v4.19.13 snapshot.
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
new file mode 100644
index 0000000..f93a56d
--- /dev/null
+++ b/kernel/trace/trace_syscalls.c
@@ -0,0 +1,817 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <trace/syscall.h>
+#include <trace/events/syscalls.h>
+#include <linux/syscalls.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/module.h> /* for MODULE_NAME_LEN via KSYM_SYMBOL_LEN */
+#include <linux/ftrace.h>
+#include <linux/perf_event.h>
+#include <asm/syscall.h>
+
+#include "trace_output.h"
+#include "trace.h"
+
+static DEFINE_MUTEX(syscall_trace_lock);
+
+static int syscall_enter_register(struct trace_event_call *event,
+ enum trace_reg type, void *data);
+static int syscall_exit_register(struct trace_event_call *event,
+ enum trace_reg type, void *data);
+
+static struct list_head *
+syscall_get_enter_fields(struct trace_event_call *call)
+{
+ struct syscall_metadata *entry = call->data;
+
+ return &entry->enter_fields;
+}
+
+extern struct syscall_metadata *__start_syscalls_metadata[];
+extern struct syscall_metadata *__stop_syscalls_metadata[];
+
+static struct syscall_metadata **syscalls_metadata;
+
+#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
+static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
+{
+ /*
+ * Only compare after the "sys" prefix. Archs that use
+ * syscall wrappers may have syscalls symbols aliases prefixed
+ * with ".SyS" or ".sys" instead of "sys", leading to an unwanted
+ * mismatch.
+ */
+ return !strcmp(sym + 3, name + 3);
+}
+#endif
+
+#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS
+/*
+ * Some architectures that allow for 32bit applications
+ * to run on a 64bit kernel, do not map the syscalls for
+ * the 32bit tasks the same as they do for 64bit tasks.
+ *
+ * *cough*x86*cough*
+ *
+ * In such a case, instead of reporting the wrong syscalls,
+ * simply ignore them.
+ *
+ * For an arch to ignore the compat syscalls it needs to
+ * define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as
+ * define the function arch_trace_is_compat_syscall() to let
+ * the tracing system know that it should ignore it.
+ */
+static int
+trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
+{
+ if (unlikely(arch_trace_is_compat_syscall(regs)))
+ return -1;
+
+ return syscall_get_nr(task, regs);
+}
+#else
+static inline int
+trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs)
+{
+ return syscall_get_nr(task, regs);
+}
+#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */
+
+static __init struct syscall_metadata *
+find_syscall_meta(unsigned long syscall)
+{
+ struct syscall_metadata **start;
+ struct syscall_metadata **stop;
+ char str[KSYM_SYMBOL_LEN];
+
+
+ start = __start_syscalls_metadata;
+ stop = __stop_syscalls_metadata;
+ kallsyms_lookup(syscall, NULL, NULL, NULL, str);
+
+ if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
+ return NULL;
+
+ for ( ; start < stop; start++) {
+ if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
+ return *start;
+ }
+ return NULL;
+}
+
+static struct syscall_metadata *syscall_nr_to_meta(int nr)
+{
+ if (!syscalls_metadata || nr >= NR_syscalls || nr < 0)
+ return NULL;
+
+ return syscalls_metadata[nr];
+}
+
+const char *get_syscall_name(int syscall)
+{
+ struct syscall_metadata *entry;
+
+ entry = syscall_nr_to_meta(syscall);
+ if (!entry)
+ return NULL;
+
+ return entry->name;
+}
+
+static enum print_line_t
+print_syscall_enter(struct trace_iterator *iter, int flags,
+ struct trace_event *event)
+{
+ struct trace_array *tr = iter->tr;
+ struct trace_seq *s = &iter->seq;
+ struct trace_entry *ent = iter->ent;
+ struct syscall_trace_enter *trace;
+ struct syscall_metadata *entry;
+ int i, syscall;
+
+ trace = (typeof(trace))ent;
+ syscall = trace->nr;
+ entry = syscall_nr_to_meta(syscall);
+
+ if (!entry)
+ goto end;
+
+ if (entry->enter_event->event.type != ent->type) {
+ WARN_ON_ONCE(1);
+ goto end;
+ }
+
+ trace_seq_printf(s, "%s(", entry->name);
+
+ for (i = 0; i < entry->nb_args; i++) {
+
+ if (trace_seq_has_overflowed(s))
+ goto end;
+
+ /* parameter types */
+ if (tr->trace_flags & TRACE_ITER_VERBOSE)
+ trace_seq_printf(s, "%s ", entry->types[i]);
+
+ /* parameter values */
+ trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+ trace->args[i],
+ i == entry->nb_args - 1 ? "" : ", ");
+ }
+
+ trace_seq_putc(s, ')');
+end:
+ trace_seq_putc(s, '\n');
+
+ return trace_handle_return(s);
+}
+
+static enum print_line_t
+print_syscall_exit(struct trace_iterator *iter, int flags,
+ struct trace_event *event)
+{
+ struct trace_seq *s = &iter->seq;
+ struct trace_entry *ent = iter->ent;
+ struct syscall_trace_exit *trace;
+ int syscall;
+ struct syscall_metadata *entry;
+
+ trace = (typeof(trace))ent;
+ syscall = trace->nr;
+ entry = syscall_nr_to_meta(syscall);
+
+ if (!entry) {
+ trace_seq_putc(s, '\n');
+ goto out;
+ }
+
+ if (entry->exit_event->event.type != ent->type) {
+ WARN_ON_ONCE(1);
+ return TRACE_TYPE_UNHANDLED;
+ }
+
+ trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+ trace->ret);
+
+ out:
+ return trace_handle_return(s);
+}
+
+extern char *__bad_type_size(void);
+
+#define SYSCALL_FIELD(type, field, name) \
+ sizeof(type) != sizeof(trace.field) ? \
+ __bad_type_size() : \
+ #type, #name, offsetof(typeof(trace), field), \
+ sizeof(trace.field), is_signed_type(type)
+
+static int __init
+__set_enter_print_fmt(struct syscall_metadata *entry, char *buf, int len)
+{
+ int i;
+ int pos = 0;
+
+ /* When len=0, we just calculate the needed length */
+#define LEN_OR_ZERO (len ? len - pos : 0)
+
+ pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+ for (i = 0; i < entry->nb_args; i++) {
+ pos += snprintf(buf + pos, LEN_OR_ZERO, "%s: 0x%%0%zulx%s",
+ entry->args[i], sizeof(unsigned long),
+ i == entry->nb_args - 1 ? "" : ", ");
+ }
+ pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
+
+ for (i = 0; i < entry->nb_args; i++) {
+ pos += snprintf(buf + pos, LEN_OR_ZERO,
+ ", ((unsigned long)(REC->%s))", entry->args[i]);
+ }
+
+#undef LEN_OR_ZERO
+
+ /* return the length of print_fmt */
+ return pos;
+}
+
+static int __init set_syscall_print_fmt(struct trace_event_call *call)
+{
+ char *print_fmt;
+ int len;
+ struct syscall_metadata *entry = call->data;
+
+ if (entry->enter_event != call) {
+ call->print_fmt = "\"0x%lx\", REC->ret";
+ return 0;
+ }
+
+ /* First: called with 0 length to calculate the needed length */
+ len = __set_enter_print_fmt(entry, NULL, 0);
+
+ print_fmt = kmalloc(len + 1, GFP_KERNEL);
+ if (!print_fmt)
+ return -ENOMEM;
+
+ /* Second: actually write the @print_fmt */
+ __set_enter_print_fmt(entry, print_fmt, len + 1);
+ call->print_fmt = print_fmt;
+
+ return 0;
+}
+
+static void __init free_syscall_print_fmt(struct trace_event_call *call)
+{
+ struct syscall_metadata *entry = call->data;
+
+ if (entry->enter_event == call)
+ kfree(call->print_fmt);
+}
+
+static int __init syscall_enter_define_fields(struct trace_event_call *call)
+{
+ struct syscall_trace_enter trace;
+ struct syscall_metadata *meta = call->data;
+ int ret;
+ int i;
+ int offset = offsetof(typeof(trace), args);
+
+ ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
+ FILTER_OTHER);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < meta->nb_args; i++) {
+ ret = trace_define_field(call, meta->types[i],
+ meta->args[i], offset,
+ sizeof(unsigned long), 0,
+ FILTER_OTHER);
+ offset += sizeof(unsigned long);
+ }
+
+ return ret;
+}
+
+static int __init syscall_exit_define_fields(struct trace_event_call *call)
+{
+ struct syscall_trace_exit trace;
+ int ret;
+
+ ret = trace_define_field(call, SYSCALL_FIELD(int, nr, __syscall_nr),
+ FILTER_OTHER);
+ if (ret)
+ return ret;
+
+ ret = trace_define_field(call, SYSCALL_FIELD(long, ret, ret),
+ FILTER_OTHER);
+
+ return ret;
+}
+
+static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
+{
+ struct trace_array *tr = data;
+ struct trace_event_file *trace_file;
+ struct syscall_trace_enter *entry;
+ struct syscall_metadata *sys_data;
+ struct ring_buffer_event *event;
+ struct ring_buffer *buffer;
+ unsigned long irq_flags;
+ int pc;
+ int syscall_nr;
+ int size;
+
+ syscall_nr = trace_get_syscall_nr(current, regs);
+ if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+ return;
+
+ /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
+ trace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]);
+ if (!trace_file)
+ return;
+
+ if (trace_trigger_soft_disabled(trace_file))
+ return;
+
+ sys_data = syscall_nr_to_meta(syscall_nr);
+ if (!sys_data)
+ return;
+
+ size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
+
+ local_save_flags(irq_flags);
+ pc = preempt_count();
+
+ buffer = tr->trace_buffer.buffer;
+ event = trace_buffer_lock_reserve(buffer,
+ sys_data->enter_event->event.type, size, irq_flags, pc);
+ if (!event)
+ return;
+
+ entry = ring_buffer_event_data(event);
+ entry->nr = syscall_nr;
+ syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args);
+
+ event_trigger_unlock_commit(trace_file, buffer, event, entry,
+ irq_flags, pc);
+}
+
+static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
+{
+ struct trace_array *tr = data;
+ struct trace_event_file *trace_file;
+ struct syscall_trace_exit *entry;
+ struct syscall_metadata *sys_data;
+ struct ring_buffer_event *event;
+ struct ring_buffer *buffer;
+ unsigned long irq_flags;
+ int pc;
+ int syscall_nr;
+
+ syscall_nr = trace_get_syscall_nr(current, regs);
+ if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+ return;
+
+ /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
+ trace_file = rcu_dereference_sched(tr->exit_syscall_files[syscall_nr]);
+ if (!trace_file)
+ return;
+
+ if (trace_trigger_soft_disabled(trace_file))
+ return;
+
+ sys_data = syscall_nr_to_meta(syscall_nr);
+ if (!sys_data)
+ return;
+
+ local_save_flags(irq_flags);
+ pc = preempt_count();
+
+ buffer = tr->trace_buffer.buffer;
+ event = trace_buffer_lock_reserve(buffer,
+ sys_data->exit_event->event.type, sizeof(*entry),
+ irq_flags, pc);
+ if (!event)
+ return;
+
+ entry = ring_buffer_event_data(event);
+ entry->nr = syscall_nr;
+ entry->ret = syscall_get_return_value(current, regs);
+
+ event_trigger_unlock_commit(trace_file, buffer, event, entry,
+ irq_flags, pc);
+}
+
+static int reg_event_syscall_enter(struct trace_event_file *file,
+ struct trace_event_call *call)
+{
+ struct trace_array *tr = file->tr;
+ int ret = 0;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+ return -ENOSYS;
+ mutex_lock(&syscall_trace_lock);
+ if (!tr->sys_refcount_enter)
+ ret = register_trace_sys_enter(ftrace_syscall_enter, tr);
+ if (!ret) {
+ rcu_assign_pointer(tr->enter_syscall_files[num], file);
+ tr->sys_refcount_enter++;
+ }
+ mutex_unlock(&syscall_trace_lock);
+ return ret;
+}
+
+static void unreg_event_syscall_enter(struct trace_event_file *file,
+ struct trace_event_call *call)
+{
+ struct trace_array *tr = file->tr;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+ return;
+ mutex_lock(&syscall_trace_lock);
+ tr->sys_refcount_enter--;
+ RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL);
+ if (!tr->sys_refcount_enter)
+ unregister_trace_sys_enter(ftrace_syscall_enter, tr);
+ mutex_unlock(&syscall_trace_lock);
+}
+
+static int reg_event_syscall_exit(struct trace_event_file *file,
+ struct trace_event_call *call)
+{
+ struct trace_array *tr = file->tr;
+ int ret = 0;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+ return -ENOSYS;
+ mutex_lock(&syscall_trace_lock);
+ if (!tr->sys_refcount_exit)
+ ret = register_trace_sys_exit(ftrace_syscall_exit, tr);
+ if (!ret) {
+ rcu_assign_pointer(tr->exit_syscall_files[num], file);
+ tr->sys_refcount_exit++;
+ }
+ mutex_unlock(&syscall_trace_lock);
+ return ret;
+}
+
+static void unreg_event_syscall_exit(struct trace_event_file *file,
+ struct trace_event_call *call)
+{
+ struct trace_array *tr = file->tr;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ if (WARN_ON_ONCE(num < 0 || num >= NR_syscalls))
+ return;
+ mutex_lock(&syscall_trace_lock);
+ tr->sys_refcount_exit--;
+ RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL);
+ if (!tr->sys_refcount_exit)
+ unregister_trace_sys_exit(ftrace_syscall_exit, tr);
+ mutex_unlock(&syscall_trace_lock);
+}
+
+static int __init init_syscall_trace(struct trace_event_call *call)
+{
+ int id;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+ if (num < 0 || num >= NR_syscalls) {
+ pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",
+ ((struct syscall_metadata *)call->data)->name);
+ return -ENOSYS;
+ }
+
+ if (set_syscall_print_fmt(call) < 0)
+ return -ENOMEM;
+
+ id = trace_event_raw_init(call);
+
+ if (id < 0) {
+ free_syscall_print_fmt(call);
+ return id;
+ }
+
+ return id;
+}
+
+struct trace_event_functions enter_syscall_print_funcs = {
+ .trace = print_syscall_enter,
+};
+
+struct trace_event_functions exit_syscall_print_funcs = {
+ .trace = print_syscall_exit,
+};
+
+struct trace_event_class __refdata event_class_syscall_enter = {
+ .system = "syscalls",
+ .reg = syscall_enter_register,
+ .define_fields = syscall_enter_define_fields,
+ .get_fields = syscall_get_enter_fields,
+ .raw_init = init_syscall_trace,
+};
+
+struct trace_event_class __refdata event_class_syscall_exit = {
+ .system = "syscalls",
+ .reg = syscall_exit_register,
+ .define_fields = syscall_exit_define_fields,
+ .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields),
+ .raw_init = init_syscall_trace,
+};
+
+unsigned long __init __weak arch_syscall_addr(int nr)
+{
+ return (unsigned long)sys_call_table[nr];
+}
+
+void __init init_ftrace_syscalls(void)
+{
+ struct syscall_metadata *meta;
+ unsigned long addr;
+ int i;
+
+ syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata),
+ GFP_KERNEL);
+ if (!syscalls_metadata) {
+ WARN_ON(1);
+ return;
+ }
+
+ for (i = 0; i < NR_syscalls; i++) {
+ addr = arch_syscall_addr(i);
+ meta = find_syscall_meta(addr);
+ if (!meta)
+ continue;
+
+ meta->syscall_nr = i;
+ syscalls_metadata[i] = meta;
+ }
+}
+
+#ifdef CONFIG_PERF_EVENTS
+
+static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls);
+static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls);
+static int sys_perf_refcount_enter;
+static int sys_perf_refcount_exit;
+
+static int perf_call_bpf_enter(struct trace_event_call *call, struct pt_regs *regs,
+ struct syscall_metadata *sys_data,
+ struct syscall_trace_enter *rec)
+{
+ struct syscall_tp_t {
+ unsigned long long regs;
+ unsigned long syscall_nr;
+ unsigned long args[SYSCALL_DEFINE_MAXARGS];
+ } param;
+ int i;
+
+ *(struct pt_regs **)¶m = regs;
+ param.syscall_nr = rec->nr;
+ for (i = 0; i < sys_data->nb_args; i++)
+ param.args[i] = rec->args[i];
+ return trace_call_bpf(call, ¶m);
+}
+
+static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
+{
+ struct syscall_metadata *sys_data;
+ struct syscall_trace_enter *rec;
+ struct hlist_head *head;
+ bool valid_prog_array;
+ int syscall_nr;
+ int rctx;
+ int size;
+
+ syscall_nr = trace_get_syscall_nr(current, regs);
+ if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+ return;
+ if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
+ return;
+
+ sys_data = syscall_nr_to_meta(syscall_nr);
+ if (!sys_data)
+ return;
+
+ head = this_cpu_ptr(sys_data->enter_event->perf_events);
+ valid_prog_array = bpf_prog_array_valid(sys_data->enter_event);
+ if (!valid_prog_array && hlist_empty(head))
+ return;
+
+ /* get the size after alignment with the u32 buffer size field */
+ size = sizeof(unsigned long) * sys_data->nb_args + sizeof(*rec);
+ size = ALIGN(size + sizeof(u32), sizeof(u64));
+ size -= sizeof(u32);
+
+ rec = perf_trace_buf_alloc(size, NULL, &rctx);
+ if (!rec)
+ return;
+
+ rec->nr = syscall_nr;
+ syscall_get_arguments(current, regs, 0, sys_data->nb_args,
+ (unsigned long *)&rec->args);
+
+ if ((valid_prog_array &&
+ !perf_call_bpf_enter(sys_data->enter_event, regs, sys_data, rec)) ||
+ hlist_empty(head)) {
+ perf_swevent_put_recursion_context(rctx);
+ return;
+ }
+
+ perf_trace_buf_submit(rec, size, rctx,
+ sys_data->enter_event->event.type, 1, regs,
+ head, NULL);
+}
+
+static int perf_sysenter_enable(struct trace_event_call *call)
+{
+ int ret = 0;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+ mutex_lock(&syscall_trace_lock);
+ if (!sys_perf_refcount_enter)
+ ret = register_trace_sys_enter(perf_syscall_enter, NULL);
+ if (ret) {
+ pr_info("event trace: Could not activate syscall entry trace point");
+ } else {
+ set_bit(num, enabled_perf_enter_syscalls);
+ sys_perf_refcount_enter++;
+ }
+ mutex_unlock(&syscall_trace_lock);
+ return ret;
+}
+
+static void perf_sysenter_disable(struct trace_event_call *call)
+{
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+ mutex_lock(&syscall_trace_lock);
+ sys_perf_refcount_enter--;
+ clear_bit(num, enabled_perf_enter_syscalls);
+ if (!sys_perf_refcount_enter)
+ unregister_trace_sys_enter(perf_syscall_enter, NULL);
+ mutex_unlock(&syscall_trace_lock);
+}
+
+static int perf_call_bpf_exit(struct trace_event_call *call, struct pt_regs *regs,
+ struct syscall_trace_exit *rec)
+{
+ struct syscall_tp_t {
+ unsigned long long regs;
+ unsigned long syscall_nr;
+ unsigned long ret;
+ } param;
+
+ *(struct pt_regs **)¶m = regs;
+ param.syscall_nr = rec->nr;
+ param.ret = rec->ret;
+ return trace_call_bpf(call, ¶m);
+}
+
+static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
+{
+ struct syscall_metadata *sys_data;
+ struct syscall_trace_exit *rec;
+ struct hlist_head *head;
+ bool valid_prog_array;
+ int syscall_nr;
+ int rctx;
+ int size;
+
+ syscall_nr = trace_get_syscall_nr(current, regs);
+ if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
+ return;
+ if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
+ return;
+
+ sys_data = syscall_nr_to_meta(syscall_nr);
+ if (!sys_data)
+ return;
+
+ head = this_cpu_ptr(sys_data->exit_event->perf_events);
+ valid_prog_array = bpf_prog_array_valid(sys_data->exit_event);
+ if (!valid_prog_array && hlist_empty(head))
+ return;
+
+ /* We can probably do that at build time */
+ size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
+ size -= sizeof(u32);
+
+ rec = perf_trace_buf_alloc(size, NULL, &rctx);
+ if (!rec)
+ return;
+
+ rec->nr = syscall_nr;
+ rec->ret = syscall_get_return_value(current, regs);
+
+ if ((valid_prog_array &&
+ !perf_call_bpf_exit(sys_data->exit_event, regs, rec)) ||
+ hlist_empty(head)) {
+ perf_swevent_put_recursion_context(rctx);
+ return;
+ }
+
+ perf_trace_buf_submit(rec, size, rctx, sys_data->exit_event->event.type,
+ 1, regs, head, NULL);
+}
+
+static int perf_sysexit_enable(struct trace_event_call *call)
+{
+ int ret = 0;
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+ mutex_lock(&syscall_trace_lock);
+ if (!sys_perf_refcount_exit)
+ ret = register_trace_sys_exit(perf_syscall_exit, NULL);
+ if (ret) {
+ pr_info("event trace: Could not activate syscall exit trace point");
+ } else {
+ set_bit(num, enabled_perf_exit_syscalls);
+ sys_perf_refcount_exit++;
+ }
+ mutex_unlock(&syscall_trace_lock);
+ return ret;
+}
+
+static void perf_sysexit_disable(struct trace_event_call *call)
+{
+ int num;
+
+ num = ((struct syscall_metadata *)call->data)->syscall_nr;
+
+ mutex_lock(&syscall_trace_lock);
+ sys_perf_refcount_exit--;
+ clear_bit(num, enabled_perf_exit_syscalls);
+ if (!sys_perf_refcount_exit)
+ unregister_trace_sys_exit(perf_syscall_exit, NULL);
+ mutex_unlock(&syscall_trace_lock);
+}
+
+#endif /* CONFIG_PERF_EVENTS */
+
+static int syscall_enter_register(struct trace_event_call *event,
+ enum trace_reg type, void *data)
+{
+ struct trace_event_file *file = data;
+
+ switch (type) {
+ case TRACE_REG_REGISTER:
+ return reg_event_syscall_enter(file, event);
+ case TRACE_REG_UNREGISTER:
+ unreg_event_syscall_enter(file, event);
+ return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+ case TRACE_REG_PERF_REGISTER:
+ return perf_sysenter_enable(event);
+ case TRACE_REG_PERF_UNREGISTER:
+ perf_sysenter_disable(event);
+ return 0;
+ case TRACE_REG_PERF_OPEN:
+ case TRACE_REG_PERF_CLOSE:
+ case TRACE_REG_PERF_ADD:
+ case TRACE_REG_PERF_DEL:
+ return 0;
+#endif
+ }
+ return 0;
+}
+
+static int syscall_exit_register(struct trace_event_call *event,
+ enum trace_reg type, void *data)
+{
+ struct trace_event_file *file = data;
+
+ switch (type) {
+ case TRACE_REG_REGISTER:
+ return reg_event_syscall_exit(file, event);
+ case TRACE_REG_UNREGISTER:
+ unreg_event_syscall_exit(file, event);
+ return 0;
+
+#ifdef CONFIG_PERF_EVENTS
+ case TRACE_REG_PERF_REGISTER:
+ return perf_sysexit_enable(event);
+ case TRACE_REG_PERF_UNREGISTER:
+ perf_sysexit_disable(event);
+ return 0;
+ case TRACE_REG_PERF_OPEN:
+ case TRACE_REG_PERF_CLOSE:
+ case TRACE_REG_PERF_ADD:
+ case TRACE_REG_PERF_DEL:
+ return 0;
+#endif
+ }
+ return 0;
+}