process.c 12.9 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45
/*
 *  linux/arch/alpha/kernel/process.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 */

/*
 * This file handles the architecture-dependent parts of process handling.
 */

#include <linux/config.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/utsname.h>
#include <linux/time.h>
#include <linux/major.h>
#include <linux/stat.h>
#include <linux/mman.h>
#include <linux/elfcore.h>
#include <linux/reboot.h>
#include <linux/tty.h>
#include <linux/console.h>

#include <asm/reg.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/hwrpb.h>
#include <asm/fpu.h>

#include "proto.h"
#include "pci_impl.h"

46 47 48 49 50
/*
 * Power off function, if any
 */
void (*pm_power_off)(void) = machine_power_off;

L
Linus Torvalds 已提交
51 52 53
void
cpu_idle(void)
{
54 55
	set_thread_flag(TIF_POLLING_NRFLAG);

L
Linus Torvalds 已提交
56 57 58 59 60
	while (1) {
		/* FIXME -- EV6 and LCA45 know how to power down
		   the CPU.  */

		while (!need_resched())
61
			cpu_relax();
L
Linus Torvalds 已提交
62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130
		schedule();
	}
}


struct halt_info {
	int mode;
	char *restart_cmd;
};

static void
common_shutdown_1(void *generic_ptr)
{
	struct halt_info *how = (struct halt_info *)generic_ptr;
	struct percpu_struct *cpup;
	unsigned long *pflags, flags;
	int cpuid = smp_processor_id();

	/* No point in taking interrupts anymore. */
	local_irq_disable();

	cpup = (struct percpu_struct *)
			((unsigned long)hwrpb + hwrpb->processor_offset
			 + hwrpb->processor_size * cpuid);
	pflags = &cpup->flags;
	flags = *pflags;

	/* Clear reason to "default"; clear "bootstrap in progress". */
	flags &= ~0x00ff0001UL;

#ifdef CONFIG_SMP
	/* Secondaries halt here. */
	if (cpuid != boot_cpuid) {
		flags |= 0x00040000UL; /* "remain halted" */
		*pflags = flags;
		clear_bit(cpuid, &cpu_present_mask);
		halt();
	}
#endif

	if (how->mode == LINUX_REBOOT_CMD_RESTART) {
		if (!how->restart_cmd) {
			flags |= 0x00020000UL; /* "cold bootstrap" */
		} else {
			/* For SRM, we could probably set environment
			   variables to get this to work.  We'd have to
			   delay this until after srm_paging_stop unless
			   we ever got srm_fixup working.

			   At the moment, SRM will use the last boot device,
			   but the file and flags will be the defaults, when
			   doing a "warm" bootstrap.  */
			flags |= 0x00030000UL; /* "warm bootstrap" */
		}
	} else {
		flags |= 0x00040000UL; /* "remain halted" */
	}
	*pflags = flags;

#ifdef CONFIG_SMP
	/* Wait for the secondaries to halt. */
	cpu_clear(boot_cpuid, cpu_possible_map);
	while (cpus_weight(cpu_possible_map))
		barrier();
#endif

	/* If booted from SRM, reset some of the original environment. */
	if (alpha_using_srm) {
#ifdef CONFIG_DUMMY_CONSOLE
131 132 133 134
		/* If we've gotten here after SysRq-b, leave interrupt
		   context before taking over the console. */
		if (in_interrupt())
			irq_exit();
L
Linus Torvalds 已提交
135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530
		/* This has the effect of resetting the VGA video origin.  */
		take_over_console(&dummy_con, 0, MAX_NR_CONSOLES-1, 1);
#endif
		pci_restore_srm_config();
		set_hae(srm_hae);
	}

	if (alpha_mv.kill_arch)
		alpha_mv.kill_arch(how->mode);

	if (! alpha_using_srm && how->mode != LINUX_REBOOT_CMD_RESTART) {
		/* Unfortunately, since MILO doesn't currently understand
		   the hwrpb bits above, we can't reliably halt the 
		   processor and keep it halted.  So just loop.  */
		return;
	}

	if (alpha_using_srm)
		srm_paging_stop();

	halt();
}

static void
common_shutdown(int mode, char *restart_cmd)
{
	struct halt_info args;
	args.mode = mode;
	args.restart_cmd = restart_cmd;
	on_each_cpu(common_shutdown_1, &args, 1, 0);
}

void
machine_restart(char *restart_cmd)
{
	common_shutdown(LINUX_REBOOT_CMD_RESTART, restart_cmd);
}


void
machine_halt(void)
{
	common_shutdown(LINUX_REBOOT_CMD_HALT, NULL);
}


void
machine_power_off(void)
{
	common_shutdown(LINUX_REBOOT_CMD_POWER_OFF, NULL);
}


/* Used by sysrq-p, among others.  I don't believe r9-r15 are ever
   saved in the context it's used.  */

void
show_regs(struct pt_regs *regs)
{
	dik_show_regs(regs, NULL);
}

/*
 * Re-start a thread when doing execve()
 */
void
start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
{
	set_fs(USER_DS);
	regs->pc = pc;
	regs->ps = 8;
	wrusp(sp);
}

/*
 * Free current thread data structures etc..
 */
void
exit_thread(void)
{
}

void
flush_thread(void)
{
	/* Arrange for each exec'ed process to start off with a clean slate
	   with respect to the FPU.  This is all exceptions disabled.  */
	current_thread_info()->ieee_state = 0;
	wrfpcr(FPCR_DYN_NORMAL | ieee_swcr_to_fpcr(0));

	/* Clean slate for TLS.  */
	current_thread_info()->pcb.unique = 0;
}

void
release_thread(struct task_struct *dead_task)
{
}

/*
 * "alpha_clone()".. By the time we get here, the
 * non-volatile registers have also been saved on the
 * stack. We do some ugly pointer stuff here.. (see
 * also copy_thread)
 *
 * Notice that "fork()" is implemented in terms of clone,
 * with parameters (SIGCHLD, 0).
 */
int
alpha_clone(unsigned long clone_flags, unsigned long usp,
	    int __user *parent_tid, int __user *child_tid,
	    unsigned long tls_value, struct pt_regs *regs)
{
	if (!usp)
		usp = rdusp();

	return do_fork(clone_flags, usp, regs, 0, parent_tid, child_tid);
}

int
alpha_vfork(struct pt_regs *regs)
{
	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(),
		       regs, 0, NULL, NULL);
}

/*
 * Copy an alpha thread..
 *
 * Note the "stack_offset" stuff: when returning to kernel mode, we need
 * to have some extra stack-space for the kernel stack that still exists
 * after the "ret_from_fork".  When returning to user mode, we only want
 * the space needed by the syscall stack frame (ie "struct pt_regs").
 * Use the passed "regs" pointer to determine how much space we need
 * for a kernel fork().
 */

int
copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
	    unsigned long unused,
	    struct task_struct * p, struct pt_regs * regs)
{
	extern void ret_from_fork(void);

	struct thread_info *childti = p->thread_info;
	struct pt_regs * childregs;
	struct switch_stack * childstack, *stack;
	unsigned long stack_offset, settls;

	stack_offset = PAGE_SIZE - sizeof(struct pt_regs);
	if (!(regs->ps & 8))
		stack_offset = (PAGE_SIZE-1) & (unsigned long) regs;
	childregs = (struct pt_regs *)
	  (stack_offset + PAGE_SIZE + (long) childti);
		
	*childregs = *regs;
	settls = regs->r20;
	childregs->r0 = 0;
	childregs->r19 = 0;
	childregs->r20 = 1;	/* OSF/1 has some strange fork() semantics.  */
	regs->r20 = 0;
	stack = ((struct switch_stack *) regs) - 1;
	childstack = ((struct switch_stack *) childregs) - 1;
	*childstack = *stack;
	childstack->r26 = (unsigned long) ret_from_fork;
	childti->pcb.usp = usp;
	childti->pcb.ksp = (unsigned long) childstack;
	childti->pcb.flags = 1;	/* set FEN, clear everything else */

	/* Set a new TLS for the child thread?  Peek back into the
	   syscall arguments that we saved on syscall entry.  Oops,
	   except we'd have clobbered it with the parent/child set
	   of r20.  Read the saved copy.  */
	/* Note: if CLONE_SETTLS is not set, then we must inherit the
	   value from the parent, which will have been set by the block
	   copy in dup_task_struct.  This is non-intuitive, but is
	   required for proper operation in the case of a threaded
	   application calling fork.  */
	if (clone_flags & CLONE_SETTLS)
		childti->pcb.unique = settls;

	return 0;
}

/*
 * Fill in the user structure for an ECOFF core dump.
 */
void
dump_thread(struct pt_regs * pt, struct user * dump)
{
	/* switch stack follows right below pt_regs: */
	struct switch_stack * sw = ((struct switch_stack *) pt) - 1;

	dump->magic = CMAGIC;
	dump->start_code  = current->mm->start_code;
	dump->start_data  = current->mm->start_data;
	dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
	dump->u_tsize = ((current->mm->end_code - dump->start_code)
			 >> PAGE_SHIFT);
	dump->u_dsize = ((current->mm->brk + PAGE_SIZE-1 - dump->start_data)
			 >> PAGE_SHIFT);
	dump->u_ssize = (current->mm->start_stack - dump->start_stack
			 + PAGE_SIZE-1) >> PAGE_SHIFT;

	/*
	 * We store the registers in an order/format that is
	 * compatible with DEC Unix/OSF/1 as this makes life easier
	 * for gdb.
	 */
	dump->regs[EF_V0]  = pt->r0;
	dump->regs[EF_T0]  = pt->r1;
	dump->regs[EF_T1]  = pt->r2;
	dump->regs[EF_T2]  = pt->r3;
	dump->regs[EF_T3]  = pt->r4;
	dump->regs[EF_T4]  = pt->r5;
	dump->regs[EF_T5]  = pt->r6;
	dump->regs[EF_T6]  = pt->r7;
	dump->regs[EF_T7]  = pt->r8;
	dump->regs[EF_S0]  = sw->r9;
	dump->regs[EF_S1]  = sw->r10;
	dump->regs[EF_S2]  = sw->r11;
	dump->regs[EF_S3]  = sw->r12;
	dump->regs[EF_S4]  = sw->r13;
	dump->regs[EF_S5]  = sw->r14;
	dump->regs[EF_S6]  = sw->r15;
	dump->regs[EF_A3]  = pt->r19;
	dump->regs[EF_A4]  = pt->r20;
	dump->regs[EF_A5]  = pt->r21;
	dump->regs[EF_T8]  = pt->r22;
	dump->regs[EF_T9]  = pt->r23;
	dump->regs[EF_T10] = pt->r24;
	dump->regs[EF_T11] = pt->r25;
	dump->regs[EF_RA]  = pt->r26;
	dump->regs[EF_T12] = pt->r27;
	dump->regs[EF_AT]  = pt->r28;
	dump->regs[EF_SP]  = rdusp();
	dump->regs[EF_PS]  = pt->ps;
	dump->regs[EF_PC]  = pt->pc;
	dump->regs[EF_GP]  = pt->gp;
	dump->regs[EF_A0]  = pt->r16;
	dump->regs[EF_A1]  = pt->r17;
	dump->regs[EF_A2]  = pt->r18;
	memcpy((char *)dump->regs + EF_SIZE, sw->fp, 32 * 8);
}

/*
 * Fill in the user structure for a ELF core dump.
 */
void
dump_elf_thread(elf_greg_t *dest, struct pt_regs *pt, struct thread_info *ti)
{
	/* switch stack follows right below pt_regs: */
	struct switch_stack * sw = ((struct switch_stack *) pt) - 1;

	dest[ 0] = pt->r0;
	dest[ 1] = pt->r1;
	dest[ 2] = pt->r2;
	dest[ 3] = pt->r3;
	dest[ 4] = pt->r4;
	dest[ 5] = pt->r5;
	dest[ 6] = pt->r6;
	dest[ 7] = pt->r7;
	dest[ 8] = pt->r8;
	dest[ 9] = sw->r9;
	dest[10] = sw->r10;
	dest[11] = sw->r11;
	dest[12] = sw->r12;
	dest[13] = sw->r13;
	dest[14] = sw->r14;
	dest[15] = sw->r15;
	dest[16] = pt->r16;
	dest[17] = pt->r17;
	dest[18] = pt->r18;
	dest[19] = pt->r19;
	dest[20] = pt->r20;
	dest[21] = pt->r21;
	dest[22] = pt->r22;
	dest[23] = pt->r23;
	dest[24] = pt->r24;
	dest[25] = pt->r25;
	dest[26] = pt->r26;
	dest[27] = pt->r27;
	dest[28] = pt->r28;
	dest[29] = pt->gp;
	dest[30] = rdusp();
	dest[31] = pt->pc;

	/* Once upon a time this was the PS value.  Which is stupid
	   since that is always 8 for usermode.  Usurped for the more
	   useful value of the thread's UNIQUE field.  */
	dest[32] = ti->pcb.unique;
}

int
dump_elf_task(elf_greg_t *dest, struct task_struct *task)
{
	struct thread_info *ti;
	struct pt_regs *pt;

	ti = task->thread_info;
	pt = (struct pt_regs *)((unsigned long)ti + 2*PAGE_SIZE) - 1;

	dump_elf_thread(dest, pt, ti);

	return 1;
}

int
dump_elf_task_fp(elf_fpreg_t *dest, struct task_struct *task)
{
	struct thread_info *ti;
	struct pt_regs *pt;
	struct switch_stack *sw;

	ti = task->thread_info;
	pt = (struct pt_regs *)((unsigned long)ti + 2*PAGE_SIZE) - 1;
	sw = (struct switch_stack *)pt - 1;

	memcpy(dest, sw->fp, 32 * 8);

	return 1;
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int
do_sys_execve(char __user *ufilename, char __user * __user *argv,
	      char __user * __user *envp, struct pt_regs *regs)
{
	int error;
	char *filename;

	filename = getname(ufilename);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	error = do_execve(filename, argv, envp, regs);
	putname(filename);
out:
	return error;
}

/*
 * Return saved PC of a blocked thread.  This assumes the frame
 * pointer is the 6th saved long on the kernel stack and that the
 * saved return address is the first long in the frame.  This all
 * holds provided the thread blocked through a call to schedule() ($15
 * is the frame pointer in schedule() and $15 is saved at offset 48 by
 * entry.S:do_switch_stack).
 *
 * Under heavy swap load I've seen this lose in an ugly way.  So do
 * some extra sanity checking on the ranges we expect these pointers
 * to be in so that we can fail gracefully.  This is just for ps after
 * all.  -- r~
 */

unsigned long
thread_saved_pc(task_t *t)
{
	unsigned long base = (unsigned long)t->thread_info;
	unsigned long fp, sp = t->thread_info->pcb.ksp;

	if (sp > base && sp+6*8 < base + 16*1024) {
		fp = ((unsigned long*)sp)[6];
		if (fp > sp && fp < base + 16*1024)
			return *(unsigned long *)fp;
	}

	return 0;
}

unsigned long
get_wchan(struct task_struct *p)
{
	unsigned long schedule_frame;
	unsigned long pc;
	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;
	/*
	 * This one depends on the frame size of schedule().  Do a
	 * "disass schedule" in gdb to find the frame size.  Also, the
	 * code assumes that sleep_on() follows immediately after
	 * interruptible_sleep_on() and that add_timer() follows
	 * immediately after interruptible_sleep().  Ugly, isn't it?
	 * Maybe adding a wchan field to task_struct would be better,
	 * after all...
	 */

	pc = thread_saved_pc(p);
	if (in_sched_functions(pc)) {
		schedule_frame = ((unsigned long *)p->thread_info->pcb.ksp)[6];
		return ((unsigned long *)schedule_frame)[12];
	}
	return pc;
}