1 files changed, 690 insertions, 0 deletions

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
new file mode 100644
index 00000000..ee7b5a0b
--- /dev/null
+++ b/kernel/trace/trace_syscalls.c
@@ -0,0 +1,690 @@
+#include <trace/syscall.h>
+#include <trace/events/syscalls.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#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 sys_refcount_enter;
+static int sys_refcount_exit;
+static DECLARE_BITMAP(enabled_enter_syscalls, NR_syscalls);
+static DECLARE_BITMAP(enabled_exit_syscalls, NR_syscalls);
+
+static int syscall_enter_register(struct ftrace_event_call *event,
+				 enum trace_reg type);
+static int syscall_exit_register(struct ftrace_event_call *event,
+				 enum trace_reg type);
+
+static int syscall_enter_define_fields(struct ftrace_event_call *call);
+static int syscall_exit_define_fields(struct ftrace_event_call *call);
+
+static struct list_head *
+syscall_get_enter_fields(struct ftrace_event_call *call)
+{
+	struct syscall_metadata *entry = call->data;
+
+	return &entry->enter_fields;
+}
+
+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 ftrace_event_class 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 ftrace_event_class 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,
+};
+
+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" instead of "sys", leading to an unwanted
+	 * mismatch.
+	 */
+	return !strcmp(sym + 3, name + 3);
+}
+#endif
+
+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];
+}
+
+enum print_line_t
+print_syscall_enter(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_enter *trace;
+	struct syscall_metadata *entry;
+	int i, ret, 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;
+	}
+
+	ret = trace_seq_printf(s, "%s(", entry->name);
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	for (i = 0; i < entry->nb_args; i++) {
+		/* parameter types */
+		if (trace_flags & TRACE_ITER_VERBOSE) {
+			ret = trace_seq_printf(s, "%s ", entry->types[i]);
+			if (!ret)
+				return TRACE_TYPE_PARTIAL_LINE;
+		}
+		/* parameter values */
+		ret = trace_seq_printf(s, "%s: %lx%s", entry->args[i],
+				       trace->args[i],
+				       i == entry->nb_args - 1 ? "" : ", ");
+		if (!ret)
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	ret = trace_seq_putc(s, ')');
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+end:
+	ret =  trace_seq_putc(s, '\n');
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+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;
+	int ret;
+
+	trace = (typeof(trace))ent;
+	syscall = trace->nr;
+	entry = syscall_nr_to_meta(syscall);
+
+	if (!entry) {
+		trace_seq_printf(s, "\n");
+		return TRACE_TYPE_HANDLED;
+	}
+
+	if (entry->exit_event->event.type != ent->type) {
+		WARN_ON_ONCE(1);
+		return TRACE_TYPE_UNHANDLED;
+	}
+
+	ret = trace_seq_printf(s, "%s -> 0x%lx\n", entry->name,
+				trace->ret);
+	if (!ret)
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	return TRACE_TYPE_HANDLED;
+}
+
+extern char *__bad_type_size(void);
+
+#define SYSCALL_FIELD(type, name)					\
+	sizeof(type) != sizeof(trace.name) ?				\
+		__bad_type_size() :					\
+		#type, #name, offsetof(typeof(trace), name),		\
+		sizeof(trace.name), is_signed_type(type)
+
+static
+int  __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 set_syscall_print_fmt(struct ftrace_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 free_syscall_print_fmt(struct ftrace_event_call *call)
+{
+	struct syscall_metadata *entry = call->data;
+
+	if (entry->enter_event == call)
+		kfree(call->print_fmt);
+}
+
+static int syscall_enter_define_fields(struct ftrace_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), 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 syscall_exit_define_fields(struct ftrace_event_call *call)
+{
+	struct syscall_trace_exit trace;
+	int ret;
+
+	ret = trace_define_field(call, SYSCALL_FIELD(int, nr), FILTER_OTHER);
+	if (ret)
+		return ret;
+
+	ret = trace_define_field(call, SYSCALL_FIELD(long, ret),
+				 FILTER_OTHER);
+
+	return ret;
+}
+
+void ftrace_syscall_enter(void *ignore, struct pt_regs *regs, long id)
+{
+	struct syscall_trace_enter *entry;
+	struct syscall_metadata *sys_data;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	int size;
+	int syscall_nr;
+
+	syscall_nr = syscall_get_nr(current, regs);
+	if (syscall_nr < 0)
+		return;
+	if (!test_bit(syscall_nr, enabled_enter_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
+
+	event = trace_current_buffer_lock_reserve(&buffer,
+			sys_data->enter_event->event.type, size, 0, 0);
+	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);
+
+	if (!filter_current_check_discard(buffer, sys_data->enter_event,
+					  entry, event))
+		trace_current_buffer_unlock_commit(buffer, event, 0, 0);
+}
+
+void ftrace_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
+{
+	struct syscall_trace_exit *entry;
+	struct syscall_metadata *sys_data;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	int syscall_nr;
+
+	syscall_nr = syscall_get_nr(current, regs);
+	if (syscall_nr < 0)
+		return;
+	if (!test_bit(syscall_nr, enabled_exit_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	event = trace_current_buffer_lock_reserve(&buffer,
+			sys_data->exit_event->event.type, sizeof(*entry), 0, 0);
+	if (!event)
+		return;
+
+	entry = ring_buffer_event_data(event);
+	entry->nr = syscall_nr;
+	entry->ret = syscall_get_return_value(current, regs);
+
+	if (!filter_current_check_discard(buffer, sys_data->exit_event,
+					  entry, event))
+		trace_current_buffer_unlock_commit(buffer, event, 0, 0);
+}
+
+int reg_event_syscall_enter(struct ftrace_event_call *call)
+{
+	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 (!sys_refcount_enter)
+		ret = register_trace_sys_enter(ftrace_syscall_enter, NULL);
+	if (!ret) {
+		set_bit(num, enabled_enter_syscalls);
+		sys_refcount_enter++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+void unreg_event_syscall_enter(struct ftrace_event_call *call)
+{
+	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);
+	sys_refcount_enter--;
+	clear_bit(num, enabled_enter_syscalls);
+	if (!sys_refcount_enter)
+		unregister_trace_sys_enter(ftrace_syscall_enter, NULL);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+int reg_event_syscall_exit(struct ftrace_event_call *call)
+{
+	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 (!sys_refcount_exit)
+		ret = register_trace_sys_exit(ftrace_syscall_exit, NULL);
+	if (!ret) {
+		set_bit(num, enabled_exit_syscalls);
+		sys_refcount_exit++;
+	}
+	mutex_unlock(&syscall_trace_lock);
+	return ret;
+}
+
+void unreg_event_syscall_exit(struct ftrace_event_call *call)
+{
+	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);
+	sys_refcount_exit--;
+	clear_bit(num, enabled_exit_syscalls);
+	if (!sys_refcount_exit)
+		unregister_trace_sys_exit(ftrace_syscall_exit, NULL);
+	mutex_unlock(&syscall_trace_lock);
+}
+
+int init_syscall_trace(struct ftrace_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;
+}
+
+unsigned long __init __weak arch_syscall_addr(int nr)
+{
+	return (unsigned long)sys_call_table[nr];
+}
+
+int __init init_ftrace_syscalls(void)
+{
+	struct syscall_metadata *meta;
+	unsigned long addr;
+	int i;
+
+	syscalls_metadata = kzalloc(sizeof(*syscalls_metadata) *
+					NR_syscalls, GFP_KERNEL);
+	if (!syscalls_metadata) {
+		WARN_ON(1);
+		return -ENOMEM;
+	}
+
+	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;
+	}
+
+	return 0;
+}
+core_initcall(init_ftrace_syscalls);
+
+#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 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;
+	int syscall_nr;
+	int rctx;
+	int size;
+
+	syscall_nr = syscall_get_nr(current, regs);
+	if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		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);
+
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+		      "perf buffer not large enough"))
+		return;
+
+	rec = (struct syscall_trace_enter *)perf_trace_buf_prepare(size,
+				sys_data->enter_event->event.type, regs, &rctx);
+	if (!rec)
+		return;
+
+	rec->nr = syscall_nr;
+	syscall_get_arguments(current, regs, 0, sys_data->nb_args,
+			       (unsigned long *)&rec->args);
+
+	head = this_cpu_ptr(sys_data->enter_event->perf_events);
+	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
+}
+
+int perf_sysenter_enable(struct ftrace_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;
+}
+
+void perf_sysenter_disable(struct ftrace_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 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;
+	int syscall_nr;
+	int rctx;
+	int size;
+
+	syscall_nr = syscall_get_nr(current, regs);
+	if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
+		return;
+
+	sys_data = syscall_nr_to_meta(syscall_nr);
+	if (!sys_data)
+		return;
+
+	/* We can probably do that at build time */
+	size = ALIGN(sizeof(*rec) + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
+
+	/*
+	 * Impossible, but be paranoid with the future
+	 * How to put this check outside runtime?
+	 */
+	if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
+		"exit event has grown above perf buffer size"))
+		return;
+
+	rec = (struct syscall_trace_exit *)perf_trace_buf_prepare(size,
+				sys_data->exit_event->event.type, regs, &rctx);
+	if (!rec)
+		return;
+
+	rec->nr = syscall_nr;
+	rec->ret = syscall_get_return_value(current, regs);
+
+	head = this_cpu_ptr(sys_data->exit_event->perf_events);
+	perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head);
+}
+
+int perf_sysexit_enable(struct ftrace_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;
+}
+
+void perf_sysexit_disable(struct ftrace_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 ftrace_event_call *event,
+				 enum trace_reg type)
+{
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return reg_event_syscall_enter(event);
+	case TRACE_REG_UNREGISTER:
+		unreg_event_syscall_enter(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;
+#endif
+	}
+	return 0;
+}
+
+static int syscall_exit_register(struct ftrace_event_call *event,
+				 enum trace_reg type)
+{
+	switch (type) {
+	case TRACE_REG_REGISTER:
+		return reg_event_syscall_exit(event);
+	case TRACE_REG_UNREGISTER:
+		unreg_event_syscall_exit(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;
+#endif
+	}
+	return 0;
+}