examples/standalone/stubs.c

   1 #include <common.h>
   2 #include <exports.h>
   3
   4 #ifndef GCC_VERSION
   5 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
   6 #endif /* GCC_VERSION */
   7
   8 #if defined(CONFIG_X86)
   9 /*
  10  * x86 does not have a dedicated register to store the pointer to
  11  * the global_data. Thus the jump table address is stored in a
  12  * global variable, but such approach does not allow for execution
  13  * from flash memory. The global_data address is passed as argv[-1]
  14  * to the application program.
  15  */
  16 static void **jt;
  17 gd_t *global_data;
  18
  19 #define EXPORT_FUNC(x) \
  20         asm volatile (                  \
  21 "       .globl " #x "\n"                \
  22 #x ":\n"                                \
  23 "       movl    %0, %%eax\n"            \
  24 "       movl    jt, %%ecx\n"            \
  25 "       jmp     *(%%ecx, %%eax)\n"      \
  26         : : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx");
  27 #elif defined(CONFIG_PPC)
  28 /*
  29  * r2 holds the pointer to the global_data, r11 is a call-clobbered
  30  * register
  31  */
  32 #define EXPORT_FUNC(x) \
  33         asm volatile (                  \
  34 "       .globl " #x "\n"                \
  35 #x ":\n"                                \
  36 "       lwz     %%r11, %0(%%r2)\n"      \
  37 "       lwz     %%r11, %1(%%r11)\n"     \
  38 "       mtctr   %%r11\n"                \
  39 "       bctr\n"                         \
  40         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r11");
  41 #elif defined(CONFIG_ARM)
  42 #ifdef CONFIG_ARM64
  43 /*
  44  * x18 holds the pointer to the global_data, x9 is a call-clobbered
  45  * register
  46  */
  47 #define EXPORT_FUNC(x) \
  48         asm volatile (                  \
  49 "       .globl " #x "\n"                \
  50 #x ":\n"                                \
  51 "       ldr     x9, [x18, %0]\n"                \
  52 "       ldr     x9, [x9, %1]\n"         \
  53 "       br      x9\n"           \
  54         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "x9");
  55 #else
  56 /*
  57  * r9 holds the pointer to the global_data, ip is a call-clobbered
  58  * register
  59  */
  60 #define EXPORT_FUNC(x) \
  61         asm volatile (                  \
  62 "       .globl " #x "\n"                \
  63 #x ":\n"                                \
  64 "       ldr     ip, [r9, %0]\n"         \
  65 "       ldr     pc, [ip, %1]\n"         \
  66         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "ip");
  67 #endif
  68 #elif defined(CONFIG_MIPS)
  69 /*
  70  * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
  71  * clobbered register that is also used to set gp ($26). Note that the
  72  * jr instruction also executes the instruction immediately following
  73  * it; however, GCC/mips generates an additional `nop' after each asm
  74  * statement
  75  */
  76 #define EXPORT_FUNC(x) \
  77         asm volatile (                  \
  78 "       .globl " #x "\n"                \
  79 #x ":\n"                                \
  80 "       lw      $25, %0($26)\n"         \
  81 "       lw      $25, %1($25)\n"         \
  82 "       jr      $25\n"                  \
  83         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "t9");
  84 #elif defined(CONFIG_NIOS2)
  85 /*
  86  * gp holds the pointer to the global_data, r8 is call-clobbered
  87  */
  88 #define EXPORT_FUNC(x) \
  89         asm volatile (                  \
  90 "       .globl " #x "\n"                \
  91 #x ":\n"                                \
  92 "       movhi   r8, %%hi(%0)\n"         \
  93 "       ori     r8, r0, %%lo(%0)\n"     \
  94 "       add     r8, r8, gp\n"           \
  95 "       ldw     r8, 0(r8)\n"            \
  96 "       ldw     r8, %1(r8)\n"           \
  97 "       jmp     r8\n"                   \
  98         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "gp");
  99 #elif defined(CONFIG_M68K)
 100 /*
 101  * d7 holds the pointer to the global_data, a0 is a call-clobbered
 102  * register
 103  */
 104 #define EXPORT_FUNC(x) \
 105         asm volatile (                  \
 106 "       .globl " #x "\n"                \
 107 #x ":\n"                                \
 108 "       move.l  %%d7, %%a0\n"           \
 109 "       adda.l  %0, %%a0\n"             \
 110 "       move.l  (%%a0), %%a0\n"         \
 111 "       adda.l  %1, %%a0\n"             \
 112 "       move.l  (%%a0), %%a0\n"         \
 113 "       jmp     (%%a0)\n"                       \
 114         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "a0");
 115 #elif defined(CONFIG_MICROBLAZE)
 116 /*
 117  * r31 holds the pointer to the global_data. r5 is a call-clobbered.
 118  */
 119 #define EXPORT_FUNC(x)                          \
 120         asm volatile (                          \
 121 "       .globl " #x "\n"                        \
 122 #x ":\n"                                        \
 123 "       lwi     r5, r31, %0\n"                  \
 124 "       lwi     r5, r5, %1\n"                   \
 125 "       bra     r5\n"                           \
 126         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r5");
 127 #elif defined(CONFIG_BLACKFIN)
 128 /*
 129  * P3 holds the pointer to the global_data, P0 is a call-clobbered
 130  * register
 131  */
 132 #define EXPORT_FUNC(x)                  \
 133         asm volatile (                  \
 134 "       .globl _" #x "\n_"              \
 135 #x ":\n"                                \
 136 "       P0 = [P3 + %0]\n"               \
 137 "       P0 = [P0 + %1]\n"               \
 138 "       JUMP (P0)\n"                    \
 139         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "P0");
 140 #elif defined(CONFIG_AVR32)
 141 /*
 142  * r6 holds the pointer to the global_data. r8 is call clobbered.
 143  */
 144 #define EXPORT_FUNC(x)                                  \
 145         asm volatile(                                   \
 146                 "       .globl\t" #x "\n"               \
 147                 #x ":\n"                                \
 148                 "       ld.w    r8, r6[%0]\n"           \
 149                 "       ld.w    pc, r8[%1]\n"           \
 150                 :                                       \
 151                 : "i"(offsetof(gd_t, jt)), "i"(XF_ ##x) \
 152                 : "r8");
 153 #elif defined(CONFIG_SH)
 154 /*
 155  * r13 holds the pointer to the global_data. r1 is a call clobbered.
 156  */
 157 #define EXPORT_FUNC(x)                                  \
 158         asm volatile (                                  \
 159                 "       .align  2\n"                    \
 160                 "       .globl " #x "\n"                \
 161                 #x ":\n"                                \
 162                 "       mov     r13, r1\n"              \
 163                 "       add     %0, r1\n"               \
 164                 "       mov.l @r1, r2\n"        \
 165                 "       add     %1, r2\n"               \
 166                 "       mov.l @r2, r1\n"        \
 167                 "       jmp     @r1\n"                  \
 168                 "       nop\n"                          \
 169                 "       nop\n"                          \
 170                 : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r1", "r2");
 171 #elif defined(CONFIG_SPARC)
 172 /*
 173  * g7 holds the pointer to the global_data. g1 is call clobbered.
 174  */
 175 #define EXPORT_FUNC(x)                                  \
 176         asm volatile(                                   \
 177 "       .globl\t" #x "\n"                               \
 178 #x ":\n"                                                \
 179 "       set %0, %%g1\n"                                 \
 180 "       or %%g1, %%g7, %%g1\n"                          \
 181 "       ld [%%g1], %%g1\n"                              \
 182 "       ld [%%g1 + %1], %%g1\n"                         \
 183 "       jmp %%g1\n"                                     \
 184 "       nop\n"                                          \
 185         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "g1" );
 186 #elif defined(CONFIG_NDS32)
 187 /*
 188  * r16 holds the pointer to the global_data. gp is call clobbered.
 189  * not support reduced register (16 GPR).
 190  */
 191 #define EXPORT_FUNC(x) \
 192         asm volatile (                  \
 193 "       .globl " #x "\n"                \
 194 #x ":\n"                                \
 195 "       lwi     $r16, [$gp + (%0)]\n"   \
 196 "       lwi     $r16, [$r16 + (%1)]\n"  \
 197 "       jr      $r16\n"                 \
 198         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "$r16");
 199 #elif defined(CONFIG_OPENRISC)
 200 /*
 201  * r10 holds the pointer to the global_data, r13 is a call-clobbered
 202  * register
 203  */
 204 #define EXPORT_FUNC(x) \
 205         asm volatile (                  \
 206 "       .globl " #x "\n"                \
 207 #x ":\n"                                \
 208 "       l.lwz   r13, %0(r10)\n" \
 209 "       l.lwz   r13, %1(r13)\n" \
 210 "       l.jr    r13\n"          \
 211 "       l.nop\n"                                \
 212         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r13");
 213 #else
 214 /*"     addi    $sp, $sp, -24\n"        \
 215 "       br      $r16\n"                 \*/
 216
 217 #error stubs definition missing for this architecture
 218 #endif
 219
 220 /* This function is necessary to prevent the compiler from
 221  * generating prologue/epilogue, preparing stack frame etc.
 222  * The stub functions are special, they do not use the stack
 223  * frame passed to them, but pass it intact to the actual
 224  * implementation. On the other hand, asm() statements with
 225  * arguments can be used only inside the functions (gcc limitation)
 226  */
 227 #if GCC_VERSION < 3004
 228 static
 229 #endif /* GCC_VERSION */
 230 void __attribute__((unused)) dummy(void)
 231 {
 232 #include <_exports.h>
 233 }
 234
 235 #include <asm/sections.h>
 236
 237 void app_startup(char * const *argv)
 238 {
 239         char *cp = __bss_start;
 240
 241         /* Zero out BSS */
 242         while (cp < _end)
 243                 *cp++ = 0;
 244
 245 #if defined(CONFIG_X86)
 246         /* x86 does not have a dedicated register for passing global_data */
 247         global_data = (gd_t *)argv[-1];
 248         jt = global_data->jt;
 249 #endif
 250 }
 251
 252 #undef EXPORT_FUNC