1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #ifndef _LINUX_TRACE_REMOTE_H 4 #define _LINUX_TRACE_REMOTE_H 5 6 #include <linux/dcache.h> 7 #include <linux/ring_buffer.h> 8 #include <linux/trace_remote_event.h> 9 10 /** 11 * struct trace_remote_callbacks - Callbacks used by Tracefs to control the remote 12 * @init: Called once the remote has been registered. Allows the 13 * caller to extend the Tracefs remote directory 14 * @load_trace_buffer: Called before Tracefs accesses the trace buffer for the first 15 * time. Must return a &trace_buffer_desc 16 * (most likely filled with trace_remote_alloc_buffer()) 17 * @unload_trace_buffer: 18 * Called once Tracefs has no use for the trace buffer 19 * (most likely call trace_remote_free_buffer()) 20 * @enable_tracing: Called on Tracefs tracing_on. It is expected from the 21 * remote to allow writing. 22 * @swap_reader_page: Called when Tracefs consumes a new page from a 23 * ring-buffer. It is expected from the remote to isolate a 24 * @reset: Called on `echo 0 > trace`. It is expected from the 25 * remote to reset all ring-buffer pages. 26 * new reader-page from the @cpu ring-buffer. 27 * @enable_event: Called on events/event_name/enable. It is expected from 28 * the remote to allow the writing event @id. 29 */ 30 struct trace_remote_callbacks { 31 int (*init)(struct dentry *d, void *priv); 32 struct trace_buffer_desc *(*load_trace_buffer)(unsigned long size, void *priv); 33 void (*unload_trace_buffer)(struct trace_buffer_desc *desc, void *priv); 34 int (*enable_tracing)(bool enable, void *priv); 35 int (*swap_reader_page)(unsigned int cpu, void *priv); 36 int (*reset)(unsigned int cpu, void *priv); 37 int (*enable_event)(unsigned short id, bool enable, void *priv); 38 }; 39 40 int trace_remote_register(const char *name, struct trace_remote_callbacks *cbs, void *priv, 41 struct remote_event *events, size_t nr_events); 42 43 int trace_remote_alloc_buffer(struct trace_buffer_desc *desc, size_t desc_size, size_t buffer_size, 44 const struct cpumask *cpumask); 45 46 void trace_remote_free_buffer(struct trace_buffer_desc *desc); 47 48 #endif 49