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