b0aae68cc5
When defining a dynamic size string, we add __str_loc_##item to the trace entry, and it stores the location of the actual string in entry->_str_data[] 'unsigned short' should be sufficient to store this information, thus we save 2 bytes per dyn-size string in the ring buffer. [ Impact: reduce memory occupied by dyn-size strings in ring buffer ] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <4A14EDB6.2050507@cn.fujitsu.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
510 lines
13 KiB
C
510 lines
13 KiB
C
/*
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* Stage 1 of the trace events.
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*
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* Override the macros in <trace/trace_events.h> to include the following:
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*
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* struct ftrace_raw_<call> {
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* struct trace_entry ent;
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* <type> <item>;
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* <type2> <item2>[<len>];
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* [...]
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* };
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*
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* The <type> <item> is created by the __field(type, item) macro or
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* the __array(type2, item2, len) macro.
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* We simply do "type item;", and that will create the fields
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* in the structure.
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*/
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#include <linux/ftrace_event.h>
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#undef __array
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#define __array(type, item, len) type item[len];
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#undef __field
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#define __field(type, item) type item;
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#undef __string
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#define __string(item, src) unsigned short __str_loc_##item;
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#undef TP_STRUCT__entry
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#define TP_STRUCT__entry(args...) args
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#undef TRACE_EVENT
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#define TRACE_EVENT(name, proto, args, tstruct, assign, print) \
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struct ftrace_raw_##name { \
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struct trace_entry ent; \
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tstruct \
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char __str_data[0]; \
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}; \
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static struct ftrace_event_call event_##name
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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/*
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* Stage 2 of the trace events.
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*
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* Include the following:
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*
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* struct ftrace_str_offsets_<call> {
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* int <str1>;
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* int <str2>;
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* [...]
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* };
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*
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* The __string() macro will create each int <str>, this is to
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* keep the offset of each string from the beggining of the event
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* once we perform the strlen() of the src strings.
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*
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*/
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#undef __array
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#define __array(type, item, len)
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#undef __field
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#define __field(type, item);
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#undef __string
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#define __string(item, src) int item;
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
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struct ftrace_str_offsets_##call { \
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tstruct; \
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};
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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/*
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* Stage 3 of the trace events.
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*
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* Override the macros in <trace/trace_events.h> to include the following:
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*
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* enum print_line_t
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* ftrace_raw_output_<call>(struct trace_iterator *iter, int flags)
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* {
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* struct trace_seq *s = &iter->seq;
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* struct ftrace_raw_<call> *field; <-- defined in stage 1
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* struct trace_entry *entry;
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* int ret;
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*
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* entry = iter->ent;
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*
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* if (entry->type != event_<call>.id) {
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* WARN_ON_ONCE(1);
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* return TRACE_TYPE_UNHANDLED;
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* }
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*
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* field = (typeof(field))entry;
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*
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* ret = trace_seq_printf(s, <TP_printk> "\n");
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* if (!ret)
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* return TRACE_TYPE_PARTIAL_LINE;
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*
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* return TRACE_TYPE_HANDLED;
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* }
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*
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* This is the method used to print the raw event to the trace
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* output format. Note, this is not needed if the data is read
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* in binary.
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*/
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#undef __entry
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#define __entry field
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#undef TP_printk
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#define TP_printk(fmt, args...) fmt "\n", args
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#undef __get_str
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#define __get_str(field) ((char *)__entry + __entry->__str_loc_##field)
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
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enum print_line_t \
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ftrace_raw_output_##call(struct trace_iterator *iter, int flags) \
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{ \
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struct trace_seq *s = &iter->seq; \
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struct ftrace_raw_##call *field; \
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struct trace_entry *entry; \
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int ret; \
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\
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entry = iter->ent; \
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\
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if (entry->type != event_##call.id) { \
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WARN_ON_ONCE(1); \
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return TRACE_TYPE_UNHANDLED; \
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} \
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\
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field = (typeof(field))entry; \
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\
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ret = trace_seq_printf(s, #call ": " print); \
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if (!ret) \
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return TRACE_TYPE_PARTIAL_LINE; \
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\
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return TRACE_TYPE_HANDLED; \
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}
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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/*
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* Setup the showing format of trace point.
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*
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* int
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* ftrace_format_##call(struct trace_seq *s)
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* {
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* struct ftrace_raw_##call field;
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* int ret;
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*
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* ret = trace_seq_printf(s, #type " " #item ";"
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* " offset:%u; size:%u;\n",
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* offsetof(struct ftrace_raw_##call, item),
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* sizeof(field.type));
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*
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* }
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*/
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#undef TP_STRUCT__entry
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#define TP_STRUCT__entry(args...) args
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#undef __field
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#define __field(type, item) \
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ret = trace_seq_printf(s, "\tfield:" #type " " #item ";\t" \
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"offset:%u;\tsize:%u;\n", \
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(unsigned int)offsetof(typeof(field), item), \
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(unsigned int)sizeof(field.item)); \
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if (!ret) \
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return 0;
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#undef __array
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#define __array(type, item, len) \
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ret = trace_seq_printf(s, "\tfield:" #type " " #item "[" #len "];\t" \
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"offset:%u;\tsize:%u;\n", \
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(unsigned int)offsetof(typeof(field), item), \
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(unsigned int)sizeof(field.item)); \
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if (!ret) \
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return 0;
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#undef __string
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#define __string(item, src) \
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ret = trace_seq_printf(s, "\tfield: __str_loc " #item ";\t" \
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"offset:%u;tsize:%u;\n", \
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(unsigned int)offsetof(typeof(field), \
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__str_loc_##item), \
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(unsigned int)sizeof(field.__str_loc_##item)); \
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if (!ret) \
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return 0;
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#undef __entry
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#define __entry REC
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#undef TP_printk
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#define TP_printk(fmt, args...) "%s, %s\n", #fmt, __stringify(args)
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#undef TP_fast_assign
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#define TP_fast_assign(args...) args
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, func, print) \
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static int \
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ftrace_format_##call(struct trace_seq *s) \
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{ \
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struct ftrace_raw_##call field __attribute__((unused)); \
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int ret = 0; \
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\
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tstruct; \
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\
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trace_seq_printf(s, "\nprint fmt: " print); \
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\
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return ret; \
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}
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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#undef __field
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#define __field(type, item) \
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ret = trace_define_field(event_call, #type, #item, \
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offsetof(typeof(field), item), \
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sizeof(field.item), is_signed_type(type)); \
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if (ret) \
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return ret;
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#undef __array
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#define __array(type, item, len) \
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BUILD_BUG_ON(len > MAX_FILTER_STR_VAL); \
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ret = trace_define_field(event_call, #type "[" #len "]", #item, \
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offsetof(typeof(field), item), \
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sizeof(field.item), 0); \
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if (ret) \
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return ret;
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#undef __string
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#define __string(item, src) \
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ret = trace_define_field(event_call, "__str_loc", #item, \
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offsetof(typeof(field), __str_loc_##item), \
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sizeof(field.__str_loc_##item), 0);
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, func, print) \
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int \
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ftrace_define_fields_##call(void) \
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{ \
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struct ftrace_raw_##call field; \
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struct ftrace_event_call *event_call = &event_##call; \
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int ret; \
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\
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__common_field(int, type, 1); \
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__common_field(unsigned char, flags, 0); \
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__common_field(unsigned char, preempt_count, 0); \
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__common_field(int, pid, 1); \
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__common_field(int, tgid, 1); \
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\
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tstruct; \
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\
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return ret; \
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}
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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/*
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* Stage 4 of the trace events.
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*
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* Override the macros in <trace/trace_events.h> to include the following:
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*
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* static void ftrace_event_<call>(proto)
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* {
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* event_trace_printk(_RET_IP_, "<call>: " <fmt>);
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* }
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*
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* static int ftrace_reg_event_<call>(void)
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* {
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* int ret;
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*
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* ret = register_trace_<call>(ftrace_event_<call>);
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* if (!ret)
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* pr_info("event trace: Could not activate trace point "
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* "probe to <call>");
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* return ret;
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* }
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*
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* static void ftrace_unreg_event_<call>(void)
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* {
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* unregister_trace_<call>(ftrace_event_<call>);
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* }
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*
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*
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* For those macros defined with TRACE_EVENT:
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*
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* static struct ftrace_event_call event_<call>;
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*
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* static void ftrace_raw_event_<call>(proto)
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* {
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* struct ring_buffer_event *event;
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* struct ftrace_raw_<call> *entry; <-- defined in stage 1
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* unsigned long irq_flags;
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* int pc;
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*
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* local_save_flags(irq_flags);
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* pc = preempt_count();
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*
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* event = trace_current_buffer_lock_reserve(event_<call>.id,
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* sizeof(struct ftrace_raw_<call>),
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* irq_flags, pc);
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* if (!event)
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* return;
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* entry = ring_buffer_event_data(event);
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*
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* <assign>; <-- Here we assign the entries by the __field and
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* __array macros.
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*
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* trace_current_buffer_unlock_commit(event, irq_flags, pc);
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* }
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*
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* static int ftrace_raw_reg_event_<call>(void)
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* {
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* int ret;
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*
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* ret = register_trace_<call>(ftrace_raw_event_<call>);
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* if (!ret)
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* pr_info("event trace: Could not activate trace point "
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* "probe to <call>");
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* return ret;
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* }
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*
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* static void ftrace_unreg_event_<call>(void)
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* {
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* unregister_trace_<call>(ftrace_raw_event_<call>);
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* }
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*
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* static struct trace_event ftrace_event_type_<call> = {
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* .trace = ftrace_raw_output_<call>, <-- stage 2
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* };
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*
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* static int ftrace_raw_init_event_<call>(void)
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* {
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* int id;
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*
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* id = register_ftrace_event(&ftrace_event_type_<call>);
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* if (!id)
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* return -ENODEV;
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* event_<call>.id = id;
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* return 0;
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* }
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*
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* static struct ftrace_event_call __used
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* __attribute__((__aligned__(4)))
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* __attribute__((section("_ftrace_events"))) event_<call> = {
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* .name = "<call>",
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* .system = "<system>",
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* .raw_init = ftrace_raw_init_event_<call>,
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* .regfunc = ftrace_reg_event_<call>,
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* .unregfunc = ftrace_unreg_event_<call>,
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* .show_format = ftrace_format_<call>,
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* }
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*
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*/
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#undef TP_FMT
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#define TP_FMT(fmt, args...) fmt "\n", ##args
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#ifdef CONFIG_EVENT_PROFILE
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#define _TRACE_PROFILE(call, proto, args) \
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static void ftrace_profile_##call(proto) \
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{ \
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extern void perf_tpcounter_event(int); \
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perf_tpcounter_event(event_##call.id); \
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} \
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\
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static int ftrace_profile_enable_##call(struct ftrace_event_call *call) \
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{ \
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int ret = 0; \
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\
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if (!atomic_inc_return(&call->profile_count)) \
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ret = register_trace_##call(ftrace_profile_##call); \
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\
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return ret; \
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} \
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\
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static void ftrace_profile_disable_##call(struct ftrace_event_call *call) \
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{ \
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if (atomic_add_negative(-1, &call->profile_count)) \
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unregister_trace_##call(ftrace_profile_##call); \
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}
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#define _TRACE_PROFILE_INIT(call) \
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.profile_count = ATOMIC_INIT(-1), \
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.profile_enable = ftrace_profile_enable_##call, \
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.profile_disable = ftrace_profile_disable_##call,
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#else
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#define _TRACE_PROFILE(call, proto, args)
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#define _TRACE_PROFILE_INIT(call)
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#endif
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#undef __entry
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#define __entry entry
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#undef __field
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#define __field(type, item)
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#undef __array
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#define __array(type, item, len)
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#undef __string
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#define __string(item, src) \
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__str_offsets.item = __str_size + \
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offsetof(typeof(*entry), __str_data); \
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__str_size += strlen(src) + 1;
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#undef __assign_str
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#define __assign_str(dst, src) \
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__entry->__str_loc_##dst = __str_offsets.dst; \
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strcpy(__get_str(dst), src);
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#undef TRACE_EVENT
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#define TRACE_EVENT(call, proto, args, tstruct, assign, print) \
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_TRACE_PROFILE(call, PARAMS(proto), PARAMS(args)) \
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\
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static struct ftrace_event_call event_##call; \
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\
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static void ftrace_raw_event_##call(proto) \
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{ \
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struct ftrace_str_offsets_##call __maybe_unused __str_offsets; \
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struct ftrace_event_call *call = &event_##call; \
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struct ring_buffer_event *event; \
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struct ftrace_raw_##call *entry; \
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unsigned long irq_flags; \
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int __str_size = 0; \
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int pc; \
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\
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local_save_flags(irq_flags); \
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pc = preempt_count(); \
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\
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tstruct; \
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\
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event = trace_current_buffer_lock_reserve(event_##call.id, \
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sizeof(struct ftrace_raw_##call) + __str_size,\
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irq_flags, pc); \
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if (!event) \
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return; \
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entry = ring_buffer_event_data(event); \
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\
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assign; \
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\
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if (!filter_current_check_discard(call, entry, event)) \
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trace_nowake_buffer_unlock_commit(event, irq_flags, pc); \
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} \
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\
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static int ftrace_raw_reg_event_##call(void) \
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{ \
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int ret; \
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\
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ret = register_trace_##call(ftrace_raw_event_##call); \
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if (ret) \
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pr_info("event trace: Could not activate trace point " \
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"probe to " #call "\n"); \
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return ret; \
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} \
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\
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static void ftrace_raw_unreg_event_##call(void) \
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{ \
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unregister_trace_##call(ftrace_raw_event_##call); \
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} \
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\
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static struct trace_event ftrace_event_type_##call = { \
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.trace = ftrace_raw_output_##call, \
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}; \
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\
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static int ftrace_raw_init_event_##call(void) \
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{ \
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int id; \
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\
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id = register_ftrace_event(&ftrace_event_type_##call); \
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if (!id) \
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return -ENODEV; \
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event_##call.id = id; \
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INIT_LIST_HEAD(&event_##call.fields); \
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init_preds(&event_##call); \
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return 0; \
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} \
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\
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static struct ftrace_event_call __used \
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__attribute__((__aligned__(4))) \
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__attribute__((section("_ftrace_events"))) event_##call = { \
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.name = #call, \
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.system = __stringify(TRACE_SYSTEM), \
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.event = &ftrace_event_type_##call, \
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.raw_init = ftrace_raw_init_event_##call, \
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.regfunc = ftrace_raw_reg_event_##call, \
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.unregfunc = ftrace_raw_unreg_event_##call, \
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.show_format = ftrace_format_##call, \
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.define_fields = ftrace_define_fields_##call, \
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_TRACE_PROFILE_INIT(call) \
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}
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#include TRACE_INCLUDE(TRACE_INCLUDE_FILE)
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#undef _TRACE_PROFILE
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#undef _TRACE_PROFILE_INIT
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