diff --git a/tools/testing/selftests/powerpc/ptrace/Makefile b/tools/testing/selftests/powerpc/ptrace/Makefile index cbeeaeae8837..1b39b86849da 100644 --- a/tools/testing/selftests/powerpc/ptrace/Makefile +++ b/tools/testing/selftests/powerpc/ptrace/Makefile @@ -36,6 +36,7 @@ $(TM_TESTS): CFLAGS += -I../tm -mhtm CFLAGS += $(KHDR_INCLUDES) -fno-pie $(OUTPUT)/ptrace-gpr: ptrace-gpr.S +$(OUTPUT)/ptrace-perf-hwbreak: ptrace-perf-asm.S $(OUTPUT)/ptrace-pkey $(OUTPUT)/core-pkey: LDLIBS += -pthread $(TEST_GEN_PROGS): ../harness.c ../utils.c ../lib/reg.S diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-perf-asm.S b/tools/testing/selftests/powerpc/ptrace/ptrace-perf-asm.S new file mode 100644 index 000000000000..9aa2e58f3189 --- /dev/null +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-perf-asm.S @@ -0,0 +1,33 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include + +.global same_watch_addr_load +.global same_watch_addr_trap + +FUNC_START(same_watch_addr_child) + nop +same_watch_addr_load: + ld 0,0(3) + nop +same_watch_addr_trap: + trap + blr +FUNC_END(same_watch_addr_child) + + +.global perf_then_ptrace_load1 +.global perf_then_ptrace_load2 +.global perf_then_ptrace_trap + +FUNC_START(perf_then_ptrace_child) + nop +perf_then_ptrace_load1: + ld 0,0(3) +perf_then_ptrace_load2: + ld 0,0(4) + nop +perf_then_ptrace_trap: + trap + blr +FUNC_END(perf_then_ptrace_child) diff --git a/tools/testing/selftests/powerpc/ptrace/ptrace-perf-hwbreak.c b/tools/testing/selftests/powerpc/ptrace/ptrace-perf-hwbreak.c index d8a9e95fc03d..a0a0b9bb5854 100644 --- a/tools/testing/selftests/powerpc/ptrace/ptrace-perf-hwbreak.c +++ b/tools/testing/selftests/powerpc/ptrace/ptrace-perf-hwbreak.c @@ -1,142 +1,167 @@ // SPDX-License-Identifier: GPL-2.0+ -#include -#include -#include -#include -#include -#include -#include -#include + #include -#include +#include +#include +#include +#include #include -#include "ptrace.h" -char data[16]; +#include "utils.h" -/* Overlapping address range */ -volatile __u64 *ptrace_data1 = (__u64 *)&data[0]; -volatile __u64 *perf_data1 = (__u64 *)&data[4]; +/* + * Child subroutine that performs a load on the address, then traps + */ +void same_watch_addr_child(unsigned long *addr); -/* Non-overlapping address range */ -volatile __u64 *ptrace_data2 = (__u64 *)&data[0]; -volatile __u64 *perf_data2 = (__u64 *)&data[8]; +/* Address of the ld instruction in same_watch_addr_child() */ +extern char same_watch_addr_load[]; -static unsigned long pid_max_addr(void) +/* Address of the end trap instruction in same_watch_addr_child() */ +extern char same_watch_addr_trap[]; + +/* + * Child subroutine that performs a load on the first address, then a load on + * the second address (with no instructions separating this from the first + * load), then traps. + */ +void perf_then_ptrace_child(unsigned long *first_addr, unsigned long *second_addr); + +/* Address of the first ld instruction in perf_then_ptrace_child() */ +extern char perf_then_ptrace_load1[]; + +/* Address of the second ld instruction in perf_then_ptrace_child() */ +extern char perf_then_ptrace_load2[]; + +/* Address of the end trap instruction in perf_then_ptrace_child() */ +extern char perf_then_ptrace_trap[]; + +static inline long sys_ptrace(long request, pid_t pid, unsigned long addr, unsigned long data) { - FILE *fp; - char *line, *c; - char addr[100]; - size_t len = 0; - - fp = fopen("/proc/kallsyms", "r"); - if (!fp) { - printf("Failed to read /proc/kallsyms. Exiting..\n"); - exit(EXIT_FAILURE); - } - - while (getline(&line, &len, fp) != -1) { - if (!strstr(line, "pid_max") || strstr(line, "pid_max_max") || - strstr(line, "pid_max_min")) - continue; - - strncpy(addr, line, len < 100 ? len : 100); - c = strchr(addr, ' '); - *c = '\0'; - return strtoul(addr, &c, 16); - } - fclose(fp); - printf("Could not find pid_max. Exiting..\n"); - exit(EXIT_FAILURE); - return -1; + return syscall(__NR_ptrace, request, pid, addr, data); } -static void perf_user_event_attr_set(struct perf_event_attr *attr, __u64 addr, __u64 len) +static long ptrace_traceme(void) { - memset(attr, 0, sizeof(struct perf_event_attr)); - attr->type = PERF_TYPE_BREAKPOINT; - attr->size = sizeof(struct perf_event_attr); - attr->bp_type = HW_BREAKPOINT_R; - attr->bp_addr = addr; - attr->bp_len = len; - attr->exclude_kernel = 1; - attr->exclude_hv = 1; + return sys_ptrace(PTRACE_TRACEME, 0, 0, 0); } -static void perf_kernel_event_attr_set(struct perf_event_attr *attr) +static long ptrace_getregs(pid_t pid, struct pt_regs *result) { - memset(attr, 0, sizeof(struct perf_event_attr)); - attr->type = PERF_TYPE_BREAKPOINT; - attr->size = sizeof(struct perf_event_attr); - attr->bp_type = HW_BREAKPOINT_R; - attr->bp_addr = pid_max_addr(); - attr->bp_len = sizeof(unsigned long); - attr->exclude_user = 1; - attr->exclude_hv = 1; + return sys_ptrace(PTRACE_GETREGS, pid, 0, (unsigned long)result); } -static int perf_cpu_event_open(int cpu, __u64 addr, __u64 len) +static long ptrace_setregs(pid_t pid, struct pt_regs *result) { - struct perf_event_attr attr; - - perf_user_event_attr_set(&attr, addr, len); - return syscall(__NR_perf_event_open, &attr, -1, cpu, -1, 0); + return sys_ptrace(PTRACE_SETREGS, pid, 0, (unsigned long)result); } -static int perf_thread_event_open(pid_t child_pid, __u64 addr, __u64 len) +static long ptrace_cont(pid_t pid, long signal) { - struct perf_event_attr attr; - - perf_user_event_attr_set(&attr, addr, len); - return syscall(__NR_perf_event_open, &attr, child_pid, -1, -1, 0); + return sys_ptrace(PTRACE_CONT, pid, 0, signal); } -static int perf_thread_cpu_event_open(pid_t child_pid, int cpu, __u64 addr, __u64 len) +static long ptrace_singlestep(pid_t pid, long signal) { - struct perf_event_attr attr; - - perf_user_event_attr_set(&attr, addr, len); - return syscall(__NR_perf_event_open, &attr, child_pid, cpu, -1, 0); + return sys_ptrace(PTRACE_SINGLESTEP, pid, 0, signal); } -static int perf_thread_kernel_event_open(pid_t child_pid) +static long ppc_ptrace_gethwdbginfo(pid_t pid, struct ppc_debug_info *dbginfo) { - struct perf_event_attr attr; - - perf_kernel_event_attr_set(&attr); - return syscall(__NR_perf_event_open, &attr, child_pid, -1, -1, 0); + return sys_ptrace(PPC_PTRACE_GETHWDBGINFO, pid, 0, (unsigned long)dbginfo); } -static int perf_cpu_kernel_event_open(int cpu) +static long ppc_ptrace_sethwdbg(pid_t pid, struct ppc_hw_breakpoint *bp_info) { - struct perf_event_attr attr; - - perf_kernel_event_attr_set(&attr); - return syscall(__NR_perf_event_open, &attr, -1, cpu, -1, 0); + return sys_ptrace(PPC_PTRACE_SETHWDEBUG, pid, 0, (unsigned long)bp_info); } -static int child(void) +static long ppc_ptrace_delhwdbg(pid_t pid, int bp_id) { - int ret; + return sys_ptrace(PPC_PTRACE_DELHWDEBUG, pid, 0L, bp_id); +} - ret = ptrace(PTRACE_TRACEME, 0, NULL, 0); - if (ret) { - printf("Error: PTRACE_TRACEME failed\n"); - return 0; - } - kill(getpid(), SIGUSR1); /* --> parent (SIGUSR1) */ +static long ptrace_getreg_pc(pid_t pid, void **pc) +{ + struct pt_regs regs; + long err; + + err = ptrace_getregs(pid, ®s); + if (err) + return err; + + *pc = (void *)regs.nip; return 0; } -static void ptrace_ppc_hw_breakpoint(struct ppc_hw_breakpoint *info, int type, - __u64 addr, int len) +static long ptrace_setreg_pc(pid_t pid, void *pc) +{ + struct pt_regs regs; + long err; + + err = ptrace_getregs(pid, ®s); + if (err) + return err; + + regs.nip = (unsigned long)pc; + + err = ptrace_setregs(pid, ®s); + if (err) + return err; + + return 0; +} + +static int perf_event_open(struct perf_event_attr *attr, pid_t pid, int cpu, + int group_fd, unsigned long flags) +{ + return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags); +} + +static void perf_user_event_attr_set(struct perf_event_attr *attr, void *addr, u64 len) +{ + memset(attr, 0, sizeof(struct perf_event_attr)); + + attr->type = PERF_TYPE_BREAKPOINT; + attr->size = sizeof(struct perf_event_attr); + attr->bp_type = HW_BREAKPOINT_R; + attr->bp_addr = (u64)addr; + attr->bp_len = len; + attr->exclude_kernel = 1; + attr->exclude_hv = 1; +} + +static int perf_watchpoint_open(pid_t child_pid, void *addr, u64 len) +{ + struct perf_event_attr attr; + + perf_user_event_attr_set(&attr, addr, len); + return perf_event_open(&attr, child_pid, -1, -1, 0); +} + +static int perf_read_counter(int perf_fd, u64 *count) +{ + /* + * A perf counter is retrieved by the read() syscall. It contains + * the current count as 8 bytes that are interpreted as a u64 + */ + ssize_t len = read(perf_fd, count, sizeof(*count)); + + if (len != sizeof(*count)) + return -1; + + return 0; +} + +static void ppc_ptrace_init_breakpoint(struct ppc_hw_breakpoint *info, + int type, void *addr, int len) { info->version = 1; info->trigger_type = type; info->condition_mode = PPC_BREAKPOINT_CONDITION_NONE; - info->addr = addr; - info->addr2 = addr + len; + info->addr = (u64)addr; + info->addr2 = (u64)addr + len; info->condition_value = 0; if (!len) info->addr_mode = PPC_BREAKPOINT_MODE_EXACT; @@ -144,516 +169,277 @@ static void ptrace_ppc_hw_breakpoint(struct ppc_hw_breakpoint *info, int type, info->addr_mode = PPC_BREAKPOINT_MODE_RANGE_INCLUSIVE; } -static int ptrace_open(pid_t child_pid, __u64 wp_addr, int len) +/* + * Checks if we can place at least 2 watchpoints on the child process + */ +static int check_watchpoints(pid_t pid) { - struct ppc_hw_breakpoint info; - - ptrace_ppc_hw_breakpoint(&info, PPC_BREAKPOINT_TRIGGER_RW, wp_addr, len); - return ptrace(PPC_PTRACE_SETHWDEBUG, child_pid, 0, &info); -} - -static int test1(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread event by ptrace) - * if (existing cpu event by perf) - * if (addr range overlaps) - * fail; - */ - - perf_fd = perf_cpu_event_open(0, (__u64)perf_data1, sizeof(*perf_data1)); - if (perf_fd < 0) - return -1; - - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd > 0 || errno != ENOSPC) - ret = -1; - - close(perf_fd); - return ret; -} - -static int test2(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread event by ptrace) - * if (existing cpu event by perf) - * if (addr range does not overlaps) - * allow; - */ - - perf_fd = perf_cpu_event_open(0, (__u64)perf_data2, sizeof(*perf_data2)); - if (perf_fd < 0) - return -1; - - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data2, sizeof(*ptrace_data2)); - if (ptrace_fd < 0) { - ret = -1; - goto perf_close; - } - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - -perf_close: - close(perf_fd); - return ret; -} - -static int test3(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread event by ptrace) - * if (existing thread event by perf on the same thread) - * if (addr range overlaps) - * fail; - */ - perf_fd = perf_thread_event_open(child_pid, (__u64)perf_data1, - sizeof(*perf_data1)); - if (perf_fd < 0) - return -1; - - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd > 0 || errno != ENOSPC) - ret = -1; - - close(perf_fd); - return ret; -} - -static int test4(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread event by ptrace) - * if (existing thread event by perf on the same thread) - * if (addr range does not overlaps) - * fail; - */ - perf_fd = perf_thread_event_open(child_pid, (__u64)perf_data2, - sizeof(*perf_data2)); - if (perf_fd < 0) - return -1; - - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data2, sizeof(*ptrace_data2)); - if (ptrace_fd < 0) { - ret = -1; - goto perf_close; - } - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - -perf_close: - close(perf_fd); - return ret; -} - -static int test5(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int cpid; - int ret = 0; - - /* Test: - * if (new per thread event by ptrace) - * if (existing thread event by perf on the different thread) - * allow; - */ - cpid = fork(); - if (!cpid) { - /* Temporary Child */ - pause(); - exit(EXIT_SUCCESS); - } - - perf_fd = perf_thread_event_open(cpid, (__u64)perf_data1, sizeof(*perf_data1)); - if (perf_fd < 0) { - ret = -1; - goto kill_child; - } - - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) { - ret = -1; - goto perf_close; - } - - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); -perf_close: - close(perf_fd); -kill_child: - kill(cpid, SIGINT); - return ret; -} - -static int test6(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread kernel event by perf) - * if (existing thread event by ptrace on the same thread) - * allow; - * -- OR -- - * if (new per cpu kernel event by perf) - * if (existing thread event by ptrace) - * allow; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_thread_kernel_event_open(child_pid); - if (perf_fd < 0) { - ret = -1; - goto ptrace_close; - } - close(perf_fd); - - perf_fd = perf_cpu_kernel_event_open(0); - if (perf_fd < 0) { - ret = -1; - goto ptrace_close; - } - close(perf_fd); - -ptrace_close: - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test7(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread event by perf) - * if (existing thread event by ptrace on the same thread) - * if (addr range overlaps) - * fail; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_thread_event_open(child_pid, (__u64)perf_data1, - sizeof(*perf_data1)); - if (perf_fd > 0 || errno != ENOSPC) - ret = -1; - - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test8(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread event by perf) - * if (existing thread event by ptrace on the same thread) - * if (addr range does not overlaps) - * allow; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data2, sizeof(*ptrace_data2)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_thread_event_open(child_pid, (__u64)perf_data2, - sizeof(*perf_data2)); - if (perf_fd < 0) { - ret = -1; - goto ptrace_close; - } - close(perf_fd); - -ptrace_close: - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test9(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int cpid; - int ret = 0; - - /* Test: - * if (new per thread event by perf) - * if (existing thread event by ptrace on the other thread) - * allow; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) - return -1; - - cpid = fork(); - if (!cpid) { - /* Temporary Child */ - pause(); - exit(EXIT_SUCCESS); - } - - perf_fd = perf_thread_event_open(cpid, (__u64)perf_data1, sizeof(*perf_data1)); - if (perf_fd < 0) { - ret = -1; - goto kill_child; - } - close(perf_fd); - -kill_child: - kill(cpid, SIGINT); - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test10(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per cpu event by perf) - * if (existing thread event by ptrace on the same thread) - * if (addr range overlaps) - * fail; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_cpu_event_open(0, (__u64)perf_data1, sizeof(*perf_data1)); - if (perf_fd > 0 || errno != ENOSPC) - ret = -1; - - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test11(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per cpu event by perf) - * if (existing thread event by ptrace on the same thread) - * if (addr range does not overlap) - * allow; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data2, sizeof(*ptrace_data2)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_cpu_event_open(0, (__u64)perf_data2, sizeof(*perf_data2)); - if (perf_fd < 0) { - ret = -1; - goto ptrace_close; - } - close(perf_fd); - -ptrace_close: - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test12(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread and per cpu event by perf) - * if (existing thread event by ptrace on the same thread) - * if (addr range overlaps) - * fail; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_thread_cpu_event_open(child_pid, 0, (__u64)perf_data1, sizeof(*perf_data1)); - if (perf_fd > 0 || errno != ENOSPC) - ret = -1; - - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test13(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int ret = 0; - - /* Test: - * if (new per thread and per cpu event by perf) - * if (existing thread event by ptrace on the same thread) - * if (addr range does not overlap) - * allow; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data2, sizeof(*ptrace_data2)); - if (ptrace_fd < 0) - return -1; - - perf_fd = perf_thread_cpu_event_open(child_pid, 0, (__u64)perf_data2, sizeof(*perf_data2)); - if (perf_fd < 0) { - ret = -1; - goto ptrace_close; - } - close(perf_fd); - -ptrace_close: - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int test14(pid_t child_pid) -{ - int perf_fd; - int ptrace_fd; - int cpid; - int ret = 0; - - /* Test: - * if (new per thread and per cpu event by perf) - * if (existing thread event by ptrace on the other thread) - * allow; - */ - ptrace_fd = ptrace_open(child_pid, (__u64)ptrace_data1, sizeof(*ptrace_data1)); - if (ptrace_fd < 0) - return -1; - - cpid = fork(); - if (!cpid) { - /* Temporary Child */ - pause(); - exit(EXIT_SUCCESS); - } - - perf_fd = perf_thread_cpu_event_open(cpid, 0, (__u64)perf_data1, - sizeof(*perf_data1)); - if (perf_fd < 0) { - ret = -1; - goto kill_child; - } - close(perf_fd); - -kill_child: - kill(cpid, SIGINT); - ptrace(PPC_PTRACE_DELHWDEBUG, child_pid, 0, ptrace_fd); - return ret; -} - -static int do_test(const char *msg, int (*fun)(pid_t arg), pid_t arg) -{ - int ret; - - ret = fun(arg); - if (ret) - printf("%s: Error\n", msg); - else - printf("%s: Ok\n", msg); - return ret; -} - -char *desc[14] = { - "perf cpu event -> ptrace thread event (Overlapping)", - "perf cpu event -> ptrace thread event (Non-overlapping)", - "perf thread event -> ptrace same thread event (Overlapping)", - "perf thread event -> ptrace same thread event (Non-overlapping)", - "perf thread event -> ptrace other thread event", - "ptrace thread event -> perf kernel event", - "ptrace thread event -> perf same thread event (Overlapping)", - "ptrace thread event -> perf same thread event (Non-overlapping)", - "ptrace thread event -> perf other thread event", - "ptrace thread event -> perf cpu event (Overlapping)", - "ptrace thread event -> perf cpu event (Non-overlapping)", - "ptrace thread event -> perf same thread & cpu event (Overlapping)", - "ptrace thread event -> perf same thread & cpu event (Non-overlapping)", - "ptrace thread event -> perf other thread & cpu event", -}; - -static int test(pid_t child_pid) -{ - int ret = TEST_PASS; - - ret |= do_test(desc[0], test1, child_pid); - ret |= do_test(desc[1], test2, child_pid); - ret |= do_test(desc[2], test3, child_pid); - ret |= do_test(desc[3], test4, child_pid); - ret |= do_test(desc[4], test5, child_pid); - ret |= do_test(desc[5], test6, child_pid); - ret |= do_test(desc[6], test7, child_pid); - ret |= do_test(desc[7], test8, child_pid); - ret |= do_test(desc[8], test9, child_pid); - ret |= do_test(desc[9], test10, child_pid); - ret |= do_test(desc[10], test11, child_pid); - ret |= do_test(desc[11], test12, child_pid); - ret |= do_test(desc[12], test13, child_pid); - ret |= do_test(desc[13], test14, child_pid); - - return ret; -} - -static void get_dbginfo(pid_t child_pid, struct ppc_debug_info *dbginfo) -{ - if (ptrace(PPC_PTRACE_GETHWDBGINFO, child_pid, NULL, dbginfo)) { - perror("Can't get breakpoint info"); - exit(-1); - } -} - -static int ptrace_perf_hwbreak(void) -{ - int ret; - pid_t child_pid; struct ppc_debug_info dbginfo; - child_pid = fork(); - if (!child_pid) - return child(); - - /* parent */ - wait(NULL); /* <-- child (SIGUSR1) */ - - get_dbginfo(child_pid, &dbginfo); + FAIL_IF_MSG(ppc_ptrace_gethwdbginfo(pid, &dbginfo), "PPC_PTRACE_GETHWDBGINFO failed"); SKIP_IF_MSG(dbginfo.num_data_bps <= 1, "Not enough data watchpoints (need at least 2)"); - ret = perf_cpu_event_open(0, (__u64)perf_data1, sizeof(*perf_data1)); - SKIP_IF_MSG(ret < 0, "perf_event_open syscall failed"); - close(ret); + return 0; +} - ret = test(child_pid); +/* + * Wrapper around a plain fork() call that sets up the child for + * ptrace-ing. Both the parent and child return from this, though + * the child is stopped until ptrace_cont(pid) is run by the parent. + */ +static int ptrace_fork_child(pid_t *pid) +{ + int status; - ptrace(PTRACE_CONT, child_pid, NULL, 0); - return ret; + *pid = fork(); + + if (*pid < 0) + FAIL_IF_MSG(1, "Failed to fork child"); + + if (!*pid) { + FAIL_IF_EXIT_MSG(ptrace_traceme(), "PTRACE_TRACEME failed"); + FAIL_IF_EXIT_MSG(raise(SIGSTOP), "Child failed to raise SIGSTOP"); + } else { + /* Synchronise on child SIGSTOP */ + FAIL_IF_MSG(waitpid(*pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + } + + return 0; +} + +/* + * Tests the interaction between ptrace and perf watching the same data. + * + * We expect ptrace to take 'priority', as it is has before-execute + * semantics. + * + * The perf counter should not be incremented yet because perf has after-execute + * semantics. E.g., if ptrace changes the child PC, we don't even execute the + * instruction at all. + * + * When the child is stopped for ptrace, we test both continue and single step. + * Both should increment the perf counter. We also test changing the PC somewhere + * different and stepping, which should not increment the perf counter. + */ +int same_watch_addr_test(void) +{ + struct ppc_hw_breakpoint bp_info; /* ptrace breakpoint info */ + int bp_id; /* Breakpoint handle of ptrace watchpoint */ + int perf_fd; /* File descriptor of perf performance counter */ + u64 perf_count; /* Most recently fetched perf performance counter value */ + pid_t pid; /* PID of child process */ + void *pc; /* Most recently fetched child PC value */ + int status; /* Stop status of child after waitpid */ + unsigned long value; /* Dummy value to be read/written to by child */ + int err; + + err = ptrace_fork_child(&pid); + if (err) + return err; + + if (!pid) { + same_watch_addr_child(&value); + exit(1); + } + + err = check_watchpoints(pid); + if (err) + return err; + + /* Place a perf watchpoint counter on value */ + perf_fd = perf_watchpoint_open(pid, &value, sizeof(value)); + FAIL_IF_MSG(perf_fd < 0, "Failed to open perf performance counter"); + + /* Place a ptrace watchpoint on value */ + ppc_ptrace_init_breakpoint(&bp_info, PPC_BREAKPOINT_TRIGGER_READ, &value, sizeof(value)); + bp_id = ppc_ptrace_sethwdbg(pid, &bp_info); + FAIL_IF_MSG(bp_id < 0, "Failed to set ptrace watchpoint"); + + /* Let the child run. It should stop on the ptrace watchpoint */ + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_load, "Child did not stop on load instruction"); + + /* + * We stopped before executing the load, so perf should not have + * recorded any events yet + */ + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 0, "perf recorded unexpected event"); + + /* Single stepping over the load should increment the perf counter */ + FAIL_IF_MSG(ptrace_singlestep(pid, 0), "Failed to single step child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_load + 4, "Failed to single step load instruction"); + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 1, "perf counter did not increment"); + + /* + * Set up a ptrace watchpoint on the value again and trigger it. + * The perf counter should not have incremented because we do not + * execute the load yet. + */ + FAIL_IF_MSG(ppc_ptrace_delhwdbg(pid, bp_id), "Failed to remove old ptrace watchpoint"); + bp_id = ppc_ptrace_sethwdbg(pid, &bp_info); + FAIL_IF_MSG(bp_id < 0, "Failed to set ptrace watchpoint"); + FAIL_IF_MSG(ptrace_setreg_pc(pid, same_watch_addr_load), "Failed to set child PC"); + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_load, "Child did not stop on load trap"); + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 1, "perf counter should not have changed"); + + /* Continuing over the load should increment the perf counter */ + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_trap, "Child did not stop on end trap"); + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 2, "perf counter did not increment"); + + /* + * If we set the child PC back to the load instruction, then continue, + * we should reach the end trap (because ptrace is one-shot) and have + * another perf event. + */ + FAIL_IF_MSG(ptrace_setreg_pc(pid, same_watch_addr_load), "Failed to set child PC"); + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_trap, "Child did not stop on end trap"); + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 3, "perf counter did not increment"); + + /* + * If we set the child PC back to the load instruction, set a ptrace + * watchpoint on the load, then continue, we should immediately get + * the ptrace trap without incrementing the perf counter + */ + FAIL_IF_MSG(ppc_ptrace_delhwdbg(pid, bp_id), "Failed to remove old ptrace watchpoint"); + bp_id = ppc_ptrace_sethwdbg(pid, &bp_info); + FAIL_IF_MSG(bp_id < 0, "Failed to set ptrace watchpoint"); + FAIL_IF_MSG(ptrace_setreg_pc(pid, same_watch_addr_load), "Failed to set child PC"); + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_load, "Child did not stop on load instruction"); + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 3, "perf counter should not have changed"); + + /* + * If we change the PC while stopped on the load instruction, we should + * not increment the perf counter (because ptrace is before-execute, + * perf is after-execute). + */ + FAIL_IF_MSG(ptrace_setreg_pc(pid, same_watch_addr_load + 4), "Failed to set child PC"); + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != same_watch_addr_trap, "Child did not stop on end trap"); + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 3, "perf counter should not have changed"); + + /* Clean up child */ + FAIL_IF_MSG(kill(pid, SIGKILL) != 0, "Failed to kill child"); + + return 0; +} + +/* + * Tests the interaction between ptrace and perf when: + * 1. perf watches a value + * 2. ptrace watches a different value + * 3. The perf value is read, then the ptrace value is read immediately after + * + * A breakpoint implementation may accidentally misattribute/skip one of + * the ptrace or perf handlers, as interrupt based work is done after perf + * and before ptrace. + * + * We expect the perf counter to increment before the ptrace watchpoint + * triggers. + */ +int perf_then_ptrace_test(void) +{ + struct ppc_hw_breakpoint bp_info; /* ptrace breakpoint info */ + int bp_id; /* Breakpoint handle of ptrace watchpoint */ + int perf_fd; /* File descriptor of perf performance counter */ + u64 perf_count; /* Most recently fetched perf performance counter value */ + pid_t pid; /* PID of child process */ + void *pc; /* Most recently fetched child PC value */ + int status; /* Stop status of child after waitpid */ + unsigned long perf_value; /* Dummy value to be watched by perf */ + unsigned long ptrace_value; /* Dummy value to be watched by ptrace */ + int err; + + err = ptrace_fork_child(&pid); + if (err) + return err; + + /* + * If we are the child, run a subroutine that reads the perf value, + * then reads the ptrace value with consecutive load instructions + */ + if (!pid) { + perf_then_ptrace_child(&perf_value, &ptrace_value); + exit(0); + } + + err = check_watchpoints(pid); + if (err) + return err; + + /* Place a perf watchpoint counter */ + perf_fd = perf_watchpoint_open(pid, &perf_value, sizeof(perf_value)); + FAIL_IF_MSG(perf_fd < 0, "Failed to open perf performance counter"); + + /* Place a ptrace watchpoint */ + ppc_ptrace_init_breakpoint(&bp_info, PPC_BREAKPOINT_TRIGGER_READ, + &ptrace_value, sizeof(ptrace_value)); + bp_id = ppc_ptrace_sethwdbg(pid, &bp_info); + FAIL_IF_MSG(bp_id < 0, "Failed to set ptrace watchpoint"); + + /* Let the child run. It should stop on the ptrace watchpoint */ + FAIL_IF_MSG(ptrace_cont(pid, 0), "Failed to continue child"); + + FAIL_IF_MSG(waitpid(pid, &status, 0) == -1, "Failed to wait for child"); + FAIL_IF_MSG(!WIFSTOPPED(status), "Child is not stopped"); + FAIL_IF_MSG(ptrace_getreg_pc(pid, &pc), "Failed to get child PC"); + FAIL_IF_MSG(pc != perf_then_ptrace_load2, "Child did not stop on ptrace load"); + + /* perf should have recorded the first load */ + FAIL_IF_MSG(perf_read_counter(perf_fd, &perf_count), "Failed to read perf counter"); + FAIL_IF_MSG(perf_count != 1, "perf counter did not increment"); + + /* Clean up child */ + FAIL_IF_MSG(kill(pid, SIGKILL) != 0, "Failed to kill child"); + + return 0; } int main(int argc, char *argv[]) { - return test_harness(ptrace_perf_hwbreak, "ptrace-perf-hwbreak"); + int err = 0; + + err |= test_harness(same_watch_addr_test, "same_watch_addr"); + err |= test_harness(perf_then_ptrace_test, "perf_then_ptrace"); + + return err; }