Merge with /home/stefan/git/u-boot/denx
[platform/kernel/u-boot.git] / examples / stubs.c
1 #include <exports.h>
2
3 #ifndef GCC_VERSION
4 #define GCC_VERSION (__GNUC__ * 1000 + __GNUC_MINOR__)
5 #endif /* GCC_VERSION */
6
7 #if defined(CONFIG_I386)
8 /*
9  * x86 does not have a dedicated register to store the pointer to
10  * the global_data. Thus the jump table address is stored in a
11  * global variable, but such approach does not allow for execution
12  * from flash memory. The global_data address is passed as argv[-1]
13  * to the application program.
14  */
15 static void **jt;
16 gd_t *global_data;
17
18 #define EXPORT_FUNC(x) \
19         asm volatile (                  \
20 "       .globl " #x "\n"                \
21 #x ":\n"                                \
22 "       movl    %0, %%eax\n"            \
23 "       movl    jt, %%ecx\n"            \
24 "       jmp     *(%%ecx, %%eax)\n"      \
25         : : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx");
26 #elif defined(CONFIG_PPC)
27 /*
28  * r29 holds the pointer to the global_data, r11 is a call-clobbered
29  * register
30  */
31 #define EXPORT_FUNC(x) \
32         asm volatile (                  \
33 "       .globl " #x "\n"                \
34 #x ":\n"                                \
35 "       lwz     %%r11, %0(%%r29)\n"     \
36 "       lwz     %%r11, %1(%%r11)\n"     \
37 "       mtctr   %%r11\n"                \
38 "       bctr\n"                         \
39         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r11");
40 #elif defined(CONFIG_ARM)
41 /*
42  * r8 holds the pointer to the global_data, ip is a call-clobbered
43  * register
44  */
45 #define EXPORT_FUNC(x) \
46         asm volatile (                  \
47 "       .globl " #x "\n"                \
48 #x ":\n"                                \
49 "       ldr     ip, [r8, %0]\n"         \
50 "       ldr     pc, [ip, %1]\n"         \
51         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "ip");
52 #elif defined(CONFIG_MIPS)
53 /*
54  * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
55  * clobbered register that is also used to set gp ($26). Note that the
56  * jr instruction also executes the instruction immediately following
57  * it; however, GCC/mips generates an additional `nop' after each asm
58  * statement
59  */
60 #define EXPORT_FUNC(x) \
61         asm volatile (                  \
62 "       .globl " #x "\n"                \
63 #x ":\n"                                \
64 "       lw      $25, %0($26)\n"         \
65 "       lw      $25, %1($25)\n"         \
66 "       jr      $25\n"                  \
67         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "t9");
68 #elif defined(CONFIG_NIOS)
69 /*
70  * %g7 holds the pointer to the global_data. %g0 is call clobbered.
71  */
72 #define EXPORT_FUNC(x) \
73         asm volatile (                  \
74 "       .globl " #x "\n"                \
75 #x ":\n"                                \
76 "       pfx     %%hi(%0)\n"             \
77 "       movi    %%g0, %%lo(%0)\n"       \
78 "       add     %%g0, %%g7\n"           \
79 "       ld      %%g0, [%%g0]\n"         \
80 "       pfx     %1\n"                   \
81 "       ld      %%g0, [%%g0]\n"         \
82 "       jmp     %%g0\n"                 \
83 "       nop     \n"                     \
84         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x) : "r0");
85 #elif defined(CONFIG_NIOS2)
86 /*
87  * r15 holds the pointer to the global_data, r8 is call-clobbered
88  */
89 #define EXPORT_FUNC(x) \
90         asm volatile (                  \
91 "       .globl " #x "\n"                \
92 #x ":\n"                                \
93 "       movhi   r8, %%hi(%0)\n"         \
94 "       ori     r8, r0, %%lo(%0)\n"     \
95 "       add     r8, r8, r15\n"          \
96 "       ldw     r8, 0(r8)\n"            \
97 "       ldw     r8, %1(r8)\n"           \
98 "       jmp     r8\n"                   \
99         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r15");
100 #elif defined(CONFIG_M68K)
101 /*
102  * d7 holds the pointer to the global_data, a0 is a call-clobbered
103  * register
104  */
105 #define EXPORT_FUNC(x) \
106         asm volatile (                  \
107 "       .globl " #x "\n"                \
108 #x ":\n"                                \
109 "       move.l  %%d7, %%a0\n"           \
110 "       adda.l  %0, %%a0\n"             \
111 "       move.l  (%%a0), %%a0\n"         \
112 "       adda.l  %1, %%a0\n"             \
113 "       move.l  (%%a0), %%a0\n"         \
114 "       jmp     (%%a0)\n"                       \
115         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "a0");
116 #elif defined(CONFIG_MICROBLAZE)
117 /*
118  * r31 holds the pointer to the global_data. r5 is a call-clobbered.
119  */
120 #define EXPORT_FUNC(x)                          \
121         asm volatile (                          \
122 "       .globl " #x "\n"                        \
123 #x ":\n"                                        \
124 "       lwi     r5, r31, %0\n"                  \
125 "       lwi     r5, r5, %1\n"                   \
126 "       bra     r5\n"                           \
127         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "r5");
128 #elif defined(CONFIG_BLACKFIN)
129 /*
130  * P5 holds the pointer to the global_data, P0 is a call-clobbered
131  * register
132  */
133 #define EXPORT_FUNC(x)                  \
134         asm volatile (                  \
135 "       .globl " #x "\n"                \
136 #x ":\n"                                \
137 "       P0 = [P5 + %0]\n"               \
138 "       P0 = [P0 + %1]\n"               \
139 "       JUMP (P0)\n"                    \
140         : : "i"(offsetof(gd_t, jt)), "i"(XF_ ## x * sizeof(void *)) : "P0");
141 #elif defined(CONFIG_AVR32)
142 /*
143  * r6 holds the pointer to the global_data. r8 is call clobbered.
144  */
145 #define EXPORT_FUNC(x)                                  \
146         asm volatile(                                   \
147                 "       .globl\t" #x "\n"               \
148                 #x ":\n"                                \
149                 "       ld.w    r8, r6[%0]\n"           \
150                 "       ld.w    pc, r8[%1]\n"           \
151                 :                                       \
152                 : "i"(offsetof(gd_t, jt)), "i"(XF_ ##x) \
153                 : "r8");
154 #else
155 #error stubs definition missing for this architecture
156 #endif
157
158 /* This function is necessary to prevent the compiler from
159  * generating prologue/epilogue, preparing stack frame etc.
160  * The stub functions are special, they do not use the stack
161  * frame passed to them, but pass it intact to the actual
162  * implementation. On the other hand, asm() statements with
163  * arguments can be used only inside the functions (gcc limitation)
164  */
165 #if GCC_VERSION < 3004
166 static
167 #endif /* GCC_VERSION */
168 void __attribute__((unused)) dummy(void)
169 {
170 #include <_exports.h>
171 }
172
173 extern unsigned long __bss_start, _end;
174
175 void app_startup(char **argv)
176 {
177         unsigned long * cp = &__bss_start;
178
179         /* Zero out BSS */
180         while (cp < &_end) {
181                 *cp++ = 0;
182         }
183
184 #if defined(CONFIG_I386)
185         /* x86 does not have a dedicated register for passing global_data */
186         global_data = (gd_t *)argv[-1];
187         jt = global_data->jt;
188 #endif
189 }
190
191 #undef EXPORT_FUNC