Rename ringbuffer-context.h to ust-ringbuffer-context.h

[lttng-ust.git] / include / lttng / ust-ringbuffer-context.h

diff --git a/include/lttng/ust-ringbuffer-context.h b/include/lttng/ust-ringbuffer-context.h
new file mode 100644 (file)
index 0000000..133d802
--- /dev/null
+++ b/include/lttng/ust-ringbuffer-context.h
@@ -0,0 +1,131 @@
+/*
+ * SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2010-2021 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * Ring buffer context header.
+ */
+
+#ifndef _LTTNG_UST_RING_BUFFER_CONTEXT_H
+#define _LTTNG_UST_RING_BUFFER_CONTEXT_H
+
+#include <errno.h>
+#include <stdint.h>
+#include <stddef.h>
+#include <urcu/arch.h>
+#include <string.h>
+
+#include <lttng/ust-tracer.h>
+#include <lttng/ust-utils.h>
+#include <lttng/ust-compiler.h>
+
+struct lttng_ust_ring_buffer;
+struct lttng_ust_ring_buffer_channel;
+struct lttng_ust_ring_buffer_ctx;
+struct lttng_ust_ring_buffer_ctx_private;
+
+/*
+ * ring buffer context
+ *
+ * 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_ring_buffer_ctx {
+       uint32_t struct_size;                   /* Size of this structure. */
+
+       void *client_priv;                      /* Ring buffer client private data */
+       size_t data_size;                       /* size of payload */
+       int largest_align;                      /*
+                                                * alignment of the largest element
+                                                * in the payload
+                                                */
+       void *ip;                               /* caller ip address */
+
+       /* Private ring buffer context, set by reserve callback. */
+       struct lttng_ust_ring_buffer_ctx_private *priv;
+
+       /* End of base ABI. Fields below should be used after checking struct_size. */
+};
+
+/**
+ * lttng_ust_ring_buffer_ctx_init - initialize ring buffer context
+ * @ctx: ring buffer context to initialize
+ * @client_priv: client private data
+ * @data_size: size of record data payload
+ * @largest_align: largest alignment within data payload types
+ * @ip: caller ip address
+ */
+static inline
+void lttng_ust_ring_buffer_ctx_init(struct lttng_ust_ring_buffer_ctx *ctx,
+                                       void *client_priv, size_t data_size, int largest_align,
+                                       void *ip)
+       lttng_ust_notrace;
+static inline
+void lttng_ust_ring_buffer_ctx_init(struct lttng_ust_ring_buffer_ctx *ctx,
+                                       void *client_priv, size_t data_size, int largest_align,
+                                       void *ip)
+{
+       ctx->struct_size = sizeof(struct lttng_ust_ring_buffer_ctx);
+       ctx->client_priv = client_priv;
+       ctx->data_size = data_size;
+       ctx->largest_align = largest_align;
+       ctx->ip = ip;
+       ctx->priv = NULL;
+}
+
+/*
+ * We need to define LTTNG_UST_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 LTTNG_UST_RING_BUFFER_ALIGN_ATTR is only available for the client
+ * code.
+ */
+#ifdef LTTNG_UST_RING_BUFFER_NATURAL_ALIGN
+
+# define LTTNG_UST_RING_BUFFER_ALIGN_ATTR      /* Default arch alignment */
+
+/*
+ * lttng_ust_ring_buffer_align - Calculate the offset needed to align the type.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @size_of_type: Must be non-zero, power of 2.
+ */
+static inline
+unsigned int lttng_ust_ring_buffer_align(size_t align_drift, size_t size_of_type)
+       lttng_ust_notrace;
+static inline
+unsigned int lttng_ust_ring_buffer_align(size_t align_drift, size_t size_of_type)
+{
+       return lttng_ust_offset_align(align_drift, size_of_type);
+}
+
+#else
+
+# define LTTNG_UST_RING_BUFFER_ALIGN_ATTR __attribute__((packed))
+
+/*
+ * lttng_ust_ring_buffer_align - Calculate the offset needed to align the type.
+ * @align_drift:  object offset from an "alignment"-aligned address.
+ * @size_of_type: Must be non-zero, power of 2.
+ */
+static inline
+unsigned int lttng_ust_ring_buffer_align(size_t align_drift, size_t size_of_type)
+       lttng_ust_notrace;
+static inline
+unsigned int lttng_ust_ring_buffer_align(size_t align_drift __attribute__((unused)),
+               size_t size_of_type __attribute__((unused)))
+{
+       /*
+        * On architectures with efficient unaligned memory access, the content
+        * of the ringbuffer is packed and so the offset is always zero.
+        */
+       return 0;
+}
+
+#endif
+
+#endif /* _LTTNG_UST_RING_BUFFER_CONTEXT_H */