MdePkg/Library/BaseIoLibIntrinsic/IoLibMsc.c

   1 /** @file
   2   I/O Library. This file has compiler specifics for Microsft C as there is no
   3   ANSI C standard for doing IO.
   4
   5   MSC - uses intrinsic functions and the optimize will remove the function call
   6   overhead.
   7
   8   We don't advocate putting compiler specifics in libraries or drivers but there
   9   is no other way to make this work.
  10
  11   Copyright (c) 2006 - 2021, Intel Corporation. All rights reserved.<BR>
  12   SPDX-License-Identifier: BSD-2-Clause-Patent
  13
  14 **/
  15
  16 #include "BaseIoLibIntrinsicInternal.h"
  17 #include "IoLibTdx.h"
  18
  19 //
  20 // Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  21 //
  22
  23 int
  24 _inp (
  25   unsigned short  port
  26   );
  27
  28 unsigned short
  29 _inpw (
  30   unsigned short  port
  31   );
  32
  33 unsigned long
  34 _inpd (
  35   unsigned short  port
  36   );
  37
  38 int
  39 _outp (
  40   unsigned short  port,
  41   int             databyte
  42   );
  43
  44 unsigned short
  45 _outpw (
  46   unsigned short  port,
  47   unsigned short  dataword
  48   );
  49
  50 unsigned long
  51 _outpd (
  52   unsigned short  port,
  53   unsigned long   dataword
  54   );
  55
  56 void
  57 _ReadWriteBarrier (
  58   void
  59   );
  60
  61 #pragma intrinsic(_inp)
  62 #pragma intrinsic(_inpw)
  63 #pragma intrinsic(_inpd)
  64 #pragma intrinsic(_outp)
  65 #pragma intrinsic(_outpw)
  66 #pragma intrinsic(_outpd)
  67 #pragma intrinsic(_ReadWriteBarrier)
  68
  69 //
  70 // _ReadWriteBarrier() forces memory reads and writes to complete at the point
  71 // in the call. This is only a hint to the compiler and does emit code.
  72 // In past versions of the compiler, _ReadWriteBarrier was enforced only
  73 // locally and did not affect functions up the call tree. In Visual C++
  74 // 2005, _ReadWriteBarrier is enforced all the way up the call tree.
  75 //
  76
  77 /**
  78   Reads an 8-bit I/O port.
  79
  80   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  81   This function must guarantee that all I/O read and write operations are
  82   serialized.
  83
  84   If 8-bit I/O port operations are not supported, then ASSERT().
  85
  86   For Td guest TDVMCALL_IO is invoked to read I/O port.
  87
  88   @param  Port  The I/O port to read.
  89
  90   @return The value read.
  91
  92 **/
  93 UINT8
  94 EFIAPI
  95 IoRead8 (
  96   IN      UINTN  Port
  97   )
  98 {
  99   UINT8    Value;
 100   BOOLEAN  Flag;
 101
 102   Flag = FilterBeforeIoRead (FilterWidth8, Port, &Value);
 103   if (Flag) {
 104     if (IsTdxGuest ()) {
 105       Value = TdIoRead8 (Port);
 106     } else {
 107       _ReadWriteBarrier ();
 108       Value = (UINT8)_inp ((UINT16)Port);
 109       _ReadWriteBarrier ();
 110     }
 111   }
 112
 113   FilterAfterIoRead (FilterWidth8, Port, &Value);
 114
 115   return Value;
 116 }
 117
 118 /**
 119   Writes an 8-bit I/O port.
 120
 121   Writes the 8-bit I/O port specified by Port with the value specified by Value
 122   and returns Value. This function must guarantee that all I/O read and write
 123   operations are serialized.
 124
 125   If 8-bit I/O port operations are not supported, then ASSERT().
 126
 127   For Td guest TDVMCALL_IO is invoked to write I/O port.
 128
 129   @param  Port  The I/O port to write.
 130   @param  Value The value to write to the I/O port.
 131
 132   @return The value written to the I/O port.
 133
 134 **/
 135 UINT8
 136 EFIAPI
 137 IoWrite8 (
 138   IN      UINTN  Port,
 139   IN      UINT8  Value
 140   )
 141 {
 142   BOOLEAN  Flag;
 143
 144   Flag = FilterBeforeIoWrite (FilterWidth8, Port, &Value);
 145   if (Flag) {
 146     if (IsTdxGuest ()) {
 147       TdIoWrite8 (Port, Value);
 148     } else {
 149       _ReadWriteBarrier ();
 150       (UINT8)_outp ((UINT16)Port, Value);
 151       _ReadWriteBarrier ();
 152     }
 153   }
 154
 155   FilterAfterIoWrite (FilterWidth8, Port, &Value);
 156
 157   return Value;
 158 }
 159
 160 /**
 161   Reads a 16-bit I/O port.
 162
 163   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
 164   This function must guarantee that all I/O read and write operations are
 165   serialized.
 166
 167   If 16-bit I/O port operations are not supported, then ASSERT().
 168   If Port is not aligned on a 16-bit boundary, then ASSERT().
 169
 170   For Td guest TDVMCALL_IO is invoked to read I/O port.
 171
 172   @param  Port  The I/O port to read.
 173
 174   @return The value read.
 175
 176 **/
 177 UINT16
 178 EFIAPI
 179 IoRead16 (
 180   IN      UINTN  Port
 181   )
 182 {
 183   UINT16   Value;
 184   BOOLEAN  Flag;
 185
 186   ASSERT ((Port & 1) == 0);
 187
 188   Flag = FilterBeforeIoRead (FilterWidth16, Port, &Value);
 189   if (Flag) {
 190     if (IsTdxGuest ()) {
 191       Value = TdIoRead16 (Port);
 192     } else {
 193       _ReadWriteBarrier ();
 194       Value = _inpw ((UINT16)Port);
 195       _ReadWriteBarrier ();
 196     }
 197   }
 198
 199   FilterBeforeIoRead (FilterWidth16, Port, &Value);
 200
 201   return Value;
 202 }
 203
 204 /**
 205   Writes a 16-bit I/O port.
 206
 207   Writes the 16-bit I/O port specified by Port with the value specified by Value
 208   and returns Value. This function must guarantee that all I/O read and write
 209   operations are serialized.
 210
 211   If 16-bit I/O port operations are not supported, then ASSERT().
 212   If Port is not aligned on a 16-bit boundary, then ASSERT().
 213
 214   For Td guest TDVMCALL_IO is invoked to write I/O port.
 215
 216   @param  Port  The I/O port to write.
 217   @param  Value The value to write to the I/O port.
 218
 219   @return The value written to the I/O port.
 220
 221 **/
 222 UINT16
 223 EFIAPI
 224 IoWrite16 (
 225   IN      UINTN   Port,
 226   IN      UINT16  Value
 227   )
 228 {
 229   BOOLEAN  Flag;
 230
 231   ASSERT ((Port & 1) == 0);
 232
 233   Flag = FilterBeforeIoWrite (FilterWidth16, Port, &Value);
 234   if (Flag) {
 235     if (IsTdxGuest ()) {
 236       TdIoWrite16 (Port, Value);
 237     } else {
 238       _ReadWriteBarrier ();
 239       _outpw ((UINT16)Port, Value);
 240       _ReadWriteBarrier ();
 241     }
 242   }
 243
 244   FilterAfterIoWrite (FilterWidth16, Port, &Value);
 245
 246   return Value;
 247 }
 248
 249 /**
 250   Reads a 32-bit I/O port.
 251
 252   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 253   This function must guarantee that all I/O read and write operations are
 254   serialized.
 255
 256   If 32-bit I/O port operations are not supported, then ASSERT().
 257   If Port is not aligned on a 32-bit boundary, then ASSERT().
 258
 259   For Td guest TDVMCALL_IO is invoked to read I/O port.
 260
 261   @param  Port  The I/O port to read.
 262
 263   @return The value read.
 264
 265 **/
 266 UINT32
 267 EFIAPI
 268 IoRead32 (
 269   IN      UINTN  Port
 270   )
 271 {
 272   UINT32   Value;
 273   BOOLEAN  Flag;
 274
 275   ASSERT ((Port & 3) == 0);
 276
 277   Flag = FilterBeforeIoRead (FilterWidth32, Port, &Value);
 278   if (Flag) {
 279     if (IsTdxGuest ()) {
 280       Value = TdIoRead32 (Port);
 281     } else {
 282       _ReadWriteBarrier ();
 283       Value = _inpd ((UINT16)Port);
 284       _ReadWriteBarrier ();
 285     }
 286   }
 287
 288   FilterAfterIoRead (FilterWidth32, Port, &Value);
 289
 290   return Value;
 291 }
 292
 293 /**
 294   Writes a 32-bit I/O port.
 295
 296   Writes the 32-bit I/O port specified by Port with the value specified by Value
 297   and returns Value. This function must guarantee that all I/O read and write
 298   operations are serialized.
 299
 300   If 32-bit I/O port operations are not supported, then ASSERT().
 301   If Port is not aligned on a 32-bit boundary, then ASSERT().
 302
 303   For Td guest TDVMCALL_IO is invoked to write I/O port.
 304
 305   @param  Port  The I/O port to write.
 306   @param  Value The value to write to the I/O port.
 307
 308   @return The value written to the I/O port.
 309
 310 **/
 311 UINT32
 312 EFIAPI
 313 IoWrite32 (
 314   IN      UINTN   Port,
 315   IN      UINT32  Value
 316   )
 317 {
 318   BOOLEAN  Flag;
 319
 320   ASSERT ((Port & 3) == 0);
 321
 322   Flag = FilterBeforeIoWrite (FilterWidth32, Port, &Value);
 323   if (Flag) {
 324     if (IsTdxGuest ()) {
 325       TdIoWrite32 (Port, Value);
 326     } else {
 327       _ReadWriteBarrier ();
 328       _outpd ((UINT16)Port, Value);
 329       _ReadWriteBarrier ();
 330     }
 331   }
 332
 333   FilterAfterIoWrite (FilterWidth32, Port, &Value);
 334
 335   return Value;
 336 }