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1.1 root 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 __data16_array( variable, array ) variable array
16: #define __bss16( variable ) variable
17: #define __bss16_array( variable, array ) variable array
18: #define __text16( variable ) variable
19: #define __text16_array( variable,array ) variable array
20: #define __use_data16( variable ) variable
21: #define __use_text16( variable ) variable
22: #define __from_data16( pointer ) pointer
23: #define __from_text16( pointer ) pointer
24:
25: /* Real-mode data and code segments */
26: static inline __attribute__ (( always_inline )) unsigned int _rm_cs ( void ) {
27: uint16_t cs;
28: __asm__ __volatile__ ( "movw %%cs, %w0" : "=r" ( cs ) );
29: return cs;
30: }
31:
32: static inline __attribute__ (( always_inline )) unsigned int _rm_ds ( void ) {
33: uint16_t ds;
34: __asm__ __volatile__ ( "movw %%ds, %w0" : "=r" ( ds ) );
35: return ds;
36: }
37:
38: #define rm_cs ( _rm_cs() )
39: #define rm_ds ( _rm_ds() )
40:
41: /* Copy to/from base memory */
42:
43: static inline void copy_to_real_libkir ( unsigned int dest_seg,
44: unsigned int dest_off,
45: const void *src, size_t n ) {
46: unsigned int discard_D, discard_S, discard_c;
47:
48: __asm__ __volatile__ ( "pushw %%es\n\t"
49: "movw %3, %%es\n\t"
50: "rep movsb\n\t"
51: "popw %%es\n\t"
52: : "=D" ( discard_D ), "=S" ( discard_S ),
53: "=c" ( discard_c )
54: : "r" ( dest_seg ), "D" ( dest_off ),
55: "S" ( src ),
56: "c" ( n )
57: : "memory" );
58: }
59:
60: static inline void copy_from_real_libkir ( void *dest,
61: unsigned int src_seg,
62: unsigned int src_off,
63: size_t n ) {
64: unsigned int discard_D, discard_S, discard_c;
65:
66: __asm__ __volatile__ ( "pushw %%ds\n\t"
67: "movw %4, %%ds\n\t"
68: "rep movsb\n\t"
69: "popw %%ds\n\t"
70: : "=D" ( discard_D ), "=S" ( discard_S ),
71: "=c" ( discard_c )
72: : "D" ( dest ),
73: "r" ( src_seg ), "S" ( src_off ),
74: "c" ( n )
75: : "memory" );
76: }
77:
78: #define copy_to_real copy_to_real_libkir
79: #define copy_from_real copy_from_real_libkir
80:
81: /*
82: * Transfer individual values to/from base memory. There may well be
83: * a neater way to do this. We have two versions: one for constant
84: * offsets (where the mov instruction must be of the form "mov
85: * %es:123, %xx") and one for non-constant offsets (where the mov
86: * instruction must be of the form "mov %es:(%xx), %yx". If it's
87: * possible to incorporate both forms into one __asm__ instruction, I
88: * don't know how to do it.
89: *
90: * Ideally, the mov instruction should be "mov%z0"; the "%z0" is meant
91: * to expand to either "b", "w" or "l" depending on the size of
92: * operand 0. This would remove the (minor) ambiguity in the mov
93: * instruction. However, gcc on at least my system barfs with an
94: * "internal compiler error" when confronted with %z0.
95: *
96: */
97:
98: #define put_real_kir_const_off( var, seg, off ) \
99: __asm__ ( "movw %w1, %%es\n\t" \
100: "mov %0, %%es:%c2\n\t" \
101: "pushw %%ds\n\t" /* restore %es */ \
102: "popw %%es\n\t" \
103: : \
104: : "r,r" ( var ), "rm,rm" ( seg ), "i,!r" ( off ) \
105: )
106:
107: #define put_real_kir_nonconst_off( var, seg, off ) \
108: __asm__ ( "movw %w1, %%es\n\t" \
109: "mov %0, %%es:(%2)\n\t" \
110: "pushw %%ds\n\t" /* restore %es */ \
111: "popw %%es\n\t" \
112: : \
113: : "r" ( var ), "rm" ( seg ), "r" ( off ) \
114: )
115:
116: #define put_real_kir( var, seg, off ) \
117: do { \
118: if ( __builtin_constant_p ( off ) ) \
119: put_real_kir_const_off ( var, seg, off ); \
120: else \
121: put_real_kir_nonconst_off ( var, seg, off ); \
122: } while ( 0 )
123:
124: #define get_real_kir_const_off( var, seg, off ) \
125: __asm__ ( "movw %w1, %%es\n\t" \
126: "mov %%es:%c2, %0\n\t" \
127: "pushw %%ds\n\t" /* restore %es */ \
128: "popw %%es\n\t" \
129: : "=r,r" ( var ) \
130: : "rm,rm" ( seg ), "i,!r" ( off ) \
131: )
132:
133: #define get_real_kir_nonconst_off( var, seg, off ) \
134: __asm__ ( "movw %w1, %%es\n\t" \
135: "mov %%es:(%2), %0\n\t" \
136: "pushw %%ds\n\t" /* restore %es */ \
137: "popw %%es\n\t" \
138: : "=r" ( var ) \
139: : "rm" ( seg ), "r" ( off ) \
140: )
141:
142: #define get_real_kir( var, seg, off ) \
143: do { \
144: if ( __builtin_constant_p ( off ) ) \
145: get_real_kir_const_off ( var, seg, off ); \
146: else \
147: get_real_kir_nonconst_off ( var, seg, off ); \
148: } while ( 0 )
149:
150: #define put_real put_real_kir
151: #define get_real get_real_kir
152:
153: /**
154: * A pointer to a user buffer
155: *
156: * This is actually a struct segoff, but encoded as a uint32_t to
157: * ensure that gcc passes it around efficiently.
158: */
159: typedef uint32_t userptr_t;
160:
161: /**
162: * Copy data to user buffer
163: *
164: * @v buffer User buffer
165: * @v offset Offset within user buffer
166: * @v src Source
167: * @v len Length
168: */
169: static inline __attribute__ (( always_inline )) void
170: copy_to_user ( userptr_t buffer, off_t offset, const void *src, size_t len ) {
171: copy_to_real ( ( buffer >> 16 ), ( ( buffer & 0xffff ) + offset ),
172: src, len );
173: }
174:
175: /**
176: * Copy data from user buffer
177: *
178: * @v dest Destination
179: * @v buffer User buffer
180: * @v offset Offset within user buffer
181: * @v len Length
182: */
183: static inline __attribute__ (( always_inline )) void
184: copy_from_user ( void *dest, userptr_t buffer, off_t offset, size_t len ) {
185: copy_from_real ( dest, ( buffer >> 16 ),
186: ( ( buffer & 0xffff ) + offset ), len );
187: }
188:
189: /**
190: * Convert segment:offset address to user buffer
191: *
192: * @v segment Real-mode segment
193: * @v offset Real-mode offset
194: * @ret buffer User buffer
195: */
196: static inline __attribute__ (( always_inline )) userptr_t
197: real_to_user ( unsigned int segment, unsigned int offset ) {
198: return ( ( segment << 16 ) | offset );
199: }
200:
201: /**
202: * Convert virtual address to user buffer
203: *
204: * @v virtual Virtual address
205: * @ret buffer User buffer
206: *
207: * This constructs a user buffer from an ordinary pointer. Use it
208: * when you need to pass a pointer to an internal buffer to a function
209: * that expects a @c userptr_t.
210: */
211: static inline __attribute__ (( always_inline )) userptr_t
212: virt_to_user ( void * virtual ) {
213: return real_to_user ( rm_ds, ( intptr_t ) virtual );
214: }
215:
216: /* TEXT16_CODE: declare a fragment of code that resides in .text16 */
217: #define TEXT16_CODE( asm_code_str ) \
218: ".section \".text16\", \"ax\", @progbits\n\t" \
219: ".code16\n\t" \
220: ".arch i386\n\t" \
221: asm_code_str "\n\t" \
222: ".code16gcc\n\t" \
223: ".previous\n\t"
224:
225: /* REAL_CODE: declare a fragment of code that executes in real mode */
226: #define REAL_CODE( asm_code_str ) \
227: ".code16\n\t" \
228: asm_code_str "\n\t" \
229: ".code16gcc\n\t"
230:
231: #endif /* ASSEMBLY */
232:
233: #endif /* LIBKIR_H */
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