/
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static struct event event;
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static int child(void)
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{
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/* Even though we have EBE=0 we can still see the EBB regs */
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FAIL_IF(mfspr(SPRN_BESCR) != 0);
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FAIL_IF(mfspr(SPRN_EBBHR) != 0);
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FAIL_IF(mfspr(SPRN_EBBRR) != 0);
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FAIL_IF(catch_sigill(write_pmc1));
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/* We can still read from the event, though it is on our parent */
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FAIL_IF(event_read(&event));
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return 0;
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}
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/* Tests that fork clears EBB state */
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int fork_cleanup(void)
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{
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pid_t pid;
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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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FAIL_IF(event_open(&event));
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ebb_enable_pmc_counting(1);
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setup_ebb_handler(standard_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_MMCR0, MMCR0_FC);
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mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
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/* Don't need to actually take any EBBs */
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pid = fork();
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if (pid == 0)
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exit(child());
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/* Child does the actual testing */
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FAIL_IF(wait_for_child(pid));
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/* After fork */
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event_close(&event);
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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(fork_cleanup, "fork_cleanup");
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}
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