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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | #include <exports.h> #if defined(CONFIG_I386) /* * x86 does not have a dedicated register to store the pointer to * the global_data. Thus the jump table address is stored in a * global variable, but such approach does not allow for execution * from flash memory. The global_data address is passed as argv[-1] * to the application program. */ static void **jt; gd_t *global_data; #define EXPORT_FUNC(x) \ asm volatile ( \ " .globl " #x "\n" \ #x ":\n" \ " movl %0, %%eax\n" \ " movl jt, %%ecx\n" \ " jmp *(%%ecx, %%eax)\n" \ : : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx"); #elif defined(CONFIG_PPC) /* * r29 holds the pointer to the global_data, r11 is a call-clobbered * register */ #define EXPORT_FUNC(x) \ asm volatile ( \ " .globl " #x "\n" \ #x ":\n" \ " lwz %%r11, %0(%%r29)\n" \ " lwz %%r11, %1(%%r11)\n" \ " mtctr %%r11\n" \ " bctr\n" \ : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r11"); #elif defined(CONFIG_ARM) /* * r8 holds the pointer to the global_data, ip is a call-clobbered * register */ #define EXPORT_FUNC(x) \ asm volatile ( \ " .globl " #x "\n" \ #x ":\n" \ " ldr ip, [r8, %0]\n" \ " ldr pc, [ip, %1]\n" \ : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "ip"); #elif defined(CONFIG_MIPS) /* * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call- * clobbered register that is also used to set gp ($26). Note that the * jr instruction also executes the instruction immediately following * it; however, GCC/mips generates an additional `nop' after each asm * statement */ #define EXPORT_FUNC(x) \ asm volatile ( \ " .globl " #x "\n" \ #x ":\n" \ " lw $25, %0($26)\n" \ " lw $25, %1($25)\n" \ " jr $25\n" \ : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "t9"); #elif defined(CONFIG_NIOS) /* * %g7 holds the pointer to the global_data. %g0 is call clobbered. */ #define EXPORT_FUNC(x) \ asm volatile ( \ " .globl " #x "\n" \ #x ":\n" \ " pfx %%hi(%0)\n" \ " movi %%g0, %%lo(%0)\n" \ " add %%g0, %%g7\n" \ " ld %%g0, [%%g0]\n" \ " pfx %1\n" \ " ld %%g0, [%%g0]\n" \ " jmp %%g0\n" \ " nop \n" \ : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x) : "r0"); #else #error stubs definition missing for this architecture #endif /* This function is necessary to prevent the compiler from * generating prologue/epilogue, preparing stack frame etc. * The stub functions are special, they do not use the stack * frame passed to them, but pass it intact to the actual * implementation. On the other hand, asm() statements with * arguments can be used only inside the functions (gcc limitation) */ static void __attribute__((unused)) dummy(void) { #include <_exports.h> } void app_startup(char **argv) { #if defined(CONFIG_I386) /* x86 does not have a dedicated register for passing global_data */ global_data = (gd_t *)argv[-1]; jt = global_data->jt; #endif } #undef EXPORT_FUNC |