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27b207fd WD |
1 | #include <exports.h> |
2 | ||
3 | #if defined(CONFIG_I386) | |
4 | /* | |
5 | * x86 does not have a dedicated register to store the pointer to | |
6 | * the global_data. Thus the jump table address is stored in a | |
7 | * global variable, but such approach does not allow for execution | |
8 | * from flash memory. The global_data address is passed as argv[-1] | |
9 | * to the application program. | |
10 | */ | |
11 | static void **jt; | |
77846748 | 12 | gd_t *global_data; |
27b207fd WD |
13 | |
14 | #define EXPORT_FUNC(x) \ | |
15 | asm volatile ( \ | |
16 | " .globl " #x "\n" \ | |
17 | #x ":\n" \ | |
18 | " movl %0, %%eax\n" \ | |
19 | " movl jt, %%ecx\n" \ | |
20 | " jmp *(%%ecx, %%eax)\n" \ | |
21 | : : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx"); | |
22 | #elif defined(CONFIG_PPC) | |
23 | /* | |
24 | * r29 holds the pointer to the global_data, r11 is a call-clobbered | |
25 | * register | |
26 | */ | |
27 | #define EXPORT_FUNC(x) \ | |
28 | asm volatile ( \ | |
29 | " .globl " #x "\n" \ | |
30 | #x ":\n" \ | |
31 | " lwz %%r11, %0(%%r29)\n" \ | |
32 | " lwz %%r11, %1(%%r11)\n" \ | |
33 | " mtctr %%r11\n" \ | |
34 | " bctr\n" \ | |
35 | : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r11"); | |
36 | #elif defined(CONFIG_ARM) | |
37 | /* | |
38 | * r8 holds the pointer to the global_data, ip is a call-clobbered | |
39 | * register | |
40 | */ | |
41 | #define EXPORT_FUNC(x) \ | |
42 | asm volatile ( \ | |
43 | " .globl " #x "\n" \ | |
44 | #x ":\n" \ | |
45 | " ldr ip, [r8, %0]\n" \ | |
46 | " ldr pc, [ip, %1]\n" \ | |
47 | : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "ip"); | |
48 | #elif defined(CONFIG_MIPS) | |
49 | /* | |
50 | * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call- | |
51 | * clobbered register that is also used to set gp ($26). Note that the | |
52 | * jr instruction also executes the instruction immediately following | |
53 | * it; however, GCC/mips generates an additional `nop' after each asm | |
54 | * statement | |
55 | */ | |
56 | #define EXPORT_FUNC(x) \ | |
57 | asm volatile ( \ | |
58 | " .globl " #x "\n" \ | |
59 | #x ":\n" \ | |
60 | " lw $25, %0($26)\n" \ | |
61 | " lw $25, %1($25)\n" \ | |
62 | " jr $25\n" \ | |
63 | : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "t9"); | |
4a551709 WD |
64 | #elif defined(CONFIG_NIOS) |
65 | /* | |
66 | * %g7 holds the pointer to the global_data. %g0 is call clobbered. | |
67 | */ | |
68 | #define EXPORT_FUNC(x) \ | |
69 | asm volatile ( \ | |
70 | " .globl " #x "\n" \ | |
71 | #x ":\n" \ | |
72 | " pfx %%hi(%0)\n" \ | |
73 | " movi %%g0, %%lo(%0)\n" \ | |
74 | " add %%g0, %%g7\n" \ | |
75 | " ld %%g0, [%%g0]\n" \ | |
76 | " pfx %1\n" \ | |
77 | " ld %%g0, [%%g0]\n" \ | |
78 | " jmp %%g0\n" \ | |
79 | " nop \n" \ | |
80 | : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x) : "r0"); | |
bf9e3b38 WD |
81 | #elif defined(CONFIG_M68K) |
82 | /* | |
83 | * d7 holds the pointer to the global_data, a0 is a call-clobbered | |
84 | * register | |
85 | */ | |
86 | #define EXPORT_FUNC(x) \ | |
87 | asm volatile ( \ | |
88 | " .globl " #x "\n" \ | |
89 | #x ":\n" \ | |
90 | " move.l %%d7, %%a0\n" \ | |
91 | " adda.l %0, %%a0\n" \ | |
92 | " move.l (%%a0), %%a0\n" \ | |
93 | " adda.l %1, %%a0\n" \ | |
94 | " move.l (%%a0), %%a0\n" \ | |
95 | " jmp (%%a0)\n" \ | |
96 | : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "a0"); | |
27b207fd WD |
97 | #else |
98 | #error stubs definition missing for this architecture | |
99 | #endif | |
100 | ||
101 | /* This function is necessary to prevent the compiler from | |
102 | * generating prologue/epilogue, preparing stack frame etc. | |
103 | * The stub functions are special, they do not use the stack | |
104 | * frame passed to them, but pass it intact to the actual | |
105 | * implementation. On the other hand, asm() statements with | |
106 | * arguments can be used only inside the functions (gcc limitation) | |
107 | */ | |
108 | static void __attribute__((unused)) dummy(void) | |
109 | { | |
110 | #include <_exports.h> | |
111 | } | |
112 | ||
d716b126 WD |
113 | extern unsigned long __bss_start, _end; |
114 | ||
27b207fd WD |
115 | void app_startup(char **argv) |
116 | { | |
d716b126 WD |
117 | unsigned long * cp = &__bss_start; |
118 | ||
119 | /* Zero out BSS */ | |
120 | while (cp < &_end) { | |
121 | *cp++ = 0; | |
122 | } | |
123 | ||
27b207fd WD |
124 | #if defined(CONFIG_I386) |
125 | /* x86 does not have a dedicated register for passing global_data */ | |
77846748 WD |
126 | global_data = (gd_t *)argv[-1]; |
127 | jt = global_data->jt; | |
27b207fd WD |
128 | #endif |
129 | } | |
130 | ||
131 | #undef EXPORT_FUNC |