| 1 | #include <stdarg.h> |
| 2 | |
| 3 | /* LTT flags |
| 4 | * |
| 5 | * LTT_FLAG_TRACE : first arg contains trace to write into. |
| 6 | * (type : struct ltt_trace_struct *) |
| 7 | * LTT_FLAG_CHANNEL : following arg contains channel index to write into. |
| 8 | * (type : uint8_t) |
| 9 | * LTT_FLAG_FORCE : Force write in disabled traces (internal ltt use) |
| 10 | */ |
| 11 | |
| 12 | #define _LTT_FLAG_TRACE 0 |
| 13 | #define _LTT_FLAG_CHANNEL 1 |
| 14 | #define _LTT_FLAG_FORCE 2 |
| 15 | |
| 16 | #define LTT_FLAG_TRACE (1 << _LTT_FLAG_TRACE) |
| 17 | #define LTT_FLAG_CHANNEL (1 << _LTT_FLAG_CHANNEL) |
| 18 | #define LTT_FLAG_FORCE (1 << _LTT_FLAG_FORCE) |
| 19 | |
| 20 | /* Calculate data size */ |
| 21 | /* Assume that the padding for alignment starts at a |
| 22 | * sizeof(void *) address. */ |
| 23 | static inline __attribute__((no_instrument_function)) |
| 24 | size_t ltt_get_data_size(ltt_facility_t fID, uint8_t eID, |
| 25 | const char *fmt, va_list args) |
| 26 | { |
| 27 | |
| 28 | |
| 29 | |
| 30 | } |
| 31 | |
| 32 | static inline __attribute__((no_instrument_function)) |
| 33 | size_t ltt_write_event_data(char *buffer, |
| 34 | ltt_facility_t fID, uint8_t eID, |
| 35 | const char *fmt, va_list args) |
| 36 | { |
| 37 | |
| 38 | |
| 39 | |
| 40 | } |
| 41 | |
| 42 | |
| 43 | __attribute__((no_instrument_function)) |
| 44 | void vtrace(ltt_facility_t fID, uint8_t eID, long flags, |
| 45 | const char *fmt, va_list args) |
| 46 | { |
| 47 | size_t data_size, slot_size; |
| 48 | uint8_t channel_index; |
| 49 | struct ltt_channel_struct *channel; |
| 50 | struct ltt_trace_struct *trace, *dest_trace; |
| 51 | void *transport_data; |
| 52 | uint64_t tsc; |
| 53 | char *buffer; |
| 54 | |
| 55 | /* This test is useful for quickly exiting static tracing when no |
| 56 | * trace is active. */ |
| 57 | if (likely(ltt_traces.num_active_traces == 0 && !(flags & LTT_FLAG_FORCE))) |
| 58 | return; |
| 59 | |
| 60 | data_size = ltt_get_data_size(fID, eID, fmt, args); |
| 61 | preempt_disable(); |
| 62 | ltt_nesting[smp_processor_id()]++; |
| 63 | |
| 64 | if (unlikely(flags & LTT_FLAG_TRACE)) |
| 65 | dest_trace = va_arg(args, struct ltt_trace_struct *); |
| 66 | if (unlikely(flags & LTT_FLAG_CHANNEL)) |
| 67 | channel_index = va_arg(args, uint8_t); |
| 68 | else |
| 69 | channel_index = ltt_get_channel_index(fID, eID); |
| 70 | |
| 71 | /* Iterate on each traces */ |
| 72 | list_for_each_entry_rcu(trace, <t_traces.head, list) { |
| 73 | if (unlikely(!trace->active && !(flags & LTT_FLAG_FORCE))) |
| 74 | continue; |
| 75 | if (unlikely(flags & LTT_FLAG_TRACE && trace != dest_trace)) |
| 76 | continue; |
| 77 | channel = ltt_get_channel_from_index(trace, channel_index); |
| 78 | /* reserve space : header and data */ |
| 79 | buffer = ltt_reserve_slot(trace, channel, &transport_data, |
| 80 | data_size, &slot_size, &tsc); |
| 81 | if (unlikely(!buffer)) |
| 82 | continue; /* buffer full */ |
| 83 | /* Out-of-order write : header and data */ |
| 84 | buffer = ltt_write_event_header(trace, channel, buffer, |
| 85 | fID, eID, data_size, tsc); |
| 86 | ltt_write_event_data(buffer, fID, eID, fmt, args); |
| 87 | /* Out-of-order commit */ |
| 88 | ltt_commit_slot(channel, &transport_data, buffer, slot_size); |
| 89 | } |
| 90 | |
| 91 | ltt_nesting[smp_processor_id()]--; |
| 92 | preempt_enable(); |
| 93 | } |
| 94 | |
| 95 | __attribute__((no_instrument_function)) |
| 96 | void trace(ltt_facility_t fID, uint8_t eID, const char *fmt, ...) |
| 97 | { |
| 98 | va_list args; |
| 99 | |
| 100 | va_start(args, fmt); |
| 101 | vtrace(fmt, args); |
| 102 | va_end(args); |
| 103 | } |
| 104 | |