| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * ring buffer based function tracer |
| * |
| * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com> |
| * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> |
| * |
| * Originally taken from the RT patch by: |
| * Arnaldo Carvalho de Melo <acme@redhat.com> |
| * |
| * Based on code from the latency_tracer, that is: |
| * Copyright (C) 2004-2006 Ingo Molnar |
| * Copyright (C) 2004 Nadia Yvette Chambers |
| */ |
| #include <linux/ring_buffer.h> |
| #include <linux/utsname.h> |
| #include <linux/stacktrace.h> |
| #include <linux/writeback.h> |
| #include <linux/kallsyms.h> |
| #include <linux/security.h> |
| #include <linux/seq_file.h> |
| #include <linux/irqflags.h> |
| #include <linux/debugfs.h> |
| #include <linux/tracefs.h> |
| #include <linux/pagemap.h> |
| #include <linux/hardirq.h> |
| #include <linux/linkage.h> |
| #include <linux/uaccess.h> |
| #include <linux/vmalloc.h> |
| #include <linux/ftrace.h> |
| #include <linux/module.h> |
| #include <linux/percpu.h> |
| #include <linux/splice.h> |
| #include <linux/kdebug.h> |
| #include <linux/string.h> |
| #include <linux/mount.h> |
| #include <linux/rwsem.h> |
| #include <linux/slab.h> |
| #include <linux/ctype.h> |
| #include <linux/init.h> |
| #include <linux/panic_notifier.h> |
| #include <linux/poll.h> |
| #include <linux/nmi.h> |
| #include <linux/fs.h> |
| #include <linux/trace.h> |
| #include <linux/sched/clock.h> |
| #include <linux/sched/rt.h> |
| #include <linux/fsnotify.h> |
| #include <linux/irq_work.h> |
| #include <linux/workqueue.h> |
| |
| #include <asm/setup.h> /* COMMAND_LINE_SIZE */ |
| |
| #include "trace.h" |
| #include "trace_output.h" |
| |
| #ifdef CONFIG_FTRACE_STARTUP_TEST |
| /* |
| * We need to change this state when a selftest is running. |
| * A selftest will lurk into the ring-buffer to count the |
| * entries inserted during the selftest although some concurrent |
| * insertions into the ring-buffer such as trace_printk could occurred |
| * at the same time, giving false positive or negative results. |
| */ |
| static bool __read_mostly tracing_selftest_running; |
| |
| /* |
| * If boot-time tracing including tracers/events via kernel cmdline |
| * is running, we do not want to run SELFTEST. |
| */ |
| bool __read_mostly tracing_selftest_disabled; |
| |
| void __init disable_tracing_selftest(const char *reason) |
| { |
| if (!tracing_selftest_disabled) { |
| tracing_selftest_disabled = true; |
| pr_info("Ftrace startup test is disabled due to %s\n", reason); |
| } |
| } |
| #else |
| #define tracing_selftest_running 0 |
| #define tracing_selftest_disabled 0 |
| #endif |
| |
| /* Pipe tracepoints to printk */ |
| static struct trace_iterator *tracepoint_print_iter; |
| int tracepoint_printk; |
| static bool tracepoint_printk_stop_on_boot __initdata; |
| static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key); |
| |
| /* For tracers that don't implement custom flags */ |
| static struct tracer_opt dummy_tracer_opt[] = { |
| { } |
| }; |
| |
| static int |
| dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) |
| { |
| return 0; |
| } |
| |
| /* |
| * To prevent the comm cache from being overwritten when no |
| * tracing is active, only save the comm when a trace event |
| * occurred. |
| */ |
| DEFINE_PER_CPU(bool, trace_taskinfo_save); |
| |
| /* |
| * Kill all tracing for good (never come back). |
| * It is initialized to 1 but will turn to zero if the initialization |
| * of the tracer is successful. But that is the only place that sets |
| * this back to zero. |
| */ |
| static int tracing_disabled = 1; |
| |
| cpumask_var_t __read_mostly tracing_buffer_mask; |
| |
| /* |
| * ftrace_dump_on_oops - variable to dump ftrace buffer on oops |
| * |
| * If there is an oops (or kernel panic) and the ftrace_dump_on_oops |
| * is set, then ftrace_dump is called. This will output the contents |
| * of the ftrace buffers to the console. This is very useful for |
| * capturing traces that lead to crashes and outputing it to a |
| * serial console. |
| * |
| * It is default off, but you can enable it with either specifying |
| * "ftrace_dump_on_oops" in the kernel command line, or setting |
| * /proc/sys/kernel/ftrace_dump_on_oops |
| * Set 1 if you want to dump buffers of all CPUs |
| * Set 2 if you want to dump the buffer of the CPU that triggered oops |
| * Set instance name if you want to dump the specific trace instance |
| * Multiple instance dump is also supported, and instances are seperated |
| * by commas. |
| */ |
| /* Set to string format zero to disable by default */ |
| char ftrace_dump_on_oops[MAX_TRACER_SIZE] = "0"; |
| |
| /* When set, tracing will stop when a WARN*() is hit */ |
| int __disable_trace_on_warning; |
| |
| #ifdef CONFIG_TRACE_EVAL_MAP_FILE |
| /* Map of enums to their values, for "eval_map" file */ |
| struct trace_eval_map_head { |
| struct module *mod; |
| unsigned long length; |
| }; |
| |
| union trace_eval_map_item; |
| |
| struct trace_eval_map_tail { |
| /* |
| * "end" is first and points to NULL as it must be different |
| * than "mod" or "eval_string" |
| */ |
| union trace_eval_map_item *next; |
| const char *end; /* points to NULL */ |
| }; |
| |
| static DEFINE_MUTEX(trace_eval_mutex); |
| |
| /* |
| * The trace_eval_maps are saved in an array with two extra elements, |
| * one at the beginning, and one at the end. The beginning item contains |
| * the count of the saved maps (head.length), and the module they |
| * belong to if not built in (head.mod). The ending item contains a |
| * pointer to the next array of saved eval_map items. |
| */ |
| union trace_eval_map_item { |
| struct trace_eval_map map; |
| struct trace_eval_map_head head; |
| struct trace_eval_map_tail tail; |
| }; |
| |
| static union trace_eval_map_item *trace_eval_maps; |
| #endif /* CONFIG_TRACE_EVAL_MAP_FILE */ |
| |
| int tracing_set_tracer(struct trace_array *tr, const char *buf); |
| static void ftrace_trace_userstack(struct trace_array *tr, |
| struct trace_buffer *buffer, |
| unsigned int trace_ctx); |
| |
| static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; |
| static char *default_bootup_tracer; |
| |
| static bool allocate_snapshot; |
| static bool snapshot_at_boot; |
| |
| static char boot_instance_info[COMMAND_LINE_SIZE] __initdata; |
| static int boot_instance_index; |
| |
| static char boot_snapshot_info[COMMAND_LINE_SIZE] __initdata; |
| static int boot_snapshot_index; |
| |
| static int __init set_cmdline_ftrace(char *str) |
| { |
| strscpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); |
| default_bootup_tracer = bootup_tracer_buf; |
| /* We are using ftrace early, expand it */ |
| trace_set_ring_buffer_expanded(NULL); |
| return 1; |
| } |
| __setup("ftrace=", set_cmdline_ftrace); |
| |
| int ftrace_dump_on_oops_enabled(void) |
| { |
| if (!strcmp("0", ftrace_dump_on_oops)) |
| return 0; |
| else |
| return 1; |
| } |
| |
| static int __init set_ftrace_dump_on_oops(char *str) |
| { |
| if (!*str) { |
| strscpy(ftrace_dump_on_oops, "1", MAX_TRACER_SIZE); |
| return 1; |
| } |
| |
| if (*str == ',') { |
| strscpy(ftrace_dump_on_oops, "1", MAX_TRACER_SIZE); |
| strscpy(ftrace_dump_on_oops + 1, str, MAX_TRACER_SIZE - 1); |
| return 1; |
| } |
| |
| if (*str++ == '=') { |
| strscpy(ftrace_dump_on_oops, str, MAX_TRACER_SIZE); |
| return 1; |
| } |
| |
| return 0; |
| } |
| __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); |
| |
| static int __init stop_trace_on_warning(char *str) |
| { |
| if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0)) |
| __disable_trace_on_warning = 1; |
| return 1; |
| } |
| __setup("traceoff_on_warning", stop_trace_on_warning); |
| |
| static int __init boot_alloc_snapshot(char *str) |
| { |
| char *slot = boot_snapshot_info + boot_snapshot_index; |
| int left = sizeof(boot_snapshot_info) - boot_snapshot_index; |
| int ret; |
| |
| if (str[0] == '=') { |
| str++; |
| if (strlen(str) >= left) |
| return -1; |
| |
| ret = snprintf(slot, left, "%s\t", str); |
| boot_snapshot_index += ret; |
| } else { |
| allocate_snapshot = true; |
| /* We also need the main ring buffer expanded */ |
| trace_set_ring_buffer_expanded(NULL); |
| } |
| return 1; |
| } |
| __setup("alloc_snapshot", boot_alloc_snapshot); |
| |
| |
| static int __init boot_snapshot(char *str) |
| { |
| snapshot_at_boot = true; |
| boot_alloc_snapshot(str); |
| return 1; |
| } |
| __setup("ftrace_boot_snapshot", boot_snapshot); |
| |
| |
| static int __init boot_instance(char *str) |
| { |
| char *slot = boot_instance_info + boot_instance_index; |
| int left = sizeof(boot_instance_info) - boot_instance_index; |
| int ret; |
| |
| if (strlen(str) >= left) |
| return -1; |
| |
| ret = snprintf(slot, left, "%s\t", str); |
| boot_instance_index += ret; |
| |
| return 1; |
| } |
| __setup("trace_instance=", boot_instance); |
| |
| |
| static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; |
| |
| static int __init set_trace_boot_options(char *str) |
| { |
| strscpy(trace_boot_options_buf, str, MAX_TRACER_SIZE); |
| return 1; |
| } |
| __setup("trace_options=", set_trace_boot_options); |
| |
| static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata; |
| static char *trace_boot_clock __initdata; |
| |
| static int __init set_trace_boot_clock(char *str) |
| { |
| strscpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE); |
| trace_boot_clock = trace_boot_clock_buf; |
| return 1; |
| } |
| __setup("trace_clock=", set_trace_boot_clock); |
| |
| static int __init set_tracepoint_printk(char *str) |
| { |
| /* Ignore the "tp_printk_stop_on_boot" param */ |
| if (*str == '_') |
| return 0; |
| |
| if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0)) |
| tracepoint_printk = 1; |
| return 1; |
| } |
| __setup("tp_printk", set_tracepoint_printk); |
| |
| static int __init set_tracepoint_printk_stop(char *str) |
| { |
| tracepoint_printk_stop_on_boot = true; |
| return 1; |
| } |
| __setup("tp_printk_stop_on_boot", set_tracepoint_printk_stop); |
| |
| unsigned long long ns2usecs(u64 nsec) |
| { |
| nsec += 500; |
| do_div(nsec, 1000); |
| return nsec; |
| } |
| |
| static void |
| trace_process_export(struct trace_export *export, |
| struct ring_buffer_event *event, int flag) |
| { |
| struct trace_entry *entry; |
| unsigned int size = 0; |
| |
| if (export->flags & flag) { |
| entry = ring_buffer_event_data(event); |
| size = ring_buffer_event_length(event); |
| export->write(export, entry, size); |
| } |
| } |
| |
| static DEFINE_MUTEX(ftrace_export_lock); |
| |
| static struct trace_export __rcu *ftrace_exports_list __read_mostly; |
| |
| static DEFINE_STATIC_KEY_FALSE(trace_function_exports_enabled); |
| static DEFINE_STATIC_KEY_FALSE(trace_event_exports_enabled); |
| static DEFINE_STATIC_KEY_FALSE(trace_marker_exports_enabled); |
| |
| static inline void ftrace_exports_enable(struct trace_export *export) |
| { |
| if (export->flags & TRACE_EXPORT_FUNCTION) |
| static_branch_inc(&trace_function_exports_enabled); |
| |
| if (export->flags & TRACE_EXPORT_EVENT) |
| static_branch_inc(&trace_event_exports_enabled); |
| |
| if (export->flags & TRACE_EXPORT_MARKER) |
| static_branch_inc(&trace_marker_exports_enabled); |
| } |
| |
| static inline void ftrace_exports_disable(struct trace_export *export) |
| { |
| if (export->flags & TRACE_EXPORT_FUNCTION) |
| static_branch_dec(&trace_function_exports_enabled); |
| |
| if (export->flags & TRACE_EXPORT_EVENT) |
| static_branch_dec(&trace_event_exports_enabled); |
| |
| if (export->flags & TRACE_EXPORT_MARKER) |
| static_branch_dec(&trace_marker_exports_enabled); |
| } |
| |
| static void ftrace_exports(struct ring_buffer_event *event, int flag) |
| { |
| struct trace_export *export; |
| |
| preempt_disable_notrace(); |
| |
| export = rcu_dereference_raw_check(ftrace_exports_list); |
| while (export) { |
| trace_process_export(export, event, flag); |
| export = rcu_dereference_raw_check(export->next); |
| } |
| |
| preempt_enable_notrace(); |
| } |
| |
| static inline void |
| add_trace_export(struct trace_export **list, struct trace_export *export) |
| { |
| rcu_assign_pointer(export->next, *list); |
| /* |
| * We are entering export into the list but another |
| * CPU might be walking that list. We need to make sure |
| * the export->next pointer is valid before another CPU sees |
| * the export pointer included into the list. |
| */ |
| rcu_assign_pointer(*list, export); |
| } |
| |
| static inline int |
| rm_trace_export(struct trace_export **list, struct trace_export *export) |
| { |
| struct trace_export **p; |
| |
| for (p = list; *p != NULL; p = &(*p)->next) |
| if (*p == export) |
| break; |
| |
| if (*p != export) |
| return -1; |
| |
| rcu_assign_pointer(*p, (*p)->next); |
| |
| return 0; |
| } |
| |
| static inline void |
| add_ftrace_export(struct trace_export **list, struct trace_export *export) |
| { |
| ftrace_exports_enable(export); |
| |
| add_trace_export(list, export); |
| } |
| |
| static inline int |
| rm_ftrace_export(struct trace_export **list, struct trace_export *export) |
| { |
| int ret; |
| |
| ret = rm_trace_export(list, export); |
| ftrace_exports_disable(export); |
| |
| return ret; |
| } |
| |
| int register_ftrace_export(struct trace_export *export) |
| { |
| if (WARN_ON_ONCE(!export->write)) |
| return -1; |
| |
| mutex_lock(&ftrace_export_lock); |
| |
| add_ftrace_export(&ftrace_exports_list, export); |
| |
| mutex_unlock(&ftrace_export_lock); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(register_ftrace_export); |
| |
| int unregister_ftrace_export(struct trace_export *export) |
| { |
| int ret; |
| |
| mutex_lock(&ftrace_export_lock); |
| |
| ret = rm_ftrace_export(&ftrace_exports_list, export); |
| |
| mutex_unlock(&ftrace_export_lock); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(unregister_ftrace_export); |
| |
| /* trace_flags holds trace_options default values */ |
| #define TRACE_DEFAULT_FLAGS \ |
| (FUNCTION_DEFAULT_FLAGS | \ |
| TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | \ |
| TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO | \ |
| TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE | \ |
| TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS | \ |
| TRACE_ITER_HASH_PTR) |
| |
| /* trace_options that are only supported by global_trace */ |
| #define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK | \ |
| TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD) |
| |
| /* trace_flags that are default zero for instances */ |
| #define ZEROED_TRACE_FLAGS \ |
| (TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK) |
| |
| /* |
| * The global_trace is the descriptor that holds the top-level tracing |
| * buffers for the live tracing. |
| */ |
| static struct trace_array global_trace = { |
| .trace_flags = TRACE_DEFAULT_FLAGS, |
| }; |
| |
| void trace_set_ring_buffer_expanded(struct trace_array *tr) |
| { |
| if (!tr) |
| tr = &global_trace; |
| tr->ring_buffer_expanded = true; |
| } |
| |
| LIST_HEAD(ftrace_trace_arrays); |
| |
| int trace_array_get(struct trace_array *this_tr) |
| { |
| struct trace_array *tr; |
| int ret = -ENODEV; |
| |
| mutex_lock(&trace_types_lock); |
| list_for_each_entry(tr, &ftrace_trace_arrays, list) { |
| if (tr == this_tr) { |
| tr->ref++; |
| ret = 0; |
| break; |
| } |
| } |
| mutex_unlock(&trace_types_lock); |
| |
| return ret; |
| } |
| |
| static void __trace_array_put(struct trace_array *this_tr) |
| { |
| WARN_ON(!this_tr->ref); |
| this_tr->ref--; |
| } |
| |
| /** |
| * trace_array_put - Decrement the reference counter for this trace array. |
| * @this_tr : pointer to the trace array |
| * |
| * NOTE: Use this when we no longer need the trace array returned by |
| * trace_array_get_by_name(). This ensures the trace array can be later |
| * destroyed. |
| * |
| */ |
| void trace_array_put(struct trace_array *this_tr) |
| { |
| if (!this_tr) |
| return; |
| |
| mutex_lock(&trace_types_lock); |
| __trace_array_put(this_tr); |
| mutex_unlock(&trace_types_lock); |
| } |
| EXPORT_SYMBOL_GPL(trace_array_put); |
| |
| int tracing_check_open_get_tr(struct trace_array *tr) |
| { |
| int ret; |
| |
| ret = security_locked_down(LOCKDOWN_TRACEFS); |
| if (ret) |
| return ret; |
| |
| if (tracing_disabled) |
| return -ENODEV; |
| |
| if (tr && trace_array_get(tr) < 0) |
| return -ENODEV; |
| |
| return 0; |
| } |
| |
| int call_filter_check_discard(struct trace_event_call *call, void *rec, |
| struct trace_buffer *buffer, |
| struct ring_buffer_event *event) |
| { |
| if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) && |
| !filter_match_preds(call->filter, rec)) { |
| __trace_event_discard_commit(buffer, event); |
| return 1; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * trace_find_filtered_pid - check if a pid exists in a filtered_pid list |
| * @filtered_pids: The list of pids to check |
| * @search_pid: The PID to find in @filtered_pids |
| * |
| * Returns true if @search_pid is found in @filtered_pids, and false otherwise. |
| */ |
| bool |
| trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid) |
| { |
| return trace_pid_list_is_set(filtered_pids, search_pid); |
| } |
| |
| /** |
| * trace_ignore_this_task - should a task be ignored for tracing |
| * @filtered_pids: The list of pids to check |
| * @filtered_no_pids: The list of pids not to be traced |
| * @task: The task that should be ignored if not filtered |
| * |
| * Checks if @task should be traced or not from @filtered_pids. |
| * Returns true if @task should *NOT* be traced. |
| * Returns false if @task should be traced. |
| */ |
| bool |
| trace_ignore_this_task(struct trace_pid_list *filtered_pids, |
| struct trace_pid_list *filtered_no_pids, |
| struct task_struct *task) |
| { |
| /* |
| * If filtered_no_pids is not empty, and the task's pid is listed |
| * in filtered_no_pids, then return true. |
| * Otherwise, if filtered_pids is empty, that means we can |
| * trace all tasks. If it has content, then only trace pids |
| * within filtered_pids. |
| */ |
| |
| return (filtered_pids && |
| !trace_find_filtered_pid(filtered_pids, task->pid)) || |
| (filtered_no_pids && |
| trace_find_filtered_pid(filtered_no_pids, task->pid)); |
| } |
| |
| /** |
| * trace_filter_add_remove_task - Add or remove a task from a pid_list |
| * @pid_list: The list to modify |
| * @self: The current task for fork or NULL for exit |
| * @task: The task to add or remove |
| * |
| * If adding a task, if @self is defined, the task is only added if @self |
| * is also included in @pid_list. This happens on fork and tasks should |
| * only be added when the parent is listed. If @self is NULL, then the |
| * @task pid will be removed from the list, which would happen on exit |
| * of a task. |
| */ |
| void trace_filter_add_remove_task(struct trace_pid_list *pid_list, |
| struct task_struct *self, |
| struct task_struct *task) |
| { |
| if (!pid_list) |
| return; |
| |
| /* For forks, we only add if the forking task is listed */ |
| if (self) { |
| if (!trace_find_filtered_pid(pid_list, self->pid)) |
| return; |
| } |
| |
| /* "self" is set for forks, and NULL for exits */ |
| if (self) |
| trace_pid_list_set(pid_list, task->pid); |
| else |
| trace_pid_list_clear(pid_list, task->pid); |
| } |
| |
| /** |
| * trace_pid_next - Used for seq_file to get to the next pid of a pid_list |
| * @pid_list: The pid list to show |
| * @v: The last pid that was shown (+1 the actual pid to let zero be displayed) |
| * @pos: The position of the file |
| * |
| * This is used by the seq_file "next" operation to iterate the pids |
| * listed in a trace_pid_list structure. |
| * |
| * Returns the pid+1 as we want to display pid of zero, but NULL would |
| * stop the iteration. |
| */ |
| void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos) |
| { |
| long pid = (unsigned long)v; |
| unsigned int next; |
| |
| (*pos)++; |
| |
| /* pid already is +1 of the actual previous bit */ |
| if (trace_pid_list_next(pid_list, pid, &next) < 0) |
| return NULL; |
| |
| pid = next; |
| |
| /* Return pid + 1 to allow zero to be represented */ |
| return (void *)(pid + 1); |
| } |
| |
| /** |
| * trace_pid_start - Used for seq_file to start reading pid lists |
| * @pid_list: The pid list to show |
| * @pos: The position of the file |
| * |
| * This is used by seq_file "start" operation to start the iteration |
| * of listing pids. |
| * |
| * Returns the pid+1 as we want to display pid of zero, but NULL would |
| * stop the iteration. |
| */ |
| void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos) |
| { |
| unsigned long pid; |
| unsigned int first; |
| loff_t l = 0; |
| |
| if (trace_pid_list_first(pid_list, &first) < 0) |
| return NULL; |
| |
| pid = first; |
| |
| /* Return pid + 1 so that zero can be the exit value */ |
| for (pid++; pid && l < *pos; |
| pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l)) |
| ; |
| return (void *)pid; |
| } |
| |
| /** |
| * trace_pid_show - show the current pid in seq_file processing |
| * @m: The seq_file structure to write into |
| * @v: A void pointer of the pid (+1) value to display |
| * |
| * Can be directly used by seq_file operations to display the current |
| * pid value. |
| */ |
| int trace_pid_show(struct seq_file *m, void *v) |
| { |
| unsigned long pid = (unsigned long)v - 1; |
| |
| seq_printf(m, "%lu\n", pid); |
| return 0; |
| } |
| |
| /* 128 should be much more than enough */ |
| #define PID_BUF_SIZE 127 |
| |
| int trace_pid_write(struct trace_pid_list *filtered_pids, |
| struct trace_pid_list **new_pid_list, |
| const char __user *ubuf, size_t cnt) |
| { |
| struct trace_pid_list *pid_list; |
| struct trace_parser parser; |
| unsigned long val; |
| int nr_pids = 0; |
| ssize_t read = 0; |
| ssize_t ret; |
| loff_t pos; |
| pid_t pid; |
| |
| if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1)) |
| return -ENOMEM; |
| |
| /* |
| * Always recreate a new array. The write is an all or nothing |
| * operation. Always create a new array when adding new pids by |
| * the user. If the operation fails, then the current list is |
| * not modified. |
| */ |
| pid_list = trace_pid_list_alloc(); |
| if (!pid_list) { |
| trace_parser_put(&parser); |
| return -ENOMEM; |
| } |
| |
| if (filtered_pids) { |
| /* copy the current bits to the new max */ |
| ret = trace_pid_list_first(filtered_pids, &pid); |
| while (!ret) { |
| trace_pid_list_set(pid_list, pid); |
| ret = trace_pid_list_next(filtered_pids, pid + 1, &pid); |
| nr_pids++; |
| } |
| } |
| |
| ret = 0; |
| while (cnt > 0) { |
| |
| pos = 0; |
| |
| ret = trace_get_user(&parser, ubuf, cnt, &pos); |
| if (ret < 0) |
| break; |
| |
| read += ret; |
| ubuf += ret; |
| cnt -= ret; |
| |
| if (!trace_parser_loaded(&parser)) |
| break; |
| |
| ret = -EINVAL; |
| if (kstrtoul(parser.buffer, 0, &val)) |
| break; |
| |
| pid = (pid_t)val; |
| |
| if (trace_pid_list_set(pid_list, pid) < 0) { |
| ret = -1; |
| break; |
| } |
| nr_pids++; |
| |
| trace_parser_clear(&parser); |
| ret = 0; |
| } |
| trace_parser_put(&parser); |
| |
| if (ret < 0) { |
| trace_pid_list_free(pid_list); |
| return ret; |
| } |
| |
| if (!nr_pids) { |
| /* Cleared the list of pids */ |
| trace_pid_list_free(pid_list); |
| pid_list = NULL; |
| } |
| |
| *new_pid_list = pid_list; |
| |
| return read; |
| } |
| |
| static u64 buffer_ftrace_now(struct array_buffer *buf, int cpu) |
| { |
| u64 ts; |
| |
| /* Early boot up does not have a buffer yet */ |
| if (!buf->buffer) |
| return trace_clock_local(); |
| |
| ts = ring_buffer_time_stamp(buf->buffer); |
| ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts); |
| |
| return ts; |
| } |
| |
| u64 ftrace_now(int cpu) |
| { |
| return buffer_ftrace_now(&global_trace.array_buffer, cpu); |
| } |
| |
| /** |
| * tracing_is_enabled - Show if global_trace has been enabled |
| * |
| * Shows if the global trace has been enabled or not. It uses the |
| * mirror flag "buffer_disabled" to be used in fast paths such as for |
| * the irqsoff tracer. But it may be inaccurate due to races. If you |
| * need to know the accurate state, use tracing_is_on() which is a little |
| * slower, but accurate. |
| */ |
| int tracing_is_enabled(void) |
| { |
| /* |
| * For quick access (irqsoff uses this in fast path), just |
| * return the mirror variable of the state of the ring buffer. |
| * It's a little racy, but we don't really care. |
| */ |
| smp_rmb(); |
| return !global_trace.buffer_disabled; |
| } |
| |
| /* |
| * trace_buf_size is the size in bytes that is allocated |
| * for a buffer. Note, the number of bytes is always rounded |
| * to page size. |
| * |
| * This number is purposely set to a low number of 16384. |
| * If the dump on oops happens, it will be much appreciated |
| * to not have to wait for all that output. Anyway this can be |
| * boot time and run time configurable. |
| */ |
| #define TRACE_BUF_SIZE_DEFAULT 1441792UL /* 16384 * 88 (sizeof(entry)) */ |
| |
| static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT; |
| |
| /* trace_types holds a link list of available tracers. */ |
| static struct tracer *trace_types __read_mostly; |
| |
| /* |
| * trace_types_lock is used to protect the trace_types list. |
| */ |
| DEFINE_MUTEX(trace_types_lock); |
| |
| /* |
| * serialize the access of the ring buffer |
| * |
| * ring buffer serializes readers, but it is low level protection. |
| * The validity of the events (which returns by ring_buffer_peek() ..etc) |
| * are not protected by ring buffer. |
| * |
| * The content of events may become garbage if we allow other process consumes |
| * these events concurrently: |
| * A) the page of the consumed events may become a normal page |
| * (not reader page) in ring buffer, and this page will be rewritten |
| * by events producer. |
| * B) The page of the consumed events may become a page for splice_read, |
| * and this page will be returned to system. |
| * |
| * These primitives allow multi process access to different cpu ring buffer |
| * concurrently. |
| * |
| * These primitives don't distinguish read-only and read-consume access. |
| * Multi read-only access are also serialized. |
| */ |
| |
| #ifdef CONFIG_SMP |
| static DECLARE_RWSEM(all_cpu_access_lock); |
| static DEFINE_PER_CPU(struct mutex, cpu_access_lock); |
| |
| static inline void trace_access_lock(int cpu) |
| { |
| if (cpu == RING_BUFFER_ALL_CPUS) { |
| /* gain it for accessing the whole ring buffer. */ |
| down_write(&all_cpu_access_lock); |
| } else { |
| /* gain it for accessing a cpu ring buffer. */ |
| |
| /* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */ |
| down_read(&all_cpu_access_lock); |
| |
| /* Secondly block other access to this @cpu ring buffer. */ |
| mutex_lock(&per_cpu(cpu_access_lock, cpu)); |
| } |
| } |
| |
| static inline void trace_access_unlock(int cpu) |
| { |
| if (cpu == RING_BUFFER_ALL_CPUS) { |
| up_write(&all_cpu_access_lock); |
| } else { |
| mutex_unlock(&per_cpu(cpu_access_lock, cpu)); |
| up_read(&all_cpu_access_lock); |
| } |
| } |
| |
| static inline void trace_access_lock_init(void) |
| { |
| int cpu; |
| |
| for_each_possible_cpu(cpu) |
| mutex_init(&per_cpu(cpu_access_lock, cpu)); |
| } |
| |
| #else |
| |
| static DEFINE_MUTEX(access_lock); |
| |
| static inline void trace_access_lock(int cpu) |
| { |
| (void)cpu; |
| mutex_lock(&access_lock); |
| } |
| |
| static inline void trace_access_unlock(int cpu) |
| { |
| (void)cpu; |
| mutex_unlock(&access_lock); |
| } |
| |
| static inline void trace_access_lock_init(void) |
| { |
| } |
| |
| #endif |
| |
| #ifdef CONFIG_STACKTRACE |
| static void __ftrace_trace_stack(struct trace_buffer *buffer, |
| unsigned int trace_ctx, |
| int skip, struct pt_regs *regs); |
| static inline void ftrace_trace_stack(struct trace_array *tr, |
| struct trace_buffer *buffer, |
| unsigned int trace_ctx, |
| int skip, struct pt_regs *regs); |
| |
| #else |
| static inline void __ftrace_trace_stack(struct trace_buffer *buffer, |
| unsigned int trace_ctx, |
| int skip, struct pt_regs *regs) |
| { |
| } |
| static inline void ftrace_trace_stack(struct trace_array *tr, |
| struct trace_buffer *buffer, |
| unsigned long trace_ctx, |
| int skip, struct pt_regs *regs) |
| { |
| } |
| |
| #endif |
| |
| static __always_inline void |
| trace_event_setup(struct ring_buffer_event *event, |
| int type, unsigned int trace_ctx) |
| { |
| struct trace_entry *ent = ring_buffer_event_data(event); |
| |
| tracing_generic_entry_update(ent, type, trace_ctx); |
| } |
| |
| static __always_inline struct ring_buffer_event * |
| __trace_buffer_lock_reserve(struct trace_buffer *buffer, |
| int type, |
| unsigned long len, |
| unsigned int trace_ctx) |
| { |
| struct ring_buffer_event *event; |
| |
| event = ring_buffer_lock_reserve(buffer, len); |
| if (event != NULL) |
| trace_event_setup(event, type, trace_ctx); |
| |
| return event; |
| } |
| |
| void tracer_tracing_on(struct trace_array *tr) |
| { |
| if (tr->array_buffer.buffer) |
| ring_buffer_record_on(tr->array_buffer.buffer); |
| /* |
| * This flag is looked at when buffers haven't been allocated |
| * yet, or by some tracers (like irqsoff), that just want to |
| * know if the ring buffer has been disabled, but it can handle |
| * races of where it gets disabled but we still do a record. |
| * As the check is in the fast path of the tracers, it is more |
| * important to be fast than accurate. |
| */ |
| tr->buffer_disabled = 0; |
| /* Make the flag seen by readers */ |
| smp_wmb(); |
| } |
| |
| /** |
| * tracing_on - enable tracing buffers |
| * |
| * This function enables tracing buffers that may have been |
| * disabled with tracing_off. |
| */ |
| void tracing_on(void) |
| { |
| tracer_tracing_on(&global_trace); |
| } |
| EXPORT_SYMBOL_GPL(tracing_on); |
| |
| |
| static __always_inline void |
| __buffer_unlock_commit(struct trace_buffer *buffer, struct ring_buffer_event *event) |
| { |
| __this_cpu_write(trace_taskinfo_save, true); |
| |
| /* If this is the temp buffer, we need to commit fully */ |
| if (this_cpu_read(trace_buffered_event) == event) { |
| /* Length is in event->array[0] */ |
| ring_buffer_write(buffer, event->array[0], &event->array[1]); |
| /* Release the temp buffer */ |
| this_cpu_dec(trace_buffered_event_cnt); |
| /* ring_buffer_unlock_commit() enables preemption */ |
| preempt_enable_notrace(); |
| } else |
| ring_buffer_unlock_commit(buffer); |
| } |
| |
| int __trace_array_puts(struct trace_array *tr, unsigned long ip, |
| const char *str, int size) |
| { |
| struct ring_buffer_event *event; |
| struct trace_buffer *buffer; |
| struct print_entry *entry; |
| unsigned int trace_ctx; |
| int alloc; |
| |
| if (!(tr->trace_flags & TRACE_ITER_PRINTK)) |
| return 0; |
| |
| if (unlikely(tracing_selftest_running && tr == &global_trace)) |
| return 0; |
| |
| if (unlikely(tracing_disabled)) |
| return 0; |
| |
| alloc = sizeof(*entry) + size + 2; /* possible \n added */ |
| |
| trace_ctx = tracing_gen_ctx(); |
| buffer = tr->array_buffer.buffer; |
| ring_buffer_nest_start(buffer); |
| event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, |
| trace_ctx); |
| if (!event) { |
| size = 0; |
| goto out; |
| } |
| |
| entry = ring_buffer_event_data(event); |
| entry->ip = ip; |
| |
| memcpy(&entry->buf, str, size); |
| |
| /* Add a newline if necessary */ |
| if (entry->buf[size - 1] != '\n') { |
| entry->buf[size] = '\n'; |
| entry->buf[size + 1] = '\0'; |
| } else |
| entry->buf[size] = '\0'; |
| |
| __buffer_unlock_commit(buffer, event); |
| ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL); |
| out: |
| ring_buffer_nest_end(buffer); |
| return size; |
| } |
| EXPORT_SYMBOL_GPL(__trace_array_puts); |
| |
| /** |
| * __trace_puts - write a constant string into the trace buffer. |
| * @ip: The address of the caller |
| * @str: The constant string to write |
| * @size: The size of the string. |
| */ |
| int __trace_puts(unsigned long ip, const char *str, int size) |
| { |
| return __trace_array_puts(&global_trace, ip, str, size); |
| } |
| EXPORT_SYMBOL_GPL(__trace_puts); |
| |
| /** |
| * __trace_bputs - write the pointer to a constant string into trace buffer |
| * @ip: The address of the caller |
| * @str: The constant string to write to the buffer to |
| */ |
| int __trace_bputs(unsigned long ip, const char *str) |
| { |
| struct ring_buffer_event *event; |
| struct trace_buffer *buffer; |
| struct bputs_entry *entry; |
| unsigned int trace_ctx; |
| int size = sizeof(struct bputs_entry); |
| int ret = 0; |
| |
| if (!(global_trace.trace_flags & TRACE_ITER_PRINTK)) |
| return 0; |
| |
| if (unlikely(tracing_selftest_running || tracing_disabled)) |
| return 0; |
| |
| trace_ctx = tracing_gen_ctx(); |
| buffer = global_trace.array_buffer.buffer; |
| |
| ring_buffer_nest_start(buffer); |
| event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size, |
| trace_ctx); |
| if (!event) |
| goto out; |
| |
| entry = ring_buffer_event_data(event); |
| entry->ip = ip; |
| entry->str = str; |
| |
| __buffer_unlock_commit(buffer, event); |
| ftrace_trace_stack(&global_trace, buffer, trace_ctx, 4, NULL); |
| |
| ret = 1; |
| out: |
| ring_buffer_nest_end(buffer); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(__trace_bputs); |
| |
| #ifdef CONFIG_TRACER_SNAPSHOT |
| static void tracing_snapshot_instance_cond(struct trace_array *tr, |
| void *cond_data) |
| { |
| struct tracer *tracer = tr->current_trace; |
| unsigned long flags; |
| |
| if (in_nmi()) { |
| trace_array_puts(tr, "*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n"); |
| trace_array_puts(tr, "*** snapshot is being ignored ***\n"); |
| return; |
| } |
| |
| if (!tr->allocated_snapshot) { |
| trace_array_puts(tr, "*** SNAPSHOT NOT ALLOCATED ***\n"); |
| trace_array_puts(tr, "*** stopping trace here! ***\n"); |
| tracer_tracing_off(tr); |
| return; |
| } |
| |
| /* Note, snapshot can not be used when the tracer uses it */ |
| if (tracer->use_max_tr) { |
| trace_array_puts(tr, "*** LATENCY TRACER ACTIVE ***\n"); |
| trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n"); |
| return; |
| } |
| |
| if (tr->mapped) { |
| trace_array_puts(tr, "*** BUFFER MEMORY MAPPED ***\n"); |
| trace_array_puts(tr, "*** Can not use snapshot (sorry) ***\n"); |
| return; |
| } |
| |
| local_irq_save(flags); |
| update_max_tr(tr, current, smp_processor_id(), cond_data); |
| local_irq_restore(flags); |
| } |
| |
| void tracing_snapshot_instance(struct trace_array *tr) |
| { |
| tracing_snapshot_instance_cond(tr, NULL); |
| } |
| |
| /** |
| * tracing_snapshot - take a snapshot of the current buffer. |
| * |
| * This causes a swap between the snapshot buffer and the current live |
| * tracing buffer. You can use this to take snapshots of the live |
| * trace when some condition is triggered, but continue to trace. |
| * |
| * Note, make sure to allocate the snapshot with either |
| * a tracing_snapshot_alloc(), or by doing it manually |
| * with: echo 1 > /sys/kernel/tracing/snapshot |
| * |
| * If the snapshot buffer is not allocated, it will stop tracing. |
| * Basically making a permanent snapshot. |
| */ |
| void tracing_snapshot(void) |
| { |
| struct trace_array *tr = &global_trace; |
| |
| tracing_snapshot_instance(tr); |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot); |
| |
| /** |
| * tracing_snapshot_cond - conditionally take a snapshot of the current buffer. |
| * @tr: The tracing instance to snapshot |
| * @cond_data: The data to be tested conditionally, and possibly saved |
| * |
| * This is the same as tracing_snapshot() except that the snapshot is |
| * conditional - the snapshot will only happen if the |
| * cond_snapshot.update() implementation receiving the cond_data |
| * returns true, which means that the trace array's cond_snapshot |
| * update() operation used the cond_data to determine whether the |
| * snapshot should be taken, and if it was, presumably saved it along |
| * with the snapshot. |
| */ |
| void tracing_snapshot_cond(struct trace_array *tr, void *cond_data) |
| { |
| tracing_snapshot_instance_cond(tr, cond_data); |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_cond); |
| |
| /** |
| * tracing_cond_snapshot_data - get the user data associated with a snapshot |
| * @tr: The tracing instance |
| * |
| * When the user enables a conditional snapshot using |
| * tracing_snapshot_cond_enable(), the user-defined cond_data is saved |
| * with the snapshot. This accessor is used to retrieve it. |
| * |
| * Should not be called from cond_snapshot.update(), since it takes |
| * the tr->max_lock lock, which the code calling |
| * cond_snapshot.update() has already done. |
| * |
| * Returns the cond_data associated with the trace array's snapshot. |
| */ |
| void *tracing_cond_snapshot_data(struct trace_array *tr) |
| { |
| void *cond_data = NULL; |
| |
| local_irq_disable(); |
| arch_spin_lock(&tr->max_lock); |
| |
| if (tr->cond_snapshot) |
| cond_data = tr->cond_snapshot->cond_data; |
| |
| arch_spin_unlock(&tr->max_lock); |
| local_irq_enable(); |
| |
| return cond_data; |
| } |
| EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data); |
| |
| static int resize_buffer_duplicate_size(struct array_buffer *trace_buf, |
| struct array_buffer *size_buf, int cpu_id); |
| static void set_buffer_entries(struct array_buffer *buf, unsigned long val); |
| |
| int tracing_alloc_snapshot_instance(struct trace_array *tr) |
| { |
| int order; |
| int ret; |
| |
| if (!tr->allocated_snapshot) { |
| |
| /* Make the snapshot buffer have the same order as main buffer */ |
| order = ring_buffer_subbuf_order_get(tr->array_buffer.buffer); |
| ret = ring_buffer_subbuf_order_set(tr->max_buffer.buffer, order); |
| if (ret < 0) |
| return ret; |
| |
| /* allocate spare buffer */ |
| ret = resize_buffer_duplicate_size(&tr->max_buffer, |
| &tr->array_buffer, RING_BUFFER_ALL_CPUS); |
| if (ret < 0) |
| return ret; |
| |
| tr->allocated_snapshot = true; |
| } |
| |
| return 0; |
| } |
| |
| static void free_snapshot(struct trace_array *tr) |
| { |
| /* |
| * We don't free the ring buffer. instead, resize it because |
| * The max_tr ring buffer has some state (e.g. ring->clock) and |
| * we want preserve it. |
| */ |
| ring_buffer_subbuf_order_set(tr->max_buffer.buffer, 0); |
| ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS); |
| set_buffer_entries(&tr->max_buffer, 1); |
| tracing_reset_online_cpus(&tr->max_buffer); |
| tr->allocated_snapshot = false; |
| } |
| |
| static int tracing_arm_snapshot_locked(struct trace_array *tr) |
| { |
| int ret; |
| |
| lockdep_assert_held(&trace_types_lock); |
| |
| spin_lock(&tr->snapshot_trigger_lock); |
| if (tr->snapshot == UINT_MAX || tr->mapped) { |
| spin_unlock(&tr->snapshot_trigger_lock); |
| return -EBUSY; |
| } |
| |
| tr->snapshot++; |
| spin_unlock(&tr->snapshot_trigger_lock); |
| |
| ret = tracing_alloc_snapshot_instance(tr); |
| if (ret) { |
| spin_lock(&tr->snapshot_trigger_lock); |
| tr->snapshot--; |
| spin_unlock(&tr->snapshot_trigger_lock); |
| } |
| |
| return ret; |
| } |
| |
| int tracing_arm_snapshot(struct trace_array *tr) |
| { |
| int ret; |
| |
| mutex_lock(&trace_types_lock); |
| ret = tracing_arm_snapshot_locked(tr); |
| mutex_unlock(&trace_types_lock); |
| |
| return ret; |
| } |
| |
| void tracing_disarm_snapshot(struct trace_array *tr) |
| { |
| spin_lock(&tr->snapshot_trigger_lock); |
| if (!WARN_ON(!tr->snapshot)) |
| tr->snapshot--; |
| spin_unlock(&tr->snapshot_trigger_lock); |
| } |
| |
| /** |
| * tracing_alloc_snapshot - allocate snapshot buffer. |
| * |
| * This only allocates the snapshot buffer if it isn't already |
| * allocated - it doesn't also take a snapshot. |
| * |
| * This is meant to be used in cases where the snapshot buffer needs |
| * to be set up for events that can't sleep but need to be able to |
| * trigger a snapshot. |
| */ |
| int tracing_alloc_snapshot(void) |
| { |
| struct trace_array *tr = &global_trace; |
| int ret; |
| |
| ret = tracing_alloc_snapshot_instance(tr); |
| WARN_ON(ret < 0); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); |
| |
| /** |
| * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer. |
| * |
| * This is similar to tracing_snapshot(), but it will allocate the |
| * snapshot buffer if it isn't already allocated. Use this only |
| * where it is safe to sleep, as the allocation may sleep. |
| * |
| * This causes a swap between the snapshot buffer and the current live |
| * tracing buffer. You can use this to take snapshots of the live |
| * trace when some condition is triggered, but continue to trace. |
| */ |
| void tracing_snapshot_alloc(void) |
| { |
| int ret; |
| |
| ret = tracing_alloc_snapshot(); |
| if (ret < 0) |
| return; |
| |
| tracing_snapshot(); |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); |
| |
| /** |
| * tracing_snapshot_cond_enable - enable conditional snapshot for an instance |
| * @tr: The tracing instance |
| * @cond_data: User data to associate with the snapshot |
| * @update: Implementation of the cond_snapshot update function |
| * |
| * Check whether the conditional snapshot for the given instance has |
| * already been enabled, or if the current tracer is already using a |
| * snapshot; if so, return -EBUSY, else create a cond_snapshot and |
| * save the cond_data and update function inside. |
| * |
| * Returns 0 if successful, error otherwise. |
| */ |
| int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, |
| cond_update_fn_t update) |
| { |
| struct cond_snapshot *cond_snapshot; |
| int ret = 0; |
| |
| cond_snapshot = kzalloc(sizeof(*cond_snapshot), GFP_KERNEL); |
| if (!cond_snapshot) |
| return -ENOMEM; |
| |
| cond_snapshot->cond_data = cond_data; |
| cond_snapshot->update = update; |
| |
| mutex_lock(&trace_types_lock); |
| |
| if (tr->current_trace->use_max_tr) { |
| ret = -EBUSY; |
| goto fail_unlock; |
| } |
| |
| /* |
| * The cond_snapshot can only change to NULL without the |
| * trace_types_lock. We don't care if we race with it going |
| * to NULL, but we want to make sure that it's not set to |
| * something other than NULL when we get here, which we can |
| * do safely with only holding the trace_types_lock and not |
| * having to take the max_lock. |
| */ |
| if (tr->cond_snapshot) { |
| ret = -EBUSY; |
| goto fail_unlock; |
| } |
| |
| ret = tracing_arm_snapshot_locked(tr); |
| if (ret) |
| goto fail_unlock; |
| |
| local_irq_disable(); |
| arch_spin_lock(&tr->max_lock); |
| tr->cond_snapshot = cond_snapshot; |
| arch_spin_unlock(&tr->max_lock); |
| local_irq_enable(); |
| |
| mutex_unlock(&trace_types_lock); |
| |
| return ret; |
| |
| fail_unlock: |
| mutex_unlock(&trace_types_lock); |
| kfree(cond_snapshot); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable); |
| |
| /** |
| * tracing_snapshot_cond_disable - disable conditional snapshot for an instance |
| * @tr: The tracing instance |
| * |
| * Check whether the conditional snapshot for the given instance is |
| * enabled; if so, free the cond_snapshot associated with it, |
| * otherwise return -EINVAL. |
| * |
| * Returns 0 if successful, error otherwise. |
| */ |
| int tracing_snapshot_cond_disable(struct trace_array *tr) |
| { |
| int ret = 0; |
| |
| local_irq_disable(); |
| arch_spin_lock(&tr->max_lock); |
| |
| if (!tr->cond_snapshot) |
| ret = -EINVAL; |
| else { |
| kfree(tr->cond_snapshot); |
| tr->cond_snapshot = NULL; |
| } |
| |
| arch_spin_unlock(&tr->max_lock); |
| local_irq_enable(); |
| |
| tracing_disarm_snapshot(tr); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); |
| #else |
| void tracing_snapshot(void) |
| { |
| WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used"); |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot); |
| void tracing_snapshot_cond(struct trace_array *tr, void *cond_data) |
| { |
| WARN_ONCE(1, "Snapshot feature not enabled, but internal conditional snapshot used"); |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_cond); |
| int tracing_alloc_snapshot(void) |
| { |
| WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used"); |
| return -ENODEV; |
| } |
| EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); |
| void tracing_snapshot_alloc(void) |
| { |
| /* Give warning */ |
| tracing_snapshot(); |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_alloc); |
| void *tracing_cond_snapshot_data(struct trace_array *tr) |
| { |
| return NULL; |
| } |
| EXPORT_SYMBOL_GPL(tracing_cond_snapshot_data); |
| int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, cond_update_fn_t update) |
| { |
| return -ENODEV; |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_cond_enable); |
| int tracing_snapshot_cond_disable(struct trace_array *tr) |
| { |
| return false; |
| } |
| EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); |
| #define free_snapshot(tr) do { } while (0) |
| #define tracing_arm_snapshot_locked(tr) ({ -EBUSY; }) |
| #endif /* CONFIG_TRACER_SNAPSHOT */ |
| |
| void tracer_tracing_off(struct trace_array *tr) |
| { |
| if (tr->array_buffer.buffer) |
| ring_buffer_record_off(tr->array_buffer.buffer); |
| /* |
| * This flag is looked at when buffers haven't been allocated |
| * yet, or by some tracers (like irqsoff), that just want to |
| * know if the ring buffer has been disabled, but it can handle |
| * races of where it gets disabled but we still do a record. |
| * As the check is in the fast path of the tracers, it is more |
| * important to be fast than accurate. |
| */ |
| tr->buffer_disabled = 1; |
| /* Make the flag seen by readers */ |
| smp_wmb(); |
| } |
| |
| /** |
| * tracing_off - turn off tracing buffers |
| * |
| * This function stops the tracing buffers from recording data. |
| * It does not disable any overhead the tracers themselves may |
| * be causing. This function simply causes all recording to |
| * the ring buffers to fail. |
| */ |
| void tracing_off(void) |
| { |
| tracer_tracing_off(&global_trace); |
| } |
| EXPORT_SYMBOL_GPL(tracing_off); |
| |
| void disable_trace_on_warning(void) |
| { |
| if (__disable_trace_on_warning) { |
| trace_array_printk_buf(global_trace.array_buffer.buffer, _THIS_IP_, |
| "Disabling tracing due to warning\n"); |
| tracing_off(); |
| } |
| } |
| |
| /** |
| * tracer_tracing_is_on - show real state of ring buffer enabled |
| * @tr : the trace array to know if ring buffer is enabled |
| * |
| * Shows real state of the ring buffer if it is enabled or not. |
| */ |
| bool tracer_tracing_is_on(struct trace_array *tr) |
| { |
| if (tr->array_buffer.buffer) |
| return ring_buffer_record_is_set_on(tr->array_buffer.buffer); |
| return !tr->buffer_disabled; |
| } |
| |
| /** |
| * tracing_is_on - show state of ring buffers enabled |
| */ |
| int tracing_is_on(void) |
| { |
| return tracer_tracing_is_on(&global_trace); |
| } |
| EXPORT_SYMBOL_GPL(tracing_is_on); |
| |
| static int __init set_buf_size(char *str) |
| { |
| unsigned long buf_size; |
| |
| if (!str) |
| return 0; |
| buf_size = memparse(str, &str); |
| /* |
| * nr_entries can not be zero and the startup |
| * tests require some buffer space. Therefore |
| * ensure we have at least 4096 bytes of buffer. |
| */ |
| trace_buf_size = max(4096UL, buf_size); |
| return 1; |
| } |
| __setup("trace_buf_size=", set_buf_size); |
| |
| static int __init set_tracing_thresh(char *str) |
| { |
| unsigned long threshold; |
| int ret; |
| |
| if (!str) |
| return 0; |
| ret = kstrtoul(str, 0, &threshold); |
| if (ret < 0) |
| return 0; |
| tracing_thresh = threshold * 1000; |
| return 1; |
| } |
| __setup("tracing_thresh=", set_tracing_thresh); |
| |
| unsigned long nsecs_to_usecs(unsigned long nsecs) |
| { |
| return nsecs / 1000; |
| } |
| |
| /* |
| * TRACE_FLAGS is defined as a tuple matching bit masks with strings. |
| * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that |
| * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list |
| * of strings in the order that the evals (enum) were defined. |
| */ |
| #undef C |
| #define C(a, b) b |
| |
| /* These must match the bit positions in trace_iterator_flags */ |
| static const char *trace_options[] = { |
| TRACE_FLAGS |
| NULL |
| }; |
| |
| static struct { |
| u64 (*func)(void); |
| const char *name; |
| int in_ns; /* is this clock in nanoseconds? */ |
| } trace_clocks[] = { |
| { trace_clock_local, "local", 1 }, |
| { trace_clock_global, "global", 1 }, |
| { trace_clock_counter, "counter", 0 }, |
| { trace_clock_jiffies, "uptime", 0 }, |
| { trace_clock, "perf", 1 }, |
| { ktime_get_mono_fast_ns, "mono", 1 }, |
| { ktime_get_raw_fast_ns, "mono_raw", 1 }, |
| { ktime_get_boot_fast_ns, "boot", 1 }, |
| { ktime_get_tai_fast_ns, "tai", 1 }, |
| ARCH_TRACE_CLOCKS |
| }; |
| |
| bool trace_clock_in_ns(struct trace_array *tr) |
| { |
| if (trace_clocks[tr->clock_id].in_ns) |
| return true; |
| |
| return false; |
| } |
| |
| /* |
| * trace_parser_get_init - gets the buffer for trace parser |
| */ |
| int trace_parser_get_init(struct trace_parser *parser, int size) |
| { |
| memset(parser, 0, sizeof(*parser)); |
| |
| parser->buffer = kmalloc(size, GFP_KERNEL); |
| if (!parser->buffer) |
| return 1; |
| |
| parser->size = size; |
| return 0; |
| } |
| |
| /* |
| * trace_parser_put - frees the buffer for trace parser |
| */ |
| void trace_parser_put(struct trace_parser *parser) |
| { |
| kfree(parser->buffer); |
| parser->buffer = NULL; |
| } |
| |
| /* |
| * trace_get_user - reads the user input string separated by space |
| * (matched by isspace(ch)) |
| * |
| * For each string found the 'struct trace_parser' is updated, |
| * and the function returns. |
| * |
| * Returns number of bytes read. |
| * |
| * See kernel/trace/trace.h for 'struct trace_parser' details. |
| */ |
| int trace_get_user(struct trace_parser *parser, const char __user *ubuf, |
| size_t cnt, loff_t *ppos) |
| { |
| char ch; |
| size_t read = 0; |
| ssize_t ret; |
| |
| if (!*ppos) |
| trace_parser_clear(parser); |
| |
| ret = get_user(ch, ubuf++); |
| if (ret) |
| goto out; |
| |
| read++; |
| cnt--; |
| |
| /* |
| * The parser is not finished with the last write, |
| * continue reading the user input without skipping spaces. |
| */ |
| if (!parser->cont) { |
| /* skip white space */ |
| while (cnt && isspace(ch)) { |
| ret = get_user(ch, ubuf++); |
| if (ret) |
| goto out; |
| read++; |
| cnt--; |
| } |
| |
| parser->idx = 0; |
| |
| /* only spaces were written */ |
| if (isspace(ch) || !ch) { |
| *ppos += read; |
| ret = read; |
| goto out; |
| } |
| } |
| |
| /* read the non-space input */ |
| while (cnt && !isspace(ch) && ch) { |
| if (parser->idx < parser->size - 1) |
| parser->buffer[parser->idx++] = ch; |
| else { |
| ret = -EINVAL; |
| goto out; |
| } |
| ret = get_user(ch, ubuf++); |
| if (ret) |
| goto out; |
| read++; |
| cnt--; |
| } |
| |
| /* We either got finished input or we have to wait for another call. */ |
| if (isspace(ch) || !ch) { |
| parser->buffer[parser->idx] = 0; |
| parser->cont = false; |
| } else if (parser->idx < parser->size - 1) { |
| parser->cont = true; |
| parser->buffer[parser->idx++] = ch; |
| /* Make sure the parsed string always terminates with '\0'. */ |
| parser->buffer[parser->idx] = 0; |
| } else { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| *ppos += read; |
| ret = read; |
| |
| out: |
| return ret; |
| } |
| |
| /* TODO add a seq_buf_to_buffer() */ |
| static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) |
| { |
| int len; |
| |
| if (trace_seq_used(s) <= s->readpos) |
| return -EBUSY; |
| |
| len = trace_seq_used(s) - s->readpos; |
| if (cnt > len) |
| cnt = len; |
| memcpy(buf, s->buffer + s->readpos, cnt); |
| |
| s->readpos += cnt; |
| return cnt; |
| } |
| |
| unsigned long __read_mostly tracing_thresh; |
| |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| static const struct file_operations tracing_max_lat_fops; |
| |
| #ifdef LATENCY_FS_NOTIFY |
| |
| static struct workqueue_struct *fsnotify_wq; |
| |
| static void latency_fsnotify_workfn(struct work_struct *work) |
| { |
| struct trace_array *tr = container_of(work, struct trace_array, |
| fsnotify_work); |
| fsnotify_inode(tr->d_max_latency->d_inode, FS_MODIFY); |
| } |
| |
| static void latency_fsnotify_workfn_irq(struct irq_work *iwork) |
| { |
| struct trace_array *tr = container_of(iwork, struct trace_array, |
| fsnotify_irqwork); |
| queue_work(fsnotify_wq, &tr->fsnotify_work); |
| } |
| |
| static void trace_create_maxlat_file(struct trace_array *tr, |
| struct dentry *d_tracer) |
| { |
| INIT_WORK(&tr->fsnotify_work, latency_fsnotify_workfn); |
| init_irq_work(&tr->fsnotify_irqwork, latency_fsnotify_workfn_irq); |
| tr->d_max_latency = trace_create_file("tracing_max_latency", |
| TRACE_MODE_WRITE, |
| d_tracer, tr, |
| &tracing_max_lat_fops); |
| } |
| |
| __init static int latency_fsnotify_init(void) |
| { |
| fsnotify_wq = alloc_workqueue("tr_max_lat_wq", |
| WQ_UNBOUND | WQ_HIGHPRI, 0); |
| if (!fsnotify_wq) { |
| pr_err("Unable to allocate tr_max_lat_wq\n"); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| late_initcall_sync(latency_fsnotify_init); |
| |
| void latency_fsnotify(struct trace_array *tr) |
| { |
| if (!fsnotify_wq) |
| return; |
| /* |
| * We cannot call queue_work(&tr->fsnotify_work) from here because it's |
| * possible that we are called from __schedule() or do_idle(), which |
| * could cause a deadlock. |
| */ |
| irq_work_queue(&tr->fsnotify_irqwork); |
| } |
| |
| #else /* !LATENCY_FS_NOTIFY */ |
| |
| #define trace_create_maxlat_file(tr, d_tracer) \ |
| trace_create_file("tracing_max_latency", TRACE_MODE_WRITE, \ |
| d_tracer, tr, &tracing_max_lat_fops) |
| |
| #endif |
| |
| /* |
| * Copy the new maximum trace into the separate maximum-trace |
| * structure. (this way the maximum trace is permanently saved, |
| * for later retrieval via /sys/kernel/tracing/tracing_max_latency) |
| */ |
| static void |
| __update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) |
| { |
| struct array_buffer *trace_buf = &tr->array_buffer; |
| struct array_buffer *max_buf = &tr->max_buffer; |
| struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu); |
| struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu); |
| |
| max_buf->cpu = cpu; |
| max_buf->time_start = data->preempt_timestamp; |
| |
| max_data->saved_latency = tr->max_latency; |
| max_data->critical_start = data->critical_start; |
| max_data->critical_end = data->critical_end; |
| |
| strncpy(max_data->comm, tsk->comm, TASK_COMM_LEN); |
| max_data->pid = tsk->pid; |
| /* |
| * If tsk == current, then use current_uid(), as that does not use |
| * RCU. The irq tracer can be called out of RCU scope. |
| */ |
| if (tsk == current) |
| max_data->uid = current_uid(); |
| else |
| max_data->uid = task_uid(tsk); |
| |
| max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO; |
| max_data->policy = tsk->policy; |
| max_data->rt_priority = tsk->rt_priority; |
| |
| /* record this tasks comm */ |
| tracing_record_cmdline(tsk); |
| latency_fsnotify(tr); |
| } |
| |
| /** |
| * update_max_tr - snapshot all trace buffers from global_trace to max_tr |
| * @tr: tracer |
| * @tsk: the task with the latency |
| * @cpu: The cpu that initiated the trace. |
| * @cond_data: User data associated with a conditional snapshot |
| * |
| * Flip the buffers between the @tr and the max_tr and record information |
| * about which task was the cause of this latency. |
| */ |
| void |
| update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu, |
| void *cond_data) |
| { |
| if (tr->stop_count) |
| return; |
| |
| WARN_ON_ONCE(!irqs_disabled()); |
| |
| if (!tr->allocated_snapshot) { |
| /* Only the nop tracer should hit this when disabling */ |
| WARN_ON_ONCE(tr->current_trace != &nop_trace); |
| return; |
| } |
| |
| arch_spin_lock(&tr->max_lock); |
| |
| /* Inherit the recordable setting from array_buffer */ |
| if (ring_buffer_record_is_set_on(tr->array_buffer.buffer)) |
| ring_buffer_record_on(tr->max_buffer.buffer); |
| else |
| ring_buffer_record_off(tr->max_buffer.buffer); |
| |
| #ifdef CONFIG_TRACER_SNAPSHOT |
| if (tr->cond_snapshot && !tr->cond_snapshot->update(tr, cond_data)) { |
| arch_spin_unlock(&tr->max_lock); |
| return; |
| } |
| #endif |
| swap(tr->array_buffer.buffer, tr->max_buffer.buffer); |
| |
| __update_max_tr(tr, tsk, cpu); |
| |
| arch_spin_unlock(&tr->max_lock); |
| |
| /* Any waiters on the old snapshot buffer need to wake up */ |
| ring_buffer_wake_waiters(tr->array_buffer.buffer, RING_BUFFER_ALL_CPUS); |
| } |
| |
| /** |
| * update_max_tr_single - only copy one trace over, and reset the rest |
| * @tr: tracer |
| * @tsk: task with the latency |
| * @cpu: the cpu of the buffer to copy. |
| * |
| * Flip the trace of a single CPU buffer between the @tr and the max_tr. |
| */ |
| void |
| update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) |
| { |
| int ret; |
| |
| if (tr->stop_count) |
| return; |
| |
| WARN_ON_ONCE(!irqs_disabled()); |
| if (!tr->allocated_snapshot) { |
| /* Only the nop tracer should hit this when disabling */ |
| WARN_ON_ONCE(tr->current_trace != &nop_trace); |
| return; |
| } |
| |
| arch_spin_lock(&tr->max_lock); |
| |
| ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->array_buffer.buffer, cpu); |
| |
| if (ret == -EBUSY) { |
| /* |
| * We failed to swap the buffer due to a commit taking |
| * place on this CPU. We fail to record, but we reset |
| * the max trace buffer (no one writes directly to it) |
| * and flag that it failed. |
| * Another reason is resize is in progress. |
| */ |
| trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_, |
| "Failed to swap buffers due to commit or resize in progress\n"); |
| } |
| |
| WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); |
| |
| __update_max_tr(tr, tsk, cpu); |
| arch_spin_unlock(&tr->max_lock); |
| } |
| |
| #endif /* CONFIG_TRACER_MAX_TRACE */ |
| |
| struct pipe_wait { |
| struct trace_iterator *iter; |
| int wait_index; |
| }; |
| |
| static bool wait_pipe_cond(void *data) |
| { |
| struct pipe_wait *pwait = data; |
| struct trace_iterator *iter = pwait->iter; |
| |
| if (atomic_read_acquire(&iter->wait_index) != pwait->wait_index) |
| return true; |
| |
| return iter->closed; |
| } |
| |
| static int wait_on_pipe(struct trace_iterator *iter, int full) |
| { |
| struct pipe_wait pwait; |
| int ret; |
| |
| /* Iterators are static, they should be filled or empty */ |
| if (trace_buffer_iter(iter, iter->cpu_file)) |
| return 0; |
| |
| pwait.wait_index = atomic_read_acquire(&iter->wait_index); |
| pwait.iter = iter; |
| |
| ret = ring_buffer_wait(iter->array_buffer->buffer, iter->cpu_file, full, |
| wait_pipe_cond, &pwait); |
| |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| /* |
| * Make sure this is still the snapshot buffer, as if a snapshot were |
| * to happen, this would now be the main buffer. |
| */ |
| if (iter->snapshot) |
| iter->array_buffer = &iter->tr->max_buffer; |
| #endif |
| return ret; |
| } |
| |
| #ifdef CONFIG_FTRACE_STARTUP_TEST |
| static bool selftests_can_run; |
| |
| struct trace_selftests { |
| struct list_head list; |
| struct tracer *type; |
| }; |
| |
| static LIST_HEAD(postponed_selftests); |
| |
| static int save_selftest(struct tracer *type) |
| { |
| struct trace_selftests *selftest; |
| |
| selftest = kmalloc(sizeof(*selftest), GFP_KERNEL); |
| if (!selftest) |
| return -ENOMEM; |
| |
| selftest->type = type; |
| list_add(&selftest->list, &postponed_selftests); |
| return 0; |
| } |
| |
| static int run_tracer_selftest(struct tracer *type) |
| { |
| struct trace_array *tr = &global_trace; |
| struct tracer *saved_tracer = tr->current_trace; |
| int ret; |
| |
| if (!type->selftest || tracing_selftest_disabled) |
| return 0; |
| |
| /* |
| * If a tracer registers early in boot up (before scheduling is |
| * initialized and such), then do not run its selftests yet. |
| * Instead, run it a little later in the boot process. |
| */ |
| if (!selftests_can_run) |
| return save_selftest(type); |
| |
| if (!tracing_is_on()) { |
| pr_warn("Selftest for tracer %s skipped due to tracing disabled\n", |
| type->name); |
| return 0; |
| } |
| |
| /* |
| * Run a selftest on this tracer. |
| * Here we reset the trace buffer, and set the current |
| * tracer to be this tracer. The tracer can then run some |
| * internal tracing to verify that everything is in order. |
| * If we fail, we do not register this tracer. |
| */ |
| tracing_reset_online_cpus(&tr->array_buffer); |
| |
| tr->current_trace = type; |
| |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| if (type->use_max_tr) { |
| /* If we expanded the buffers, make sure the max is expanded too */ |
| if (tr->ring_buffer_expanded) |
| ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size, |
| RING_BUFFER_ALL_CPUS); |
| tr->allocated_snapshot = true; |
| } |
| #endif |
| |
| /* the test is responsible for initializing and enabling */ |
| pr_info("Testing tracer %s: ", type->name); |
| ret = type->selftest(type, tr); |
| /* the test is responsible for resetting too */ |
| tr->current_trace = saved_tracer; |
| if (ret) { |
| printk(KERN_CONT "FAILED!\n"); |
| /* Add the warning after printing 'FAILED' */ |
| WARN_ON(1); |
| return -1; |
| } |
| /* Only reset on passing, to avoid touching corrupted buffers */ |
| tracing_reset_online_cpus(&tr->array_buffer); |
| |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| if (type->use_max_tr) { |
| tr->allocated_snapshot = false; |
| |
| /* Shrink the max buffer again */ |
| if (tr->ring_buffer_expanded) |
| ring_buffer_resize(tr->max_buffer.buffer, 1, |
| RING_BUFFER_ALL_CPUS); |
| } |
| #endif |
| |
| printk(KERN_CONT "PASSED\n"); |
| return 0; |
| } |
| |
| static int do_run_tracer_selftest(struct tracer *type) |
| { |
| int ret; |
| |
| /* |
| * Tests can take a long time, especially if they are run one after the |
| * other, as does happen during bootup when all the tracers are |
| * registered. This could cause the soft lockup watchdog to trigger. |
| */ |
| cond_resched(); |
| |
| tracing_selftest_running = true; |
| ret = run_tracer_selftest(type); |
| tracing_selftest_running = false; |
| |
| return ret; |
| } |
| |
| static __init int init_trace_selftests(void) |
| { |
| struct trace_selftests *p, *n; |
| struct tracer *t, **last; |
| int ret; |
| |
| selftests_can_run = true; |
| |
| mutex_lock(&trace_types_lock); |
| |
| if (list_empty(&postponed_selftests)) |
| goto out; |
| |
| pr_info("Running postponed tracer tests:\n"); |
| |
| tracing_selftest_running = true; |
| list_for_each_entry_safe(p, n, &postponed_selftests, list) { |
| /* This loop can take minutes when sanitizers are enabled, so |
| * lets make sure we allow RCU processing. |
| */ |
| cond_resched(); |
| ret = run_tracer_selftest(p->type); |
| /* If the test fails, then warn and remove from available_tracers */ |
| if (ret < 0) { |
| WARN(1, "tracer: %s failed selftest, disabling\n", |
| p->type->name); |
| last = &trace_types; |
| for (t = trace_types; t; t = t->next) { |
| if (t == p->type) { |
| *last = t->next; |
| break; |
| } |
| last = &t->next; |
| } |
| } |
| list_del(&p->list); |
| kfree(p); |
| } |
| tracing_selftest_running = false; |
| |
| out: |
| mutex_unlock(&trace_types_lock); |
| |
| return 0; |
| } |
| core_initcall(init_trace_selftests); |
| #else |
| static inline int run_tracer_selftest(struct tracer *type) |
| { |
| return 0; |
| } |
| static inline int do_run_tracer_selftest(struct tracer *type) |
| { |
| return 0; |
| } |
| #endif /* CONFIG_FTRACE_STARTUP_TEST */ |
| |
| static void add_tracer_options(struct trace_array *tr, struct tracer *t); |
| |
| static void __init apply_trace_boot_options(void); |
| |
| /** |
| * register_tracer - register a tracer with the ftrace system. |
| * @type: the plugin for the tracer |
| * |
| * Register a new plugin tracer. |
| */ |
| int __init register_tracer(struct tracer *type) |
| { |
| struct tracer *t; |
| int ret = 0; |
| |
| if (!type->name) { |
| pr_info("Tracer must have a name\n"); |
| return -1; |
| } |
| |
| if (strlen(type->name) >= MAX_TRACER_SIZE) { |
| pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE); |
| return -1; |
| } |
| |
| if (security_locked_down(LOCKDOWN_TRACEFS)) { |
| pr_warn("Can not register tracer %s due to lockdown\n", |
| type->name); |
| return -EPERM; |
| } |
| |
| mutex_lock(&trace_types_lock); |
| |
| for (t = trace_types; t; t = t->next) { |
| if (strcmp(type->name, t->name) == 0) { |
| /* already found */ |
| pr_info("Tracer %s already registered\n", |
| type->name); |
| ret = -1; |
| goto out; |
| } |
| } |
| |
| if (!type->set_flag) |
| type->set_flag = &dummy_set_flag; |
| if (!type->flags) { |
| /*allocate a dummy tracer_flags*/ |
| type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL); |
| if (!type->flags) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| type->flags->val = 0; |
| type->flags->opts = dummy_tracer_opt; |
| } else |
| if (!type->flags->opts) |
| type->flags->opts = dummy_tracer_opt; |
| |
| /* store the tracer for __set_tracer_option */ |
| type->flags->trace = type; |
| |
| ret = do_run_tracer_selftest(type); |
| if (ret < 0) |
| goto out; |
| |
| type->next = trace_types; |
| trace_types = type; |
| add_tracer_options(&global_trace, type); |
| |
| out: |
| mutex_unlock(&trace_types_lock); |
| |
| if (ret || !default_bootup_tracer) |
| goto out_unlock; |
| |
| if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE)) |
| goto out_unlock; |
| |
| printk(KERN_INFO "Starting tracer '%s'\n", type->name); |
| /* Do we want this tracer to start on bootup? */ |
| tracing_set_tracer(&global_trace, type->name); |
| default_bootup_tracer = NULL; |
| |
| apply_trace_boot_options(); |
| |
| /* disable other selftests, since this will break it. */ |
| disable_tracing_selftest("running a tracer"); |
| |
| out_unlock: |
| return ret; |
| } |
| |
| static void tracing_reset_cpu(struct array_buffer *buf, int cpu) |
| { |
| struct trace_buffer *buffer = buf->buffer; |
| |
| if (!buffer) |
| return; |
| |
| ring_buffer_record_disable(buffer); |
| |
| /* Make sure all commits have finished */ |
| synchronize_rcu(); |
| ring_buffer_reset_cpu(buffer, cpu); |
| |
| ring_buffer_record_enable(buffer); |
| } |
| |
| void tracing_reset_online_cpus(struct array_buffer *buf) |
| { |
| struct trace_buffer *buffer = buf->buffer; |
| |
| if (!buffer) |
| return; |
| |
| ring_buffer_record_disable(buffer); |
| |
| /* Make sure all commits have finished */ |
| synchronize_rcu(); |
| |
| buf->time_start = buffer_ftrace_now(buf, buf->cpu); |
| |
| ring_buffer_reset_online_cpus(buffer); |
| |
| ring_buffer_record_enable(buffer); |
| } |
| |
| /* Must have trace_types_lock held */ |
| void tracing_reset_all_online_cpus_unlocked(void) |
| { |
| struct trace_array *tr; |
| |
| lockdep_assert_held(&trace_types_lock); |
| |
| list_for_each_entry(tr, &ftrace_trace_arrays, list) { |
| if (!tr->clear_trace) |
| continue; |
| tr->clear_trace = false; |
| tracing_reset_online_cpus(&tr->array_buffer); |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| tracing_reset_online_cpus(&tr->max_buffer); |
| #endif |
| } |
| } |
| |
| void tracing_reset_all_online_cpus(void) |
| { |
| mutex_lock(&trace_types_lock); |
| tracing_reset_all_online_cpus_unlocked(); |
| mutex_unlock(&trace_types_lock); |
| } |
| |
| int is_tracing_stopped(void) |
| { |
| return global_trace.stop_count; |
| } |
| |
| static void tracing_start_tr(struct trace_array *tr) |
| { |
| struct trace_buffer *buffer; |
| unsigned long flags; |
| |
| if (tracing_disabled) |
| return; |
| |
| raw_spin_lock_irqsave(&tr->start_lock, flags); |
| if (--tr->stop_count) { |
| if (WARN_ON_ONCE(tr->stop_count < 0)) { |
| /* Someone screwed up their debugging */ |
| tr->stop_count = 0; |
| } |
| goto out; |
| } |
| |
| /* Prevent the buffers from switching */ |
| arch_spin_lock(&tr->max_lock); |
| |
| buffer = tr->array_buffer.buffer; |
| if (buffer) |
| ring_buffer_record_enable(buffer); |
| |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| buffer = tr->max_buffer.buffer; |
| if (buffer) |
| ring_buffer_record_enable(buffer); |
| #endif |
| |
| arch_spin_unlock(&tr->max_lock); |
| |
| out: |
| raw_spin_unlock_irqrestore(&tr->start_lock, flags); |
| } |
| |
| /** |
| * tracing_start - quick start of the tracer |
| * |
| * If tracing is enabled but was stopped by tracing_stop, |
| * this will start the tracer back up. |
| */ |
| void tracing_start(void) |
| |
| { |
| return tracing_start_tr(&global_trace); |
| } |
| |
| static void tracing_stop_tr(struct trace_array *tr) |
| { |
| struct trace_buffer *buffer; |
| unsigned long flags; |
| |
| raw_spin_lock_irqsave(&tr->start_lock, flags); |
| if (tr->stop_count++) |
| goto out; |
| |
| /* Prevent the buffers from switching */ |
| arch_spin_lock(&tr->max_lock); |
| |
| buffer = tr->array_buffer.buffer; |
| if (buffer) |
| ring_buffer_record_disable(buffer); |
| |
| #ifdef CONFIG_TRACER_MAX_TRACE |
| buffer = tr->max_buffer.buffer; |
| if (buffer) |
| ring_buffer_record_disable(buffer); |
| #endif |
| |
| arch_spin_unlock(&tr->max_lock); |
| |
| out: |
| raw_spin_unlock_irqrestore(&tr->start_lock, flags); |
| } |
| |
| /** |
| * tracing_stop - quick stop of the tracer |
| * |
| * Light weight way to stop tracing. Use in conjunction with |
| * tracing_start. |
| */ |
| void tracing_stop(void) |
| { |
| return tracing_stop_tr(&global_trace); |
| } |
| |
| /* |
| * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq |
| * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function |
| * simplifies those functions and keeps them in sync. |
| */ |
| enum print_line_t trace_handle_return(struct trace_seq *s) |
| { |
| return trace_seq_has_overflowed(s) ? |
| TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED; |
| } |
| EXPORT_SYMBOL_GPL(trace_handle_return); |
| |
| static unsigned short migration_disable_value(void) |
| { |
| #if defined(CONFIG_SMP) |
| return current->migration_disabled; |
| #else |
| return 0; |
| #endif |
| } |
| |
| unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status) |
| { |
| unsigned int trace_flags = irqs_status; |
| unsigned int pc; |
| |
| pc = preempt_count(); |
| |
| if (pc & NMI_MASK) |
| trace_flags |= TRACE_FLAG_NMI; |
| if (pc & HARDIRQ_MASK) |
| trace_flags |= TRACE_FLAG_HARDIRQ; |
| if (in_serving_softirq()) |
| trace_flags |= TRACE_FLAG_SOFTIRQ; |
| if (softirq_count() >> (SOFTIRQ_SHIFT + 1)) |
| trace_flags |= TRACE_FLAG_BH_OFF; |
| |
| if (tif_need_resched()) |
| trace_flags |= TRACE_FLAG_NEED_RESCHED; |
| if (test_preempt_need_resched()) |
| trace_flags |= TRACE_FLAG_PREEMPT_RESCHED; |
| return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) | |
| (min_t(unsigned int, migration_disable_value(), 0xf)) << 4; |
| } |
| |
| struct ring_buffer_event * |
| trace_buffer_lock_reserve(struct trace_buffer *buffer, |
| int type, |
| unsigned long len, |
| unsigned int trace_ctx) |
| { |
| return __trace_buffer_lock_reserve(buffer, type, len, trace_ctx); |
| } |
| |
| DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event); |
| DEFINE_PER_CPU(int, trace_buffered_event_cnt); |
| static int trace_buffered_event_ref; |
| |
| /** |
| * trace_buffered_event_enable - enable buffering events |
| * |
| * When events are being filtered, it is quicker to use a temporary |
| * buffer to write the event data into if there's a likely chance |
| * that it will not be committed. The discard of the ring buffer |
| * is not as fast as committing, and is much slower than copying |
| * a commit. |
| * |
| * When an event is to be filtered, allocate per cpu buffers to |
| * write the event data into, and if the event is filtered and discarded |
| * it is simply dropped, otherwise, the entire data is to be committed |
| * in one shot. |
| */ |
| void trace_buffered_event_enable(void) |
| { |
| struct ring_buffer_event *event; |
| struct page *page; |
| int cpu; |
| |
| WARN_ON_ONCE(!mutex_is_locked(&event_mutex)); |
| |
| if (trace_buffered_event_ref++) |
| return; |
| |
| for_each_tracing_cpu(cpu) { |
| page = alloc_pages_node(cpu_to_node(cpu), |
| GFP_KERNEL | __GFP_NORETRY, 0); |
| /* This is just an optimization and can handle failures */ |
| if (!page) { |
| pr_err("Failed to allocate event buffer\n"); |
| break; |
| } |
| |
| event = page_address(page); |
| memset(event, 0, sizeof(*event)); |
| |
| per_cpu(trace_buffered_event, cpu) = event; |
| |
| preempt_disable(); |
| if (cpu == smp_processor_id() && |
| __this_cpu_read(trace_buffered_event) != |
| per_cpu(trace_buffered_event, cpu)) |
| WARN_ON_ONCE(1); |
| preempt_enable(); |
| } |
| } |
| |
| static void enable_trace_buffered_event(void *data) |
| { |
| /* Probably not needed, but do it anyway */ |
| smp_rmb(); |
| this_cpu_dec(trace_buffered_event_cnt); |
| } |
| |
| static void disable_trace_buffered_event(void *data) |
| { |
| this_cpu_inc(trace_buffered_event_cnt); |
| } |
| |
| /** |
| * trace_buffered_event_disable - disable buffering events |
| * |
| * When a filter is removed, it is faster to not use the buffered |
| * events, and to commit directly into the ring buffer. Free up |
| * the temp buffers when there are no more users. This requires |
| * special synchronization with current events. |
| */ |
| void trace_buffered_event_disable(void) |
| { |
| int cpu; |
| |
| WARN_ON_ONCE(!mutex_is_locked(&event_mutex)); |
| |
| if (WARN_ON_ONCE(!trace_buffered_event_ref)) |
| return; |
| |
| if (--trace_buffered_event_ref) |
| return; |
| |
| /* For each CPU, set the buffer as used. */ |
| on_each_cpu_mask(tracing_buffer_mask, disable_trace_buffered_event, |
| NULL, true); |
| |
| /* Wait for all current users to finish */ |
| synchronize_rcu(); |
| |
| for_each_tracing_cpu(cpu) { |
| free_page((unsigned long)per_cpu(trace_buffered_event, cpu)); |
| per_cpu(trace_buffered_event, cpu) = NULL; |
| } |
| |
| /* |
| * Wait for all CPUs that potentially started checking if they can use |
| * their event buffer only after the previous synchronize_rcu() call and |
| * they still read a valid pointer from trace_buffered_event. It must be |
| * ensured they don't see cleared trace_buffered_event_cnt else they |
| * could wrongly decide to use the pointed-to buffer which is now freed. |
| */ |
| synchronize_rcu(); |
| |
| /* For each CPU, relinquish the buffer */ |
| on_each_cpu_mask(tracing_buffer_mask, enable_trace_buffered_event, NULL, |
| true); |
| } |
| |
| static struct trace_buffer *temp_buffer; |
| |
| struct ring_buffer_event * |
| trace_event_buffer_lock_reserve(struct trace_buffer **current_rb, |
| struct trace_event_file *trace_file, |
| int type, unsigned long len, |
| unsigned int trace_ctx) |
| { |
| struct ring_buffer_event *entry; |
| struct trace_array *tr = trace_file->tr; |
| int val; |
| |
| *current_rb = tr->array_buffer.buffer; |
| |
| if (!tr->no_filter_buffering_ref && |
| (trace_file->flags & (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED))) { |
| preempt_disable_notrace(); |
| /* |
| * Filtering is on, so try to use the per cpu buffer first. |
| * This buffer will simulate a ring_buffer_event, |
| * where the type_len is zero and the array[0] will |
| * hold the full length. |
| * (see include/linux/ring-buffer.h for details on |
| * how the ring_buffer_event is structured). |
| * |
| * Using a temp buffer during filtering and copying it |
| * on a matched filter is quicker than writing directly |
| * into the ring buffer and then discarding it when |
| * it doesn't match. That is because the discard |
| * requires several atomic operations to get right. |
| * Copying on match and doing nothing on a failed match |
| * is still quicker than no copy on match, but having |
| * to discard out of the ring buffer on a failed match. |
| */ |
| if ((entry = __this_cpu_read(trace_buffered_event))) { |
| int max_len = PAGE_SIZE - struct_size(entry, array, 1); |
| |
| val = this_cpu_inc_return(trace_buffered_event_cnt); |
| |
| /* |
| * Preemption is disabled, but interrupts and NMIs |
| * can still come in now. If that happens after |
| * the above increment, then it will have to go |
| * back to the old method of allocating the event |
| * on the ring buffer, and if the filter fails, it |
| * will have to call ring_buffer_discard_commit() |
| * to remove it. |
| * |
| * Need to also check the unlikely case that the |
| * length is bigger than the temp buffer size. |
| * If that happens, then the reserve is pretty much |
| * guaranteed to fail, as the ring buffer currently |
| * only allows events less than a page. But that may |
| * change in the future, so let the ring buffer reserve |
| * handle the failure in that case. |
| */ |
| if (val == 1 && likely(len <= max_len)) { |
| trace_event_setup(entry, type, trace_ctx); |
| entry->array[0] = len; |
| /* Return with preemption disabled */ |
| return entry; |
| } |
| this_cpu_dec(trace_buffered_event_cnt); |
| } |
| /* __trace_buffer_lock_reserve() disables preemption */ |
| preempt_enable_notrace(); |
| } |
| |
| entry = __trace_buffer_lock_reserve(*current_rb, type, len, |
| trace_ctx); |
| /* |
| * If tracing is off, but we have triggers enabled |
| * we still need to look at the event data. Use the temp_buffer |
| * to store the trace event for the trigger to use. It's recursive |
| * safe and will not be recorded anywhere. |
| */ |
| if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) { |
| *current_rb = temp_buffer; |
| entry = __trace_buffer_lock_reserve(*current_rb, type, len, |
| trace_ctx); |
| } |
| return entry; |
| } |
| EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve); |
| |
| static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock); |
| static DEFINE_MUTEX(tracepoint_printk_mutex); |
| |
| static void output_printk(struct trace_event_buffer *fbuffer) |
| { |
| struct trace_event_call *event_call; |
| struct trace_event_file *file; |
| struct trace_event *event; |
| unsigned long flags; |
| struct trace_iterator *iter = tracepoint_print_iter; |
| |
| /* We should never get here if iter is NULL */ |
| if (WARN_ON_ONCE(!iter)) |
| return; |
| |
| event_call = fbuffer->trace_file->event_call; |
| if (!event_call || !event_call->event.funcs || |
| !event_call->event.funcs->trace) |
| return; |
| |
| file = fbuffer->trace_file; |
| if (test_bit(EVENT_FILE_FL_SOFT_DISABLED_BIT, &file->flags) || |
| (unlikely(file->flags & EVENT_FILE_FL_FILTERED) && |
| !filter_match_preds(file->filter, fbuffer->entry))) |
| return; |
| |
| event = &fbuffer->trace_file->event_call->event; |
| |
| raw_spin_lock_irqsave(&tracepoint_iter_lock, flags); |
| trace_seq_init(&iter->seq); |
| iter->ent = fbuffer->entry; |
| event_call->event.funcs->trace(iter, 0, event); |
| trace_seq_putc(&iter->seq, 0); |
| printk("%s", iter->seq.buffer); |
| |
| raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags); |
| } |
| |
| int tracepoint_printk_sysctl(const struct ctl_table *table, int write, |
| void *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int save_tracepoint_printk; |
| int ret; |
| |
| mutex_lock(&tracepoint_printk_mutex); |
| save_tracepoint_printk = tracepoint_printk; |
| |
| ret = proc_dointvec(table, write, buffer, lenp, ppos); |
| |
| /* |
| * This will force exiting early, as tracepoint_printk |
| * is always zero when tracepoint_printk_iter is not allocated |
| */ |
| if (!tracepoint_print_iter) |
| tracepoint_printk = 0; |
| |
| if (save_tracepoint_printk == tracepoint_printk) |
| goto out; |
| |
| if (tracepoint_printk) |
| static_key_enable(&tracepoint_printk_key.key); |
| else |
| static_key_disable(&tracepoint_printk_key.key); |
| |
| out: |
| mutex_unlock(&tracepoint_printk_mutex); |
| |
| return ret; |
| } |
| |
| void trace_event_buffer_commit(struct trace_event_buffer *fbuffer) |
| { |
| enum event_trigger_type tt = ETT_NONE; |
| struct trace_event_file *file = fbuffer->trace_file; |
| |
| if (__event_trigger_test_discard(file, fbuffer->buffer, fbuffer->event, |
| fbuffer->entry, &tt)) |
| goto discard; |
| |
| if (static_key_false(&tracepoint_printk_key.key)) |
| output_printk(fbuffer); |
| |
| if (static_branch_unlikely(&trace_event_exports_enabled)) |
| ftrace_exports(fbuffer->event, TRACE_EXPORT_EVENT); |
| |
| trace_buffer_unlock_commit_regs(file->tr, fbuffer->buffer, |
| fbuffer->event, fbuffer->trace_ctx, fbuffer->regs); |
| |
| discard: |
| if (tt) |
| event_triggers_post_call(file, tt); |
| |
| } |
| EXPORT_SYMBOL_GPL(trace_event_buffer_commit); |
| |
| /* |
| * Skip 3: |
| * |
| * trace_buffer_unlock_commit_regs() |
| * trace_event_buffer_commit() |
| * trace_event_raw_event_xxx() |
| */ |
| # define STACK_SKIP 3 |
| |
| void trace_buffer_unlock_commit_regs(struct trace_array *tr, |
| struct trace_buffer *buffer, |
| struct ring_buffer_event *event, |
| unsigned int trace_ctx, |
| struct pt_regs *regs) |
| { |
| __buffer_unlock_commit(buffer, event); |
| |
| /* |
| * If regs is not set, then skip the necessary functions. |
| * Note, we can still get here via blktrace, wakeup tracer |
| * and mmiotrace, but that's ok if they lose a function or |
| * two. They are not that meaningful. |
| */ |
| ftrace_trace_stack(tr, buffer, trace_ctx, regs ? 0 : STACK_SKIP, regs); |
| ftrace_trace_userstack(tr, buffer, trace_ctx); |
| } |
| |
| /* |
| * Similar to trace_buffer_unlock_commit_regs() but do not dump stack. |
| */ |
| void |
| trace_buffer_unlock_commit_nostack(struct trace_buffer *buffer, |
| struct ring_buffer_event *event) |
| { |
| __buffer_unlock_commit(buffer, event); |
| } |
| |
| void |
| trace_function(struct trace_array *tr, unsigned long ip, unsigned long |
| parent_ip, unsigned int trace_ctx) |
| { |
| struct trace_event_call *call = &event_function; |
| struct trace_buffer *buffer = tr->array_buffer.buffer; |
| struct ring_buffer_event *event; |
| struct ftrace_entry *entry; |
| |
| event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry), |
| trace_ctx); |
| if (!event) |
| return; |
| entry = ring_buffer_event_data(event); |
| entry->ip = ip; |
| entry->parent_ip = parent_ip; |
| |
| if (!call_filter_check_discard(call, entry, buffer, event)) { |
| if (static_branch_unlikely(&trace_function_exports_enabled)) |
| ftrace_exports(event, TRACE_EXPORT_FUNCTION); |
| __buffer_unlock_commit(buffer, event); |
| } |
| } |
| |
| #ifdef CONFIG_STACKTRACE |
| |
| /* Allow 4 levels of nesting: normal, softirq, irq, NMI */ |
| #define FTRACE_KSTACK_NESTING 4 |
| |
| #define FTRACE_KSTACK_ENTRIES (PAGE_SIZE / FTRACE_KSTACK_NESTING) |
| |
| struct ftrace_stack { |
| unsigned long calls[FTRACE_KSTACK_ENTRIES]; |
| }; |
| |
| |
| struct ftrace_stacks { |
| struct ftrace_stack stacks[FTRACE_KSTACK_NESTING]; |
| }; |
| |
| static DEFINE_PER_CPU(struct ftrace_stacks, ftrace_stacks); |
| static DEFINE_PER_CPU(int, ftrace_stack_reserve); |
| |
| static void __ftrace_trace_stack(struct trace_buffer *buffer, |
| unsigned int trace_ctx, |
| int skip, struct pt_regs *regs) |
| { |
| struct trace_event_call *call = &event_kernel_stack; |
| struct ring_buffer_event *event; |
| unsigned int size, nr_entries; |
| struct ftrace_stack *fstack; |
| struct stack_entry *entry; |
| int stackidx; |
| |
| /* |
| * Add one, for this function and the call to save_stack_trace() |
| * If regs is set, then these functions will not be in the way. |
| */ |
| #ifndef CONFIG_UNWINDER_ORC |
| if (!regs) |
| skip++; |
| #endif |
| |
| preempt_disable_notrace(); |
| |
| stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1; |
| |
| /* This should never happen. If it does, yell once and skip */ |
| if (WARN_ON_ONCE(stackidx >= FTRACE_KSTACK_NESTING)) |
| goto out; |
| |
| /* |
| * The above __this_cpu_inc_return() is 'atomic' cpu local. An |
| * interrupt will either see the value pre increment or post |
| * increment. If the interrupt happens pre increment it will have |
| * restored the counter when it returns. We just need a barrier to |
| * keep gcc from moving things around. |
| */ |
| barrier(); |
| |
| fstack = this_cpu_ptr(ftrace_stacks.stacks) + stackidx; |
| size = ARRAY_SIZE(fstack->calls); |
| |
| if (regs) { |
| nr_entries = stack_trace_save_regs(regs, fstack->calls, |
| size, skip); |
| } else { |
| nr_entries = stack_trace_save(fstack->calls, size, skip); |
| } |
| |
| event = __trace_buffer_lock_reserve(buffer, TRACE_STACK, |
| struct_size(entry, caller, nr_entries), |
| trace_ctx); |
| if (!event) |
| goto out; |
| entry = ring_buffer_event_data(event); |
| |
| entry->size = nr_entries; |
| memcpy(&entry->caller, fstack->calls, |
| flex_array_size(entry, caller, nr_entries)); |
| |
| if (!call_filter_check_discard(call, entry, buffer, event)) |
| __buffer_unlock_commit(buffer, event); |
| |
| out: |
| /* Again, don't let gcc optimize things here */ |
| barrier(); |
| __this_cpu_dec(ftrace_stack_reserve); |
| preempt_enable_notrace(); |
| |
| } |
| |
| static inline void ftrace_trace_stack(struct trace_array *tr, |
| struct trace_buffer *buffer, |
| unsigned int trace_ctx, |
| int skip, struct pt_regs *regs) |
| { |
| if (!(tr->trace_flags & TRACE_ITER_STACKTRACE)) |
| return; |
| |
| __ftrace_trace_stack(buffer, trace_ctx, skip, regs); |
| } |
| |
| void __trace_stack(struct trace_array *tr, unsigned int trace_ctx, |
| int skip) |
| { |
| struct trace_buffer *buffer = tr->array_buffer.buffer; |
| |
| if (rcu_is_watching()) { |
| __ftrace_trace_stack(buffer, trace_ctx, skip, NULL); |
| return; |
| } |
| |
| if (WARN_ON_ONCE(IS_ENABLED(CONFIG_GENERIC_ENTRY))) |
| return; |
| |
| /* |
| * When an NMI triggers, RCU is enabled via ct_nmi_enter(), |
| * but if the above rcu_is_watching() failed, then the NMI |
| * triggered someplace critical, and ct_irq_enter() should |
| * not be called from NMI. |
| */ |
| if (unlikely(in_nmi())) |
| return; |
| |
| ct_irq_enter_irqson(); |
| __ftrace_trace_stack(buffer, trace_ctx, skip, NULL); |
| ct_irq_exit_irqson(); |
| } |
| |
| /** |
| * trace_dump_stack - record a stack back trace in the trace buffer |
| * @skip: Number of functions to skip (helper handlers) |
| */ |
| void trace_dump_stack(int skip) |
| { |
| if (tracing_disabled || tracing_selftest_running) |
| return; |
| |
| #ifndef CONFIG_UNWINDER_ORC |
| /* Skip 1 to skip this function. */ |
| skip++; |
| #endif |
| __ftrace_trace_stack(global_trace.array_buffer.buffer, |
| tracing_gen_ctx(), skip, NULL); |
| } |
| EXPORT_SYMBOL_GPL(trace_dump_stack); |
| |
| #ifdef CONFIG_USER_STACKTRACE_SUPPORT |
| static DEFINE_PER_CPU(int, user_stack_count); |
| |
| static void |
| ftrace_trace_userstack(struct trace_array *tr, |
| struct trace_buffer *buffer, unsigned int trace_ctx) |
| { |
| struct trace_event_call *call = &event_user_stack; |
| struct ring_buffer_event *event; |
| struct userstack_entry *entry; |
| |
| if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE)) |
| return; |
| |
| /* |
| * NMIs can not handle page faults, even with fix ups. |
| * The save user stack can (and often does) fault. |
| */ |
| if (unlikely(in_nmi())) |
| return; |
| |
| /* |
| * prevent recursion, since the user stack tracing may |
| * trigger other kernel events. |
| */ |
| preempt_disable(); |
| if (__this_cpu_read(user_stack_count)) |
| goto out; |
| |
| __this_cpu_inc(user_stack_count); |
| |
| event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK, |
| sizeof(*entry), trace_ctx); |
| if (!event) |
| goto out_drop_count; |
| entry = ring_buffer_event_data(event); |
| |
| entry->tgid = current->tgid; |
| memset(&entry->caller, 0, sizeof(entry->caller)); |
| |
| stack_trace_save_user(entry->caller, FTRACE_STACK_ENTRIES); |
| if (!call_filter_check_discard(call, entry, buffer, event)) |
| __buffer_unlock_commit(buffer, event); |
| |
| out_drop_count: |
| __this_cpu_dec(user_stack_count); |
| out: |
| preempt_enable(); |
| } |
| #else /* CONFIG_USER_STACKTRACE_SUPPORT */ |
| static void ftrace_trace_userstack(struct trace_array *tr, |
| struct trace_buffer *buffer, |
| unsigned int trace_ctx) |
| { |
| } |
| #endif /* !CONFIG_USER_STACKTRACE_SUPPORT */ |
| |
| #endif /* CONFIG_STACKTRACE */ |
| |
| static inline void |
| func_repeats_set_delta_ts(struct func_repeats_entry *entry, |
| unsigned long long delta) |
| { |
| entry->bottom_delta_ts = delta & U32_MAX; |
| entry->top_delta_ts = (delta >> 32); |
| } |
| |
| void trace_last_func_repeats(struct trace_array *tr, |
| struct trace_func_repeats *last_info, |
| unsigned int trace_ctx) |
| { |
| struct trace_buffer *buffer = tr->array_buffer.buffer; |
| struct func_repeats_entry *entry; |
| struct ring_buffer_event *event; |
| u64 delta; |
| |
| event = __trace_buffer_lock_reserve(buffer, TRACE_FUNC_REPEATS, |
| sizeof(*entry), trace_ctx); |
| if (!event) |
| return; |
| |
| delta = ring_buffer_event_time_stamp(buffer, event) - |
| last_info->ts_last_call; |
| |
| entry = ring_buffer_event_data(event); |
| entry->ip = last_info->ip; |
| entry->parent_ip = last_info->parent_ip; |
| entry->count = last_info->count; |
| func_repeats_set_delta_ts(entry, delta); |
| |
| __buffer_unlock_commit(buffer, event); |
| } |
| |
| /* created for use with alloc_percpu */ |
| struct trace_buffer_struct { |
| int nesting; |
| char buffer[4][TRACE_BUF_SIZE]; |
| }; |
| |
| static struct trace_buffer_struct __percpu *trace_percpu_buffer; |
| |
| /* |
| * This allows for lockless recording. If we're nested too deeply, then |
| * this returns NULL. |
| */ |
| static char *get_trace_buf(void) |
| { |
| struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer); |
| |
| if (!trace_percpu_buffer || buffer->nesting >= 4) |
| return NULL; |
| |
| buffer->nesting++; |
| |
| /* Interrupts must see nesting incremented before we use the buffer */ |
| barrier(); |
| return &buffer->buffer[buffer->nesting - 1][0]; |
| } |
| |
| static void put_trace_buf(void) |
| { |
| /* Don't let the decrement of nesting leak before this */ |
| barrier(); |
| this_cpu_dec(trace_percpu_buffer->nesting); |
| } |
| |
| static int alloc_percpu_trace_buffer(void) |
| { |
| struct trace_buffer_struct __percpu *buffers; |
| |
| if (trace_percpu_buffer) |
| return 0; |
| |
| buffers = alloc_percpu(struct trace_buffer_struct); |
| if (MEM_FAIL(!buffers, "Could not allocate percpu trace_printk buffer")) |
| return -ENOMEM; |
| |
| trace_percpu_buffer = buffers; |
| return 0; |
| } |
| |
| static int buffers_allocated; |
| |
| void trace_printk_init_buffers(void) |
| { |
| if (buffers_allocated) |
| return; |
| |
| if (alloc_percpu_trace_buffer()) |
| return; |
| |
| /* trace_printk() is for debug use only. Don't use it in production. */ |
| |
| pr_warn("\n"); |
| pr_warn("**********************************************************\n"); |
| pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); |
| pr_warn("** **\n"); |
| pr_warn("** trace_printk() being used. Allocating extra memory. **\n"); |
| pr_warn("** **\n"); |
| pr_warn("** This means that this is a DEBUG kernel and it is **\n"); |
| pr_warn("** unsafe for production use. **\n"); |
| pr_warn("** **\n"); |
| pr_warn("** If you see this message and you are not debugging **\n"); |
| pr_warn("** the kernel, report this immediately to your vendor! **\n"); |
| pr_warn("** **\n"); |
| pr_warn("** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **\n"); |
| pr_warn("**********************************************************\n"); |
| |
| /* Expand the buffers to set size */ |
| tracing_update_buffers(&global_trace); |
| |
| buffers_allocated = 1; |
| |
| /* |
| * trace_printk_init_buffers() can be called by modules. |
| * If that happens, then we need to start cmdline recording |
| * directly here. If the global_trace.buffer is already |
| * allocated here, then this was called by module code. |
| */ |
| if (global_trace.array_buffer.buffer) |
| tracing_start_cmdline_record(); |
| } |
| EXPORT_SYMBOL_GPL(trace_printk_init_buffers); |
| |
| void trace_printk_start_comm(void) |
| { |
| /* Start tracing comms if trace printk is set */ |
| if (!buffers_allocated) |
| return; |
| tracing_start_cmdline_record(); |
| } |
| |
| static void trace_printk_start_stop_comm(int enabled) |
| { |
| if (!buffers_allocated) |
| return; |
| |
| if (enabled) |
| tracing_start_cmdline_record(); |
| else |
| tracing_stop_cmdline_record(); |
| } |
| |
| /** |
| * trace_vbprintk - write binary msg to tracing buffer |
| * @ip: The address of the caller |
| * @fmt: The string format to write to the buffer |
| * @args: Arguments for @fmt |
| */ |
| int trace_vbprintk(unsigned long ip, const char *fmt, va_list args) |
| { |
| struct trace_event_call *call = &event_bprint; |
| struct ring_buffer_event *event; |
| struct trace_buffer *buffer; |
| struct trace_array *tr = &global_trace; |
| struct bprint_entry *entry; |
| unsigned int trace_ctx; |
| char *tbuffer; |
| int len = 0, size; |
| |
| if (unlikely(tracing_selftest_running || tracing_disabled)) |
| return 0; |
| |
| /* Don't pollute graph traces with trace_vprintk internals */ |
| pause_graph_tracing(); |
| |
| trace_ctx = tracing_gen_ctx(); |
| preempt_disable_notrace(); |
| |
| tbuffer = get_trace_buf(); |
| if (!tbuffer) { |
| len = 0; |
| goto out_nobuffer; |
| } |
| |
| len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args); |
| |
| if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0) |
| goto out_put; |
| |
| size = sizeof(*entry) + sizeof(u32) * len; |
| buffer = tr->array_buffer.buffer; |
| ring_buffer_nest_start(buffer); |
| event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size, |
| trace_ctx); |
| if (!event) |
| goto out; |
| entry = ring_buffer_event_data(event); |
| entry->ip = ip; |
| entry->fmt = fmt; |
| |
| memcpy(entry->buf, tbuffer, sizeof(u32) * len); |
| if (!call_filter_check_discard(call, entry, buffer, event)) { |
| __buffer_unlock_commit(buffer, event); |
| ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL); |
| } |
| |
| out: |
| ring_buffer_nest_end(buffer); |
| out_put: |
| put_trace_buf(); |
| |
| out_nobuffer: |
| preempt_enable_notrace(); |
| unpause_graph_tracing(); |
| |
| return len; |
| } |
| EXPORT_SYMBOL_GPL(trace_vbprintk); |
| |
| __printf(3, 0) |
| static int |
| __trace_array_vprintk(struct trace_buffer *buffer, |
| unsigned long ip, const char *fmt, va_list args) |
| { |
| struct trace_event_call *call = &event_print; |
| struct ring_buffer_event *event; |
| int len = 0, size; |
| struct print_entry *entry; |
| unsigned int trace_ctx; |
| char *tbuffer; |
| |
| if (tracing_disabled) |
| return 0; |
| |
| /* Don't pollute graph traces with trace_vprintk internals */ |
| pause_graph_tracing(); |
| |
| trace_ctx = tracing_gen_ctx(); |
| preempt_disable_notrace(); |
| |
| |
| tbuffer = get_trace_buf(); |
| if (!tbuffer) { |
| len = 0; |
| goto out_nobuffer; |
| } |
| |
| len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args); |
| |
| size = sizeof(*entry) + len + 1; |
| ring_buffer_nest_start(buffer); |
| event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size, |
| trace_ctx); |
| if (!event) |
| goto out; |
| entry = ring_buffer_event_data(event); |
| entry->ip = ip; |
| |
| memcpy(&entry->buf, tbuffer, len + 1); |
| if (!call_filter_check_discard(call, entry, buffer, event)) { |
| __buffer_unlock_commit(buffer, event); |
| ftrace_trace_stack(&global_trace, buffer, trace_ctx, 6, NULL); |
| } |
| |
| out: |
| ring_buffer_nest_end(buffer); |
| put_trace_buf(); |
| |
| out_nobuffer: |
| preempt_enable_notrace(); |
| unpause_graph_tracing(); |
| |
| return len; |
| } |
| |
| __printf(3, 0) |
| int trace_array_vprintk(struct trace_array *tr, |
| unsigned long ip, const char *fmt, va_list args) |
| { |
| if (tracing_selftest_running && tr == &global_trace) |
| return 0; |
| |
| return __trace_array_vprintk(tr->array_buffer.buffer, ip, fmt, args); |
| } |
| |
| /** |
| * trace_array_printk - Print a message to a specific instance |
| * @tr: The instance trace_array descriptor |
| * @ip: The instruction pointer that this is called from. |
| * @fmt: The format to print (printf format) |
| * |
| * If a subsystem sets up its own instance, they have the right to |
| * printk strings into their tracing instance buffer using this |
| * function. Note, this function will not write into the top level |
| * buffer (use trace_printk() for that), as writing into the top level |
| * buffer should only have events that can be individually disabled. |
| * trace_printk() is only used for debugging a kernel, and should not |
| * be ever incorporated in normal use. |
| * |
| * trace_array_printk() can be used, as it will not add noise to the |
| * top level tracing buffer. |
| * |
| * Note, trace_array_init_printk() must be called on @tr before this |
| * can be used. |
| */ |
| __printf(3, 0) |
| int trace_array_printk(struct trace_array *tr, |
| unsigned long ip, const char *fmt, ...) |
| { |
| int ret; |
| va_list ap; |
|