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 - 2007 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 <linux/kdebug.h> 19 #include <linux/tick.h> 20 #include <linux/reboot.h> 21 #include <linux/fs.h> 22 #include <asm/uaccess.h> 23 #include <asm/mmu_context.h> 24 #include <asm/pgalloc.h> 25 #include <asm/system.h> 26 #include <asm/ubc.h> 27 28 static int hlt_counter; 29 int ubc_usercnt = 0; 30 31 void (*pm_idle)(void); 32 void (*pm_power_off)(void); 33 EXPORT_SYMBOL(pm_power_off); 34 35 void disable_hlt(void) 36 { 37 hlt_counter++; 38 } 39 EXPORT_SYMBOL(disable_hlt); 40 41 void enable_hlt(void) 42 { 43 hlt_counter--; 44 } 45 EXPORT_SYMBOL(enable_hlt); 46 47 static int __init nohlt_setup(char *__unused) 48 { 49 hlt_counter = 1; 50 return 1; 51 } 52 __setup("nohlt", nohlt_setup); 53 54 static int __init hlt_setup(char *__unused) 55 { 56 hlt_counter = 0; 57 return 1; 58 } 59 __setup("hlt", hlt_setup); 60 61 void default_idle(void) 62 { 63 if (!hlt_counter) { 64 clear_thread_flag(TIF_POLLING_NRFLAG); 65 smp_mb__after_clear_bit(); 66 set_bl_bit(); 67 while (!need_resched()) 68 cpu_sleep(); 69 clear_bl_bit(); 70 set_thread_flag(TIF_POLLING_NRFLAG); 71 } else 72 while (!need_resched()) 73 cpu_relax(); 74 } 75 76 void cpu_idle(void) 77 { 78 set_thread_flag(TIF_POLLING_NRFLAG); 79 80 /* endless idle loop with no priority at all */ 81 while (1) { 82 void (*idle)(void) = pm_idle; 83 84 if (!idle) 85 idle = default_idle; 86 87 tick_nohz_stop_sched_tick(); 88 while (!need_resched()) 89 idle(); 90 tick_nohz_restart_sched_tick(); 91 92 preempt_enable_no_resched(); 93 schedule(); 94 preempt_disable(); 95 check_pgt_cache(); 96 } 97 } 98 99 void machine_restart(char * __unused) 100 { 101 /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */ 102 asm volatile("ldc %0, sr\n\t" 103 "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001)); 104 } 105 106 void machine_halt(void) 107 { 108 local_irq_disable(); 109 110 while (1) 111 cpu_sleep(); 112 } 113 114 void machine_power_off(void) 115 { 116 if (pm_power_off) 117 pm_power_off(); 118 } 119 120 void show_regs(struct pt_regs * regs) 121 { 122 printk("\n"); 123 printk("Pid : %d, Comm: %20s\n", current->pid, current->comm); 124 print_symbol("PC is at %s\n", instruction_pointer(regs)); 125 printk("PC : %08lx SP : %08lx SR : %08lx ", 126 regs->pc, regs->regs[15], regs->sr); 127 #ifdef CONFIG_MMU 128 printk("TEA : %08x ", ctrl_inl(MMU_TEA)); 129 #else 130 printk(" "); 131 #endif 132 printk("%s\n", print_tainted()); 133 134 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 135 regs->regs[0],regs->regs[1], 136 regs->regs[2],regs->regs[3]); 137 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 138 regs->regs[4],regs->regs[5], 139 regs->regs[6],regs->regs[7]); 140 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 141 regs->regs[8],regs->regs[9], 142 regs->regs[10],regs->regs[11]); 143 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 144 regs->regs[12],regs->regs[13], 145 regs->regs[14]); 146 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 147 regs->mach, regs->macl, regs->gbr, regs->pr); 148 149 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 150 } 151 152 /* 153 * Create a kernel thread 154 */ 155 156 /* 157 * This is the mechanism for creating a new kernel thread. 158 * 159 */ 160 extern void kernel_thread_helper(void); 161 __asm__(".align 5\n" 162 "kernel_thread_helper:\n\t" 163 "jsr @r5\n\t" 164 " nop\n\t" 165 "mov.l 1f, r1\n\t" 166 "jsr @r1\n\t" 167 " mov r0, r4\n\t" 168 ".align 2\n\t" 169 "1:.long do_exit"); 170 171 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 172 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 173 { 174 struct pt_regs regs; 175 176 memset(®s, 0, sizeof(regs)); 177 regs.regs[4] = (unsigned long)arg; 178 regs.regs[5] = (unsigned long)fn; 179 180 regs.pc = (unsigned long)kernel_thread_helper; 181 regs.sr = (1 << 30); 182 183 /* Ok, create the new process.. */ 184 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 185 ®s, 0, NULL, NULL); 186 } 187 188 /* 189 * Free current thread data structures etc.. 190 */ 191 void exit_thread(void) 192 { 193 if (current->thread.ubc_pc) { 194 current->thread.ubc_pc = 0; 195 ubc_usercnt -= 1; 196 } 197 } 198 199 void flush_thread(void) 200 { 201 #if defined(CONFIG_SH_FPU) 202 struct task_struct *tsk = current; 203 /* Forget lazy FPU state */ 204 clear_fpu(tsk, task_pt_regs(tsk)); 205 clear_used_math(); 206 #endif 207 } 208 209 void release_thread(struct task_struct *dead_task) 210 { 211 /* do nothing */ 212 } 213 214 /* Fill in the fpu structure for a core dump.. */ 215 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 216 { 217 int fpvalid = 0; 218 219 #if defined(CONFIG_SH_FPU) 220 struct task_struct *tsk = current; 221 222 fpvalid = !!tsk_used_math(tsk); 223 if (fpvalid) { 224 unlazy_fpu(tsk, regs); 225 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 226 } 227 #endif 228 229 return fpvalid; 230 } 231 232 /* 233 * Capture the user space registers if the task is not running (in user space) 234 */ 235 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) 236 { 237 struct pt_regs ptregs; 238 239 ptregs = *task_pt_regs(tsk); 240 elf_core_copy_regs(regs, &ptregs); 241 242 return 1; 243 } 244 245 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu) 246 { 247 int fpvalid = 0; 248 249 #if defined(CONFIG_SH_FPU) 250 fpvalid = !!tsk_used_math(tsk); 251 if (fpvalid) { 252 unlazy_fpu(tsk, task_pt_regs(tsk)); 253 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 254 } 255 #endif 256 257 return fpvalid; 258 } 259 260 asmlinkage void ret_from_fork(void); 261 262 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, 263 unsigned long unused, 264 struct task_struct *p, struct pt_regs *regs) 265 { 266 struct thread_info *ti = task_thread_info(p); 267 struct pt_regs *childregs; 268 #if defined(CONFIG_SH_FPU) 269 struct task_struct *tsk = current; 270 271 unlazy_fpu(tsk, regs); 272 p->thread.fpu = tsk->thread.fpu; 273 copy_to_stopped_child_used_math(p); 274 #endif 275 276 childregs = task_pt_regs(p); 277 *childregs = *regs; 278 279 if (user_mode(regs)) { 280 childregs->regs[15] = usp; 281 ti->addr_limit = USER_DS; 282 } else { 283 childregs->regs[15] = (unsigned long)childregs; 284 ti->addr_limit = KERNEL_DS; 285 } 286 287 if (clone_flags & CLONE_SETTLS) 288 childregs->gbr = childregs->regs[0]; 289 290 childregs->regs[0] = 0; /* Set return value for child */ 291 292 p->thread.sp = (unsigned long) childregs; 293 p->thread.pc = (unsigned long) ret_from_fork; 294 295 p->thread.ubc_pc = 0; 296 297 return 0; 298 } 299 300 /* Tracing by user break controller. */ 301 static void ubc_set_tracing(int asid, unsigned long pc) 302 { 303 #if defined(CONFIG_CPU_SH4A) 304 unsigned long val; 305 306 val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE); 307 val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid)); 308 309 ctrl_outl(val, UBC_CBR0); 310 ctrl_outl(pc, UBC_CAR0); 311 ctrl_outl(0x0, UBC_CAMR0); 312 ctrl_outl(0x0, UBC_CBCR); 313 314 val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE); 315 ctrl_outl(val, UBC_CRR0); 316 317 /* Read UBC register that we wrote last, for checking update */ 318 val = ctrl_inl(UBC_CRR0); 319 320 #else /* CONFIG_CPU_SH4A */ 321 ctrl_outl(pc, UBC_BARA); 322 323 #ifdef CONFIG_MMU 324 ctrl_outb(asid, UBC_BASRA); 325 #endif 326 327 ctrl_outl(0, UBC_BAMRA); 328 329 if (current_cpu_data.type == CPU_SH7729 || 330 current_cpu_data.type == CPU_SH7710 || 331 current_cpu_data.type == CPU_SH7712) { 332 ctrl_outw(BBR_INST | BBR_READ | BBR_CPU, UBC_BBRA); 333 ctrl_outl(BRCR_PCBA | BRCR_PCTE, UBC_BRCR); 334 } else { 335 ctrl_outw(BBR_INST | BBR_READ, UBC_BBRA); 336 ctrl_outw(BRCR_PCBA, UBC_BRCR); 337 } 338 #endif /* CONFIG_CPU_SH4A */ 339 } 340 341 /* 342 * switch_to(x,y) should switch tasks from x to y. 343 * 344 */ 345 struct task_struct *__switch_to(struct task_struct *prev, 346 struct task_struct *next) 347 { 348 #if defined(CONFIG_SH_FPU) 349 unlazy_fpu(prev, task_pt_regs(prev)); 350 #endif 351 352 #ifdef CONFIG_PREEMPT 353 { 354 unsigned long flags; 355 struct pt_regs *regs; 356 357 local_irq_save(flags); 358 regs = task_pt_regs(prev); 359 if (user_mode(regs) && regs->regs[15] >= 0xc0000000) { 360 int offset = (int)regs->regs[15]; 361 362 /* Reset stack pointer: clear critical region mark */ 363 regs->regs[15] = regs->regs[1]; 364 if (regs->pc < regs->regs[0]) 365 /* Go to rewind point */ 366 regs->pc = regs->regs[0] + offset; 367 } 368 local_irq_restore(flags); 369 } 370 #endif 371 372 #ifdef CONFIG_MMU 373 /* 374 * Restore the kernel mode register 375 * k7 (r7_bank1) 376 */ 377 asm volatile("ldc %0, r7_bank" 378 : /* no output */ 379 : "r" (task_thread_info(next))); 380 #endif 381 382 /* If no tasks are using the UBC, we're done */ 383 if (ubc_usercnt == 0) 384 /* If no tasks are using the UBC, we're done */; 385 else if (next->thread.ubc_pc && next->mm) { 386 int asid = 0; 387 #ifdef CONFIG_MMU 388 asid |= cpu_asid(smp_processor_id(), next->mm); 389 #endif 390 ubc_set_tracing(asid, next->thread.ubc_pc); 391 } else { 392 #if defined(CONFIG_CPU_SH4A) 393 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 394 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 395 #else 396 ctrl_outw(0, UBC_BBRA); 397 ctrl_outw(0, UBC_BBRB); 398 #endif 399 } 400 401 return prev; 402 } 403 404 asmlinkage int sys_fork(unsigned long r4, unsigned long r5, 405 unsigned long r6, unsigned long r7, 406 struct pt_regs __regs) 407 { 408 #ifdef CONFIG_MMU 409 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 410 return do_fork(SIGCHLD, regs->regs[15], regs, 0, NULL, NULL); 411 #else 412 /* fork almost works, enough to trick you into looking elsewhere :-( */ 413 return -EINVAL; 414 #endif 415 } 416 417 asmlinkage int sys_clone(unsigned long clone_flags, unsigned long newsp, 418 unsigned long parent_tidptr, 419 unsigned long child_tidptr, 420 struct pt_regs __regs) 421 { 422 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 423 if (!newsp) 424 newsp = regs->regs[15]; 425 return do_fork(clone_flags, newsp, regs, 0, 426 (int __user *)parent_tidptr, 427 (int __user *)child_tidptr); 428 } 429 430 /* 431 * This is trivial, and on the face of it looks like it 432 * could equally well be done in user mode. 433 * 434 * Not so, for quite unobvious reasons - register pressure. 435 * In user mode vfork() cannot have a stack frame, and if 436 * done by calling the "clone()" system call directly, you 437 * do not have enough call-clobbered registers to hold all 438 * the information you need. 439 */ 440 asmlinkage int sys_vfork(unsigned long r4, unsigned long r5, 441 unsigned long r6, unsigned long r7, 442 struct pt_regs __regs) 443 { 444 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 445 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->regs[15], regs, 446 0, NULL, NULL); 447 } 448 449 /* 450 * sys_execve() executes a new program. 451 */ 452 asmlinkage int sys_execve(char __user *ufilename, char __user * __user *uargv, 453 char __user * __user *uenvp, unsigned long r7, 454 struct pt_regs __regs) 455 { 456 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 457 int error; 458 char *filename; 459 460 filename = getname(ufilename); 461 error = PTR_ERR(filename); 462 if (IS_ERR(filename)) 463 goto out; 464 465 error = do_execve(filename, uargv, uenvp, regs); 466 if (error == 0) { 467 task_lock(current); 468 current->ptrace &= ~PT_DTRACE; 469 task_unlock(current); 470 } 471 putname(filename); 472 out: 473 return error; 474 } 475 476 unsigned long get_wchan(struct task_struct *p) 477 { 478 unsigned long pc; 479 480 if (!p || p == current || p->state == TASK_RUNNING) 481 return 0; 482 483 /* 484 * The same comment as on the Alpha applies here, too ... 485 */ 486 pc = thread_saved_pc(p); 487 488 #ifdef CONFIG_FRAME_POINTER 489 if (in_sched_functions(pc)) { 490 unsigned long schedule_frame = (unsigned long)p->thread.sp; 491 return ((unsigned long *)schedule_frame)[21]; 492 } 493 #endif 494 495 return pc; 496 } 497 498 asmlinkage void break_point_trap(void) 499 { 500 /* Clear tracing. */ 501 #if defined(CONFIG_CPU_SH4A) 502 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 503 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 504 #else 505 ctrl_outw(0, UBC_BBRA); 506 ctrl_outw(0, UBC_BBRB); 507 #endif 508 current->thread.ubc_pc = 0; 509 ubc_usercnt -= 1; 510 511 force_sig(SIGTRAP, current); 512 } 513 514 /* 515 * Generic trap handler. 516 */ 517 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5, 518 unsigned long r6, unsigned long r7, 519 struct pt_regs __regs) 520 { 521 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 522 523 /* Rewind */ 524 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 525 526 if (notify_die(DIE_TRAP, "debug trap", regs, 0, regs->tra & 0xff, 527 SIGTRAP) == NOTIFY_STOP) 528 return; 529 530 force_sig(SIGTRAP, current); 531 } 532 533 /* 534 * Special handler for BUG() traps. 535 */ 536 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5, 537 unsigned long r6, unsigned long r7, 538 struct pt_regs __regs) 539 { 540 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 541 542 /* Rewind */ 543 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 544 545 if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff, 546 SIGTRAP) == NOTIFY_STOP) 547 return; 548 549 #ifdef CONFIG_BUG 550 if (__kernel_text_address(instruction_pointer(regs))) { 551 u16 insn = *(u16 *)instruction_pointer(regs); 552 if (insn == TRAPA_BUG_OPCODE) 553 handle_BUG(regs); 554 } 555 #endif 556 557 force_sig(SIGTRAP, current); 558 } 559