MdePkg/Library/BaseIoLibIntrinsic/IoLibGcc.c

   1 /** @file
   2   I/O Library. This file has compiler specifics for GCC as there is no
   3   ANSI C standard for doing IO.
   4
   5   GCC - uses EFIAPI assembler. __asm__ calls GAS. __volatile__ makes sure the
   6   compiler puts the assembler in this exact location. The complex GNUC
   7   operations are not optimzed. It would be possible to also write these
   8   with EFIAPI assembler.
   9
  10   We don't advocate putting compiler specifics in libraries or drivers but there
  11   is no other way to make this work.
  12
  13   Copyright (c) 2006 - 2021, Intel Corporation. All rights reserved.<BR>
  14   SPDX-License-Identifier: BSD-2-Clause-Patent
  15
  16 **/
  17
  18 #include "BaseIoLibIntrinsicInternal.h"
  19 #include "IoLibTdx.h"
  20
  21 /**
  22   Reads an 8-bit I/O port.
  23
  24   Reads the 8-bit I/O port specified by Port. The 8-bit read value is returned.
  25   This function must guarantee that all I/O read and write operations are
  26   serialized.
  27
  28   If 8-bit I/O port operations are not supported, then ASSERT()
  29
  30   For Td guest TDVMCALL_IO is invoked to read I/O port.
  31
  32   @param  Port  The I/O port to read.
  33
  34   @return The value read.
  35
  36 **/
  37 UINT8
  38 EFIAPI
  39 IoRead8 (
  40   IN      UINTN  Port
  41   )
  42 {
  43   UINT8    Data;
  44   BOOLEAN  Flag;
  45
  46   Flag = FilterBeforeIoRead (FilterWidth8, Port, &Data);
  47   if (Flag) {
  48     if (IsTdxGuest ()) {
  49       Data = TdIoRead8 (Port);
  50     } else {
  51       __asm__ __volatile__ ("inb %w1,%b0" : "=a" (Data) : "d" ((UINT16)Port));
  52     }
  53   }
  54
  55   FilterAfterIoRead (FilterWidth8, Port, &Data);
  56
  57   return Data;
  58 }
  59
  60 /**
  61   Writes an 8-bit I/O port.
  62
  63   Writes the 8-bit I/O port specified by Port with the value specified by Value
  64   and returns Value. This function must guarantee that all I/O read and write
  65   operations are serialized.
  66
  67   If 8-bit I/O port operations are not supported, then ASSERT().
  68
  69   For Td guest TDVMCALL_IO is invoked to write I/O port.
  70
  71   @param  Port  The I/O port to write.
  72   @param  Value The value to write to the I/O port.
  73
  74   @return The value written the I/O port.
  75
  76 **/
  77 UINT8
  78 EFIAPI
  79 IoWrite8 (
  80   IN      UINTN  Port,
  81   IN      UINT8  Value
  82   )
  83 {
  84   BOOLEAN  Flag;
  85
  86   Flag = FilterBeforeIoWrite (FilterWidth8, Port, &Value);
  87   if (Flag) {
  88     if (IsTdxGuest ()) {
  89       TdIoWrite8 (Port, Value);
  90     } else {
  91       __asm__ __volatile__ ("outb %b0,%w1" : : "a" (Value), "d" ((UINT16)Port));
  92     }
  93   }
  94
  95   FilterAfterIoWrite (FilterWidth8, Port, &Value);
  96
  97   return Value;
  98 }
  99
 100 /**
 101   Reads a 16-bit I/O port.
 102
 103   Reads the 16-bit I/O port specified by Port. The 16-bit read value is returned.
 104   This function must guarantee that all I/O read and write operations are
 105   serialized.
 106
 107   If 16-bit I/O port operations are not supported, then ASSERT().
 108   If Port is not aligned on a 16-bit boundary, then ASSERT().
 109
 110   For Td guest TDVMCALL_IO is invoked to read I/O port.
 111
 112   @param  Port  The I/O port to read.
 113
 114   @return The value read.
 115
 116 **/
 117 UINT16
 118 EFIAPI
 119 IoRead16 (
 120   IN      UINTN  Port
 121   )
 122 {
 123   UINT16   Data;
 124   BOOLEAN  Flag;
 125
 126   ASSERT ((Port & 1) == 0);
 127
 128   Flag = FilterBeforeIoRead (FilterWidth16, Port, &Data);
 129   if (Flag) {
 130     if (IsTdxGuest ()) {
 131       Data = TdIoRead16 (Port);
 132     } else {
 133       __asm__ __volatile__ ("inw %w1,%w0" : "=a" (Data) : "d" ((UINT16)Port));
 134     }
 135   }
 136
 137   FilterAfterIoRead (FilterWidth16, Port, &Data);
 138
 139   return Data;
 140 }
 141
 142 /**
 143   Writes a 16-bit I/O port.
 144
 145   Writes the 16-bit I/O port specified by Port with the value specified by Value
 146   and returns Value. This function must guarantee that all I/O read and write
 147   operations are serialized.
 148
 149   If 16-bit I/O port operations are not supported, then ASSERT().
 150   If Port is not aligned on a 16-bit boundary, then ASSERT().
 151
 152   For Td guest TDVMCALL_IO is invoked to write I/O port.
 153
 154   @param  Port  The I/O port to write.
 155   @param  Value The value to write to the I/O port.
 156
 157   @return The value written the I/O port.
 158
 159 **/
 160 UINT16
 161 EFIAPI
 162 IoWrite16 (
 163   IN      UINTN   Port,
 164   IN      UINT16  Value
 165   )
 166 {
 167   BOOLEAN  Flag;
 168
 169   ASSERT ((Port & 1) == 0);
 170
 171   Flag = FilterBeforeIoWrite (FilterWidth16, Port, &Value);
 172   if (Flag) {
 173     if (IsTdxGuest ()) {
 174       TdIoWrite16 (Port, Value);
 175     } else {
 176       __asm__ __volatile__ ("outw %w0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 177     }
 178   }
 179
 180   FilterAfterIoWrite (FilterWidth16, Port, &Value);
 181
 182   return Value;
 183 }
 184
 185 /**
 186   Reads a 32-bit I/O port.
 187
 188   Reads the 32-bit I/O port specified by Port. The 32-bit read value is returned.
 189   This function must guarantee that all I/O read and write operations are
 190   serialized.
 191
 192   If 32-bit I/O port operations are not supported, then ASSERT().
 193   If Port is not aligned on a 32-bit boundary, then ASSERT().
 194
 195   For Td guest TDVMCALL_IO is invoked to read I/O port.
 196
 197   @param  Port  The I/O port to read.
 198
 199   @return The value read.
 200
 201 **/
 202 UINT32
 203 EFIAPI
 204 IoRead32 (
 205   IN      UINTN  Port
 206   )
 207 {
 208   UINT32   Data;
 209   BOOLEAN  Flag;
 210
 211   ASSERT ((Port & 3) == 0);
 212
 213   Flag = FilterBeforeIoRead (FilterWidth32, Port, &Data);
 214   if (Flag) {
 215     if (IsTdxGuest ()) {
 216       Data = TdIoRead32 (Port);
 217     } else {
 218       __asm__ __volatile__ ("inl %w1,%0" : "=a" (Data) : "d" ((UINT16)Port));
 219     }
 220   }
 221
 222   FilterAfterIoRead (FilterWidth32, Port, &Data);
 223
 224   return Data;
 225 }
 226
 227 /**
 228   Writes a 32-bit I/O port.
 229
 230   Writes the 32-bit I/O port specified by Port with the value specified by Value
 231   and returns Value. This function must guarantee that all I/O read and write
 232   operations are serialized.
 233
 234   If 32-bit I/O port operations are not supported, then ASSERT().
 235   If Port is not aligned on a 32-bit boundary, then ASSERT().
 236
 237   For Td guest TDVMCALL_IO is invoked to write I/O port.
 238
 239   @param  Port  The I/O port to write.
 240   @param  Value The value to write to the I/O port.
 241
 242   @return The value written the I/O port.
 243
 244 **/
 245 UINT32
 246 EFIAPI
 247 IoWrite32 (
 248   IN      UINTN   Port,
 249   IN      UINT32  Value
 250   )
 251 {
 252   BOOLEAN  Flag;
 253
 254   ASSERT ((Port & 3) == 0);
 255
 256   Flag = FilterBeforeIoWrite (FilterWidth32, Port, &Value);
 257   if (Flag) {
 258     if (IsTdxGuest ()) {
 259       TdIoWrite32 (Port, Value);
 260     } else {
 261       __asm__ __volatile__ ("outl %0,%w1" : : "a" (Value), "d" ((UINT16)Port));
 262     }
 263   }
 264
 265   FilterAfterIoWrite (FilterWidth32, Port, &Value);
 266
 267   return Value;
 268 }