166 lines
4.3 KiB
C
166 lines
4.3 KiB
C
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#include <exports.h>
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#ifndef GCC_VERSION
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#define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
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#endif /* GCC_VERSION */
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#if defined(CONFIG_I386)
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/*
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* x86 does not have a dedicated register to store the pointer to
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* the global_data. Thus the jump table address is stored in a
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* global variable, but such approach does not allow for execution
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* from flash memory. The global_data address is passed as argv[-1]
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* to the application program.
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*/
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static void **jt;
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gd_t *global_data;
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" movl %0, %%eax\n" \
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" movl jt, %%ecx\n" \
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" jmp *(%%ecx, %%eax)\n" \
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: : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx");
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#elif defined(CONFIG_PPC)
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/*
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* r29 holds the pointer to the global_data, r11 is a call-clobbered
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* register
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" lwz %%r11, %0(%%r29)\n" \
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" lwz %%r11, %1(%%r11)\n" \
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" mtctr %%r11\n" \
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" bctr\n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r11");
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#elif defined(CONFIG_ARM)
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/*
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* r8 holds the pointer to the global_data, ip is a call-clobbered
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* register
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" ldr ip, [r8, %0]\n" \
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" ldr pc, [ip, %1]\n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "ip");
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#elif defined(CONFIG_MIPS)
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/*
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* k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
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* clobbered register that is also used to set gp ($26). Note that the
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* jr instruction also executes the instruction immediately following
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* it; however, GCC/mips generates an additional `nop' after each asm
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* statement
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" lw $25, %0($26)\n" \
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" lw $25, %1($25)\n" \
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" jr $25\n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "t9");
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#elif defined(CONFIG_NIOS)
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/*
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* %g7 holds the pointer to the global_data. %g0 is call clobbered.
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" pfx %%hi(%0)\n" \
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" movi %%g0, %%lo(%0)\n" \
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" add %%g0, %%g7\n" \
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" ld %%g0, [%%g0]\n" \
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" pfx %1\n" \
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" ld %%g0, [%%g0]\n" \
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" jmp %%g0\n" \
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" nop \n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x) : "r0");
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#elif defined(CONFIG_NIOS2)
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/*
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* r15 holds the pointer to the global_data, r8 is call-clobbered
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" movhi r8, %%hi(%0)\n" \
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" ori r8, r0, %%lo(%0)\n" \
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" add r8, r0, r15\n" \
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" ldw r8, 0(r8)\n" \
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" ldw r8, %1(r8)\n" \
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" jmp r8\n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r15");
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#elif defined(CONFIG_M68K)
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/*
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* d7 holds the pointer to the global_data, a0 is a call-clobbered
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* register
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" move.l %%d7, %%a0\n" \
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" adda.l %0, %%a0\n" \
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" move.l (%%a0), %%a0\n" \
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" adda.l %1, %%a0\n" \
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" move.l (%%a0), %%a0\n" \
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" jmp (%%a0)\n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "a0");
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#elif defined(CONFIG_MICROBLAZE)
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/*
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* r31 holds the pointer to the global_data. r5 is a call-clobbered.
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*/
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#define EXPORT_FUNC(x) \
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asm volatile ( \
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" .globl " #x "\n" \
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#x ":\n" \
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" lwi r5, r31, %0\n" \
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" lwi r5, r5, %1\n" \
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" bra r5\n" \
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: : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r5");
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#else
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#error stubs definition missing for this architecture
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#endif
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/* This function is necessary to prevent the compiler from
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* generating prologue/epilogue, preparing stack frame etc.
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* The stub functions are special, they do not use the stack
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* frame passed to them, but pass it intact to the actual
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* implementation. On the other hand, asm() statements with
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* arguments can be used only inside the functions (gcc limitation)
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*/
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#if GCC_VERSION < 3004
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static
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#endif /* GCC_VERSION */
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void __attribute__((unused)) dummy(void)
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{
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#include <_exports.h>
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}
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extern unsigned long __bss_start, _end;
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void app_startup(char **argv)
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{
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unsigned long * cp = &__bss_start;
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/* Zero out BSS */
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while (cp < &_end) {
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*cp++ = 0;
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}
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#if defined(CONFIG_I386)
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/* x86 does not have a dedicated register for passing global_data */
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global_data = (gd_t *)argv[-1];
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jt = global_data->jt;
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#endif
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}
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#undef EXPORT_FUNC
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