1 /* 2 * arch/sh/kernel/process.c 3 * 4 * This file handles the architecture-dependent parts of process handling.. 5 * 6 * Copyright (C) 1995 Linus Torvalds 7 * 8 * SuperH version: Copyright (C) 1999, 2000 Niibe Yutaka & Kaz Kojima 9 * Copyright (C) 2006 Lineo Solutions Inc. support SH4A UBC 10 * Copyright (C) 2002 - 2006 Paul Mundt 11 */ 12 #include <linux/module.h> 13 #include <linux/mm.h> 14 #include <linux/elfcore.h> 15 #include <linux/pm.h> 16 #include <linux/kallsyms.h> 17 #include <linux/kexec.h> 18 #include <asm/uaccess.h> 19 #include <asm/mmu_context.h> 20 #include <asm/ubc.h> 21 22 static int hlt_counter; 23 int ubc_usercnt = 0; 24 25 #define HARD_IDLE_TIMEOUT (HZ / 3) 26 27 void (*pm_idle)(void); 28 void (*pm_power_off)(void); 29 EXPORT_SYMBOL(pm_power_off); 30 31 void disable_hlt(void) 32 { 33 hlt_counter++; 34 } 35 EXPORT_SYMBOL(disable_hlt); 36 37 void enable_hlt(void) 38 { 39 hlt_counter--; 40 } 41 EXPORT_SYMBOL(enable_hlt); 42 43 void default_idle(void) 44 { 45 if (!hlt_counter) 46 cpu_sleep(); 47 else 48 cpu_relax(); 49 } 50 51 void cpu_idle(void) 52 { 53 /* endless idle loop with no priority at all */ 54 while (1) { 55 void (*idle)(void) = pm_idle; 56 57 if (!idle) 58 idle = default_idle; 59 60 while (!need_resched()) 61 idle(); 62 63 preempt_enable_no_resched(); 64 schedule(); 65 preempt_disable(); 66 } 67 } 68 69 void machine_restart(char * __unused) 70 { 71 /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */ 72 asm volatile("ldc %0, sr\n\t" 73 "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001)); 74 } 75 76 void machine_halt(void) 77 { 78 local_irq_disable(); 79 80 while (1) 81 cpu_sleep(); 82 } 83 84 void machine_power_off(void) 85 { 86 if (pm_power_off) 87 pm_power_off(); 88 } 89 90 void show_regs(struct pt_regs * regs) 91 { 92 printk("\n"); 93 printk("Pid : %d, Comm: %20s\n", current->pid, current->comm); 94 print_symbol("PC is at %s\n", instruction_pointer(regs)); 95 printk("PC : %08lx SP : %08lx SR : %08lx ", 96 regs->pc, regs->regs[15], regs->sr); 97 #ifdef CONFIG_MMU 98 printk("TEA : %08x ", ctrl_inl(MMU_TEA)); 99 #else 100 printk(" "); 101 #endif 102 printk("%s\n", print_tainted()); 103 104 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 105 regs->regs[0],regs->regs[1], 106 regs->regs[2],regs->regs[3]); 107 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 108 regs->regs[4],regs->regs[5], 109 regs->regs[6],regs->regs[7]); 110 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 111 regs->regs[8],regs->regs[9], 112 regs->regs[10],regs->regs[11]); 113 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 114 regs->regs[12],regs->regs[13], 115 regs->regs[14]); 116 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 117 regs->mach, regs->macl, regs->gbr, regs->pr); 118 119 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 120 } 121 122 /* 123 * Create a kernel thread 124 */ 125 126 /* 127 * This is the mechanism for creating a new kernel thread. 128 * 129 */ 130 extern void kernel_thread_helper(void); 131 __asm__(".align 5\n" 132 "kernel_thread_helper:\n\t" 133 "jsr @r5\n\t" 134 " nop\n\t" 135 "mov.l 1f, r1\n\t" 136 "jsr @r1\n\t" 137 " mov r0, r4\n\t" 138 ".align 2\n\t" 139 "1:.long do_exit"); 140 141 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 142 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 143 { 144 struct pt_regs regs; 145 146 memset(®s, 0, sizeof(regs)); 147 regs.regs[4] = (unsigned long)arg; 148 regs.regs[5] = (unsigned long)fn; 149 150 regs.pc = (unsigned long)kernel_thread_helper; 151 regs.sr = (1 << 30); 152 153 /* Ok, create the new process.. */ 154 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 155 ®s, 0, NULL, NULL); 156 } 157 158 /* 159 * Free current thread data structures etc.. 160 */ 161 void exit_thread(void) 162 { 163 if (current->thread.ubc_pc) { 164 current->thread.ubc_pc = 0; 165 ubc_usercnt -= 1; 166 } 167 } 168 169 void flush_thread(void) 170 { 171 #if defined(CONFIG_SH_FPU) 172 struct task_struct *tsk = current; 173 /* Forget lazy FPU state */ 174 clear_fpu(tsk, task_pt_regs(tsk)); 175 clear_used_math(); 176 #endif 177 } 178 179 void release_thread(struct task_struct *dead_task) 180 { 181 /* do nothing */ 182 } 183 184 /* Fill in the fpu structure for a core dump.. */ 185 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 186 { 187 int fpvalid = 0; 188 189 #if defined(CONFIG_SH_FPU) 190 struct task_struct *tsk = current; 191 192 fpvalid = !!tsk_used_math(tsk); 193 if (fpvalid) { 194 unlazy_fpu(tsk, regs); 195 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 196 } 197 #endif 198 199 return fpvalid; 200 } 201 202 /* 203 * Capture the user space registers if the task is not running (in user space) 204 */ 205 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) 206 { 207 struct pt_regs ptregs; 208 209 ptregs = *task_pt_regs(tsk); 210 elf_core_copy_regs(regs, &ptregs); 211 212 return 1; 213 } 214 215 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu) 216 { 217 int fpvalid = 0; 218 219 #if defined(CONFIG_SH_FPU) 220 fpvalid = !!tsk_used_math(tsk); 221 if (fpvalid) { 222 unlazy_fpu(tsk, task_pt_regs(tsk)); 223 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 224 } 225 #endif 226 227 return fpvalid; 228 } 229 230 asmlinkage void ret_from_fork(void); 231 232 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, 233 unsigned long unused, 234 struct task_struct *p, struct pt_regs *regs) 235 { 236 struct thread_info *ti = task_thread_info(p); 237 struct pt_regs *childregs; 238 #if defined(CONFIG_SH_FPU) 239 struct task_struct *tsk = current; 240 241 unlazy_fpu(tsk, regs); 242 p->thread.fpu = tsk->thread.fpu; 243 copy_to_stopped_child_used_math(p); 244 #endif 245 246 childregs = task_pt_regs(p); 247 *childregs = *regs; 248 249 if (user_mode(regs)) { 250 childregs->regs[15] = usp; 251 ti->addr_limit = USER_DS; 252 } else { 253 childregs->regs[15] = (unsigned long)childregs; 254 ti->addr_limit = KERNEL_DS; 255 } 256 257 if (clone_flags & CLONE_SETTLS) 258 childregs->gbr = childregs->regs[0]; 259 260 childregs->regs[0] = 0; /* Set return value for child */ 261 262 p->thread.sp = (unsigned long) childregs; 263 p->thread.pc = (unsigned long) ret_from_fork; 264 265 p->thread.ubc_pc = 0; 266 267 return 0; 268 } 269 270 /* Tracing by user break controller. */ 271 static void ubc_set_tracing(int asid, unsigned long pc) 272 { 273 #if defined(CONFIG_CPU_SH4A) 274 unsigned long val; 275 276 val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE); 277 val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid)); 278 279 ctrl_outl(val, UBC_CBR0); 280 ctrl_outl(pc, UBC_CAR0); 281 ctrl_outl(0x0, UBC_CAMR0); 282 ctrl_outl(0x0, UBC_CBCR); 283 284 val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE); 285 ctrl_outl(val, UBC_CRR0); 286 287 /* Read UBC register that we wrote last, for checking update */ 288 val = ctrl_inl(UBC_CRR0); 289 290 #else /* CONFIG_CPU_SH4A */ 291 ctrl_outl(pc, UBC_BARA); 292 293 #ifdef CONFIG_MMU 294 /* We don't have any ASID settings for the SH-2! */ 295 if (current_cpu_data.type != CPU_SH7604) 296 ctrl_outb(asid, UBC_BASRA); 297 #endif 298 299 ctrl_outl(0, UBC_BAMRA); 300 301 if (current_cpu_data.type == CPU_SH7729 || 302 current_cpu_data.type == CPU_SH7710) { 303 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA); 304 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR); 305 } else { 306 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA); 307 ctrl_outw(BRCR_PCBA, UBC_BRCR); 308 } 309 #endif /* CONFIG_CPU_SH4A */ 310 } 311 312 /* 313 * switch_to(x,y) should switch tasks from x to y. 314 * 315 */ 316 struct task_struct *__switch_to(struct task_struct *prev, 317 struct task_struct *next) 318 { 319 #if defined(CONFIG_SH_FPU) 320 unlazy_fpu(prev, task_pt_regs(prev)); 321 #endif 322 323 #ifdef CONFIG_PREEMPT 324 { 325 unsigned long flags; 326 struct pt_regs *regs; 327 328 local_irq_save(flags); 329 regs = task_pt_regs(prev); 330 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) { 331 int offset = (int)regs->regs[15]; 332 333 /* Reset stack pointer: clear critical region mark */ 334 regs->regs[15] = regs->regs[1]; 335 if (regs->pc < regs->regs[0]) 336 /* Go to rewind point */ 337 regs->pc = regs->regs[0] + offset; 338 } 339 local_irq_restore(flags); 340 } 341 #endif 342 343 #ifdef CONFIG_MMU 344 /* 345 * Restore the kernel mode register 346 * k7 (r7_bank1) 347 */ 348 asm volatile("ldc %0, r7_bank" 349 : /* no output */ 350 : "r" (task_thread_info(next))); 351 #endif 352 353 /* If no tasks are using the UBC, we're done */ 354 if (ubc_usercnt == 0) 355 /* If no tasks are using the UBC, we're done */; 356 else if (next->thread.ubc_pc && next->mm) { 357 int asid = 0; 358 #ifdef CONFIG_MMU 359 asid |= cpu_asid(smp_processor_id(), next->mm); 360 #endif 361 ubc_set_tracing(asid, next->thread.ubc_pc); 362 } else { 363 #if defined(CONFIG_CPU_SH4A) 364 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 365 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 366 #else 367 ctrl_outw(0, UBC_BBRA); 368 ctrl_outw(0, UBC_BBRB); 369 #endif 370 } 371 372 return prev; 373 } 374 375 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 376 unsigned long r6, unsigned long r7, 377 struct pt_regs __regs) 378 { 379 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 380 #ifdef CONFIG_MMU 381 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 382 #else 383 /* fork almost works, enough to trick you into looking elsewhere :-( */ 384 return -EINVAL; 385 #endif 386 } 387 388 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 389 unsigned long parent_tidptr, 390 unsigned long child_tidptr, 391 struct pt_regs __regs) 392 { 393 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 394 if (!newsp) 395 newsp = regs->regs[15]; 396 return do_fork(clone_flags, newsp, regs, 0, 397 (int __user *)parent_tidptr, 398 (int __user *)child_tidptr); 399 } 400 401 /* 402 * This is trivial, and on the face of it looks like it 403 * could equally well be done in user mode. 404 * 405 * Not so, for quite unobvious reasons - register pressure. 406 * In user mode vfork() cannot have a stack frame, and if 407 * done by calling the "clone()" system call directly, you 408 * do not have enough call-clobbered registers to hold all 409 * the information you need. 410 */ 411 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 412 unsigned long r6, unsigned long r7, 413 struct pt_regs __regs) 414 { 415 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 416 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 417 0, NULL, NULL); 418 } 419 420 /* 421 * sys_execve() executes a new program. 422 */ 423 asmlinkage int sys_execve(char *ufilename, char **uargv, 424 char **uenvp, unsigned long r7, 425 struct pt_regs __regs) 426 { 427 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 428 int error; 429 char *filename; 430 431 filename = getname((char __user *)ufilename); 432 error = PTR_ERR(filename); 433 if (IS_ERR(filename)) 434 goto out; 435 436 error = do_execve(filename, 437 (char __user * __user *)uargv, 438 (char __user * __user *)uenvp, 439 regs); 440 if (error == 0) { 441 task_lock(current); 442 current->ptrace &= ~PT_DTRACE; 443 task_unlock(current); 444 } 445 putname(filename); 446 out: 447 return error; 448 } 449 450 unsigned long get_wchan(struct task_struct *p) 451 { 452 unsigned long schedule_frame; 453 unsigned long pc; 454 455 if (!p || p == current || p->state == TASK_RUNNING) 456 return 0; 457 458 /* 459 * The same comment as on the Alpha applies here, too ... 460 */ 461 pc = thread_saved_pc(p); 462 if (in_sched_functions(pc)) { 463 schedule_frame = (unsigned long)p->thread.sp; 464 return ((unsigned long *)schedule_frame)[21]; 465 } 466 467 return pc; 468 } 469 470 asmlinkage void break_point_trap(void) 471 { 472 /* Clear tracing. */ 473 #if defined(CONFIG_CPU_SH4A) 474 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 475 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 476 #else 477 ctrl_outw(0, UBC_BBRA); 478 ctrl_outw(0, UBC_BBRB); 479 #endif 480 current->thread.ubc_pc = 0; 481 ubc_usercnt -= 1; 482 483 force_sig(SIGTRAP, current); 484 } 485 486 /* 487 * Generic trap handler. 488 */ 489 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5, 490 unsigned long r6, unsigned long r7, 491 struct pt_regs __regs) 492 { 493 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 494 495 /* Rewind */ 496 regs->pc -= 2; 497 498 force_sig(SIGTRAP, current); 499 } 500 501 /* 502 * Special handler for BUG() traps. 503 */ 504 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5, 505 unsigned long r6, unsigned long r7, 506 struct pt_regs __regs) 507 { 508 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 509 510 /* Rewind */ 511 regs->pc -= 2; 512 513 #ifdef CONFIG_BUG 514 if (__kernel_text_address(instruction_pointer(regs))) { 515 u16 insn = *(u16 *)instruction_pointer(regs); 516 if (insn == TRAPA_BUG_OPCODE) 517 handle_BUG(regs); 518 } 519 #endif 520 521 force_sig(SIGTRAP, current); 522 } 523