148 lines
5.2 KiB
C
148 lines
5.2 KiB
C
/*
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* Copyright (c) 2016-2017, NVIDIA CORPORATION. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef EVENTLIB_INIT_H
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#define EVENTLIB_INIT_H
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/* All pointers targeted to shared memory are annotated with 'shmptr' */
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#define shmptr /* empty, pure annotation */
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#include "eventlib.h"
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#include "utility.h"
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#include "eventlib_tbuf.h"
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#include "eventlib_flt.h"
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#define ALIGN_64_DOWN(x) ((x) & ~((typeof(x))(sizeof(uint64_t) - 1)))
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#define ALIGN_64_UP(x) ALIGN_64_DOWN((x) + ((uint32_t)sizeof(uint64_t) - 1))
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#define ALIGN_64_CHECK(x) ((x) == ALIGN_64_DOWN(x))
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/* Eventlib uses two shared memory blocks, one is read only for readers,
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* and other is read-write for readers.
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*
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* These blocks can be physically accessed by different eventlib builds
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* simultaneuosly. Thus special mesures have to be taken to ensure
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* compatibility.
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*
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* - Blocks are separated into subblocks corresponding to subsystems. At this
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* time, subsystems are "tracebuf" and "filtering". One more could be -
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* alive management. Room for subsystems costs 8 bytes per subsystem per
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* shmem block - thus should not be an issue to reserve space for 8 of them.
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* - Each subblock holds some sort of version/compatibility information, that
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* can be used in subsystem-specific way to find out if reader's
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* implementation of this subsystem can understand writer's implementation
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* of this subsystem. Details are subsystem-specific.
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* - Thus reader can understand some of writer's subsystems, but maybe not
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* all. Understanding 'tracebuf' subsystem is required.Not understanding
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* other subsystem is possible but then reader will have only limited
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* information.
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*/
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#define EVENTLIB_SUBSYS_TRACEBUF 0
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#define EVENTLIB_SUBSYS_FILTERING 1
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#define EVENTLIB_SUBSYS_MAX 2
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#define EVENTLIB_TBUFS_MAX 6
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#define EVENTLIB_MAGIC_W2R 0x52574c45 /* 'ELWR' in little endian */
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#define EVENTLIB_MAGIC_R2W 0x57524c45 /* 'ELRW' in little endian */
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struct eventlib_shared {
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/* Different magic is used for two shared memory blocks */
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uint32_t magic;
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/* Number of trace buffers
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* Below value is updated from writer context
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*/
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uint32_t num_buffers;
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/* Locatons of subsystem's information. If subsystem is not presented
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* in particular block, corresponding offset/size are kept zeroed.
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*/
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struct {
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uint32_t offset;
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uint32_t size;
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} subsys[EVENTLIB_SUBSYS_MAX];
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} __attribute__((__packed__));
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struct eventlib_init {
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/* writer, init time: offsets of currently unallocated space */
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uint32_t w2r_offset, r2w_offset;
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/* Local copy of subsystem information is used to protect against
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* unexpected asynchronous changes (not expected under normal use).
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*/
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struct eventlib_shared w2r_copy;
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struct eventlib_shared r2w_copy;
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struct eventlib_tbuf_ctx tbuf[EVENTLIB_TBUFS_MAX];
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struct eventlib_flt_ctx flt;
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};
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static inline void *subsys_shm_area(shmptr struct eventlib_shared *sh,
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struct eventlib_shared *copy, int subsys)
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{
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if (sh == NULL)
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return NULL;
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return ((void *)((uintptr_t)sh + copy->subsys[subsys].offset));
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}
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#define subsys_w2r_area(ctx, subsys) \
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subsys_shm_area(ctx->w2r_shm, &ctx->priv->w2r_copy, \
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EVENTLIB_SUBSYS_ ## subsys)
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#define subsys_r2w_area(ctx, subsys) \
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subsys_shm_area(ctx->r2w_shm, &ctx->priv->r2w_copy, \
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EVENTLIB_SUBSYS_ ## subsys)
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static inline uint32_t subsys_shm_size(struct eventlib_shared *copy, int subsys)
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{
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return copy->subsys[subsys].size;
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}
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#define subsys_w2r_size(ctx, subsys) \
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subsys_shm_size(&ctx->priv->w2r_copy, EVENTLIB_SUBSYS_ ## subsys)
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#define subsys_r2w_size(ctx, subsys) \
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subsys_shm_size(&ctx->priv->r2w_copy, EVENTLIB_SUBSYS_ ## subsys)
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static inline int subsys_shm_carve(struct eventlib_shared *copy,
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uint32_t *shm_size, uint32_t *shm_offset, int subsys, uint32_t size)
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{
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if (size > *shm_size - *shm_offset)
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return -ENOSPC;
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copy->subsys[subsys].offset = *shm_offset;
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copy->subsys[subsys].size = size;
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*shm_offset += ALIGN_64_UP(size);
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return 0;
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}
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#define subsys_w2r_carve(ctx, subsys, size) \
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subsys_shm_carve(&ctx->priv->w2r_copy, &ctx->w2r_shm_size, \
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&ctx->priv->w2r_offset, EVENTLIB_SUBSYS_ ## subsys, size)
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#define subsys_r2w_carve(ctx, subsys, size) \
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subsys_shm_carve(&ctx->priv->r2w_copy, &ctx->r2w_shm_size, \
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&ctx->priv->r2w_offset, EVENTLIB_SUBSYS_ ## subsys, size)
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#endif
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