iPXE
libkir.h
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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  */
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
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 */
uint16_t segment
Code segment.
Definition: librm.h:252
unsigned short uint16_t
Definition: stdint.h:11
static __always_inline void off_t userptr_t off_t src_off
Definition: efi_uaccess.h:66
static off_t const void * src
Definition: libkir.h:170
void * discard_S
Definition: bigint.h:57
static __always_inline void copy_from_user(void *dest, userptr_t src, off_t src_off, size_t len)
Copy data from user buffer.
Definition: uaccess.h:337
static __always_inline void off_t dest_off
Definition: efi_uaccess.h:66
static off_t const void size_t len
Definition: libkir.h:170
#define rm_ds
Definition: libkir.h:39
unsigned long intptr_t
Definition: stdint.h:21
static userptr_t buffer
Definition: libkir.h:184
static __attribute__((always_inline)) unsigned int _rm_cs(void)
Copy data to user buffer.
Definition: libkir.h:26
uint32_t userptr_t
A pointer to a user buffer.
Definition: libkir.h:159
static void copy_from_real_libkir(void *dest, unsigned int src_seg, unsigned int src_off, size_t n)
Definition: libkir.h:60
static void * dest
Definition: strings.h:176
#define copy_to_real
Definition: libkir.h:78
static __always_inline void copy_to_user(userptr_t dest, off_t dest_off, const void *src, size_t len)
Copy data to user buffer.
Definition: uaccess.h:324
void * discard_D
Definition: bigint.h:29
unsigned int uint32_t
Definition: stdint.h:12
uint32_t ds
Definition: librm.h:254
__asm__ __volatile__("\n1:\n\t" "movb -1(%2,%1), %%al\n\t" "stosb\n\t" "loop 1b\n\t" "xorl %%eax, %%eax\n\t" "mov %3, %1\n\t" "rep stosb\n\t" :"=&D"(discard_D), "=&c"(discard_c) :"r"(data), "g"(pad_len), "0"(value0), "1"(len) :"eax")
#define copy_from_real
Definition: libkir.h:79
signed long off_t
Definition: stdint.h:8
__asm__(".section \".rodata\", \"a\", " PROGBITS "\n\t" "\nprivate_key_data:\n\t" ".size private_key_data, ( . - private_key_data )\n\t" ".equ private_key_len, ( . - private_key_data )\n\t" ".previous\n\t")
userptr_t virt_to_user(volatile const void *addr)
Convert virtual address to user pointer.
static void copy_to_real_libkir(unsigned int dest_seg, unsigned int dest_off, const void *src, size_t n)
Definition: libkir.h:43
static __always_inline userptr_t real_to_user(unsigned int segment, unsigned int offset)
Convert segment:offset address to user buffer.
Definition: realmode.h:75
long discard_c
Definition: bigint.h:30
unsigned int n
Definition: entropy.h:159
uint32_t cs
Definition: librm.h:263
static off_t offset
Definition: libkir.h:170
unsigned long userptr_t
A pointer to a user buffer.
Definition: uaccess.h:33