1 #include <common.h>
2 #include <exports.h>
3 #include <linux/compiler.h>
4
5 #define FO(x) offsetof(struct jt_funcs, x)
6
7 #if defined(CONFIG_X86)
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 struct jt_funcs *jt;
16 gd_t *global_data;
17
18 #define EXPORT_FUNC(f, a, 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"(FO(x)) : "eax", "ecx");
26 #elif defined(CONFIG_PPC)
27 /*
28 * r2 holds the pointer to the global_data, r11 is a call-clobbered
29 * register
30 */
31 #define EXPORT_FUNC(f, a, x, ...) \
32 asm volatile ( \
33 " .globl " #x "\n" \
34 #x ":\n" \
35 " lwz %%r11, %0(%%r2)\n" \
36 " lwz %%r11, %1(%%r11)\n" \
37 " mtctr %%r11\n" \
38 " bctr\n" \
39 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r11");
40 #elif defined(CONFIG_ARM)
41 #ifdef CONFIG_ARM64
42 /*
43 * x18 holds the pointer to the global_data, x9 is a call-clobbered
44 * register
45 */
46 #define EXPORT_FUNC(f, a, x, ...) \
47 asm volatile ( \
48 " .globl " #x "\n" \
49 #x ":\n" \
50 " ldr x9, [x18, %0]\n" \
51 " ldr x9, [x9, %1]\n" \
52 " br x9\n" \
53 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "x9");
54 #else
55 /*
56 * r9 holds the pointer to the global_data, ip is a call-clobbered
57 * register
58 */
59 #define EXPORT_FUNC(f, a, x, ...) \
60 asm volatile ( \
61 " .globl " #x "\n" \
62 #x ":\n" \
63 " ldr ip, [r9, %0]\n" \
64 " ldr pc, [ip, %1]\n" \
65 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "ip");
66 #endif
67 #elif defined(CONFIG_MIPS)
68 #ifdef CONFIG_CPU_MIPS64
69 /*
70 * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
71 * clobbered register that is also used to set gp ($26). Note that the
72 * jr instruction also executes the instruction immediately following
73 * it; however, GCC/mips generates an additional `nop' after each asm
74 * statement
75 */
76 #define EXPORT_FUNC(f, a, x, ...) \
77 asm volatile ( \
78 " .globl " #x "\n" \
79 #x ":\n" \
80 " ld $25, %0($26)\n" \
81 " ld $25, %1($25)\n" \
82 " jr $25\n" \
83 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t9");
84 #else
85 /*
86 * k0 ($26) holds the pointer to the global_data; t9 ($25) is a call-
87 * clobbered register that is also used to set gp ($26). Note that the
88 * jr instruction also executes the instruction immediately following
89 * it; however, GCC/mips generates an additional `nop' after each asm
90 * statement
91 */
92 #define EXPORT_FUNC(f, a, x, ...) \
93 asm volatile ( \
94 " .globl " #x "\n" \
95 #x ":\n" \
96 " lw $25, %0($26)\n" \
97 " lw $25, %1($25)\n" \
98 " jr $25\n" \
99 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t9");
100 #endif
101 #elif defined(CONFIG_NIOS2)
102 /*
103 * gp holds the pointer to the global_data, r8 is call-clobbered
104 */
105 #define EXPORT_FUNC(f, a, x, ...) \
106 asm volatile ( \
107 " .globl " #x "\n" \
108 #x ":\n" \
109 " movhi r8, %%hi(%0)\n" \
110 " ori r8, r0, %%lo(%0)\n" \
111 " add r8, r8, gp\n" \
112 " ldw r8, 0(r8)\n" \
113 " ldw r8, %1(r8)\n" \
114 " jmp r8\n" \
115 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "gp");
116 #elif defined(CONFIG_M68K)
117 /*
118 * d7 holds the pointer to the global_data, a0 is a call-clobbered
119 * register
120 */
121 #define EXPORT_FUNC(f, a, x, ...) \
122 asm volatile ( \
123 " .globl " #x "\n" \
124 #x ":\n" \
125 " move.l %%d7, %%a0\n" \
126 " adda.l %0, %%a0\n" \
127 " move.l (%%a0), %%a0\n" \
128 " adda.l %1, %%a0\n" \
129 " move.l (%%a0), %%a0\n" \
130 " jmp (%%a0)\n" \
131 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "a0");
132 #elif defined(CONFIG_MICROBLAZE)
133 /*
134 * r31 holds the pointer to the global_data. r5 is a call-clobbered.
135 */
136 #define EXPORT_FUNC(f, a, x, ...) \
137 asm volatile ( \
138 " .globl " #x "\n" \
139 #x ":\n" \
140 " lwi r5, r31, %0\n" \
141 " lwi r5, r5, %1\n" \
142 " bra r5\n" \
143 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r5");
144 #elif defined(CONFIG_SH)
145 /*
146 * r13 holds the pointer to the global_data. r1 is a call clobbered.
147 */
148 #define EXPORT_FUNC(f, a, x, ...) \
149 asm volatile ( \
150 " .align 2\n" \
151 " .globl " #x "\n" \
152 #x ":\n" \
153 " mov r13, r1\n" \
154 " add %0, r1\n" \
155 " mov.l @r1, r2\n" \
156 " add %1, r2\n" \
157 " mov.l @r2, r1\n" \
158 " jmp @r1\n" \
159 " nop\n" \
160 " nop\n" \
161 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r1", "r2");
162 #elif defined(CONFIG_NDS32)
163 /*
164 * r16 holds the pointer to the global_data. gp is call clobbered.
165 * not support reduced register (16 GPR).
166 */
167 #define EXPORT_FUNC(f, a, x, ...) \
168 asm volatile ( \
169 " .globl " #x "\n" \
170 #x ":\n" \
171 " lwi $r16, [$gp + (%0)]\n" \
172 " lwi $r16, [$r16 + (%1)]\n" \
173 " jr $r16\n" \
174 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "$r16");
175 #elif defined(CONFIG_RISCV)
176 /*
177 * gp holds the pointer to the global_data. t0 is call clobbered.
178 */
179 #ifdef CONFIG_ARCH_RV64I
180 #define EXPORT_FUNC(f, a, x, ...) \
181 asm volatile ( \
182 " .globl " #x "\n" \
183 #x ":\n" \
184 " ld t0, %0(gp)\n" \
185 " ld t0, %1(t0)\n" \
186 " jr t0\n" \
187 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t0");
188 #else
189 #define EXPORT_FUNC(f, a, x, ...) \
190 asm volatile ( \
191 " .globl " #x "\n" \
192 #x ":\n" \
193 " lw t0, %0(gp)\n" \
194 " lw t0, %1(t0)\n" \
195 " jr t0\n" \
196 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "t0");
197 #endif
198 #elif defined(CONFIG_ARC)
199 /*
200 * r25 holds the pointer to the global_data. r10 is call clobbered.
201 */
202 #define EXPORT_FUNC(f, a, x, ...) \
203 asm volatile( \
204 " .align 4\n" \
205 " .globl " #x "\n" \
206 #x ":\n" \
207 " ld r10, [r25, %0]\n" \
208 " ld r10, [r10, %1]\n" \
209 " j [r10]\n" \
210 : : "i"(offsetof(gd_t, jt)), "i"(FO(x)) : "r10");
211 #elif defined(CONFIG_XTENSA)
212 /*
213 * Global data ptr is in global_data, jump table ptr is in jt.
214 * Windowed ABI: Jump just past 'entry' in target and adjust stack frame
215 * (extract stack frame size from target 'entry' instruction).
216 */
217
218 static void **jt;
219
220 #if defined(__XTENSA_CALL0_ABI__)
221 #define EXPORT_FUNC(f, a, x, ...) \
222 asm volatile ( \
223 " .extern jt\n" \
224 " .globl " #x "\n" \
225 " .align 4\n" \
226 #x ":\n" \
227 " l32i a8, %0, 0\n" \
228 " l32i a8, a8, %1\n" \
229 " jx a8\n" \
230 : : "r"(jt), "i" (FO(x)) : "a8");
231 #elif defined(__XTENSA_WINDOWED_ABI__)
232 #if XCHAL_HAVE_BE
233 # define SFT "8"
234 #else
235 # define SFT "12"
236 #endif
237 #define EXPORT_FUNC(f, a, x, ...) \
238 asm volatile ( \
239 " .extern jt\n" \
240 " .globl " #x "\n" \
241 " .align 4\n" \
242 #x ":\n" \
243 " entry sp, 16\n" \
244 " l32i a8, %0, 0\n" \
245 " l32i a8, a8, %1\n" \
246 " l32i a9, a8, 0\n" \
247 " extui a9, a9, " SFT ", 12\n" \
248 " subx8 a9, a9, sp\n" \
249 " movi a10, 16\n" \
250 " sub a9, a10, a9\n" \
251 " movsp sp, a9\n" \
252 " addi a8, a8, 3\n" \
253 " jx a8\n" \
254 : : "r"(jt), "i" (FO(x)) : "a8", "a9", "a10");
255 #else
256 #error Unsupported Xtensa ABI
257 #endif
258 #else
259 /*" addi $sp, $sp, -24\n" \
260 " br $r16\n" \*/
261
262 #error stubs definition missing for this architecture
263 #endif
264
265 /* This function is necessary to prevent the compiler from
266 * generating prologue/epilogue, preparing stack frame etc.
267 * The stub functions are special, they do not use the stack
268 * frame passed to them, but pass it intact to the actual
269 * implementation. On the other hand, asm() statements with
270 * arguments can be used only inside the functions (gcc limitation)
271 */
272 #if GCC_VERSION < 30400
273 static
274 #endif /* GCC_VERSION */
dummy(void)275 void __attribute__((unused)) dummy(void)
276 {
277 #include <_exports.h>
278 }
279
280 #include <asm/sections.h>
281
app_startup(char * const * argv)282 void app_startup(char * const *argv)
283 {
284 char *cp = __bss_start;
285
286 /* Zero out BSS */
287 while (cp < _end)
288 *cp++ = 0;
289
290 #if defined(CONFIG_X86)
291 /* x86 does not have a dedicated register for passing global_data */
292 global_data = (gd_t *)argv[-1];
293 jt = global_data->jt;
294 #endif
295 }
296
297 #undef EXPORT_FUNC
298