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/*
* Copyright (c) 2016-2017, NVIDIA CORPORATION. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
#ifndef TRACEBUF_H
#define TRACEBUF_H
#include <linux/stddef.h>
#include <stdbool.h>
struct tracectx {
volatile struct tracebuf *shared;
uintptr_t begin;
uintptr_t end;
uint32_t length;
uint32_t maxsize;
};
struct tracebuf {
uint64_t version;
uint64_t position;
uint64_t seqid;
uint32_t length;
uint32_t maxsize;
} __packed;
struct tracehdr {
uint64_t params;
uint64_t seqid;
uint32_t length;
uint32_t reserved;
} __packed;
struct pullstate {
uint64_t wrapcnt;
uint64_t current;
bool wrapped;
bool copos;
};
/*
* Description for pull_init()
* - Initialize a new pullstate structure used to mark the location
* from which subsequent reads will occur.
* - Subsequent reads will advance the read position within the
* pullstate structure.
* Parameters
* - Param `ctx` is provided by the caller.
* - Param `state` is filled by the callee.
* Return values
* - Operation never fails.
*/
void pull_init(struct tracectx *ctx, struct pullstate *state);
/*
* Description for tracebuf_init()
* - Initialize or re-initialize memory to prepare for binding.
* - Memory address and length must be aligned to MIN_WORD_SIZE and
* of "sufficient" size, where "sufficient" is currently some
* implementation-defined value not to be smaller than 4KB.
* Parameters
* - Param `ctx` is filled by the callee on success.
* - Param `buffer` and `length` are provided by the caller.
* Return values
* - Returns 0 on success.
*/
int tracebuf_init(struct tracectx *ctx, void *buffer, uint32_t length);
/*
* Description for tracebuf_bind()
* - Binds to the specified region of memory. The specified region
* of memory must have been previously initialized with the exact
* same parameters for memory address and length.
* - Memory address and length must be aligned to MIN_WORD_SIZE and
* of "sufficient" size, where "sufficient" is currently some
* implementation-defined value not to be smaller than 4KB.
* Parameters
* - Param `ctx` is filled by the callee on success.
* - Param `buffer` and `length` are provided by the caller.
* Return values
* - Returns 0 on success.
*/
int tracebuf_bind(struct tracectx *ctx, void *buffer, uint32_t length);
/*
* Description for tracebuf_push()
* - Add a message to the buffer; this operation never fails.
* - If there is insufficient message space available, the oldest
* message(s) will be overwritten.
* - Payloads may get truncated if its size is larger than
* tracebuf.maxsize, or padded up to at least MIN_WORD_SIZE.
* Parameters
* - Param `ctx` is provided by the caller.
* - Param `hdr.params` is provided by the caller.
* - Param `hdr.seqid` and `hdr.length` is filled by the callee.
* - Param `payload` and `paylen` are provided by the caller.
* Return values
* - Operation never fails.
*/
void tracebuf_push(struct tracectx *ctx, struct tracehdr *hdr,
void *payload, uint32_t paylen);
/*
* Description for tracebuf_pull()
* - Attempt to get a message from the buffer; may fail for many
* different reasons. See possible return values below.
* - Read position is determined by state specified in the pullstate
* structure; this state is implicitly updated after each request.
* - Value in *paylen specifies bytes available on input, and
* is updated to bytes written after a successful request.
* - If input space is insufficient, the payload will be truncated.
* Parameters
* - Param `ctx` is provided by the caller.
* - Param `state` is provided by the caller.
* - Param `hdr` is filled by the callee on success.
* - Param `payload` is provided by the caller.
* - Param `paylen` is provided by the caller and updated by the callee.
* Return values
* - Returns -EAGAIN when the current read request should be retried.
* - Returns -EINTR when the overall read sequence needs to be restarted.
* - Returns -ENOBUFS when there is no more data available.
* - Returns 0 on success.
*/
int tracebuf_pull(struct tracectx *ctx, struct pullstate *state,
struct tracehdr *hdr, void *payload, uint32_t *paylen);
#ifdef ENABLE_DEBUG_HOOK
void debug_callback(struct tracectx *ctx, char *prefix);
#endif
#endif
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