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