// SPDX-License-Identifier: GPL-2.0
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/*
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* Inspired by breakpoint overflow test done by
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* Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests
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* (git://github.com/deater/perf_event_tests)
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*/
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/*
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* Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
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* 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
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*/
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#define __SANE_USERSPACE_TYPES__
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <string.h>
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#include <sys/ioctl.h>
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#include <time.h>
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#include <fcntl.h>
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#include <signal.h>
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#include <sys/mman.h>
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#include <linux/compiler.h>
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#include <linux/hw_breakpoint.h>
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#include "tests.h"
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#include "debug.h"
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#include "perf.h"
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#include "cloexec.h"
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static int fd1;
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static int fd2;
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static int fd3;
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static int overflows;
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static int overflows_2;
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volatile long the_var;
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/*
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* Use ASM to ensure watchpoint and breakpoint can be triggered
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* at one instruction.
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*/
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#if defined (__x86_64__)
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extern void __test_function(volatile long *ptr);
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asm (
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".pushsection .text;"
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".globl __test_function\n"
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".type __test_function, @function;"
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"__test_function:\n"
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"incq (%rdi)\n"
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"ret\n"
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".popsection\n");
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#else
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static void __test_function(volatile long *ptr)
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{
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*ptr = 0x1234;
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}
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#endif
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static noinline int test_function(void)
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{
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__test_function(&the_var);
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the_var++;
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return time(NULL);
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}
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static void sig_handler_2(int signum __maybe_unused,
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siginfo_t *oh __maybe_unused,
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void *uc __maybe_unused)
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{
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overflows_2++;
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if (overflows_2 > 10) {
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ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
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ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
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ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
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}
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}
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static void sig_handler(int signum __maybe_unused,
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siginfo_t *oh __maybe_unused,
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void *uc __maybe_unused)
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{
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overflows++;
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if (overflows > 10) {
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/*
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* This should be executed only once during
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* this test, if we are here for the 10th
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* time, consider this the recursive issue.
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*
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* We can get out of here by disable events,
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* so no new SIGIO is delivered.
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*/
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ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
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ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
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ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
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}
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}
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static int __event(bool is_x, void *addr, int sig)
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{
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struct perf_event_attr pe;
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int fd;
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memset(&pe, 0, sizeof(struct perf_event_attr));
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pe.type = PERF_TYPE_BREAKPOINT;
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pe.size = sizeof(struct perf_event_attr);
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pe.config = 0;
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pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
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pe.bp_addr = (unsigned long) addr;
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pe.bp_len = sizeof(long);
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pe.sample_period = 1;
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pe.sample_type = PERF_SAMPLE_IP;
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pe.wakeup_events = 1;
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pe.disabled = 1;
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pe.exclude_kernel = 1;
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pe.exclude_hv = 1;
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fd = sys_perf_event_open(&pe, 0, -1, -1,
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perf_event_open_cloexec_flag());
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if (fd < 0) {
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pr_debug("failed opening event %llx\n", pe.config);
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return TEST_FAIL;
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}
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fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
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fcntl(fd, F_SETSIG, sig);
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fcntl(fd, F_SETOWN, getpid());
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ioctl(fd, PERF_EVENT_IOC_RESET, 0);
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return fd;
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}
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static int bp_event(void *addr, int sig)
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{
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return __event(true, addr, sig);
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}
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static int wp_event(void *addr, int sig)
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{
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return __event(false, addr, sig);
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}
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static long long bp_count(int fd)
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{
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long long count;
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int ret;
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ret = read(fd, &count, sizeof(long long));
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if (ret != sizeof(long long)) {
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pr_debug("failed to read: %d\n", ret);
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return TEST_FAIL;
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}
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return count;
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}
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int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
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{
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struct sigaction sa;
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long long count1, count2, count3;
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/* setup SIGIO signal handler */
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memset(&sa, 0, sizeof(struct sigaction));
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sa.sa_sigaction = (void *) sig_handler;
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sa.sa_flags = SA_SIGINFO;
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if (sigaction(SIGIO, &sa, NULL) < 0) {
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pr_debug("failed setting up signal handler\n");
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return TEST_FAIL;
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}
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sa.sa_sigaction = (void *) sig_handler_2;
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if (sigaction(SIGUSR1, &sa, NULL) < 0) {
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pr_debug("failed setting up signal handler 2\n");
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return TEST_FAIL;
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}
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/*
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* We create following events:
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*
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* fd1 - breakpoint event on __test_function with SIGIO
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* signal configured. We should get signal
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* notification each time the breakpoint is hit
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*
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* fd2 - breakpoint event on sig_handler with SIGUSR1
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* configured. We should get SIGUSR1 each time when
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* breakpoint is hit
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*
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* fd3 - watchpoint event on __test_function with SIGIO
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* configured.
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*
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* Following processing should happen:
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* Exec: Action: Result:
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* incq (%rdi) - fd1 event breakpoint hit -> count1 == 1
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* - SIGIO is delivered
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* sig_handler - fd2 event breakpoint hit -> count2 == 1
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* - SIGUSR1 is delivered
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* sig_handler_2 -> overflows_2 == 1 (nested signal)
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* sys_rt_sigreturn - return from sig_handler_2
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* overflows++ -> overflows = 1
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* sys_rt_sigreturn - return from sig_handler
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* incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn)
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* - SIGIO is delivered
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* sig_handler - fd2 event breakpoint hit -> count2 == 2
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* - SIGUSR1 is delivered
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* sig_handler_2 -> overflows_2 == 2 (nested signal)
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* sys_rt_sigreturn - return from sig_handler_2
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* overflows++ -> overflows = 2
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* sys_rt_sigreturn - return from sig_handler
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* the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint)
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* - SIGIO is delivered
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* sig_handler - fd2 event breakpoint hit -> count2 == 3
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* - SIGUSR1 is delivered
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* sig_handler_2 -> overflows_2 == 3 (nested signal)
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* sys_rt_sigreturn - return from sig_handler_2
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* overflows++ -> overflows == 3
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* sys_rt_sigreturn - return from sig_handler
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*
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* The test case check following error conditions:
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* - we get stuck in signal handler because of debug
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* exception being triggered receursively due to
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* the wrong RF EFLAG management
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*
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* - we never trigger the sig_handler breakpoint due
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* to the rong RF EFLAG management
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*
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*/
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fd1 = bp_event(__test_function, SIGIO);
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fd2 = bp_event(sig_handler, SIGUSR1);
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fd3 = wp_event((void *)&the_var, SIGIO);
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ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
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ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
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ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
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/*
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* Kick off the test by trigering 'fd1'
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* breakpoint.
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*/
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test_function();
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ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
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ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
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ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
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count1 = bp_count(fd1);
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count2 = bp_count(fd2);
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count3 = bp_count(fd3);
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close(fd1);
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close(fd2);
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close(fd3);
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pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
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count1, count2, count3, overflows, overflows_2);
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if (count1 != 1) {
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if (count1 == 11)
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pr_debug("failed: RF EFLAG recursion issue detected\n");
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else
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pr_debug("failed: wrong count for bp1%lld\n", count1);
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}
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if (overflows != 3)
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pr_debug("failed: wrong overflow hit\n");
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if (overflows_2 != 3)
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pr_debug("failed: wrong overflow_2 hit\n");
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if (count2 != 3)
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pr_debug("failed: wrong count for bp2\n");
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if (count3 != 2)
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pr_debug("failed: wrong count for bp3\n");
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return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
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TEST_OK : TEST_FAIL;
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}
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bool test__bp_signal_is_supported(void)
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{
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/*
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* PowerPC and S390 do not support creation of instruction
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* breakpoints using the perf_event interface.
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*
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* ARM requires explicit rounding down of the instruction
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* pointer in Thumb mode, and then requires the single-step
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* to be handled explicitly in the overflow handler to avoid
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* stepping into the SIGIO handler and getting stuck on the
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* breakpointed instruction.
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*
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* Since arm64 has the same issue with arm for the single-step
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* handling, this case also gets suck on the breakpointed
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* instruction.
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*
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* Just disable the test for these architectures until these
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* issues are resolved.
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*/
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#if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) || \
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defined(__aarch64__)
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return false;
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#else
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return true;
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#endif
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}
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