// SPDX-License-Identifier: GPL-2.0
/*
* Inspired by breakpoint overflow test done by
* Vince Weaver <[email protected]> for perf_event_tests
* (git://github.com/deater/perf_event_tests)
*/
/*
* Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
* 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
*/
#define __SANE_USERSPACE_TYPES__
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <time.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/mman.h>
#include <linux/compiler.h>
#include <linux/hw_breakpoint.h>
#include "tests.h"
#include "debug.h"
#include "event.h"
#include "parse-events.h"
#include "perf-sys.h"
#include "cloexec.h"
static int fd1;
static int fd2;
static int fd3;
static int overflows;
static int overflows_2;
volatile long the_var;
/*
* Use ASM to ensure watchpoint and breakpoint can be triggered
* at one instruction.
*/
#if defined (__x86_64__)
extern void __test_function(volatile long *ptr);
asm (
".pushsection .text;"
".globl __test_function\n"
".type __test_function, @function;"
"__test_function:\n"
"incq (%rdi)\n"
"ret\n"
".popsection\n");
#else
static void __test_function(volatile long *ptr)
{
*ptr = 0x1234;
}
#endif
static noinline int test_function(void)
{
__test_function(&the_var);
the_var++;
return time(NULL);
}
static void sig_handler_2(int signum __maybe_unused,
siginfo_t *oh __maybe_unused,
void *uc __maybe_unused)
{
overflows_2++;
if (overflows_2 > 10) {
ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
}
}
static void sig_handler(int signum __maybe_unused,
siginfo_t *oh __maybe_unused,
void *uc __maybe_unused)
{
overflows++;
if (overflows > 10) {
/*
* This should be executed only once during
* this test, if we are here for the 10th
* time, consider this the recursive issue.
*
* We can get out of here by disable events,
* so no new SIGIO is delivered.
*/
ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
}
}
static int __event(bool is_x, void *addr, int sig)
{
struct perf_event_attr pe;
int fd;
memset(&pe, 0, sizeof(struct perf_event_attr));
pe.type = PERF_TYPE_BREAKPOINT;
pe.size = sizeof(struct perf_event_attr);
pe.config = 0;
pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
pe.bp_addr = (unsigned long) addr;
pe.bp_len = is_x ? default_breakpoint_len() : sizeof(long);
pe.sample_period = 1;
pe.sample_type = PERF_SAMPLE_IP;
pe.wakeup_events = 1;
pe.disabled = 1;
pe.exclude_kernel = 1;
pe.exclude_hv = 1;
fd = sys_perf_event_open(&pe, 0, -1, -1,
perf_event_open_cloexec_flag());
if (fd < 0) {
pr_debug("failed opening event %llx\n", pe.config);
return TEST_FAIL;
}
fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
fcntl(fd, F_SETSIG, sig);
fcntl(fd, F_SETOWN, getpid());
ioctl(fd, PERF_EVENT_IOC_RESET, 0);
return fd;
}
static int bp_event(void *addr, int sig)
{
return __event(true, addr, sig);
}
static int wp_event(void *addr, int sig)
{
return __event(false, addr, sig);
}
static long long bp_count(int fd)
{
long long count;
int ret;
ret = read(fd, &count, sizeof(long long));
if (ret != sizeof(long long)) {
pr_debug("failed to read: %d\n", ret);
return TEST_FAIL;
}
return count;
}
static int test__bp_signal(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
{
struct sigaction sa;
long long count1, count2, count3;
if (!BP_SIGNAL_IS_SUPPORTED) {
pr_debug("Test not supported on this architecture");
return TEST_SKIP;
}
/* setup SIGIO signal handler */
memset(&sa, 0, sizeof(struct sigaction));
sa.sa_sigaction = (void *) sig_handler;
sa.sa_flags = SA_SIGINFO;
if (sigaction(SIGIO, &sa, NULL) < 0) {
pr_debug("failed setting up signal handler\n");
return TEST_FAIL;
}
sa.sa_sigaction = (void *) sig_handler_2;
if (sigaction(SIGUSR1, &sa, NULL) < 0) {
pr_debug("failed setting up signal handler 2\n");
return TEST_FAIL;
}
/*
* We create following events:
*
* fd1 - breakpoint event on __test_function with SIGIO
* signal configured. We should get signal
* notification each time the breakpoint is hit
*
* fd2 - breakpoint event on sig_handler with SIGUSR1
* configured. We should get SIGUSR1 each time when
* breakpoint is hit
*
* fd3 - watchpoint event on __test_function with SIGIO
* configured.
*
* Following processing should happen:
* Exec: Action: Result:
* incq (%rdi) - fd1 event breakpoint hit -> count1 == 1
* - SIGIO is delivered
* sig_handler - fd2 event breakpoint hit -> count2 == 1
* - SIGUSR1 is delivered
* sig_handler_2 -> overflows_2 == 1 (nested signal)
* sys_rt_sigreturn - return from sig_handler_2
* overflows++ -> overflows = 1
* sys_rt_sigreturn - return from sig_handler
* incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn)
* - SIGIO is delivered
* sig_handler - fd2 event breakpoint hit -> count2 == 2
* - SIGUSR1 is delivered
* sig_handler_2 -> overflows_2 == 2 (nested signal)
* sys_rt_sigreturn - return from sig_handler_2
* overflows++ -> overflows = 2
* sys_rt_sigreturn - return from sig_handler
* the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint)
* - SIGIO is delivered
* sig_handler - fd2 event breakpoint hit -> count2 == 3
* - SIGUSR1 is delivered
* sig_handler_2 -> overflows_2 == 3 (nested signal)
* sys_rt_sigreturn - return from sig_handler_2
* overflows++ -> overflows == 3
* sys_rt_sigreturn - return from sig_handler
*
* The test case check following error conditions:
* - we get stuck in signal handler because of debug
* exception being triggered recursively due to
* the wrong RF EFLAG management
*
* - we never trigger the sig_handler breakpoint due
* to the wrong RF EFLAG management
*
*/
fd1 = bp_event(__test_function, SIGIO);
fd2 = bp_event(sig_handler, SIGUSR1);
fd3 = wp_event((void *)&the_var, SIGIO);
ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
/*
* Kick off the test by triggering 'fd1'
* breakpoint.
*/
test_function();
ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
count1 = bp_count(fd1);
count2 = bp_count(fd2);
count3 = bp_count(fd3);
close(fd1);
close(fd2);
close(fd3);
pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
count1, count2, count3, overflows, overflows_2);
if (count1 != 1) {
if (count1 == 11)
pr_debug("failed: RF EFLAG recursion issue detected\n");
else
pr_debug("failed: wrong count for bp1: %lld, expected 1\n", count1);
}
if (overflows != 3)
pr_debug("failed: wrong overflow (%d) hit, expected 3\n", overflows);
if (overflows_2 != 3)
pr_debug("failed: wrong overflow_2 (%d) hit, expected 3\n", overflows_2);
if (count2 != 3)
pr_debug("failed: wrong count for bp2 (%lld), expected 3\n", count2);
if (count3 != 2)
pr_debug("failed: wrong count for bp3 (%lld), expected 2\n", count3);
return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
TEST_OK : TEST_FAIL;
}
DEFINE_SUITE("Breakpoint overflow signal handler", bp_signal);
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