LXR uboot/examples/standalone/stubs.c

   1#include <common.h>
   2#include <exports.h>
   3#include <linux/compiler.h>
   4
   5#define FO(x) offsetof(struct jt_funcs, x)
   6
   7#if defined(CONFIG_X86)
   8/*
   9 * x86 does not have a dedicated register to store the pointer to
  10 * the global_data. Thus the jump table address is stored in a
  11 * global variable, but such approach does not allow for execution
  12 * from flash memory. The global_data address is passed as argv[-1]
  13 * to the application program.
  14 */
  15static struct jt_funcs *jt;
  16gd_t *global_data;
  17
  18#define EXPORT_FUNC(f, a, x, ...) \
  19        asm volatile (                  \
  20"       .globl " #x "\n"                \
  21#x ":\n"                                \
  22"       movl    %0, %%eax\n"            \
  23"       movl    jt, %%ecx\n"            \
  24"       jmp     *(%%ecx, %%eax)\n"      \
  25        : : "i"(FO(x)) : "eax", "ecx");
  26#elif defined(CONFIG_PPC)
  27/*
  28 * r2 holds the pointer to the global_data, r11 is a call-clobbered
  29 * register
  30 */
  31#define EXPORT_FUNC(f, a, x, ...) \
  32        asm volatile (                  \
  33"       .globl " #x "\n"                \
  34#x ":\n"                                \
  35"       lwz     %%r11, %0(%%r2)\n"      \
  36"       lwz     %%r11, %1(%%r11)\n"     \
  37"       mtctr   %%r11\n"                \
  38"       bctr\n"                         \
  39        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r11");
  40#elif defined(CONFIG_ARM)
  41#ifdef CONFIG_ARM64
  42/*
  43 * x18 holds the pointer to the global_data, x9 is a call-clobbered
  44 * register
  45 */
  46#define EXPORT_FUNC(f, a, x, ...) \
  47        asm volatile (                  \
  48"       .globl " #x "\n"                \
  49#x ":\n"                                \
  50"       ldr     x9, [x18, %0]\n"                \
  51"       ldr     x9, [x9, %1]\n"         \
  52"       br      x9\n"           \
  53        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "x9");
  54#else
  55/*
  56 * r9 holds the pointer to the global_data, ip is a call-clobbered
  57 * register
  58 */
  59#define EXPORT_FUNC(f, a, x, ...) \
  60        asm volatile (                  \
  61"       .globl " #x "\n"                \
  62#x ":\n"                                \
  63"       ldr     ip, [r9, %0]\n"         \
  64"       ldr     pc, [ip, %1]\n"         \
  65        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "ip");
  66#endif
  67#elif defined(CONFIG_MIPS)
  68#ifdef CONFIG_CPU_MIPS64
  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(f, a, x, ...) \
  77        asm volatile (                  \
  78"       .globl " #x "\n"                \
  79#x ":\n"                                \
  80"       ld      $25, %0($26)\n"         \
  81"       ld      $25, %1($25)\n"         \
  82"       jr      $25\n"                  \
  83        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t9");
  84#else
  85/*
  86 * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
  87 * clobbered register that is also used to set gp ($26). Note that the
  88 * jr instruction also executes the instruction immediately following
  89 * it; however, GCC/mips generates an additional `nop' after each asm
  90 * statement
  91 */
  92#define EXPORT_FUNC(f, a, x, ...) \
  93        asm volatile (                  \
  94"       .globl " #x "\n"                \
  95#x ":\n"                                \
  96"       lw      $25, %0($26)\n"         \
  97"       lw      $25, %1($25)\n"         \
  98"       jr      $25\n"                  \
  99        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t9");
 100#endif
 101#elif defined(CONFIG_NIOS2)
 102/*
 103 * gp holds the pointer to the global_data, r8 is call-clobbered
 104 */
 105#define EXPORT_FUNC(f, a, x, ...) \
 106        asm volatile (                  \
 107"       .globl " #x "\n"                \
 108#x ":\n"                                \
 109"       movhi   r8, %%hi(%0)\n"         \
 110"       ori     r8, r0, %%lo(%0)\n"     \
 111"       add     r8, r8, gp\n"           \
 112"       ldw     r8, 0(r8)\n"            \
 113"       ldw     r8, %1(r8)\n"           \
 114"       jmp     r8\n"                   \
 115        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "gp");
 116#elif defined(CONFIG_M68K)
 117/*
 118 * d7 holds the pointer to the global_data, a0 is a call-clobbered
 119 * register
 120 */
 121#define EXPORT_FUNC(f, a, x, ...) \
 122        asm volatile (                  \
 123"       .globl " #x "\n"                \
 124#x ":\n"                                \
 125"       move.l  %%d7, %%a0\n"           \
 126"       adda.l  %0, %%a0\n"             \
 127"       move.l  (%%a0), %%a0\n"         \
 128"       adda.l  %1, %%a0\n"             \
 129"       move.l  (%%a0), %%a0\n"         \
 130"       jmp     (%%a0)\n"                       \
 131        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "a0");
 132#elif defined(CONFIG_MICROBLAZE)
 133/*
 134 * r31 holds the pointer to the global_data. r5 is a call-clobbered.
 135 */
 136#define EXPORT_FUNC(f, a, x, ...)                               \
 137        asm volatile (                          \
 138"       .globl " #x "\n"                        \
 139#x ":\n"                                        \
 140"       lwi     r5, r31, %0\n"                  \
 141"       lwi     r5, r5, %1\n"                   \
 142"       bra     r5\n"                           \
 143        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r5");
 144#elif defined(CONFIG_SH)
 145/*
 146 * r13 holds the pointer to the global_data. r1 is a call clobbered.
 147 */
 148#define EXPORT_FUNC(f, a, x, ...)                                       \
 149        asm volatile (                                  \
 150                "       .align  2\n"                    \
 151                "       .globl " #x "\n"                \
 152                #x ":\n"                                \
 153                "       mov     r13, r1\n"              \
 154                "       add     %0, r1\n"               \
 155                "       mov.l @r1, r2\n"        \
 156                "       add     %1, r2\n"               \
 157                "       mov.l @r2, r1\n"        \
 158                "       jmp     @r1\n"                  \
 159                "       nop\n"                          \
 160                "       nop\n"                          \
 161                : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r1", "r2");
 162#elif defined(CONFIG_NDS32)
 163/*
 164 * r16 holds the pointer to the global_data. gp is call clobbered.
 165 * not support reduced register (16 GPR).
 166 */
 167#define EXPORT_FUNC(f, a, x, ...) \
 168        asm volatile (                  \
 169"       .globl " #x "\n"                \
 170#x ":\n"                                \
 171"       lwi     $r16, [$gp + (%0)]\n"   \
 172"       lwi     $r16, [$r16 + (%1)]\n"  \
 173"       jr      $r16\n"                 \
 174        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "$r16");
 175#elif defined(CONFIG_ARC)
 176/*
 177 * r25 holds the pointer to the global_data. r10 is call clobbered.
 178  */
 179#define EXPORT_FUNC(f, a, x, ...) \
 180        asm volatile( \
 181"       .align 4\n" \
 182"       .globl " #x "\n" \
 183#x ":\n" \
 184"       ld      r10, [r25, %0]\n" \
 185"       ld      r10, [r10, %1]\n" \
 186"       j       [r10]\n" \
 187        : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r10");
 188#elif defined(CONFIG_XTENSA)
 189/*
 190 * Global data ptr is in global_data, jump table ptr is in jt.
 191 * Windowed ABI: Jump just past 'entry' in target and adjust stack frame
 192 * (extract stack frame size from target 'entry' instruction).
 193 */
 194
 195static void **jt;
 196
 197#if defined(__XTENSA_CALL0_ABI__)
 198#define EXPORT_FUNC(f, a, x, ...)       \
 199        asm volatile (                  \
 200"       .extern jt\n"                   \
 201"       .globl " #x "\n"                \
 202"       .align 4\n"                     \
 203#x ":\n"                                \
 204"       l32i    a8, %0, 0\n"            \
 205"       l32i    a8, a8, %1\n"           \
 206"       jx      a8\n"                   \
 207        : : "r"(jt), "i" (FO(x)) : "a8");
 208#elif defined(__XTENSA_WINDOWED_ABI__)
 209#if XCHAL_HAVE_BE
 210# define SFT "8"
 211#else
 212# define SFT "12"
 213#endif
 214#define EXPORT_FUNC(f, a, x, ...)       \
 215        asm volatile (                  \
 216"       .extern jt\n"                   \
 217"       .globl " #x "\n"                \
 218"       .align 4\n"                     \
 219#x ":\n"                                \
 220"       entry   sp, 16\n"               \
 221"       l32i    a8, %0, 0\n"            \
 222"       l32i    a8, a8, %1\n"           \
 223"       l32i    a9, a8, 0\n"            \
 224"       extui   a9, a9, " SFT ", 12\n"  \
 225"       subx8   a9, a9, sp\n"           \
 226"       movi    a10, 16\n"              \
 227"       sub     a9, a10, a9\n"          \
 228"       movsp   sp, a9\n"               \
 229"       addi    a8, a8, 3\n"            \
 230"       jx      a8\n"                   \
 231        : : "r"(jt), "i" (FO(x)) : "a8", "a9", "a10");
 232#else
 233#error Unsupported Xtensa ABI
 234#endif
 235#else
 236/*"     addi    $sp, $sp, -24\n"        \
 237"       br      $r16\n"                 \*/
 238
 239#error stubs definition missing for this architecture
 240#endif
 241
 242/* This function is necessary to prevent the compiler from
 243 * generating prologue/epilogue, preparing stack frame etc.
 244 * The stub functions are special, they do not use the stack
 245 * frame passed to them, but pass it intact to the actual
 246 * implementation. On the other hand, asm() statements with
 247 * arguments can be used only inside the functions (gcc limitation)
 248 */
 249#if GCC_VERSION < 30400
 250static
 251#endif /* GCC_VERSION */
 252void __attribute__((unused)) dummy(void)
 253{
 254#include <_exports.h>
 255}
 256
 257#include <asm/sections.h>
 258
 259void app_startup(char * const *argv)
 260{
 261        char *cp = __bss_start;
 262
 263        /* Zero out BSS */
 264        while (cp < _end)
 265                *cp++ = 0;
 266
 267#if defined(CONFIG_X86)
 268        /* x86 does not have a dedicated register for passing global_data */
 269        global_data = (gd_t *)argv[-1];
 270        jt = global_data->jt;
 271#endif
 272}
 273
 274#undef EXPORT_FUNC
 275