src/arch/i386/include/libkir.h

   1 #ifndef LIBKIR_H
   2 #define LIBKIR_H
   3
   4 #include "realmode.h"
   5
   6 #ifndef ASSEMBLY
   7
   8 /*
   9  * Full API documentation for these functions is in realmode.h.
  10  *
  11  */
  12
  13 /* Access to variables in .data16 and .text16 in a way compatible with librm */
  14 #define __data16( variable ) variable
  15 #define __text16( variable ) variable
  16 #define __use_data16( variable ) variable
  17 #define __use_text16( variable ) variable
  18
  19 /* Copy to/from base memory */
  20
  21 static inline void copy_to_real_libkir ( uint16_t dest_seg, uint16_t dest_off,
  22                                          void *src, size_t n ) {
  23         __asm__ __volatile__ ( "movw %4, %%es\n\t"
  24                                "cld\n\t"
  25                                "rep movsb\n\t"
  26                                "pushw %%ds\n\t" /* restore %es */
  27                                "popw %%es\n\t"
  28                                : "=S" ( src ), "=D" ( dest_off ),
  29                                  "=c" ( n ) /* clobbered */
  30                                : "S" ( src ), "r" ( dest_seg ),
  31                                  "D" ( dest_off ), "c" ( n )
  32                                : "memory" );
  33 }
  34
  35 static inline void copy_from_real_libkir ( void *dest,
  36                                            uint16_t src_seg, uint16_t src_off,
  37                                            size_t n ) {
  38         __asm__ __volatile__ ( "movw %%ax, %%ds\n\t"
  39                                "cld\n\t"
  40                                "rep movsb\n\t"
  41                                "pushw %%es\n\t" /* restore %ds */
  42                                "popw %%ds\n\t"
  43                                : "=S" ( src_off ), "=D" ( dest ),
  44                                  "=c" ( n ) /* clobbered */
  45                                : "a" ( src_seg ), "S" ( src_off ),
  46                                  "D" ( dest ), "c" ( n )
  47                                : "memory" );
  48 }
  49 #define copy_to_real copy_to_real_libkir
  50 #define copy_from_real copy_from_real_libkir
  51
  52 /*
  53  * Transfer individual values to/from base memory.  There may well be
  54  * a neater way to do this.  We have two versions: one for constant
  55  * offsets (where the mov instruction must be of the form "mov
  56  * %es:123, %xx") and one for non-constant offsets (where the mov
  57  * instruction must be of the form "mov %es:(%xx), %yx".  If it's
  58  * possible to incorporate both forms into one __asm__ instruction, I
  59  * don't know how to do it.
  60  *
  61  * Ideally, the mov instruction should be "mov%z0"; the "%z0" is meant
  62  * to expand to either "b", "w" or "l" depending on the size of
  63  * operand 0.  This would remove the (minor) ambiguity in the mov
  64  * instruction.  However, gcc on at least my system barfs with an
  65  * "internal compiler error" when confronted with %z0.
  66  *
  67  */
  68
  69 #define put_real_kir_const_off( var, seg, off )                              \
  70         __asm__ ( "movw %w1, %%es\n\t"                                       \
  71                   "mov %0, %%es:%c2\n\t"                                     \
  72                   "pushw %%ds\n\t" /* restore %es */                         \
  73                   "popw %%es\n\t"                                            \
  74                   :                                                          \
  75                   : "r,r" ( var ), "rm,rm" ( seg ), "i,!r" ( off )           \
  76                   )
  77
  78 #define put_real_kir_nonconst_off( var, seg, off )                           \
  79         __asm__ ( "movw %w1, %%es\n\t"                                       \
  80                   "mov %0, %%es:(%2)\n\t"                                    \
  81                   "pushw %%ds\n\t" /* restore %es */                         \
  82                   "popw %%es\n\t"                                            \
  83                   :                                                          \
  84                   : "r" ( var ), "rm" ( seg ), "r" ( off )                   \
  85                   )
  86
  87 #define put_real_kir( var, seg, off )                                        \
  88         do {                                                                 \
  89           if ( __builtin_constant_p ( off ) )                                \
  90                   put_real_kir_const_off ( var, seg, off );                  \
  91           else                                                               \
  92                   put_real_kir_nonconst_off ( var, seg, off );               \
  93         } while ( 0 )
  94
  95 #define get_real_kir_const_off( var, seg, off )                              \
  96         __asm__ ( "movw %w1, %%es\n\t"                                       \
  97                   "mov %%es:%c2, %0\n\t"                                     \
  98                   "pushw %%ds\n\t" /* restore %es */                         \
  99                   "popw %%es\n\t"                                            \
 100                   : "=r,r" ( var )                                           \
 101                   : "rm,rm" ( seg ), "i,!r" ( off )                          \
 102                   )
 103
 104 #define get_real_kir_nonconst_off( var, seg, off )                           \
 105         __asm__ ( "movw %w1, %%es\n\t"                                       \
 106                   "mov %%es:(%2), %0\n\t"                                    \
 107                   "pushw %%ds\n\t" /* restore %es */                         \
 108                   "popw %%es\n\t"                                            \
 109                   : "=r" ( var )                                             \
 110                   : "rm" ( seg ), "r" ( off )                                \
 111                   )
 112
 113 #define get_real_kir( var, seg, off )                                        \
 114         do {                                                                 \
 115           if ( __builtin_constant_p ( off ) )                                \
 116                   get_real_kir_const_off ( var, seg, off );                  \
 117           else                                                               \
 118                   get_real_kir_nonconst_off ( var, seg, off );               \
 119         } while ( 0 )
 120
 121 #define put_real put_real_kir
 122 #define get_real get_real_kir
 123
 124 /* Place/remove parameter on real-mode stack in a way that's
 125  * compatible with libkir
 126  */
 127 #define BASEMEM_PARAMETER_INIT_LIBKIR( param ) \
 128         ( ( uint16_t ) ( ( uint32_t ) & ( param ) ) )
 129 #define BASEMEM_PARAMETER_DONE_LIBKIR( param )
 130 #define BASEMEM_PARAMETER_INIT BASEMEM_PARAMETER_INIT_LIBKIR
 131 #define BASEMEM_PARAMETER_DONE BASEMEM_PARAMETER_DONE_LIBKIR
 132
 133 /* REAL_FRAGMENT: Declare and define a real-mode code fragment in
 134  * .text16.  We don't need this for REAL_EXEC, since we can just
 135  * execute our real-mode code inline, but it's handy in case someone
 136  * genuinely wants to create a block of code that can be copied to a
 137  * specific location and then executed.
 138  *
 139  * Note that we put the code in the data segment, since otherwise we
 140  * can't (easily) access it in order to copy it to its target
 141  * location.  We should never be calling any REAL_FRAGMENT routines
 142  * directly anyway.
 143  */
 144 #define REAL_FRAGMENT( name, asm_code_str )                             \
 145         extern void name ( void );                                      \
 146         extern char name ## _size[];                                    \
 147         __asm__ __volatile__ (                                          \
 148                 ".section \".data.text16\"\n\t"                         \
 149                 ".code16\n\t"                                           \
 150                 ".arch i386\n\t"                                        \
 151                 #name ":\n\t"                                           \
 152                 asm_code_str "\n\t"                                     \
 153                 "lret\n\t"                                              \
 154                 #name "_end:\n\t"                                       \
 155                 ".equ " #name "_size, " #name "_end - " #name "\n\t"    \
 156                 ".code16gcc\n\t"                                        \
 157                 ".previous\n\t"                                         \
 158                 : :                                                     \
 159         )
 160 #define FRAGMENT_SIZE( fragment ) ( (size_t) fragment ## _size )
 161
 162 /* REAL_CALL: call an external real-mode routine */
 163 #define OUT_CONSTRAINTS(...) __VA_ARGS__
 164 #define IN_CONSTRAINTS(...) "m" ( __routine ), ## __VA_ARGS__
 165 #define CLOBBER(...) __VA_ARGS__
 166 #define REAL_CALL( routine, num_out_constraints, out_constraints,            \
 167                    in_constraints, clobber )                                 \
 168         do {                                                                 \
 169                 segoff_t __routine = routine;                                \
 170                 __asm__ __volatile__ (                                       \
 171                         "pushl %" #num_out_constraints "\n\t"                \
 172                         ".code16\n\t"                                        \
 173                         "pushw %%gs\n\t"        /* preserve segs */          \
 174                         "pushw %%fs\n\t"                                     \
 175                         "pushw %%es\n\t"                                     \
 176                         "pushw %%ds\n\t"                                     \
 177                         "pushw %%cs\n\t"        /* lcall to routine */       \
 178                         "call 1f\n\t"                                        \
 179                         "jmp 2f\n\t"                                         \
 180                         "\n1:\n\t"                                           \
 181                         "addr32 pushl 12(%%esp)\n\t"                         \
 182                         "lret\n\t"                                           \
 183                         "\n2:\n\t"                                           \
 184                         "popw %%ds\n\t"         /* restore segs */           \
 185                         "popw %%es\n\t"                                      \
 186                         "popw %%fs\n\t"                                      \
 187                         "popw %%gs\n\t"                                      \
 188                         "addw $4, %%sp\n\t"                                  \
 189                         ".code16gcc\n\t"                                     \
 190                         : out_constraints : in_constraints : clobber         \
 191                 );                                                           \
 192         } while ( 0 )
 193
 194 /* REAL_EXEC: execute some inline assembly code in a way that matches
 195  * the interface of librm
 196  */
 197
 198 #define IN_CONSTRAINTS_NO_ROUTINE( routine, ... ) __VA_ARGS__
 199 #define REAL_EXEC( name, asm_code_str, num_out_constraints, out_constraints, \
 200                    in_constraints, clobber )                                 \
 201         __asm__ __volatile__ (                                               \
 202                 ".code16\n\t"                                                \
 203                 "pushw %%gs\n\t"                                             \
 204                 "pushw %%fs\n\t"                                             \
 205                 "pushw %%es\n\t"                                             \
 206                 "pushw %%ds\n\t"                                             \
 207                 "\n" #name ":\n\t"                                           \
 208                 asm_code_str                                                 \
 209                 "popw %%ds\n\t"                                              \
 210                 "popw %%es\n\t"                                              \
 211                 "popw %%fs\n\t"                                              \
 212                 "popw %%gs\n\t"                                              \
 213                 ".code16gcc\n\t"                                             \
 214                 : out_constraints                                            \
 215                 : IN_CONSTRAINTS_NO_ROUTINE ( in_constraints )               \
 216                 : clobber                                                    \
 217                 );
 218
 219 #endif /* ASSEMBLY */
 220
 221 #endif /* LIBKIR_H */