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1// SPDX-License-Identifier: GPL-2.02/*3 * Inspired by breakpoint overflow test done by4 * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests5 * (git://github.com/deater/perf_event_tests)6 */7 8/*9 * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select10 * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.11 */12#define __SANE_USERSPACE_TYPES__13 14#include <stdlib.h>15#include <stdio.h>16#include <unistd.h>17#include <string.h>18#include <sys/ioctl.h>19#include <time.h>20#include <fcntl.h>21#include <signal.h>22#include <sys/mman.h>23#include <linux/compiler.h>24#include <linux/hw_breakpoint.h>25 26#include "tests.h"27#include "debug.h"28#include "event.h"29#include "parse-events.h"30#include "perf-sys.h"31#include "cloexec.h"32 33static int fd1;34static int fd2;35static int fd3;36static int overflows;37static int overflows_2;38 39volatile long the_var;40 41 42/*43 * Use ASM to ensure watchpoint and breakpoint can be triggered44 * at one instruction.45 */46#if defined (__x86_64__)47extern void __test_function(volatile long *ptr);48asm (49 ".pushsection .text;"50 ".globl __test_function\n"51 ".type __test_function, @function;"52 "__test_function:\n"53 "incq (%rdi)\n"54 "ret\n"55 ".popsection\n");56#else57static void __test_function(volatile long *ptr)58{59 *ptr = 0x1234;60}61#endif62 63static noinline int test_function(void)64{65 __test_function(&the_var);66 the_var++;67 return time(NULL);68}69 70static void sig_handler_2(int signum __maybe_unused,71 siginfo_t *oh __maybe_unused,72 void *uc __maybe_unused)73{74 overflows_2++;75 if (overflows_2 > 10) {76 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);77 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);78 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);79 }80}81 82static void sig_handler(int signum __maybe_unused,83 siginfo_t *oh __maybe_unused,84 void *uc __maybe_unused)85{86 overflows++;87 88 if (overflows > 10) {89 /*90 * This should be executed only once during91 * this test, if we are here for the 10th92 * time, consider this the recursive issue.93 *94 * We can get out of here by disable events,95 * so no new SIGIO is delivered.96 */97 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);98 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);99 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);100 }101}102 103static int __event(bool is_x, void *addr, int sig)104{105 struct perf_event_attr pe;106 int fd;107 108 memset(&pe, 0, sizeof(struct perf_event_attr));109 pe.type = PERF_TYPE_BREAKPOINT;110 pe.size = sizeof(struct perf_event_attr);111 112 pe.config = 0;113 pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;114 pe.bp_addr = (unsigned long) addr;115 pe.bp_len = is_x ? default_breakpoint_len() : sizeof(long);116 117 pe.sample_period = 1;118 pe.sample_type = PERF_SAMPLE_IP;119 pe.wakeup_events = 1;120 121 pe.disabled = 1;122 pe.exclude_kernel = 1;123 pe.exclude_hv = 1;124 125 fd = sys_perf_event_open(&pe, 0, -1, -1,126 perf_event_open_cloexec_flag());127 if (fd < 0) {128 pr_debug("failed opening event %llx\n", pe.config);129 return TEST_FAIL;130 }131 132 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);133 fcntl(fd, F_SETSIG, sig);134 fcntl(fd, F_SETOWN, getpid());135 136 ioctl(fd, PERF_EVENT_IOC_RESET, 0);137 138 return fd;139}140 141static int bp_event(void *addr, int sig)142{143 return __event(true, addr, sig);144}145 146static int wp_event(void *addr, int sig)147{148 return __event(false, addr, sig);149}150 151static long long bp_count(int fd)152{153 long long count;154 int ret;155 156 ret = read(fd, &count, sizeof(long long));157 if (ret != sizeof(long long)) {158 pr_debug("failed to read: %d\n", ret);159 return TEST_FAIL;160 }161 162 return count;163}164 165static int test__bp_signal(struct test_suite *test __maybe_unused, int subtest __maybe_unused)166{167 struct sigaction sa;168 long long count1, count2, count3;169 170 if (!BP_SIGNAL_IS_SUPPORTED) {171 pr_debug("Test not supported on this architecture");172 return TEST_SKIP;173 }174 175 /* setup SIGIO signal handler */176 memset(&sa, 0, sizeof(struct sigaction));177 sa.sa_sigaction = (void *) sig_handler;178 sa.sa_flags = SA_SIGINFO;179 180 if (sigaction(SIGIO, &sa, NULL) < 0) {181 pr_debug("failed setting up signal handler\n");182 return TEST_FAIL;183 }184 185 sa.sa_sigaction = (void *) sig_handler_2;186 if (sigaction(SIGUSR1, &sa, NULL) < 0) {187 pr_debug("failed setting up signal handler 2\n");188 return TEST_FAIL;189 }190 191 /*192 * We create following events:193 *194 * fd1 - breakpoint event on __test_function with SIGIO195 * signal configured. We should get signal196 * notification each time the breakpoint is hit197 *198 * fd2 - breakpoint event on sig_handler with SIGUSR1199 * configured. We should get SIGUSR1 each time when200 * breakpoint is hit201 *202 * fd3 - watchpoint event on __test_function with SIGIO203 * configured.204 *205 * Following processing should happen:206 * Exec: Action: Result:207 * incq (%rdi) - fd1 event breakpoint hit -> count1 == 1208 * - SIGIO is delivered209 * sig_handler - fd2 event breakpoint hit -> count2 == 1210 * - SIGUSR1 is delivered211 * sig_handler_2 -> overflows_2 == 1 (nested signal)212 * sys_rt_sigreturn - return from sig_handler_2213 * overflows++ -> overflows = 1214 * sys_rt_sigreturn - return from sig_handler215 * incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn)216 * - SIGIO is delivered217 * sig_handler - fd2 event breakpoint hit -> count2 == 2218 * - SIGUSR1 is delivered219 * sig_handler_2 -> overflows_2 == 2 (nested signal)220 * sys_rt_sigreturn - return from sig_handler_2221 * overflows++ -> overflows = 2222 * sys_rt_sigreturn - return from sig_handler223 * the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint)224 * - SIGIO is delivered225 * sig_handler - fd2 event breakpoint hit -> count2 == 3226 * - SIGUSR1 is delivered227 * sig_handler_2 -> overflows_2 == 3 (nested signal)228 * sys_rt_sigreturn - return from sig_handler_2229 * overflows++ -> overflows == 3230 * sys_rt_sigreturn - return from sig_handler231 *232 * The test case check following error conditions:233 * - we get stuck in signal handler because of debug234 * exception being triggered recursively due to235 * the wrong RF EFLAG management236 *237 * - we never trigger the sig_handler breakpoint due238 * to the wrong RF EFLAG management239 *240 */241 242 fd1 = bp_event(__test_function, SIGIO);243 fd2 = bp_event(sig_handler, SIGUSR1);244 fd3 = wp_event((void *)&the_var, SIGIO);245 246 ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);247 ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);248 ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);249 250 /*251 * Kick off the test by triggering 'fd1'252 * breakpoint.253 */254 test_function();255 256 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);257 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);258 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);259 260 count1 = bp_count(fd1);261 count2 = bp_count(fd2);262 count3 = bp_count(fd3);263 264 close(fd1);265 close(fd2);266 close(fd3);267 268 pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",269 count1, count2, count3, overflows, overflows_2);270 271 if (count1 != 1) {272 if (count1 == 11)273 pr_debug("failed: RF EFLAG recursion issue detected\n");274 else275 pr_debug("failed: wrong count for bp1: %lld, expected 1\n", count1);276 }277 278 if (overflows != 3)279 pr_debug("failed: wrong overflow (%d) hit, expected 3\n", overflows);280 281 if (overflows_2 != 3)282 pr_debug("failed: wrong overflow_2 (%d) hit, expected 3\n", overflows_2);283 284 if (count2 != 3)285 pr_debug("failed: wrong count for bp2 (%lld), expected 3\n", count2);286 287 if (count3 != 2)288 pr_debug("failed: wrong count for bp3 (%lld), expected 2\n", count3);289 290 return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?291 TEST_OK : TEST_FAIL;292}293 294DEFINE_SUITE("Breakpoint overflow signal handler", bp_signal);295