+#include "wrapper/ringbuffer/frontend_types.h"
+
+/*
+ * Keep the natural field alignment for _each field_ within this structure if
+ * you ever add/remove a field from this header. Packed attribute is not used
+ * because gcc generates poor code on at least powerpc and mips. Don't ever
+ * let gcc add padding between the structure elements.
+ */
+
+struct packet_header {
+ /* Trace packet header */
+ uint32_t magic; /*
+ * Trace magic number.
+ * contains endianness information.
+ */
+ uint8_t uuid[16];
+ uint32_t stream_id;
+
+ struct {
+ /* Stream packet context */
+ uint64_t timestamp_begin; /* Cycle count at subbuffer start */
+ uint64_t timestamp_end; /* Cycle count at subbuffer end */
+ uint32_t events_discarded; /*
+ * Events lost in this subbuffer since
+ * the beginning of the trace.
+ * (may overflow)
+ */
+ uint32_t content_size; /* Size of data in subbuffer */
+ uint32_t packet_size; /* Subbuffer size (include padding) */
+ uint32_t cpu_id; /* CPU id associated with stream */
+ uint8_t header_end; /* End of header */
+ } ctx;
+};
+
+
+static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan)
+{
+ return trace_clock_read64();
+}
+
+static inline
+size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx)
+{
+ int i;
+ size_t orig_offset = offset;
+
+ if (likely(!ctx))
+ return 0;
+ for (i = 0; i < ctx->nr_fields; i++)
+ offset += ctx->fields[i].get_size(offset);
+ return offset - orig_offset;
+}
+
+static inline
+void ctx_record(struct lib_ring_buffer_ctx *bufctx,
+ struct ltt_channel *chan,
+ struct lttng_ctx *ctx)
+{
+ int i;
+
+ if (likely(!ctx))
+ return;
+ for (i = 0; i < ctx->nr_fields; i++)
+ ctx->fields[i].record(&ctx->fields[i], bufctx, chan);
+}
+
+/*
+ * record_header_size - Calculate the header size and padding necessary.
+ * @config: ring buffer instance configuration
+ * @chan: channel
+ * @offset: offset in the write buffer
+ * @pre_header_padding: padding to add before the header (output)
+ * @ctx: reservation context
+ *
+ * Returns the event header size (including padding).
+ *
+ * The payload must itself determine its own alignment from the biggest type it
+ * contains.
+ */
+static __inline__
+unsigned char record_header_size(const struct lib_ring_buffer_config *config,
+ struct channel *chan, size_t offset,
+ size_t *pre_header_padding,
+ struct lib_ring_buffer_ctx *ctx)
+{
+ struct ltt_channel *ltt_chan = channel_get_private(chan);
+ struct ltt_event *event = ctx->priv;
+ size_t orig_offset = offset;
+ size_t padding;
+
+ switch (ltt_chan->header_type) {
+ case 1: /* compact */
+ padding = lib_ring_buffer_align(offset, ltt_alignof(uint32_t));
+ offset += padding;
+ if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
+ offset += sizeof(uint32_t); /* id and timestamp */
+ } else {
+ /* Minimum space taken by 5-bit id */
+ offset += sizeof(uint8_t);
+ /* Align extended struct on largest member */
+ offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));
+ offset += sizeof(uint32_t); /* id */
+ offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));
+ offset += sizeof(uint64_t); /* timestamp */
+ }
+ break;
+ case 2: /* large */
+ padding = lib_ring_buffer_align(offset, ltt_alignof(uint16_t));
+ offset += padding;
+ offset += sizeof(uint16_t);
+ if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
+ offset += lib_ring_buffer_align(offset, ltt_alignof(uint32_t));
+ offset += sizeof(uint32_t); /* timestamp */
+ } else {
+ /* Align extended struct on largest member */
+ offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));
+ offset += sizeof(uint32_t); /* id */
+ offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t));
+ offset += sizeof(uint64_t); /* timestamp */
+ }
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ offset += ctx_get_size(offset, event->ctx);
+ offset += ctx_get_size(offset, ltt_chan->ctx);
+
+ *pre_header_padding = padding;
+ return offset - orig_offset;
+}
+
+#include "wrapper/ringbuffer/api.h"
+
+extern
+void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx,
+ uint32_t event_id);
+
+/*
+ * ltt_write_event_header
+ *
+ * Writes the event header to the offset (already aligned on 32-bits).
+ *
+ * @config: ring buffer instance configuration
+ * @ctx: reservation context
+ * @event_id: event ID
+ */
+static __inline__
+void ltt_write_event_header(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx,
+ uint32_t event_id)
+{
+ struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);
+ struct ltt_event *event = ctx->priv;
+
+ if (unlikely(ctx->rflags))
+ goto slow_path;
+
+ switch (ltt_chan->header_type) {
+ case 1: /* compact */
+ {
+ uint32_t id_time = 0;
+
+ bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id);
+ bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc);
+ lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
+ break;
+ }
+ case 2: /* large */
+ {
+ uint32_t timestamp = (uint32_t) ctx->tsc;
+ uint16_t id = event_id;
+
+ lib_ring_buffer_write(config, ctx, &id, sizeof(id));
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint32_t));
+ lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
+ break;
+ }
+ default:
+ WARN_ON_ONCE(1);
+ }
+
+ ctx_record(ctx, ltt_chan, event->ctx);
+ ctx_record(ctx, ltt_chan, ltt_chan->ctx);
+
+ return;
+
+slow_path:
+ ltt_write_event_header_slow(config, ctx, event_id);
+}
+
+void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config,
+ struct lib_ring_buffer_ctx *ctx,
+ uint32_t event_id)
+{
+ struct ltt_channel *ltt_chan = channel_get_private(ctx->chan);
+ struct ltt_event *event = ctx->priv;
+
+ switch (ltt_chan->header_type) {
+ case 1: /* compact */
+ if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
+ uint32_t id_time = 0;
+
+ bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id);
+ bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc);
+ lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time));
+ } else {
+ uint8_t id = 0;
+ uint64_t timestamp = ctx->tsc;
+
+ bt_bitfield_write(&id, uint8_t, 0, 5, 31);
+ lib_ring_buffer_write(config, ctx, &id, sizeof(id));
+ /* Align extended struct on largest member */
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));
+ lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));
+ lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
+ }
+ break;
+ case 2: /* large */
+ {
+ if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) {
+ uint32_t timestamp = (uint32_t) ctx->tsc;
+ uint16_t id = event_id;
+
+ lib_ring_buffer_write(config, ctx, &id, sizeof(id));
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint32_t));
+ lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
+ } else {
+ uint16_t id = 65535;
+ uint64_t timestamp = ctx->tsc;
+
+ lib_ring_buffer_write(config, ctx, &id, sizeof(id));
+ /* Align extended struct on largest member */
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));
+ lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id));
+ lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t));
+ lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp));
+ }
+ break;
+ }
+ default:
+ WARN_ON_ONCE(1);
+ }
+ ctx_record(ctx, ltt_chan, event->ctx);
+ ctx_record(ctx, ltt_chan, ltt_chan->ctx);
+}