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-rw-r--r--examples/standalone/stubs.c225
1 files changed, 225 insertions, 0 deletions
diff --git a/examples/standalone/stubs.c b/examples/standalone/stubs.c
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+#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