cregit-Linux how code gets into the kernel

Release 4.10 tools/perf/tests/bp_signal.c

Directory: tools/perf/tests
/*
 * Inspired by breakpoint overflow test done by
 * Vince Weaver <vincent.weaver@maine.edu> 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 "perf.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 (
        ".globl __test_function\n"
        "__test_function:\n"
        "incq (%rdi)\n"
        "ret\n");
#elif defined (__aarch64__)
extern void __test_function(volatile long *ptr);
asm (
        ".globl __test_function\n"
        "__test_function:\n"
        "str x30, [x0]\n"
        "ret\n");

#else

static void __test_function(volatile long *ptr) { *ptr = 0x1234; }

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#endif __attribute__ ((noinline))
static int test_function(void) { __test_function(&the_var); the_var++; return time(NULL); }

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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); } }

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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); } }

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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 = 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; }

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static int bp_event(void *addr, int sig) { return __event(true, addr, sig); }

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static int wp_event(void *addr, int sig) { return __event(false, addr, sig); }

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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; }

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int test__bp_signal(int subtest __maybe_unused) { struct sigaction sa; long long count1, count2, count3; /* 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 receursively due to * the wrong RF EFLAG management * * - we never trigger the sig_handler breakpoint due * to the rong 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 trigering '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\n", count1); } if (overflows != 3) pr_debug("failed: wrong overflow hit\n"); if (overflows_2 != 3) pr_debug("failed: wrong overflow_2 hit\n"); if (count2 != 3) pr_debug("failed: wrong count for bp2\n"); if (count3 != 2) pr_debug("failed: wrong count for bp3\n"); return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ? TEST_OK : TEST_FAIL; }

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yann droneaudyann droneaud50.54%116.67%
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Directory: tools/perf/tests
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