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 */ 15 static struct jt_funcs *jt; 16 gd_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 */ 194 195 static 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 250 static 251 #endif /* GCC_VERSION */ 252 void __attribute__((unused)) dummy(void) 253 { 254 #include <_exports.h> 255 } 256 257 #include <asm/sections.h> 258 259 void 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