Add missing ringbuffer-context.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3dcf5b2c12c88570b9089b187d7e560af26e96af

diff --git a/include/lttng/ringbuffer-context.h b/include/lttng/ringbuffer-context.h
new file mode 100644 (file)
index 0000000..614150d
--- /dev/null
+++ b/include/lttng/ringbuffer-context.h
@@ -0,0 +1,162 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2010-2021 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Ring buffer context header.
+ */
+
+#ifndef _LTTNG_RING_BUFFER_CONTEXT_H
+#define _LTTNG_RING_BUFFER_CONTEXT_H
+
+#include <errno.h>
+#include <lttng/ust-tracer.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <urcu/arch.h>
+#include <string.h>
+#include <lttng/align.h>
+#include <lttng/ust-compiler.h>
+
+struct lttng_ust_lib_ring_buffer;
+struct lttng_ust_lib_ring_buffer_channel;
+struct lttng_ust_lib_ring_buffer_ctx;
+struct lttng_ust_shm_handle;
+
+/*
+ * ring buffer context
+ *
+ * Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
+ * lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
+ * lib_ring_buffer_write().
+ *
+ * IMPORTANT: this structure is part of the ABI between the probe and
+ * UST. Fields need to be only added at the end, never reordered, never
+ * removed.
+ *
+ * The field @struct_size should be used to determine the size of the
+ * structure. It should be queried before using additional fields added
+ * at the end of the structure.
+ */
+struct lttng_ust_lib_ring_buffer_ctx {
+       uint32_t struct_size;           /* Size of this structure. */
+
+       /* input received by lib_ring_buffer_reserve(), saved here. */
+       struct lttng_ust_lib_ring_buffer_channel *chan; /* channel */
+       void *priv;                     /* client private data */
+       struct lttng_ust_shm_handle *handle;    /* shared-memory handle */
+       size_t data_size;               /* size of payload */
+       int largest_align;              /*
+                                        * alignment of the largest element
+                                        * in the payload
+                                        */
+       int cpu;                        /* processor id */
+
+       /* output from lib_ring_buffer_reserve() */
+       struct lttng_ust_lib_ring_buffer *buf;  /*
+                                        * buffer corresponding to processor id
+                                        * for this channel
+                                        */
+       size_t slot_size;               /* size of the reserved slot */
+       unsigned long buf_offset;       /* offset following the record header */
+       unsigned long pre_offset;       /*
+                                        * Initial offset position _before_
+                                        * the record is written. Positioned
+                                        * prior to record header alignment
+                                        * padding.
+                                        */
+       uint64_t tsc;                   /* time-stamp counter value */
+       unsigned int rflags;            /* reservation flags */
+       void *ip;                       /* caller ip address */
+       struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
+
+       /* End of base ABI. Fields below should be used after checking struct_size. */
+};
+
+/**
+ * lib_ring_buffer_ctx_init - initialize ring buffer context
+ * @ctx: ring buffer context to initialize
+ * @chan: channel
+ * @priv: client private data
+ * @data_size: size of record data payload
+ * @largest_align: largest alignment within data payload types
+ * @cpu: processor id
+ */
+static inline lttng_ust_notrace
+void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+                             struct lttng_ust_lib_ring_buffer_channel *chan,
+                             void *priv, size_t data_size, int largest_align,
+                             int cpu, struct lttng_ust_shm_handle *handle);
+static inline
+void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+                             struct lttng_ust_lib_ring_buffer_channel *chan,
+                             void *priv, size_t data_size, int largest_align,
+                             int cpu, struct lttng_ust_shm_handle *handle)
+{
+       ctx->struct_size = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
+       ctx->chan = chan;
+       ctx->priv = priv;
+       ctx->data_size = data_size;
+       ctx->largest_align = largest_align;
+       ctx->cpu = cpu;
+       ctx->rflags = 0;
+       ctx->handle = handle;
+       ctx->ip = 0;
+}
+
+/*
+ * We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
+ * compile-time. We have to duplicate the "config->align" information and the
+ * definition here because config->align is used both in the slow and fast
+ * paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
+ */
+#ifdef RING_BUFFER_ALIGN
+
+# define RING_BUFFER_ALIGN_ATTR                /* Default arch alignment */
+
+/*
+ * Calculate the offset needed to align the type.
+ * size_of_type must be non-zero.
+ */
+static inline lttng_ust_notrace
+unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
+static inline
+unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
+{
+       return lttng_ust_offset_align(align_drift, size_of_type);
+}
+
+#else
+
+# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
+
+/*
+ * Calculate the offset needed to align the type.
+ * size_of_type must be non-zero.
+ */
+static inline lttng_ust_notrace
+unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
+static inline
+unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
+{
+       return 0;
+}
+
+#endif
+
+/**
+ * lib_ring_buffer_align_ctx - Align context offset on "alignment"
+ * @ctx: ring buffer context.
+ */
+static inline lttng_ust_notrace
+void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+                          size_t alignment);
+static inline
+void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
+                          size_t alignment)
+{
+       ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
+                                                alignment);
+}
+
+#endif /* _LTTNG_RING_BUFFER_CONTEXT_H */