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 <asm/uaccess.h> 21 #include <asm/mmu_context.h> 22 #include <asm/pgalloc.h> 23 #include <asm/system.h> 24 #include <asm/ubc.h> 25 26 static int hlt_counter; 27 int ubc_usercnt = 0; 28 29 void (*pm_idle)(void); 30 void (*pm_power_off)(void); 31 EXPORT_SYMBOL(pm_power_off); 32 33 void disable_hlt(void) 34 { 35 hlt_counter++; 36 } 37 EXPORT_SYMBOL(disable_hlt); 38 39 void enable_hlt(void) 40 { 41 hlt_counter--; 42 } 43 EXPORT_SYMBOL(enable_hlt); 44 45 static int __init nohlt_setup(char *__unused) 46 { 47 hlt_counter = 1; 48 return 1; 49 } 50 __setup("nohlt", nohlt_setup); 51 52 static int __init hlt_setup(char *__unused) 53 { 54 hlt_counter = 0; 55 return 1; 56 } 57 __setup("hlt", hlt_setup); 58 59 void default_idle(void) 60 { 61 if (!hlt_counter) { 62 clear_thread_flag(TIF_POLLING_NRFLAG); 63 smp_mb__after_clear_bit(); 64 set_bl_bit(); 65 while (!need_resched()) 66 cpu_sleep(); 67 clear_bl_bit(); 68 set_thread_flag(TIF_POLLING_NRFLAG); 69 } else 70 while (!need_resched()) 71 cpu_relax(); 72 } 73 74 void cpu_idle(void) 75 { 76 set_thread_flag(TIF_POLLING_NRFLAG); 77 78 /* endless idle loop with no priority at all */ 79 while (1) { 80 void (*idle)(void) = pm_idle; 81 82 if (!idle) 83 idle = default_idle; 84 85 tick_nohz_stop_sched_tick(); 86 while (!need_resched()) 87 idle(); 88 tick_nohz_restart_sched_tick(); 89 90 preempt_enable_no_resched(); 91 schedule(); 92 preempt_disable(); 93 check_pgt_cache(); 94 } 95 } 96 97 void machine_restart(char * __unused) 98 { 99 /* SR.BL=1 and invoke address error to let CPU reset (manual reset) */ 100 asm volatile("ldc %0, sr\n\t" 101 "mov.l @%1, %0" : : "r" (0x10000000), "r" (0x80000001)); 102 } 103 104 void machine_halt(void) 105 { 106 local_irq_disable(); 107 108 while (1) 109 cpu_sleep(); 110 } 111 112 void machine_power_off(void) 113 { 114 if (pm_power_off) 115 pm_power_off(); 116 } 117 118 void show_regs(struct pt_regs * regs) 119 { 120 printk("\n"); 121 printk("Pid : %d, Comm: %20s\n", current->pid, current->comm); 122 print_symbol("PC is at %s\n", instruction_pointer(regs)); 123 printk("PC : %08lx SP : %08lx SR : %08lx ", 124 regs->pc, regs->regs[15], regs->sr); 125 #ifdef CONFIG_MMU 126 printk("TEA : %08x ", ctrl_inl(MMU_TEA)); 127 #else 128 printk(" "); 129 #endif 130 printk("%s\n", print_tainted()); 131 132 printk("R0 : %08lx R1 : %08lx R2 : %08lx R3 : %08lx\n", 133 regs->regs[0],regs->regs[1], 134 regs->regs[2],regs->regs[3]); 135 printk("R4 : %08lx R5 : %08lx R6 : %08lx R7 : %08lx\n", 136 regs->regs[4],regs->regs[5], 137 regs->regs[6],regs->regs[7]); 138 printk("R8 : %08lx R9 : %08lx R10 : %08lx R11 : %08lx\n", 139 regs->regs[8],regs->regs[9], 140 regs->regs[10],regs->regs[11]); 141 printk("R12 : %08lx R13 : %08lx R14 : %08lx\n", 142 regs->regs[12],regs->regs[13], 143 regs->regs[14]); 144 printk("MACH: %08lx MACL: %08lx GBR : %08lx PR : %08lx\n", 145 regs->mach, regs->macl, regs->gbr, regs->pr); 146 147 show_trace(NULL, (unsigned long *)regs->regs[15], regs); 148 } 149 150 /* 151 * Create a kernel thread 152 */ 153 154 /* 155 * This is the mechanism for creating a new kernel thread. 156 * 157 */ 158 extern void kernel_thread_helper(void); 159 __asm__(".align 5\n" 160 "kernel_thread_helper:\n\t" 161 "jsr @r5\n\t" 162 " nop\n\t" 163 "mov.l 1f, r1\n\t" 164 "jsr @r1\n\t" 165 " mov r0, r4\n\t" 166 ".align 2\n\t" 167 "1:.long do_exit"); 168 169 /* Don't use this in BL=1(cli). Or else, CPU resets! */ 170 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) 171 { 172 struct pt_regs regs; 173 174 memset(®s, 0, sizeof(regs)); 175 regs.regs[4] = (unsigned long)arg; 176 regs.regs[5] = (unsigned long)fn; 177 178 regs.pc = (unsigned long)kernel_thread_helper; 179 regs.sr = (1 << 30); 180 181 /* Ok, create the new process.. */ 182 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, 183 ®s, 0, NULL, NULL); 184 } 185 186 /* 187 * Free current thread data structures etc.. 188 */ 189 void exit_thread(void) 190 { 191 if (current->thread.ubc_pc) { 192 current->thread.ubc_pc = 0; 193 ubc_usercnt -= 1; 194 } 195 } 196 197 void flush_thread(void) 198 { 199 #if defined(CONFIG_SH_FPU) 200 struct task_struct *tsk = current; 201 /* Forget lazy FPU state */ 202 clear_fpu(tsk, task_pt_regs(tsk)); 203 clear_used_math(); 204 #endif 205 } 206 207 void release_thread(struct task_struct *dead_task) 208 { 209 /* do nothing */ 210 } 211 212 /* Fill in the fpu structure for a core dump.. */ 213 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) 214 { 215 int fpvalid = 0; 216 217 #if defined(CONFIG_SH_FPU) 218 struct task_struct *tsk = current; 219 220 fpvalid = !!tsk_used_math(tsk); 221 if (fpvalid) { 222 unlazy_fpu(tsk, regs); 223 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 224 } 225 #endif 226 227 return fpvalid; 228 } 229 230 /* 231 * Capture the user space registers if the task is not running (in user space) 232 */ 233 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) 234 { 235 struct pt_regs ptregs; 236 237 ptregs = *task_pt_regs(tsk); 238 elf_core_copy_regs(regs, &ptregs); 239 240 return 1; 241 } 242 243 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpu) 244 { 245 int fpvalid = 0; 246 247 #if defined(CONFIG_SH_FPU) 248 fpvalid = !!tsk_used_math(tsk); 249 if (fpvalid) { 250 unlazy_fpu(tsk, task_pt_regs(tsk)); 251 memcpy(fpu, &tsk->thread.fpu.hard, sizeof(*fpu)); 252 } 253 #endif 254 255 return fpvalid; 256 } 257 258 asmlinkage void ret_from_fork(void); 259 260 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp, 261 unsigned long unused, 262 struct task_struct *p, struct pt_regs *regs) 263 { 264 struct thread_info *ti = task_thread_info(p); 265 struct pt_regs *childregs; 266 #if defined(CONFIG_SH_FPU) 267 struct task_struct *tsk = current; 268 269 unlazy_fpu(tsk, regs); 270 p->thread.fpu = tsk->thread.fpu; 271 copy_to_stopped_child_used_math(p); 272 #endif 273 274 childregs = task_pt_regs(p); 275 *childregs = *regs; 276 277 if (user_mode(regs)) { 278 childregs->regs[15] = usp; 279 ti->addr_limit = USER_DS; 280 } else { 281 childregs->regs[15] = (unsigned long)childregs; 282 ti->addr_limit = KERNEL_DS; 283 } 284 285 if (clone_flags & CLONE_SETTLS) 286 childregs->gbr = childregs->regs[0]; 287 288 childregs->regs[0] = 0; /* Set return value for child */ 289 290 p->thread.sp = (unsigned long) childregs; 291 p->thread.pc = (unsigned long) ret_from_fork; 292 293 p->thread.ubc_pc = 0; 294 295 return 0; 296 } 297 298 /* Tracing by user break controller. */ 299 static void ubc_set_tracing(int asid, unsigned long pc) 300 { 301 #if defined(CONFIG_CPU_SH4A) 302 unsigned long val; 303 304 val = (UBC_CBR_ID_INST | UBC_CBR_RW_READ | UBC_CBR_CE); 305 val |= (UBC_CBR_AIE | UBC_CBR_AIV_SET(asid)); 306 307 ctrl_outl(val, UBC_CBR0); 308 ctrl_outl(pc, UBC_CAR0); 309 ctrl_outl(0x0, UBC_CAMR0); 310 ctrl_outl(0x0, UBC_CBCR); 311 312 val = (UBC_CRR_RES | UBC_CRR_PCB | UBC_CRR_BIE); 313 ctrl_outl(val, UBC_CRR0); 314 315 /* Read UBC register that we wrote last, for checking update */ 316 val = ctrl_inl(UBC_CRR0); 317 318 #else /* CONFIG_CPU_SH4A */ 319 ctrl_outl(pc, UBC_BARA); 320 321 #ifdef CONFIG_MMU 322 /* We don't have any ASID settings for the SH-2! */ 323 if (current_cpu_data.type != CPU_SH7604) 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 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 409 #ifdef CONFIG_MMU 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 *ufilename, char **uargv, 453 char **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((char __user *)ufilename); 461 error = PTR_ERR(filename); 462 if (IS_ERR(filename)) 463 goto out; 464 465 error = do_execve(filename, 466 (char __user * __user *)uargv, 467 (char __user * __user *)uenvp, 468 regs); 469 if (error == 0) { 470 task_lock(current); 471 current->ptrace &= ~PT_DTRACE; 472 task_unlock(current); 473 } 474 putname(filename); 475 out: 476 return error; 477 } 478 479 unsigned long get_wchan(struct task_struct *p) 480 { 481 unsigned long schedule_frame; 482 unsigned long pc; 483 484 if (!p || p == current || p->state == TASK_RUNNING) 485 return 0; 486 487 /* 488 * The same comment as on the Alpha applies here, too ... 489 */ 490 pc = thread_saved_pc(p); 491 if (in_sched_functions(pc)) { 492 schedule_frame = (unsigned long)p->thread.sp; 493 return ((unsigned long *)schedule_frame)[21]; 494 } 495 496 return pc; 497 } 498 499 asmlinkage void break_point_trap(void) 500 { 501 /* Clear tracing. */ 502 #if defined(CONFIG_CPU_SH4A) 503 ctrl_outl(UBC_CBR_INIT, UBC_CBR0); 504 ctrl_outl(UBC_CRR_INIT, UBC_CRR0); 505 #else 506 ctrl_outw(0, UBC_BBRA); 507 ctrl_outw(0, UBC_BBRB); 508 #endif 509 current->thread.ubc_pc = 0; 510 ubc_usercnt -= 1; 511 512 force_sig(SIGTRAP, current); 513 } 514 515 /* 516 * Generic trap handler. 517 */ 518 asmlinkage void debug_trap_handler(unsigned long r4, unsigned long r5, 519 unsigned long r6, unsigned long r7, 520 struct pt_regs __regs) 521 { 522 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 523 524 /* Rewind */ 525 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 526 527 if (notify_die(DIE_TRAP, "debug trap", regs, 0, regs->tra & 0xff, 528 SIGTRAP) == NOTIFY_STOP) 529 return; 530 531 force_sig(SIGTRAP, current); 532 } 533 534 /* 535 * Special handler for BUG() traps. 536 */ 537 asmlinkage void bug_trap_handler(unsigned long r4, unsigned long r5, 538 unsigned long r6, unsigned long r7, 539 struct pt_regs __regs) 540 { 541 struct pt_regs *regs = RELOC_HIDE(&__regs, 0); 542 543 /* Rewind */ 544 regs->pc -= instruction_size(ctrl_inw(regs->pc - 4)); 545 546 if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff, 547 SIGTRAP) == NOTIFY_STOP) 548 return; 549 550 #ifdef CONFIG_BUG 551 if (__kernel_text_address(instruction_pointer(regs))) { 552 u16 insn = *(u16 *)instruction_pointer(regs); 553 if (insn == TRAPA_BUG_OPCODE) 554 handle_BUG(regs); 555 } 556 #endif 557 558 force_sig(SIGTRAP, current); 559 } 560