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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2014, Michael Ellerman, IBM Corp.
*/
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <setjmp.h>
#include "ebb.h"
/*
* Test that a fork clears the PMU state of the child. eg. BESCR/EBBHR/EBBRR
* are cleared, and MMCR0_PMCC is reset, preventing the child from accessing
* the PMU.
*/
static struct event event;
static int child(void)
{
/* Even though we have EBE=0 we can still see the EBB regs */
FAIL_IF(mfspr(SPRN_BESCR) != 0);
FAIL_IF(mfspr(SPRN_EBBHR) != 0);
FAIL_IF(mfspr(SPRN_EBBRR) != 0);
FAIL_IF(catch_sigill(write_pmc1));
/* We can still read from the event, though it is on our parent */
FAIL_IF(event_read(&event));
return 0;
}
/* Tests that fork clears EBB state */
int fork_cleanup(void)
{
pid_t pid;
SKIP_IF(!ebb_is_supported());
event_init_named(&event, 0x1001e, "cycles");
event_leader_ebb_init(&event);
FAIL_IF(event_open(&event));
ebb_enable_pmc_counting(1);
setup_ebb_handler(standard_ebb_callee);
ebb_global_enable();
FAIL_IF(ebb_event_enable(&event));
mtspr(SPRN_MMCR0, MMCR0_FC);
mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
/* Don't need to actually take any EBBs */
pid = fork();
if (pid == 0)
exit(child());
/* Child does the actual testing */
FAIL_IF(wait_for_child(pid));
/* After fork */
event_close(&event);
return 0;
}
int main(void)
{
return test_harness(fork_cleanup, "fork_cleanup");
}
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