exception.S revision 1.1
1 /* $NetBSD: exception.S,v 1.1 2001/07/28 13:28:03 chris Exp $ */ 2 3 /* 4 * Copyright (c) 1994-1997 Mark Brinicombe. 5 * Copyright (c) 1994 Brini. 6 * All rights reserved. 7 * 8 * This code is derived from software written for Brini by Mark Brinicombe 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by Brini. 21 * 4. The name of the company nor the name of the author may be used to 22 * endorse or promote products derived from this software without specific 23 * prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY BRINI ``AS IS'' AND ANY EXPRESS OR IMPLIED 26 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL BRINI OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 29 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 30 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 31 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * RiscBSD kernel project 38 * 39 * exception.S 40 * 41 * Low level handlers for exception vectors 42 * 43 * Created : 24/09/94 44 * 45 * Based on kate/display/abort.s 46 */ 47 48 #include "opt_ipkdb.h" 49 #include <machine/asm.h> 50 #include <machine/cpu.h> 51 #include <machine/frame.h> 52 #include "assym.h" 53 54 .text 55 .align 0 56 57 Lastpending: 58 .word _C_LABEL(astpending) 59 60 /* 61 * General exception exit handler 62 * 63 * It exits straight away if not returning to USR mode. 64 * This loops around delivering any pending ASTs. 65 * Interrupts are disabled at suitable points to avoid ASTs 66 * being posted between testing and exit to user mode. 67 * 68 * This function uses PULLFRAMEFROMSVCANDEXIT thus should 69 * only be called if the exception handler used PUSHFRAMEINSVC 70 */ 71 72 exception_exit: 73 mrs r4, cpsr_all /* Get CPSR */ 74 75 ldr r0, [sp] /* Get the SPSR from stack */ 76 and r0, r0, #(PSR_MODE) /* Test for USR32 mode before the AST */ 77 teq r0, #(PSR_USR32_MODE) 78 bne do_exit /* Not USR mode so no AST delivery */ 79 80 ldr r5, Lastpending /* Get address of astpending */ 81 82 Lexception_exit_loop: 83 orr r0, r4, #(I32_bit) /* Block IRQs */ 84 msr cpsr_all, r0 85 86 ldr r1, [r5] /* Do we have an AST pending */ 87 teq r1, #0x00000000 88 bne do_ast 89 90 PULLFRAMEFROMSVCANDEXIT /* No AST so exit */ 91 92 do_ast: 93 msr cpsr_all, r4 /* Restore interrupts */ 94 95 mov r1, #0x00000000 /* Clear ast pending */ 96 str r1, [r5] 97 98 mov r0, sp /* arg 0 = trap frame */ 99 bl _C_LABEL(ast) /* call the AST handler */ 100 b Lexception_exit_loop /* Try and exit again */ 101 102 do_exit: 103 orr r0, r4, #(I32_bit) /* Disable interupts */ 104 msr cpsr_all, r0 105 106 PULLFRAMEFROMSVCANDEXIT /* Restore the trap frame and exit */ 107 108 109 /* entry point for CPU data abort */ 110 111 ASENTRY_NP(data_abort_entry) 112 sub lr, lr, #0x00000008 /* Adjust the lr */ 113 114 PUSHFRAMEINSVC /* Push trap frame and switch */ 115 /* to SVC32 mode */ 116 117 mov r0, sp /* pass the stack pointer as r0 */ 118 119 /* add lr, pc, #exception_exitLdata_abort_return - . - 8*/ 120 add lr, pc, #exception_exit - . - 8 121 ldr r1, Ldata_abort_handler_address 122 ldr pc, [r1] 123 124 Ldata_abort_return: /* XXX - could just straight to exception_exit */ 125 b exception_exit 126 127 Ldata_abort_handler_address: 128 .word _C_LABEL(data_abort_handler_address) 129 130 .data 131 .global _C_LABEL(data_abort_handler_address) 132 _C_LABEL(data_abort_handler_address): 133 .word abortdata 134 135 .text 136 abortdata: 137 add r0, pc, #abortdatamsg - . - 8 138 b _C_LABEL(panic) 139 140 abortdatamsg: 141 .asciz "abortdata" 142 .align 0 143 144 145 ASENTRY_NP(prefetch_abort_entry) 146 sub lr, lr, #0x00000004 /* Adjust the lr */ 147 148 PUSHFRAMEINSVC 149 150 mov r0, sp /* pass the stack pointer as r0 */ 151 152 # add lr, pc, #Lprefetch_abort_return - . - 8 153 add lr, pc, #exception_exit - . - 8 154 ldr r1, Lprefetch_abort_handler_address 155 ldr pc, [r1] 156 157 Lprefetch_abort_return: /* XXX - could just straight to exception_exit */ 158 b exception_exit 159 160 Lprefetch_abort_handler_address: 161 .word _C_LABEL(prefetch_abort_handler_address) 162 163 .data 164 .global _C_LABEL(prefetch_abort_handler_address) 165 166 _C_LABEL(prefetch_abort_handler_address): 167 .word abortprefetch 168 169 .text 170 abortprefetch: 171 add r0, pc, #abortprefetchmsg - . - 8 172 b _C_LABEL(panic) 173 174 abortprefetchmsg: 175 .asciz "abortprefetch" 176 .align 0 177 178 179 /* 180 * swi_entry 181 * 182 * Main entry point for the SWI vector 183 */ 184 185 ASENTRY_NP(swi_entry) 186 PUSHFRAME 187 188 sub r0, lr, #0x00000004 /* Get the address of the SWI */ 189 ldr r4, [r0] /* Get the instruction */ 190 191 bic r1, r4, #0xff000000 /* Extract the comment field */ 192 193 mov r0, sp /* Pass the frame to any function */ 194 195 bl _C_LABEL(syscall) /* It's a syscall ! */ 196 197 ldr r5, Lastpending /* Get address of astpending */ 198 mrs r4, cpsr_all /* Get CPSR */ 199 200 swi_exit_loop: 201 orr r0, r4, #(I32_bit) /* Disable IRQs */ 202 msr cpsr_all, r0 203 204 ldr r1, [r5] /* Do we have an AST pending */ 205 teq r1, #0x00000000 206 bne do_swi_ast 207 208 PULLFRAME 209 movs pc, lr /* Exit */ 210 211 do_swi_ast: 212 msr cpsr_all, r4 /* Restore interrupts */ 213 214 mov r1, #0x00000000 /* Clear ast pending */ 215 str r1, [r5] 216 217 mov r0, sp /* arg 0 = trap frame */ 218 bl _C_LABEL(ast) /* call the AST handler */ 219 b swi_exit_loop /* Try and exit again */ 220 221 222 /* 223 * We indirect the undefined vector via the handler address 224 * in the data area. 225 * Entry to the undefined handler must look like direct 226 * entry from the vector. 227 */ 228 229 ASENTRY_NP(undefined_entry) 230 #ifdef IPKDB 231 /* 232 * IPKDB must be hooked in at the earliest possible entry point. 233 * 234 */ 235 /* 236 * Make room for all registers saving real r0-r7 and r15. 237 * The remaining registers are updated later. 238 */ 239 stmfd sp!, {r0,r1} /* psr & spsr */ 240 stmfd sp!, {lr} /* pc */ 241 stmfd sp!, {r0-r14} /* r0-r7, r8-r14 */ 242 /* 243 * Get previous psr. 244 */ 245 mrs r7, cpsr_all 246 mrs r0, spsr_all 247 str r0, [sp, #(16*4)] 248 /* 249 * Test for user mode. 250 */ 251 tst r0, #0xf 252 bne Lprenotuser_push 253 add r1, sp, #(8*4) 254 stmia r1,{r8-r14}^ /* store user mode r8-r14*/ 255 b Lgoipkdb 256 /* 257 * Switch to previous mode to get r8-r13. 258 */ 259 Lprenotuser_push: 260 orr r0, r0, #(I32_bit) /* disable interrupts */ 261 msr cpsr_all, r0 262 mov r1, r8 263 mov r2, r9 264 mov r3, r10 265 mov r4, r11 266 mov r5, r12 267 mov r6, r13 268 msr cpsr_all, r7 /* back to undefined mode */ 269 add r8, sp, #(8*4) 270 stmia r8, {r1-r6} /* r8-r13 */ 271 /* 272 * Now back to previous mode to get r14 and spsr. 273 */ 274 msr cpsr_all, r0 275 mov r1, r14 276 mrs r2, spsr 277 msr cpsr_all, r7 /* back to undefined mode */ 278 str r1, [sp, #(14*4)] /* r14 */ 279 str r2, [sp, #(17*4)] /* spsr */ 280 /* 281 * Now to IPKDB. 282 */ 283 Lgoipkdb: 284 mov r0, sp 285 bl _C_LABEL(ipkdb_trap_glue) 286 ldr r1, Lipkdb_trap_return 287 str r0,[r1] 288 /* 289 * Have to load all registers from the stack. 290 * 291 * Start with spsr and pc. 292 */ 293 ldr r0, [sp, #(16*4)] /* spsr */ 294 ldr r1, [sp, #(15*4)] /* r15 */ 295 msr spsr_all, r0 296 mov r14, r1 297 /* 298 * Test for user mode. 299 */ 300 tst r0, #0xf 301 bne Lprenotuser_pull 302 add r1, sp, #(8*4) 303 ldmia r1, {r8-r14}^ /* load user mode r8-r14 */ 304 b Lpull_r0r7 305 Lprenotuser_pull: 306 /* 307 * Now previous mode spsr and r14. 308 */ 309 ldr r1, [sp, #(17*4)] /* spsr */ 310 ldr r2, [sp, #(14*4)] /* r14 */ 311 orr r0, r0, #(I32_bit) 312 msr cpsr_all, r0 /* switch to previous mode */ 313 msr spsr_all, r1 314 mov r14, r2 315 msr cpsr_all, r7 /* back to undefined mode */ 316 /* 317 * Now r8-r13. 318 */ 319 add r8, sp, #(8*4) 320 ldmia r8, {r1-r6} /* r8-r13 */ 321 msr cpsr_all, r0 322 mov r8, r1 323 mov r9, r2 324 mov r10, r3 325 mov r11, r4 326 mov r12, r5 327 mov r13, r6 328 msr cpsr_all, r7 329 Lpull_r0r7: 330 /* 331 * Now the rest of the registers. 332 */ 333 ldr r1,Lipkdb_trap_return 334 ldr r0,[r1] 335 tst r0,r0 336 ldmfd sp!, {r0-r7} /* r0-r7 */ 337 add sp, sp, #(10*4) /* adjust sp */ 338 339 /* 340 * Did IPKDB handle it? 341 */ 342 movnes pc, lr /* return */ 343 344 #endif 345 stmfd sp!, {r0, r1} 346 ldr r0, Lundefined_handler_indirection 347 ldr r1, [sp], #0x0004 348 str r1, [r0, #0x0000] 349 ldr r1, [sp], #0x0004 350 str r1, [r0, #0x0004] 351 ldmia r0, {r0, r1, pc} 352 353 #ifdef IPKDB 354 Lipkdb_trap_return: 355 .word Lipkdb_trap_return_data 356 #endif 357 358 Lundefined_handler_indirection: 359 .word Lundefined_handler_indirection_data 360 361 /* 362 * assembly bounce code for calling the kernel 363 * undefined instruction handler. This uses 364 * a standard trap frame and is called in SVC mode. 365 */ 366 367 ENTRY_NP(undefinedinstruction_bounce) 368 PUSHFRAMEINSVC 369 mov r0, sp 370 bl _C_LABEL(undefinedinstruction) 371 372 b exception_exit 373 374 .data 375 .align 0 376 377 #ifdef IPKDB 378 Lipkdb_trap_return_data: 379 .word 0 380 #endif 381 382 /* 383 * Indirection data 384 * 2 words use for preserving r0 and r1 385 * 3rd word contains the undefined handler address. 386 */ 387 388 Lundefined_handler_indirection_data: 389 .word 0 390 .word 0 391 392 .global _C_LABEL(undefined_handler_address) 393 _C_LABEL(undefined_handler_address): 394 .word _C_LABEL(undefinedinstruction_bounce) 395 396 /* End of exception.S */ 397
Indexes created Thu Oct 02 07:10:07 GMT 2025