v4.19.13 snapshot.
diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
new file mode 100644
index 0000000..69a3fe9
--- /dev/null
+++ b/kernel/trace/trace_event_perf.c
@@ -0,0 +1,514 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * trace event based perf event profiling/tracing
+ *
+ * Copyright (C) 2009 Red Hat Inc, Peter Zijlstra
+ * Copyright (C) 2009-2010 Frederic Weisbecker <fweisbec@gmail.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include "trace.h"
+#include "trace_probe.h"
+
+static char __percpu *perf_trace_buf[PERF_NR_CONTEXTS];
+
+/*
+ * Force it to be aligned to unsigned long to avoid misaligned accesses
+ * suprises
+ */
+typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
+ perf_trace_t;
+
+/* Count the events in use (per event id, not per instance) */
+static int total_ref_count;
+
+static int perf_trace_event_perm(struct trace_event_call *tp_event,
+ struct perf_event *p_event)
+{
+ if (tp_event->perf_perm) {
+ int ret = tp_event->perf_perm(tp_event, p_event);
+ if (ret)
+ return ret;
+ }
+
+ /*
+ * We checked and allowed to create parent,
+ * allow children without checking.
+ */
+ if (p_event->parent)
+ return 0;
+
+ /*
+ * It's ok to check current process (owner) permissions in here,
+ * because code below is called only via perf_event_open syscall.
+ */
+
+ /* The ftrace function trace is allowed only for root. */
+ if (ftrace_event_is_function(tp_event)) {
+ if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (!is_sampling_event(p_event))
+ return 0;
+
+ /*
+ * We don't allow user space callchains for function trace
+ * event, due to issues with page faults while tracing page
+ * fault handler and its overall trickiness nature.
+ */
+ if (!p_event->attr.exclude_callchain_user)
+ return -EINVAL;
+
+ /*
+ * Same reason to disable user stack dump as for user space
+ * callchains above.
+ */
+ if (p_event->attr.sample_type & PERF_SAMPLE_STACK_USER)
+ return -EINVAL;
+ }
+
+ /* No tracing, just counting, so no obvious leak */
+ if (!(p_event->attr.sample_type & PERF_SAMPLE_RAW))
+ return 0;
+
+ /* Some events are ok to be traced by non-root users... */
+ if (p_event->attach_state == PERF_ATTACH_TASK) {
+ if (tp_event->flags & TRACE_EVENT_FL_CAP_ANY)
+ return 0;
+ }
+
+ /*
+ * ...otherwise raw tracepoint data can be a severe data leak,
+ * only allow root to have these.
+ */
+ if (perf_paranoid_tracepoint_raw() && !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ return 0;
+}
+
+static int perf_trace_event_reg(struct trace_event_call *tp_event,
+ struct perf_event *p_event)
+{
+ struct hlist_head __percpu *list;
+ int ret = -ENOMEM;
+ int cpu;
+
+ p_event->tp_event = tp_event;
+ if (tp_event->perf_refcount++ > 0)
+ return 0;
+
+ list = alloc_percpu(struct hlist_head);
+ if (!list)
+ goto fail;
+
+ for_each_possible_cpu(cpu)
+ INIT_HLIST_HEAD(per_cpu_ptr(list, cpu));
+
+ tp_event->perf_events = list;
+
+ if (!total_ref_count) {
+ char __percpu *buf;
+ int i;
+
+ for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+ buf = (char __percpu *)alloc_percpu(perf_trace_t);
+ if (!buf)
+ goto fail;
+
+ perf_trace_buf[i] = buf;
+ }
+ }
+
+ ret = tp_event->class->reg(tp_event, TRACE_REG_PERF_REGISTER, NULL);
+ if (ret)
+ goto fail;
+
+ total_ref_count++;
+ return 0;
+
+fail:
+ if (!total_ref_count) {
+ int i;
+
+ for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+ free_percpu(perf_trace_buf[i]);
+ perf_trace_buf[i] = NULL;
+ }
+ }
+
+ if (!--tp_event->perf_refcount) {
+ free_percpu(tp_event->perf_events);
+ tp_event->perf_events = NULL;
+ }
+
+ return ret;
+}
+
+static void perf_trace_event_unreg(struct perf_event *p_event)
+{
+ struct trace_event_call *tp_event = p_event->tp_event;
+ int i;
+
+ if (--tp_event->perf_refcount > 0)
+ goto out;
+
+ tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER, NULL);
+
+ /*
+ * Ensure our callback won't be called anymore. The buffers
+ * will be freed after that.
+ */
+ tracepoint_synchronize_unregister();
+
+ free_percpu(tp_event->perf_events);
+ tp_event->perf_events = NULL;
+
+ if (!--total_ref_count) {
+ for (i = 0; i < PERF_NR_CONTEXTS; i++) {
+ free_percpu(perf_trace_buf[i]);
+ perf_trace_buf[i] = NULL;
+ }
+ }
+out:
+ module_put(tp_event->mod);
+}
+
+static int perf_trace_event_open(struct perf_event *p_event)
+{
+ struct trace_event_call *tp_event = p_event->tp_event;
+ return tp_event->class->reg(tp_event, TRACE_REG_PERF_OPEN, p_event);
+}
+
+static void perf_trace_event_close(struct perf_event *p_event)
+{
+ struct trace_event_call *tp_event = p_event->tp_event;
+ tp_event->class->reg(tp_event, TRACE_REG_PERF_CLOSE, p_event);
+}
+
+static int perf_trace_event_init(struct trace_event_call *tp_event,
+ struct perf_event *p_event)
+{
+ int ret;
+
+ ret = perf_trace_event_perm(tp_event, p_event);
+ if (ret)
+ return ret;
+
+ ret = perf_trace_event_reg(tp_event, p_event);
+ if (ret)
+ return ret;
+
+ ret = perf_trace_event_open(p_event);
+ if (ret) {
+ perf_trace_event_unreg(p_event);
+ return ret;
+ }
+
+ return 0;
+}
+
+int perf_trace_init(struct perf_event *p_event)
+{
+ struct trace_event_call *tp_event;
+ u64 event_id = p_event->attr.config;
+ int ret = -EINVAL;
+
+ mutex_lock(&event_mutex);
+ list_for_each_entry(tp_event, &ftrace_events, list) {
+ if (tp_event->event.type == event_id &&
+ tp_event->class && tp_event->class->reg &&
+ try_module_get(tp_event->mod)) {
+ ret = perf_trace_event_init(tp_event, p_event);
+ if (ret)
+ module_put(tp_event->mod);
+ break;
+ }
+ }
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+
+void perf_trace_destroy(struct perf_event *p_event)
+{
+ mutex_lock(&event_mutex);
+ perf_trace_event_close(p_event);
+ perf_trace_event_unreg(p_event);
+ mutex_unlock(&event_mutex);
+}
+
+#ifdef CONFIG_KPROBE_EVENTS
+int perf_kprobe_init(struct perf_event *p_event, bool is_retprobe)
+{
+ int ret;
+ char *func = NULL;
+ struct trace_event_call *tp_event;
+
+ if (p_event->attr.kprobe_func) {
+ func = kzalloc(KSYM_NAME_LEN, GFP_KERNEL);
+ if (!func)
+ return -ENOMEM;
+ ret = strncpy_from_user(
+ func, u64_to_user_ptr(p_event->attr.kprobe_func),
+ KSYM_NAME_LEN);
+ if (ret == KSYM_NAME_LEN)
+ ret = -E2BIG;
+ if (ret < 0)
+ goto out;
+
+ if (func[0] == '\0') {
+ kfree(func);
+ func = NULL;
+ }
+ }
+
+ tp_event = create_local_trace_kprobe(
+ func, (void *)(unsigned long)(p_event->attr.kprobe_addr),
+ p_event->attr.probe_offset, is_retprobe);
+ if (IS_ERR(tp_event)) {
+ ret = PTR_ERR(tp_event);
+ goto out;
+ }
+
+ ret = perf_trace_event_init(tp_event, p_event);
+ if (ret)
+ destroy_local_trace_kprobe(tp_event);
+out:
+ kfree(func);
+ return ret;
+}
+
+void perf_kprobe_destroy(struct perf_event *p_event)
+{
+ perf_trace_event_close(p_event);
+ perf_trace_event_unreg(p_event);
+
+ destroy_local_trace_kprobe(p_event->tp_event);
+}
+#endif /* CONFIG_KPROBE_EVENTS */
+
+#ifdef CONFIG_UPROBE_EVENTS
+int perf_uprobe_init(struct perf_event *p_event, bool is_retprobe)
+{
+ int ret;
+ char *path = NULL;
+ struct trace_event_call *tp_event;
+
+ if (!p_event->attr.uprobe_path)
+ return -EINVAL;
+ path = kzalloc(PATH_MAX, GFP_KERNEL);
+ if (!path)
+ return -ENOMEM;
+ ret = strncpy_from_user(
+ path, u64_to_user_ptr(p_event->attr.uprobe_path), PATH_MAX);
+ if (ret == PATH_MAX)
+ return -E2BIG;
+ if (ret < 0)
+ goto out;
+ if (path[0] == '\0') {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ tp_event = create_local_trace_uprobe(
+ path, p_event->attr.probe_offset, is_retprobe);
+ if (IS_ERR(tp_event)) {
+ ret = PTR_ERR(tp_event);
+ goto out;
+ }
+
+ /*
+ * local trace_uprobe need to hold event_mutex to call
+ * uprobe_buffer_enable() and uprobe_buffer_disable().
+ * event_mutex is not required for local trace_kprobes.
+ */
+ mutex_lock(&event_mutex);
+ ret = perf_trace_event_init(tp_event, p_event);
+ if (ret)
+ destroy_local_trace_uprobe(tp_event);
+ mutex_unlock(&event_mutex);
+out:
+ kfree(path);
+ return ret;
+}
+
+void perf_uprobe_destroy(struct perf_event *p_event)
+{
+ mutex_lock(&event_mutex);
+ perf_trace_event_close(p_event);
+ perf_trace_event_unreg(p_event);
+ mutex_unlock(&event_mutex);
+ destroy_local_trace_uprobe(p_event->tp_event);
+}
+#endif /* CONFIG_UPROBE_EVENTS */
+
+int perf_trace_add(struct perf_event *p_event, int flags)
+{
+ struct trace_event_call *tp_event = p_event->tp_event;
+
+ if (!(flags & PERF_EF_START))
+ p_event->hw.state = PERF_HES_STOPPED;
+
+ /*
+ * If TRACE_REG_PERF_ADD returns false; no custom action was performed
+ * and we need to take the default action of enqueueing our event on
+ * the right per-cpu hlist.
+ */
+ if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) {
+ struct hlist_head __percpu *pcpu_list;
+ struct hlist_head *list;
+
+ pcpu_list = tp_event->perf_events;
+ if (WARN_ON_ONCE(!pcpu_list))
+ return -EINVAL;
+
+ list = this_cpu_ptr(pcpu_list);
+ hlist_add_head_rcu(&p_event->hlist_entry, list);
+ }
+
+ return 0;
+}
+
+void perf_trace_del(struct perf_event *p_event, int flags)
+{
+ struct trace_event_call *tp_event = p_event->tp_event;
+
+ /*
+ * If TRACE_REG_PERF_DEL returns false; no custom action was performed
+ * and we need to take the default action of dequeueing our event from
+ * the right per-cpu hlist.
+ */
+ if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event))
+ hlist_del_rcu(&p_event->hlist_entry);
+}
+
+void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp)
+{
+ char *raw_data;
+ int rctx;
+
+ BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
+
+ if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+ "perf buffer not large enough"))
+ return NULL;
+
+ *rctxp = rctx = perf_swevent_get_recursion_context();
+ if (rctx < 0)
+ return NULL;
+
+ if (regs)
+ *regs = this_cpu_ptr(&__perf_regs[rctx]);
+ raw_data = this_cpu_ptr(perf_trace_buf[rctx]);
+
+ /* zero the dead bytes from align to not leak stack to user */
+ memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
+ return raw_data;
+}
+EXPORT_SYMBOL_GPL(perf_trace_buf_alloc);
+NOKPROBE_SYMBOL(perf_trace_buf_alloc);
+
+void perf_trace_buf_update(void *record, u16 type)
+{
+ struct trace_entry *entry = record;
+ int pc = preempt_count();
+ unsigned long flags;
+
+ local_save_flags(flags);
+ tracing_generic_entry_update(entry, flags, pc);
+ entry->type = type;
+}
+NOKPROBE_SYMBOL(perf_trace_buf_update);
+
+#ifdef CONFIG_FUNCTION_TRACER
+static void
+perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip,
+ struct ftrace_ops *ops, struct pt_regs *pt_regs)
+{
+ struct ftrace_entry *entry;
+ struct perf_event *event;
+ struct hlist_head head;
+ struct pt_regs regs;
+ int rctx;
+
+ if ((unsigned long)ops->private != smp_processor_id())
+ return;
+
+ event = container_of(ops, struct perf_event, ftrace_ops);
+
+ /*
+ * @event->hlist entry is NULL (per INIT_HLIST_NODE), and all
+ * the perf code does is hlist_for_each_entry_rcu(), so we can
+ * get away with simply setting the @head.first pointer in order
+ * to create a singular list.
+ */
+ head.first = &event->hlist_entry;
+
+#define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \
+ sizeof(u64)) - sizeof(u32))
+
+ BUILD_BUG_ON(ENTRY_SIZE > PERF_MAX_TRACE_SIZE);
+
+ memset(®s, 0, sizeof(regs));
+ perf_fetch_caller_regs(®s);
+
+ entry = perf_trace_buf_alloc(ENTRY_SIZE, NULL, &rctx);
+ if (!entry)
+ return;
+
+ entry->ip = ip;
+ entry->parent_ip = parent_ip;
+ perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN,
+ 1, ®s, &head, NULL);
+
+#undef ENTRY_SIZE
+}
+
+static int perf_ftrace_function_register(struct perf_event *event)
+{
+ struct ftrace_ops *ops = &event->ftrace_ops;
+
+ ops->flags = FTRACE_OPS_FL_RCU;
+ ops->func = perf_ftrace_function_call;
+ ops->private = (void *)(unsigned long)nr_cpu_ids;
+
+ return register_ftrace_function(ops);
+}
+
+static int perf_ftrace_function_unregister(struct perf_event *event)
+{
+ struct ftrace_ops *ops = &event->ftrace_ops;
+ int ret = unregister_ftrace_function(ops);
+ ftrace_free_filter(ops);
+ return ret;
+}
+
+int perf_ftrace_event_register(struct trace_event_call *call,
+ enum trace_reg type, void *data)
+{
+ struct perf_event *event = data;
+
+ switch (type) {
+ case TRACE_REG_REGISTER:
+ case TRACE_REG_UNREGISTER:
+ break;
+ case TRACE_REG_PERF_REGISTER:
+ case TRACE_REG_PERF_UNREGISTER:
+ return 0;
+ case TRACE_REG_PERF_OPEN:
+ return perf_ftrace_function_register(data);
+ case TRACE_REG_PERF_CLOSE:
+ return perf_ftrace_function_unregister(data);
+ case TRACE_REG_PERF_ADD:
+ event->ftrace_ops.private = (void *)(unsigned long)smp_processor_id();
+ return 1;
+ case TRACE_REG_PERF_DEL:
+ event->ftrace_ops.private = (void *)(unsigned long)nr_cpu_ids;
+ return 1;
+ }
+
+ return -EINVAL;
+}
+#endif /* CONFIG_FUNCTION_TRACER */