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Diffstat (limited to 'examples/standalone/stubs.c')
| -rw-r--r-- | examples/standalone/stubs.c | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/examples/standalone/stubs.c b/examples/standalone/stubs.c new file mode 100644 index 0000000..a8cb954 --- /dev/null +++ b/examples/standalone/stubs.c @@ -0,0 +1,225 @@ +#include <exports.h> + +#ifndef GCC_VERSION +#define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__) +#endif /* GCC_VERSION */ + +#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) +/* + * r2 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(%%r2)\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"); +#elif defined(CONFIG_NIOS2) +/* + * r15 holds the pointer to the global_data, r8 is call-clobbered + */ +#define EXPORT_FUNC(x) \ + asm volatile ( \ +" .globl " #x "\n" \ +#x ":\n" \ +" movhi r8, %%hi(%0)\n" \ +" ori r8, r0, %%lo(%0)\n" \ +" add r8, r8, r15\n" \ +" ldw r8, 0(r8)\n" \ +" ldw r8, %1(r8)\n" \ +" jmp r8\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r15"); +#elif defined(CONFIG_M68K) +/* + * d7 holds the pointer to the global_data, a0 is a call-clobbered + * register + */ +#define EXPORT_FUNC(x) \ + asm volatile ( \ +" .globl " #x "\n" \ +#x ":\n" \ +" move.l %%d7, %%a0\n" \ +" adda.l %0, %%a0\n" \ +" move.l (%%a0), %%a0\n" \ +" adda.l %1, %%a0\n" \ +" move.l (%%a0), %%a0\n" \ +" jmp (%%a0)\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "a0"); +#elif defined(CONFIG_MICROBLAZE) +/* + * r31 holds the pointer to the global_data. r5 is a call-clobbered. + */ +#define EXPORT_FUNC(x) \ + asm volatile ( \ +" .globl " #x "\n" \ +#x ":\n" \ +" lwi r5, r31, %0\n" \ +" lwi r5, r5, %1\n" \ +" bra r5\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r5"); +#elif defined(CONFIG_BLACKFIN) +/* + * P5 holds the pointer to the global_data, P0 is a call-clobbered + * register + */ +#define EXPORT_FUNC(x) \ + asm volatile ( \ +" .globl _" #x "\n_" \ +#x ":\n" \ +" P0 = [P5 + %0]\n" \ +" P0 = [P0 + %1]\n" \ +" JUMP (P0)\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "P0"); +#elif defined(CONFIG_AVR32) +/* + * r6 holds the pointer to the global_data. r8 is call clobbered. + */ +#define EXPORT_FUNC(x) \ + asm volatile( \ + " .globl\t" #x "\n" \ + #x ":\n" \ + " ld.w r8, r6[%0]\n" \ + " ld.w pc, r8[%1]\n" \ + : \ + : "i"(offsetof(gd_t, jt)), "i"(XF_ ##x) \ + : "r8"); +#elif defined(CONFIG_SH) +/* + * r13 holds the pointer to the global_data. r1 is a call clobbered. + */ +#define EXPORT_FUNC(x) \ + asm volatile ( \ + " .align 2\n" \ + " .globl " #x "\n" \ + #x ":\n" \ + " mov r13, r1\n" \ + " add %0, r1\n" \ + " mov.l @r1, r2\n" \ + " add %1, r2\n" \ + " mov.l @r2, r1\n" \ + " jmp @r1\n" \ + " nop\n" \ + " nop\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r1", "r2"); +#elif defined(CONFIG_SPARC) +/* + * g7 holds the pointer to the global_data. g1 is call clobbered. + */ +#define EXPORT_FUNC(x) \ + asm volatile( \ +" .globl\t" #x "\n" \ +#x ":\n" \ +" set %0, %%g1\n" \ +" or %%g1, %%g7, %%g1\n" \ +" ld [%%g1], %%g1\n" \ +" ld [%%g1 + %1], %%g1\n" \ +" call %%g1\n" \ +" nop\n" \ + : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x) : "g1" ); + +#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) + */ +#if GCC_VERSION < 3004 +static +#endif /* GCC_VERSION */ +void __attribute__((unused)) dummy(void) +{ +#include <_exports.h> +} + +extern unsigned long __bss_start, _end; + +void app_startup(char **argv) +{ + unsigned char * cp = (unsigned char *) &__bss_start; + + /* Zero out BSS */ + while (cp < (unsigned char *)&_end) { + *cp++ = 0; + } + +#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 |