1/* 2 * linux/arch/alpha/kernel/process.c 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 */ 6 7/* 8 * This file handles the architecture-dependent parts of process handling. 9 */ 10 11#include <linux/errno.h> 12#include <linux/module.h> 13#include <linux/sched.h> 14#include <linux/kernel.h> 15#include <linux/mm.h> 16#include <linux/smp.h> 17#include <linux/stddef.h> 18#include <linux/unistd.h> 19#include <linux/ptrace.h> 20#include <linux/slab.h> 21#include <linux/user.h> 22#include <linux/a.out.h> 23#include <linux/utsname.h> 24#include <linux/time.h> 25#include <linux/major.h> 26#include <linux/stat.h> 27#include <linux/vt.h> 28#include <linux/mman.h> 29#include <linux/elfcore.h> 30#include <linux/reboot.h> 31#include <linux/tty.h> 32#include <linux/console.h> 33 34#include <asm/reg.h> 35#include <asm/uaccess.h> 36#include <asm/system.h> 37#include <asm/io.h> 38#include <asm/pgtable.h> 39#include <asm/hwrpb.h> 40#include <asm/fpu.h> 41 42#include "proto.h" 43#include "pci_impl.h" 44 45/* 46 * Power off function, if any 47 */ 48void (*pm_power_off)(void) = machine_power_off; 49EXPORT_SYMBOL(pm_power_off); 50 51void 52cpu_idle(void) 53{ 54 set_thread_flag(TIF_POLLING_NRFLAG); 55 56 while (1) { 57 58 while (!need_resched()) 59 cpu_relax(); 60 schedule(); 61 } 62} 63 64 65struct halt_info { 66 int mode; 67 char *restart_cmd; 68}; 69 70static void 71common_shutdown_1(void *generic_ptr) 72{ 73 struct halt_info *how = (struct halt_info *)generic_ptr; 74 struct percpu_struct *cpup; 75 unsigned long *pflags, flags; 76 int cpuid = smp_processor_id(); 77 78 /* No point in taking interrupts anymore. */ 79 local_irq_disable(); 80 81 cpup = (struct percpu_struct *) 82 ((unsigned long)hwrpb + hwrpb->processor_offset 83 + hwrpb->processor_size * cpuid); 84 pflags = &cpup->flags; 85 flags = *pflags; 86 87 /* Clear reason to "default"; clear "bootstrap in progress". */ 88 flags &= ~0x00ff0001UL; 89 90#ifdef CONFIG_SMP 91 /* Secondaries halt here. */ 92 if (cpuid != boot_cpuid) { 93 flags |= 0x00040000UL; /* "remain halted" */ 94 *pflags = flags; 95 cpu_clear(cpuid, cpu_present_map); 96 halt(); 97 } 98#endif 99 100 if (how->mode == LINUX_REBOOT_CMD_RESTART) { 101 if (!how->restart_cmd) { 102 flags |= 0x00020000UL; /* "cold bootstrap" */ 103 } else { 104 /* For SRM, we could probably set environment 105 variables to get this to work. We'd have to 106 delay this until after srm_paging_stop unless 107 we ever got srm_fixup working. 108 109 At the moment, SRM will use the last boot device, 110 but the file and flags will be the defaults, when 111 doing a "warm" bootstrap. */ 112 flags |= 0x00030000UL; /* "warm bootstrap" */ 113 } 114 } else { 115 flags |= 0x00040000UL; /* "remain halted" */ 116 } 117 *pflags = flags; 118 119#ifdef CONFIG_SMP 120 /* Wait for the secondaries to halt. */ 121 cpu_clear(boot_cpuid, cpu_present_map); 122 while (cpus_weight(cpu_present_map)) 123 barrier(); 124#endif 125 126 /* If booted from SRM, reset some of the original environment. */ 127 if (alpha_using_srm) { 128#ifdef CONFIG_DUMMY_CONSOLE 129 /* If we've gotten here after SysRq-b, leave interrupt 130 context before taking over the console. */ 131 if (in_interrupt()) 132 irq_exit(); 133 /* This has the effect of resetting the VGA video origin. */ 134 take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1); 135#endif 136 pci_restore_srm_config(); 137 set_hae(srm_hae); 138 } 139 140 if (alpha_mv.kill_arch) 141 alpha_mv.kill_arch(how->mode); 142 143 if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) { 144 /* Unfortunately, since MILO doesn't currently understand 145 the hwrpb bits above, we can't reliably halt the 146 processor and keep it halted. So just loop. */ 147 return; 148 } 149 150 if (alpha_using_srm) 151 srm_paging_stop(); 152 153 halt(); 154} 155 156static void 157common_shutdown(int mode, char *restart_cmd) 158{ 159 struct halt_info args; 160 args.mode = mode; 161 args.restart_cmd = restart_cmd; 162 on_each_cpu(common_shutdown_1, &args, 1, 0); 163} 164 165void 166machine_restart(char *restart_cmd) 167{ 168 common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd); 169} 170 171 172void 173machine_halt(void) 174{ 175 common_shutdown(LINUX_REBOOT_CMD_HALT, NULL); 176} 177 178 179void 180machine_power_off(void) 181{ 182 common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL); 183} 184 185 186/* Used by sysrq-p, among others. I don't believe r9-r15 are ever 187 saved in the context it's used. */ 188 189void 190show_regs(struct pt_regs *regs) 191{ 192 dik_show_regs(regs, NULL); 193} 194 195/* 196 * Re-start a thread when doing execve() 197 */ 198void 199start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp) 200{ 201 set_fs(USER_DS); 202 regs->pc = pc; 203 regs->ps = 8; 204 wrusp(sp); 205} 206EXPORT_SYMBOL(start_thread); 207 208/* 209 * Free current thread data structures etc.. 210 */ 211void 212exit_thread(void) 213{ 214} 215 216void 217flush_thread(void) 218{ 219 /* Arrange for each exec'ed process to start off with a clean slate 220 with respect to the FPU. This is all exceptions disabled. */ 221 current_thread_info()->ieee_state = 0; 222 wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0)); 223 224 /* Clean slate for TLS. */ 225 current_thread_info()->pcb.unique = 0; 226} 227 228void 229release_thread(struct task_struct *dead_task) 230{ 231} 232 233/* 234 * "alpha_clone()".. By the time we get here, the 235 * non-volatile registers have also been saved on the 236 * stack. We do some ugly pointer stuff here.. (see 237 * also copy_thread) 238 * 239 * Notice that "fork()" is implemented in terms of clone, 240 * with parameters (SIGCHLD, 0). 241 */ 242int 243alpha_clone(unsigned long clone_flags, unsigned long usp, 244 int __user *parent_tid, int __user *child_tid, 245 unsigned long tls_value, struct pt_regs *regs) 246{ 247 if (!usp) 248 usp = rdusp(); 249 250 return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid); 251} 252 253int 254alpha_vfork(struct pt_regs *regs) 255{ 256 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), 257 regs, 0, NULL, NULL); 258} 259 260/* 261 * Copy an alpha thread.. 262 * 263 * Note the "stack_offset" stuff: when returning to kernel mode, we need 264 * to have some extra stack-space for the kernel stack that still exists 265 * after the "ret_from_fork". When returning to user mode, we only want 266 * the space needed by the syscall stack frame (ie "struct pt_regs"). 267 * Use the passed "regs" pointer to determine how much space we need 268 * for a kernel fork(). 269 */ 270 271int 272copy_thread(int nr, unsigned long clone_flags, unsigned long usp, 273 unsigned long unused, 274 struct task_struct * p, struct pt_regs * regs) 275{ 276 extern void ret_from_fork(void); 277 278 struct thread_info *childti = task_thread_info(p); 279 struct pt_regs * childregs; 280 struct switch_stack * childstack, *stack; 281 unsigned long stack_offset, settls; 282 283 stack_offset = PAGE_SIZE - sizeof(struct pt_regs); 284 if (!(regs->ps & 8)) 285 stack_offset = (PAGE_SIZE-1) & (unsigned long) regs; 286 childregs = (struct pt_regs *) 287 (stack_offset + PAGE_SIZE + task_stack_page(p)); 288 289 *childregs = *regs; 290 settls = regs->r20; 291 childregs->r0 = 0; 292 childregs->r19 = 0; 293 childregs->r20 = 1; /* OSF/1 has some strange fork() semantics. */ 294 regs->r20 = 0; 295 stack = ((struct switch_stack *) regs) - 1; 296 childstack = ((struct switch_stack *) childregs) - 1; 297 *childstack = *stack; 298 childstack->r26 = (unsigned long) ret_from_fork; 299 childti->pcb.usp = usp; 300 childti->pcb.ksp = (unsigned long) childstack; 301 childti->pcb.flags = 1; /* set FEN, clear everything else */ 302 303 /* Set a new TLS for the child thread? Peek back into the 304 syscall arguments that we saved on syscall entry. Oops, 305 except we'd have clobbered it with the parent/child set 306 of r20. Read the saved copy. */ 307 /* Note: if CLONE_SETTLS is not set, then we must inherit the 308 value from the parent, which will have been set by the block 309 copy in dup_task_struct. This is non-intuitive, but is 310 required for proper operation in the case of a threaded 311 application calling fork. */ 312 if (clone_flags & CLONE_SETTLS) 313 childti->pcb.unique = settls; 314 315 return 0; 316} 317 318/* 319 * Fill in the user structure for an ECOFF core dump. 320 */ 321void 322dump_thread(struct pt_regs * pt, struct user * dump) 323{ 324 /* switch stack follows right below pt_regs: */ 325 struct switch_stack * sw = ((struct switch_stack *) pt) - 1; 326 327 dump->magic = CMAGIC; 328 dump->start_code = current->mm->start_code; 329 dump->start_data = current->mm->start_data; 330 dump->start_stack = rdusp() & ~(PAGE_SIZE - 1); 331 dump->u_tsize = ((current->mm->end_code - dump->start_code) 332 >> PAGE_SHIFT); 333 dump->u_dsize = ((current->mm->brk + PAGE_SIZE-1 - dump->start_data) 334 >> PAGE_SHIFT); 335 dump->u_ssize = (current->mm->start_stack - dump->start_stack 336 + PAGE_SIZE-1) >> PAGE_SHIFT; 337 338 /* 339 * We store the registers in an order/format that is 340 * compatible with DEC Unix/OSF/1 as this makes life easier 341 * for gdb. 342 */ 343 dump->regs[EF_V0] = pt->r0; 344 dump->regs[EF_T0] = pt->r1; 345 dump->regs[EF_T1] = pt->r2; 346 dump->regs[EF_T2] = pt->r3; 347 dump->regs[EF_T3] = pt->r4; 348 dump->regs[EF_T4] = pt->r5; 349 dump->regs[EF_T5] = pt->r6; 350 dump->regs[EF_T6] = pt->r7; 351 dump->regs[EF_T7] = pt->r8; 352 dump->regs[EF_S0] = sw->r9; 353 dump->regs[EF_S1] = sw->r10; 354 dump->regs[EF_S2] = sw->r11; 355 dump->regs[EF_S3] = sw->r12; 356 dump->regs[EF_S4] = sw->r13; 357 dump->regs[EF_S5] = sw->r14; 358 dump->regs[EF_S6] = sw->r15; 359 dump->regs[EF_A3] = pt->r19; 360 dump->regs[EF_A4] = pt->r20; 361 dump->regs[EF_A5] = pt->r21; 362 dump->regs[EF_T8] = pt->r22; 363 dump->regs[EF_T9] = pt->r23; 364 dump->regs[EF_T10] = pt->r24; 365 dump->regs[EF_T11] = pt->r25; 366 dump->regs[EF_RA] = pt->r26; 367 dump->regs[EF_T12] = pt->r27; 368 dump->regs[EF_AT] = pt->r28; 369 dump->regs[EF_SP] = rdusp(); 370 dump->regs[EF_PS] = pt->ps; 371 dump->regs[EF_PC] = pt->pc; 372 dump->regs[EF_GP] = pt->gp; 373 dump->regs[EF_A0] = pt->r16; 374 dump->regs[EF_A1] = pt->r17; 375 dump->regs[EF_A2] = pt->r18; 376 memcpy((char *)dump->regs + EF_SIZE, sw->fp, 32 * 8); 377} 378EXPORT_SYMBOL(dump_thread); 379 380/* 381 * Fill in the user structure for a ELF core dump. 382 */ 383void 384dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti) 385{ 386 /* switch stack follows right below pt_regs: */ 387 struct switch_stack * sw = ((struct switch_stack *) pt) - 1; 388 389 dest[ 0] = pt->r0; 390 dest[ 1] = pt->r1; 391 dest[ 2] = pt->r2; 392 dest[ 3] = pt->r3; 393 dest[ 4] = pt->r4; 394 dest[ 5] = pt->r5; 395 dest[ 6] = pt->r6; 396 dest[ 7] = pt->r7; 397 dest[ 8] = pt->r8; 398 dest[ 9] = sw->r9; 399 dest[10] = sw->r10; 400 dest[11] = sw->r11; 401 dest[12] = sw->r12; 402 dest[13] = sw->r13; 403 dest[14] = sw->r14; 404 dest[15] = sw->r15; 405 dest[16] = pt->r16; 406 dest[17] = pt->r17; 407 dest[18] = pt->r18; 408 dest[19] = pt->r19; 409 dest[20] = pt->r20; 410 dest[21] = pt->r21; 411 dest[22] = pt->r22; 412 dest[23] = pt->r23; 413 dest[24] = pt->r24; 414 dest[25] = pt->r25; 415 dest[26] = pt->r26; 416 dest[27] = pt->r27; 417 dest[28] = pt->r28; 418 dest[29] = pt->gp; 419 dest[30] = rdusp(); 420 dest[31] = pt->pc; 421 422 /* Once upon a time this was the PS value. Which is stupid 423 since that is always 8 for usermode. Usurped for the more 424 useful value of the thread's UNIQUE field. */ 425 dest[32] = ti->pcb.unique; 426} 427EXPORT_SYMBOL(dump_elf_thread); 428 429int 430dump_elf_task(elf_greg_t *dest, struct task_struct *task) 431{ 432 dump_elf_thread(dest, task_pt_regs(task), task_thread_info(task)); 433 return 1; 434} 435EXPORT_SYMBOL(dump_elf_task); 436 437int 438dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task) 439{ 440 struct switch_stack *sw = (struct switch_stack *)task_pt_regs(task) - 1; 441 memcpy(dest, sw->fp, 32 * 8); 442 return 1; 443} 444EXPORT_SYMBOL(dump_elf_task_fp); 445 446/* 447 * sys_execve() executes a new program. 448 */ 449asmlinkage int 450do_sys_execve(char __user *ufilename, char __user * __user *argv, 451 char __user * __user *envp, struct pt_regs *regs) 452{ 453 int error; 454 char *filename; 455 456 filename = getname(ufilename); 457 error = PTR_ERR(filename); 458 if (IS_ERR(filename)) 459 goto out; 460 error = do_execve(filename, argv, envp, regs); 461 putname(filename); 462out: 463 return error; 464} 465 466/* 467 * Return saved PC of a blocked thread. This assumes the frame 468 * pointer is the 6th saved long on the kernel stack and that the 469 * saved return address is the first long in the frame. This all 470 * holds provided the thread blocked through a call to schedule() ($15 471 * is the frame pointer in schedule() and $15 is saved at offset 48 by 472 * entry.S:do_switch_stack). 473 * 474 * Under heavy swap load I've seen this lose in an ugly way. So do 475 * some extra sanity checking on the ranges we expect these pointers 476 * to be in so that we can fail gracefully. This is just for ps after 477 * all. -- r~ 478 */ 479 480unsigned long 481thread_saved_pc(struct task_struct *t) 482{ 483 unsigned long base = (unsigned long)task_stack_page(t); 484 unsigned long fp, sp = task_thread_info(t)->pcb.ksp; 485 486 if (sp > base && sp+6*8 < base + 16*1024) { 487 fp = ((unsigned long*)sp)[6]; 488 if (fp > sp && fp < base + 16*1024) 489 return *(unsigned long *)fp; 490 } 491 492 return 0; 493} 494 495unsigned long 496get_wchan(struct task_struct *p) 497{ 498 unsigned long schedule_frame; 499 unsigned long pc; 500 if (!p || p == current || p->state == TASK_RUNNING) 501 return 0; 502 /* 503 * This one depends on the frame size of schedule(). Do a 504 * "disass schedule" in gdb to find the frame size. Also, the 505 * code assumes that sleep_on() follows immediately after 506 * interruptible_sleep_on() and that add_timer() follows 507 * immediately after interruptible_sleep(). Ugly, isn't it? 508 * Maybe adding a wchan field to task_struct would be better, 509 * after all... 510 */ 511 512 pc = thread_saved_pc(p); 513 if (in_sched_functions(pc)) { 514 schedule_frame = ((unsigned long *)task_thread_info(p)->pcb.ksp)[6]; 515 return ((unsigned long *)schedule_frame)[12]; 516 } 517 return pc; 518} 519