Skip to content
Snippets Groups Projects
stubs.c 4.89 KiB
Newer Older
  • Learn to ignore specific revisions
  • #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)
    /*
     * 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");
    
    #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");
    
    Wolfgang Denk's avatar
    Wolfgang Denk committed
    #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");
    
    Wolfgang Denk's avatar
    Wolfgang Denk committed
    #elif defined(CONFIG_BLACKFIN)
    /*
     * P5 holds the pointer to the global_data, P0 is a call-clobbered
     * register
     */
    #define EXPORT_FUNC(x)			\
    
    Wolfgang Denk's avatar
    Wolfgang Denk committed
    	asm volatile (			\
    
    Wolfgang Denk's avatar
    Wolfgang Denk committed
    "       .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");
    
    #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)
    
    extern unsigned long __bss_start, _end;
    
    
    	unsigned long * cp = &__bss_start;
    
    	/* Zero out BSS */
    	while (cp < &_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;