os/firehose_buffer_private.h

   1 /*
   2  * Copyright (c) 2015 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 #ifndef __FIREHOSE_BUFFER_PRIVATE__
  22 #define __FIREHOSE_BUFFER_PRIVATE__
  23
  24 #if OS_FIREHOSE_SPI
  25 #ifdef KERNEL
  26 #include <stdint.h>
  27 #else
  28 #include <os/base.h>
  29 #include <os/base_private.h>
  30 #include <dispatch/dispatch.h>
  31 #endif
  32
  33 #define OS_FIREHOSE_SPI_VERSION 20160318
  34
  35 /*!
  36  * @group Firehose SPI
  37  * SPI intended for logd only
  38  * Layout of structs is subject to change without notice
  39  */
  40
  41 #define FIREHOSE_BUFFER_LIBTRACE_HEADER_SIZE    2048ul
  42 #define FIREHOSE_BUFFER_KERNEL_CHUNK_COUNT              16
  43
  44 typedef struct firehose_buffer_range_s {
  45         uint16_t fbr_offset; // offset from the start of the buffer
  46         uint16_t fbr_length;
  47 } *firehose_buffer_range_t;
  48
  49 #ifdef KERNEL
  50
  51 typedef struct firehose_chunk_s *firehose_chunk_t;
  52
  53 // implemented by the kernel
  54 extern void __firehose_buffer_push_to_logd(firehose_buffer_t fb, bool for_io);
  55 extern void __firehose_critical_region_enter(void);
  56 extern void __firehose_critical_region_leave(void);
  57 extern void __firehose_allocate(vm_offset_t *addr, vm_size_t size);
  58
  59 // exported for the kernel
  60 firehose_tracepoint_t
  61 __firehose_buffer_tracepoint_reserve(uint64_t stamp, firehose_stream_t stream,
  62                 uint16_t pubsize, uint16_t privsize, uint8_t **privptr);
  63
  64 void
  65 __firehose_buffer_tracepoint_flush(firehose_tracepoint_t vat,
  66                 firehose_tracepoint_id_u vatid);
  67
  68 firehose_buffer_t
  69 __firehose_buffer_create(size_t *size);
  70
  71 void
  72 __firehose_merge_updates(firehose_push_reply_t update);
  73
  74 #else
  75
  76 #define __firehose_critical_region_enter()
  77 #define __firehose_critical_region_leave()
  78
  79 OS_EXPORT
  80 const uint32_t _firehose_spi_version;
  81
  82 OS_ALWAYS_INLINE
  83 static inline const uint8_t *
  84 _firehose_tracepoint_reader_init(firehose_chunk_t fc, const uint8_t **endptr)
  85 {
  86         const uint8_t *start = fc->fc_data;
  87         const uint8_t *end = fc->fc_start + fc->fc_pos.fcp_next_entry_offs;
  88
  89         if (end > fc->fc_start + FIREHOSE_CHUNK_SIZE) {
  90                 end = start;
  91         }
  92         *endptr = end;
  93         return start;
  94 }
  95
  96 OS_ALWAYS_INLINE
  97 static inline firehose_tracepoint_t
  98 _firehose_tracepoint_reader_next(const uint8_t **ptr, const uint8_t *end)
  99 {
 100         const uint16_t ft_size = offsetof(struct firehose_tracepoint_s, ft_data);
 101         struct ft_unaligned_s {
 102                 struct firehose_tracepoint_s ft;
 103         } __attribute__((packed, aligned(1))) *uft;
 104
 105         do {
 106                 uft = (struct ft_unaligned_s *)*ptr;
 107                 if (uft->ft.ft_data >= end) {
 108                         // reached the end
 109                         return NULL;
 110                 }
 111                 if (!uft->ft.ft_length) {
 112                         // tracepoint write didn't even start
 113                         return NULL;
 114                 }
 115                 if (uft->ft.ft_length > end - uft->ft.ft_data) {
 116                         // invalid length
 117                         return NULL;
 118                 }
 119                 *ptr += roundup(ft_size + uft->ft.ft_length, 8);
 120                 // test whether write of the tracepoint was finished
 121         } while (os_unlikely(uft->ft.ft_id.ftid_value == 0));
 122
 123         return (firehose_tracepoint_t)uft;
 124 }
 125
 126 #define firehose_tracepoint_foreach(ft, fbc) \
 127                 for (const uint8_t *end, *p = _firehose_tracepoint_reader_init(fbc, &end); \
 128                                 ((ft) = _firehose_tracepoint_reader_next(&p, end)); )
 129
 130 OS_ALWAYS_INLINE
 131 static inline bool
 132 firehose_buffer_range_validate(firehose_chunk_t fc, firehose_tracepoint_t ft,
 133                 firehose_buffer_range_t range)
 134 {
 135         if (range->fbr_offset + range->fbr_length > FIREHOSE_CHUNK_SIZE) {
 136                 return false;
 137         }
 138         if (fc->fc_start + range->fbr_offset < ft->ft_data + ft->ft_length) {
 139                 return false;
 140         }
 141         return true;
 142 }
 143
 144 #endif // !KERNEL
 145
 146 #endif // OS_FIREHOSE_SPI
 147
 148 #endif // __FIREHOSE_BUFFER_PRIVATE__