include/side/abi/type-value.h

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright 2022-2023 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  */
   5
   6 #ifndef SIDE_ABI_TYPE_VALUE_H
   7 #define SIDE_ABI_TYPE_VALUE_H
   8
   9 #include <stdint.h>
  10 #include <side/macros.h>
  11 #include <side/endian.h>
  12
  13 /*
  14  * SIDE ABI for type values.
  15  *
  16  * The extensibility scheme for the SIDE ABI for type values is as
  17  * follows:
  18  *
  19  * * Existing type values are never changed nor extended. Type values
  20  *   can be added to the ABI by reserving a label within enum
  21  *   side_type_label.
  22  * * Each union part of the ABI has an explicit size defined by a
  23  *   side_padding() member. Each structure and union have a static
  24  *   assert validating its size.
  25  * * Changing the semantic of the existing type value fields is a
  26  *   breaking ABI change.
  27  *
  28  * Handling of unknown type values by the tracers:
  29  *
  30  * * A tracer may choose to support only a subset of the type values
  31  *   supported by libside. When encountering an unknown or unsupported
  32  *   type value, the tracer has the option to either disallow the entire
  33  *   event or skip over the unknown type, both at event registration and
  34  *   when receiving the side_call arguments.
  35  */
  36
  37 enum side_type_label_byte_order {
  38         SIDE_TYPE_BYTE_ORDER_LE = 0,
  39         SIDE_TYPE_BYTE_ORDER_BE = 1,
  40 };
  41
  42 #if (SIDE_BYTE_ORDER == SIDE_LITTLE_ENDIAN)
  43 enum side_integer128_split_index {
  44         SIDE_INTEGER128_SPLIT_LOW = 0,
  45         SIDE_INTEGER128_SPLIT_HIGH = 1,
  46         NR_SIDE_INTEGER128_SPLIT,
  47 };
  48 #else
  49 enum side_integer128_split_index {
  50         SIDE_INTEGER128_SPLIT_HIGH = 0,
  51         SIDE_INTEGER128_SPLIT_LOW = 1,
  52         NR_SIDE_INTEGER128_SPLIT,
  53 };
  54 #endif
  55
  56 union side_integer_value {
  57         uint8_t side_u8;
  58         uint16_t side_u16;
  59         uint32_t side_u32;
  60         uint64_t side_u64;
  61         /* Indexed with enum side_integer128_split_index */
  62         uint64_t side_u128_split[NR_SIDE_INTEGER128_SPLIT];
  63         int8_t side_s8;
  64         int16_t side_s16;
  65         int32_t side_s32;
  66         int64_t side_s64;
  67         /* Indexed with enum side_integer128_split_index */
  68         int64_t side_s128_split[NR_SIDE_INTEGER128_SPLIT];
  69         uintptr_t side_uptr;
  70         side_padding(32);
  71 } SIDE_PACKED;
  72 side_check_size(union side_integer_value, 32);
  73
  74 union side_bool_value {
  75         uint8_t side_bool8;
  76         uint16_t side_bool16;
  77         uint32_t side_bool32;
  78         uint64_t side_bool64;
  79         side_padding(32);
  80 } SIDE_PACKED;
  81 side_check_size(union side_bool_value, 32);
  82
  83 union side_float_value {
  84 #if __HAVE_FLOAT16
  85         _Float16 side_float_binary16;
  86 #endif
  87 #if __HAVE_FLOAT32
  88         _Float32 side_float_binary32;
  89 #endif
  90 #if __HAVE_FLOAT64
  91         _Float64 side_float_binary64;
  92 #endif
  93 #if __HAVE_FLOAT128
  94         _Float128 side_float_binary128;
  95 #endif
  96         side_padding(32);
  97 } SIDE_PACKED;
  98 side_check_size(union side_float_value, 32);
  99
 100 struct side_type_raw_string {
 101         side_ptr_t(const void) p;       /* pointer to string */
 102         uint8_t unit_size;              /* 1, 2, or 4 bytes */
 103         side_enum_t(enum side_type_label_byte_order, uint8_t) byte_order;
 104 } SIDE_PACKED;
 105 side_check_size(struct side_type_raw_string, 18);
 106
 107 #endif /* SIDE_ABI_TYPE_VALUE_H */