1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright 2014, Michael Ellerman, IBM Corp. 4 */ 5 6 #include <signal.h> 7 #include <stdio.h> 8 #include <stdlib.h> 9 #include <stdbool.h> 10 #include <sys/types.h> 11 #include <sys/wait.h> 12 #include <unistd.h> 13 #include <setjmp.h> 14 15 #include "ebb.h" 16 17 18 /* 19 * Test that a fork clears the PMU state of the child. eg. BESCR/EBBHR/EBBRR 20 * are cleared, and MMCR0_PMCC is reset, preventing the child from accessing 21 * the PMU. 22 */ 23 24 static struct event event; 25 26 static int child(void) 27 { 28 /* Even though we have EBE=0 we can still see the EBB regs */ 29 FAIL_IF(mfspr(SPRN_BESCR) != 0); 30 FAIL_IF(mfspr(SPRN_EBBHR) != 0); 31 FAIL_IF(mfspr(SPRN_EBBRR) != 0); 32 33 FAIL_IF(catch_sigill(write_pmc1)); 34 35 /* We can still read from the event, though it is on our parent */ 36 FAIL_IF(event_read(&event)); 37 38 return 0; 39 } 40 41 /* Tests that fork clears EBB state */ 42 int fork_cleanup(void) 43 { 44 pid_t pid; 45 46 SKIP_IF(!ebb_is_supported()); 47 48 event_init_named(&event, 0x1001e, "cycles"); 49 event_leader_ebb_init(&event); 50 51 FAIL_IF(event_open(&event)); 52 53 ebb_enable_pmc_counting(1); 54 setup_ebb_handler(standard_ebb_callee); 55 ebb_global_enable(); 56 57 FAIL_IF(ebb_event_enable(&event)); 58 59 mtspr(SPRN_MMCR0, MMCR0_FC); 60 mtspr(SPRN_PMC1, pmc_sample_period(sample_period)); 61 62 /* Don't need to actually take any EBBs */ 63 64 pid = fork(); 65 if (pid == 0) 66 exit(child()); 67 68 /* Child does the actual testing */ 69 FAIL_IF(wait_for_child(pid)); 70 71 /* After fork */ 72 event_close(&event); 73 74 return 0; 75 } 76 77 int main(void) 78 { 79 return test_harness(fork_cleanup, "fork_cleanup"); 80 } 81