process.c 25.7 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
/*
 *  linux/arch/i386/kernel/process.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Pentium III FXSR, SSE support
 *	Gareth Hughes <gareth@valinux.com>, May 2000
 */

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

#define __KERNEL_SYSCALLS__
#include <stdarg.h>

#include <linux/errno.h>
#include <linux/sched.h>
19
#include <linux/fs.h>
Linus Torvalds's avatar
Linus Torvalds committed
20 21 22 23 24 25 26
#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>
Linus Torvalds's avatar
Linus Torvalds committed
27
#include <linux/slab.h>
Linus Torvalds's avatar
Linus Torvalds committed
28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
#include <linux/vmalloc.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/interrupt.h>
#include <linux/config.h>
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/init.h>
#include <linux/mc146818rtc.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/ldt.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/desc.h>
#ifdef CONFIG_MATH_EMULATION
#include <asm/math_emu.h>
#endif

#include <linux/irq.h>
51
#include <linux/err.h>
Linus Torvalds's avatar
Linus Torvalds committed
52 53 54 55 56

asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");

int hlt_counter;

Jens Axboe's avatar
Jens Axboe committed
57 58 59 60 61 62 63 64
/*
 * Return saved PC of a blocked thread.
 */
unsigned long thread_saved_pc(struct task_struct *tsk)
{
	return ((unsigned long *)tsk->thread.esp)[3];
}

Linus Torvalds's avatar
Linus Torvalds committed
65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88
/*
 * Powermanagement idle function, if any..
 */
void (*pm_idle)(void);

/*
 * Power off function, if any
 */
void (*pm_power_off)(void);

void disable_hlt(void)
{
	hlt_counter++;
}

void enable_hlt(void)
{
	hlt_counter--;
}

/*
 * We use this if we don't have any better
 * idle routine..
 */
89
void default_idle(void)
Linus Torvalds's avatar
Linus Torvalds committed
90 91
{
	if (current_cpu_data.hlt_works_ok && !hlt_counter) {
92
		local_irq_disable();
Linus Torvalds's avatar
Linus Torvalds committed
93
		if (!need_resched())
Linus Torvalds's avatar
Linus Torvalds committed
94 95
			safe_halt();
		else
96
			local_irq_enable();
Linus Torvalds's avatar
Linus Torvalds committed
97 98 99 100 101
	}
}

/*
 * On SMP it's slightly faster (but much more power-consuming!)
Linus Torvalds's avatar
Linus Torvalds committed
102
 * to poll the ->work.need_resched flag instead of waiting for the
Linus Torvalds's avatar
Linus Torvalds committed
103 104 105 106 107 108
 * cross-CPU IPI to arrive. Use this option with caution.
 */
static void poll_idle (void)
{
	int oldval;

109
	local_irq_enable();
Linus Torvalds's avatar
Linus Torvalds committed
110 111 112 113 114

	/*
	 * Deal with another CPU just having chosen a thread to
	 * run here:
	 */
115
	oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
Linus Torvalds's avatar
Linus Torvalds committed
116

117 118
	if (!oldval) {
		set_thread_flag(TIF_POLLING_NRFLAG);
Linus Torvalds's avatar
Linus Torvalds committed
119 120
		asm volatile(
			"2:"
121
			"testl %0, %1;"
Linus Torvalds's avatar
Linus Torvalds committed
122 123
			"rep; nop;"
			"je 2b;"
124 125 126 127 128 129
			: : "i"(_TIF_NEED_RESCHED), "m" (current_thread_info()->flags));

		clear_thread_flag(TIF_POLLING_NRFLAG);
	} else {
		set_need_resched();
	}
Linus Torvalds's avatar
Linus Torvalds committed
130 131 132 133 134 135 136 137 138 139 140 141 142 143 144
}

/*
 * The idle thread. There's no useful work to be
 * done, so just try to conserve power and have a
 * low exit latency (ie sit in a loop waiting for
 * somebody to say that they'd like to reschedule)
 */
void cpu_idle (void)
{
	/* endless idle loop with no priority at all */
	while (1) {
		void (*idle)(void) = pm_idle;
		if (!idle)
			idle = default_idle;
145
		irq_stat[smp_processor_id()].idle_timestamp = jiffies;
Linus Torvalds's avatar
Linus Torvalds committed
146
		while (!need_resched())
Linus Torvalds's avatar
Linus Torvalds committed
147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165
			idle();
		schedule();
	}
}

static int __init idle_setup (char *str)
{
	if (!strncmp(str, "poll", 4)) {
		printk("using polling idle threads.\n");
		pm_idle = poll_idle;
	}

	return 1;
}

__setup("idle=", idle_setup);

static long no_idt[2];
static int reboot_mode;
Linus Torvalds's avatar
Linus Torvalds committed
166
int reboot_thru_bios;
Linus Torvalds's avatar
Linus Torvalds committed
167

Linus Torvalds's avatar
Linus Torvalds committed
168 169 170 171 172 173
#ifdef CONFIG_SMP
int reboot_smp = 0;
static int reboot_cpu = -1;
/* shamelessly grabbed from lib/vsprintf.c for readability */
#define is_digit(c)	((c) >= '0' && (c) <= '9')
#endif
Linus Torvalds's avatar
Linus Torvalds committed
174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189
static int __init reboot_setup(char *str)
{
	while(1) {
		switch (*str) {
		case 'w': /* "warm" reboot (no memory testing etc) */
			reboot_mode = 0x1234;
			break;
		case 'c': /* "cold" reboot (with memory testing etc) */
			reboot_mode = 0x0;
			break;
		case 'b': /* "bios" reboot by jumping through the BIOS */
			reboot_thru_bios = 1;
			break;
		case 'h': /* "hard" reboot by toggling RESET and/or crashing the CPU */
			reboot_thru_bios = 0;
			break;
Linus Torvalds's avatar
Linus Torvalds committed
190 191 192 193 194 195 196 197 198 199 200 201 202
#ifdef CONFIG_SMP
		case 's': /* "smp" reboot by executing reset on BSP or other CPU*/
			reboot_smp = 1;
			if (is_digit(*(str+1))) {
				reboot_cpu = (int) (*(str+1) - '0');
				if (is_digit(*(str+2))) 
					reboot_cpu = reboot_cpu*10 + (int)(*(str+2) - '0');
			}
				/* we will leave sorting out the final value 
				when we are ready to reboot, since we might not
 				have set up boot_cpu_id or smp_num_cpu */
			break;
#endif
Linus Torvalds's avatar
Linus Torvalds committed
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
		}
		if((str = strchr(str,',')) != NULL)
			str++;
		else
			break;
	}
	return 1;
}

__setup("reboot=", reboot_setup);

/* The following code and data reboots the machine by switching to real
   mode and jumping to the BIOS reset entry point, as if the CPU has
   really been reset.  The previous version asked the keyboard
   controller to pulse the CPU reset line, which is more thorough, but
   doesn't work with at least one type of 486 motherboard.  It is easy
   to stop this code working; hence the copious comments. */

static unsigned long long
real_mode_gdt_entries [3] =
{
	0x0000000000000000ULL,	/* Null descriptor */
	0x00009a000000ffffULL,	/* 16-bit real-mode 64k code at 0x00000000 */
	0x000092000100ffffULL	/* 16-bit real-mode 64k data at 0x00000100 */
};

static struct
{
	unsigned short       size __attribute__ ((packed));
	unsigned long long * base __attribute__ ((packed));
}
real_mode_gdt = { sizeof (real_mode_gdt_entries) - 1, real_mode_gdt_entries },
real_mode_idt = { 0x3ff, 0 };

/* This is 16-bit protected mode code to disable paging and the cache,
   switch to real mode and jump to the BIOS reset code.

   The instruction that switches to real mode by writing to CR0 must be
   followed immediately by a far jump instruction, which set CS to a
   valid value for real mode, and flushes the prefetch queue to avoid
   running instructions that have already been decoded in protected
   mode.

   Clears all the flags except ET, especially PG (paging), PE
   (protected-mode enable) and TS (task switch for coprocessor state
   save).  Flushes the TLB after paging has been disabled.  Sets CD and
   NW, to disable the cache on a 486, and invalidates the cache.  This
   is more like the state of a 486 after reset.  I don't know if
   something else should be done for other chips.

   More could be done here to set up the registers as if a CPU reset had
   occurred; hopefully real BIOSs don't assume much. */

static unsigned char real_mode_switch [] =
{
	0x66, 0x0f, 0x20, 0xc0,			/*    movl  %cr0,%eax        */
	0x66, 0x83, 0xe0, 0x11,			/*    andl  $0x00000011,%eax */
	0x66, 0x0d, 0x00, 0x00, 0x00, 0x60,	/*    orl   $0x60000000,%eax */
	0x66, 0x0f, 0x22, 0xc0,			/*    movl  %eax,%cr0        */
	0x66, 0x0f, 0x22, 0xd8,			/*    movl  %eax,%cr3        */
	0x66, 0x0f, 0x20, 0xc3,			/*    movl  %cr0,%ebx        */
	0x66, 0x81, 0xe3, 0x00, 0x00, 0x00, 0x60,	/*    andl  $0x60000000,%ebx */
	0x74, 0x02,				/*    jz    f                */
	0x0f, 0x08,				/*    invd                   */
	0x24, 0x10,				/* f: andb  $0x10,al         */
	0x66, 0x0f, 0x22, 0xc0			/*    movl  %eax,%cr0        */
};
static unsigned char jump_to_bios [] =
{
	0xea, 0x00, 0x00, 0xff, 0xff		/*    ljmp  $0xffff,$0x0000  */
};

static inline void kb_wait(void)
{
	int i;

	for (i=0; i<0x10000; i++)
		if ((inb_p(0x64) & 0x02) == 0)
			break;
}

/*
 * Switch to real mode and then execute the code
 * specified by the code and length parameters.
 * We assume that length will aways be less that 100!
 */
void machine_real_restart(unsigned char *code, int length)
{
	unsigned long flags;

293
	local_irq_disable();
Linus Torvalds's avatar
Linus Torvalds committed
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

	/* Write zero to CMOS register number 0x0f, which the BIOS POST
	   routine will recognize as telling it to do a proper reboot.  (Well
	   that's what this book in front of me says -- it may only apply to
	   the Phoenix BIOS though, it's not clear).  At the same time,
	   disable NMIs by setting the top bit in the CMOS address register,
	   as we're about to do peculiar things to the CPU.  I'm not sure if
	   `outb_p' is needed instead of just `outb'.  Use it to be on the
	   safe side.  (Yes, CMOS_WRITE does outb_p's. -  Paul G.)
	 */

	spin_lock_irqsave(&rtc_lock, flags);
	CMOS_WRITE(0x00, 0x8f);
	spin_unlock_irqrestore(&rtc_lock, flags);

	/* Remap the kernel at virtual address zero, as well as offset zero
	   from the kernel segment.  This assumes the kernel segment starts at
	   virtual address PAGE_OFFSET. */

	memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
		sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);

	/*
	 * Use `swapper_pg_dir' as our page directory.
	 */
319
	load_cr3(swapper_pg_dir);
Linus Torvalds's avatar
Linus Torvalds committed
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

	/* Write 0x1234 to absolute memory location 0x472.  The BIOS reads
	   this on booting to tell it to "Bypass memory test (also warm
	   boot)".  This seems like a fairly standard thing that gets set by
	   REBOOT.COM programs, and the previous reset routine did this
	   too. */

	*((unsigned short *)0x472) = reboot_mode;

	/* For the switch to real mode, copy some code to low memory.  It has
	   to be in the first 64k because it is running in 16-bit mode, and it
	   has to have the same physical and virtual address, because it turns
	   off paging.  Copy it near the end of the first page, out of the way
	   of BIOS variables. */

	memcpy ((void *) (0x1000 - sizeof (real_mode_switch) - 100),
		real_mode_switch, sizeof (real_mode_switch));
	memcpy ((void *) (0x1000 - 100), code, length);

	/* Set up the IDT for real mode. */

	__asm__ __volatile__ ("lidt %0" : : "m" (real_mode_idt));

	/* Set up a GDT from which we can load segment descriptors for real
	   mode.  The GDT is not used in real mode; it is just needed here to
	   prepare the descriptors. */

	__asm__ __volatile__ ("lgdt %0" : : "m" (real_mode_gdt));

	/* Load the data segment registers, and thus the descriptors ready for
	   real mode.  The base address of each segment is 0x100, 16 times the
	   selector value being loaded here.  This is so that the segment
	   registers don't have to be reloaded after switching to real mode:
	   the values are consistent for real mode operation already. */

	__asm__ __volatile__ ("movl $0x0010,%%eax\n"
				"\tmovl %%eax,%%ds\n"
				"\tmovl %%eax,%%es\n"
				"\tmovl %%eax,%%fs\n"
				"\tmovl %%eax,%%gs\n"
				"\tmovl %%eax,%%ss" : : : "eax");

	/* Jump to the 16-bit code that we copied earlier.  It disables paging
	   and the cache, switches to real mode, and jumps to the BIOS reset
	   entry point. */

	__asm__ __volatile__ ("ljmp $0x0008,%0"
				:
				: "i" ((void *) (0x1000 - sizeof (real_mode_switch) - 100)));
}

void machine_restart(char * __unused)
{
#if CONFIG_SMP
Linus Torvalds's avatar
Linus Torvalds committed
374 375 376 377 378 379 380 381 382 383 384
	int cpuid;
	
	cpuid = GET_APIC_ID(apic_read(APIC_ID));

	if (reboot_smp) {

		/* check to see if reboot_cpu is valid 
		   if its not, default to the BSP */
		if ((reboot_cpu == -1) ||  
		      (reboot_cpu > (NR_CPUS -1))  || 
		      !(phys_cpu_present_map & (1<<cpuid))) 
Linus Torvalds's avatar
Linus Torvalds committed
385
			reboot_cpu = boot_cpu_physical_apicid;
Linus Torvalds's avatar
Linus Torvalds committed
386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401

		reboot_smp = 0;  /* use this as a flag to only go through this once*/
		/* re-run this function on the other CPUs
		   it will fall though this section since we have 
		   cleared reboot_smp, and do the reboot if it is the
		   correct CPU, otherwise it halts. */
		if (reboot_cpu != cpuid)
			smp_call_function((void *)machine_restart , NULL, 1, 0);
	}

	/* if reboot_cpu is still -1, then we want a tradional reboot, 
	   and if we are not running on the reboot_cpu,, halt */
	if ((reboot_cpu != -1) && (cpuid != reboot_cpu)) {
		for (;;)
		__asm__ __volatile__ ("hlt");
	}
Linus Torvalds's avatar
Linus Torvalds committed
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
	/*
	 * Stop all CPUs and turn off local APICs and the IO-APIC, so
	 * other OSs see a clean IRQ state.
	 */
	smp_send_stop();
	disable_IO_APIC();
#endif

	if(!reboot_thru_bios) {
		/* rebooting needs to touch the page at absolute addr 0 */
		*((unsigned short *)__va(0x472)) = reboot_mode;
		for (;;) {
			int i;
			for (i=0; i<100; i++) {
				kb_wait();
				udelay(50);
				outb(0xfe,0x64);         /* pulse reset low */
				udelay(50);
			}
			/* That didn't work - force a triple fault.. */
			__asm__ __volatile__("lidt %0": :"m" (no_idt));
			__asm__ __volatile__("int3");
		}
	}

	machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
}

void machine_halt(void)
{
}

void machine_power_off(void)
{
	if (pm_power_off)
		pm_power_off();
}

extern void show_trace(unsigned long* esp);

void show_regs(struct pt_regs * regs)
{
	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;

	printk("\n");
Linus Torvalds's avatar
Linus Torvalds committed
447
	printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
Linus Torvalds's avatar
Linus Torvalds committed
448 449 450
	printk("EIP: %04x:[<%08lx>] CPU: %d",0xffff & regs->xcs,regs->eip, smp_processor_id());
	if (regs->xcs & 3)
		printk(" ESP: %04x:%08lx",0xffff & regs->xss,regs->esp);
Linus Torvalds's avatar
Linus Torvalds committed
451
	printk(" EFLAGS: %08lx    %s\n",regs->eflags, print_tainted());
Linus Torvalds's avatar
Linus Torvalds committed
452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472
	printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
		regs->eax,regs->ebx,regs->ecx,regs->edx);
	printk("ESI: %08lx EDI: %08lx EBP: %08lx",
		regs->esi, regs->edi, regs->ebp);
	printk(" DS: %04x ES: %04x\n",
		0xffff & regs->xds,0xffff & regs->xes);

	__asm__("movl %%cr0, %0": "=r" (cr0));
	__asm__("movl %%cr2, %0": "=r" (cr2));
	__asm__("movl %%cr3, %0": "=r" (cr3));
	/* This could fault if %cr4 does not exist */
	__asm__("1: movl %%cr4, %0		\n"
		"2:				\n"
		".section __ex_table,\"a\"	\n"
		".long 1b,2b			\n"
		".previous			\n"
		: "=r" (cr4): "0" (0));
	printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
	show_trace(&regs->esp);
}

473 474 475 476 477 478 479 480 481 482 483 484 485 486
/*
 * This gets run with %ebx containing the
 * function to call, and %edx containing
 * the "args".
 */
extern void kernel_thread_helper(void);
__asm__(".align 4\n"
	"kernel_thread_helper:\n\t"
	"movl %edx,%eax\n\t"
	"pushl %edx\n\t"
	"call *%ebx\n\t"
	"pushl %eax\n\t"
	"call do_exit");

Linus Torvalds's avatar
Linus Torvalds committed
487 488 489 490 491
/*
 * Create a kernel thread
 */
int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509
	struct task_struct *p;
	struct pt_regs regs;

	memset(&regs, 0, sizeof(regs));

	regs.ebx = (unsigned long) fn;
	regs.edx = (unsigned long) arg;

	regs.xds = __KERNEL_DS;
	regs.xes = __KERNEL_DS;
	regs.orig_eax = -1;
	regs.eip = (unsigned long) kernel_thread_helper;
	regs.xcs = __KERNEL_CS;
	regs.eflags = 0x286;

	/* Ok, create the new process.. */
	p = do_fork(flags | CLONE_VM, 0, &regs, 0);
	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
Linus Torvalds's avatar
Linus Torvalds committed
510 511 512 513 514 515 516
}

/*
 * Free current thread data structures etc..
 */
void exit_thread(void)
{
517 518 519 520 521 522 523
	struct task_struct *tsk = current;

	/* The process may have allocated an io port bitmap... nuke it. */
	if (unlikely(NULL != tsk->thread.ts_io_bitmap)) {
		kfree(tsk->thread.ts_io_bitmap);
		tsk->thread.ts_io_bitmap = NULL;
	}
Linus Torvalds's avatar
Linus Torvalds committed
524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541
}

void flush_thread(void)
{
	struct task_struct *tsk = current;

	memset(tsk->thread.debugreg, 0, sizeof(unsigned long)*8);
	/*
	 * Forget coprocessor state..
	 */
	clear_fpu(tsk);
	tsk->used_math = 0;
}

void release_thread(struct task_struct *dead_task)
{
	if (dead_task->mm) {
		// temporary debugging check
Dave Jones's avatar
Dave Jones committed
542 543 544 545 546
		if (dead_task->mm->context.size) {
			printk("WARNING: dead process %8s still has LDT? <%p/%d>\n",
					dead_task->comm,
					dead_task->mm->context.ldt,
					dead_task->mm->context.size);
Linus Torvalds's avatar
Linus Torvalds committed
547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562
			BUG();
		}
	}
}

/*
 * Save a segment.
 */
#define savesegment(seg,value) \
	asm volatile("movl %%" #seg ",%0":"=m" (*(int *)&(value)))

int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
	unsigned long unused,
	struct task_struct * p, struct pt_regs * regs)
{
	struct pt_regs * childregs;
563
	struct task_struct *tsk;
Linus Torvalds's avatar
Linus Torvalds committed
564

565
	childregs = ((struct pt_regs *) (THREAD_SIZE + (unsigned long) p->thread_info)) - 1;
Linus Torvalds's avatar
Linus Torvalds committed
566 567 568
	struct_cpy(childregs, regs);
	childregs->eax = 0;
	childregs->esp = esp;
569
	p->user_vm_lock = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
570 571 572 573 574 575 576 577 578

	p->thread.esp = (unsigned long) childregs;
	p->thread.esp0 = (unsigned long) (childregs+1);

	p->thread.eip = (unsigned long) ret_from_fork;

	savesegment(fs,p->thread.fs);
	savesegment(gs,p->thread.gs);

579 580 581 582
	tsk = current;
	unlazy_fpu(tsk);
	struct_cpy(&p->thread.i387, &tsk->thread.i387);

583 584 585 586 587 588 589 590 591 592 593 594 595
	if (unlikely(NULL != tsk->thread.ts_io_bitmap)) {
		p->thread.ts_io_bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
		if (!p->thread.ts_io_bitmap)
			return -ENOMEM;
		memcpy(p->thread.ts_io_bitmap, tsk->thread.ts_io_bitmap,
			IO_BITMAP_BYTES);
	}

	/*
	 * The common fastpath:
	 */
	if (!(clone_flags & (CLONE_SETTLS | CLONE_SETTID | CLONE_RELEASE_VM)))
		return 0;
596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624
	/*
	 * Set a new TLS for the child thread?
	 */
	if (clone_flags & CLONE_SETTLS) {
		struct desc_struct *desc;
		struct user_desc info;
		int idx;

		if (copy_from_user(&info, (void *)childregs->esi, sizeof(info)))
			return -EFAULT;
		if (LDT_empty(&info))
			return -EINVAL;

		idx = info.entry_number;
		if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
			return -EINVAL;

		desc = p->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
		desc->a = LDT_entry_a(&info);
		desc->b = LDT_entry_b(&info);
	}

	/*
	 * Notify the child of the TID?
	 */
	if (clone_flags & CLONE_SETTID)
		if (put_user(p->pid, (pid_t *)childregs->edx))
			return -EFAULT;

625 626 627
	/*
	 * Does the userspace VM want any unlock on mm_release()?
	 */
628 629
	if (clone_flags & CLONE_RELEASE_VM)
		p->user_vm_lock = (long *) childregs->edi;
Linus Torvalds's avatar
Linus Torvalds committed
630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709
	return 0;
}

/*
 * fill in the user structure for a core dump..
 */
void dump_thread(struct pt_regs * regs, struct user * dump)
{
	int i;

/* changed the size calculations - should hopefully work better. lbt */
	dump->magic = CMAGIC;
	dump->start_code = 0;
	dump->start_stack = regs->esp & ~(PAGE_SIZE - 1);
	dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
	dump->u_dsize = ((unsigned long) (current->mm->brk + (PAGE_SIZE-1))) >> PAGE_SHIFT;
	dump->u_dsize -= dump->u_tsize;
	dump->u_ssize = 0;
	for (i = 0; i < 8; i++)
		dump->u_debugreg[i] = current->thread.debugreg[i];  

	if (dump->start_stack < TASK_SIZE)
		dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;

	dump->regs.ebx = regs->ebx;
	dump->regs.ecx = regs->ecx;
	dump->regs.edx = regs->edx;
	dump->regs.esi = regs->esi;
	dump->regs.edi = regs->edi;
	dump->regs.ebp = regs->ebp;
	dump->regs.eax = regs->eax;
	dump->regs.ds = regs->xds;
	dump->regs.es = regs->xes;
	savesegment(fs,dump->regs.fs);
	savesegment(gs,dump->regs.gs);
	dump->regs.orig_eax = regs->orig_eax;
	dump->regs.eip = regs->eip;
	dump->regs.cs = regs->xcs;
	dump->regs.eflags = regs->eflags;
	dump->regs.esp = regs->esp;
	dump->regs.ss = regs->xss;

	dump->u_fpvalid = dump_fpu (regs, &dump->i387);
}

/*
 * This special macro can be used to load a debugging register
 */
#define loaddebug(thread,register) \
		__asm__("movl %0,%%db" #register  \
			: /* no output */ \
			:"r" (thread->debugreg[register]))

/*
 *	switch_to(x,yn) should switch tasks from x to y.
 *
 * We fsave/fwait so that an exception goes off at the right time
 * (as a call from the fsave or fwait in effect) rather than to
 * the wrong process. Lazy FP saving no longer makes any sense
 * with modern CPU's, and this simplifies a lot of things (SMP
 * and UP become the same).
 *
 * NOTE! We used to use the x86 hardware context switching. The
 * reason for not using it any more becomes apparent when you
 * try to recover gracefully from saved state that is no longer
 * valid (stale segment register values in particular). With the
 * hardware task-switch, there is no way to fix up bad state in
 * a reasonable manner.
 *
 * The fact that Intel documents the hardware task-switching to
 * be slow is a fairly red herring - this code is not noticeably
 * faster. However, there _is_ some room for improvement here,
 * so the performance issues may eventually be a valid point.
 * More important, however, is the fact that this allows us much
 * more flexibility.
 */
void __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
{
	struct thread_struct *prev = &prev_p->thread,
				 *next = &next_p->thread;
710 711
	int cpu = smp_processor_id();
	struct tss_struct *tss = init_tss + cpu;
Linus Torvalds's avatar
Linus Torvalds committed
712

713 714
	/* never put a printk in __switch_to... printk() calls wake_up*() indirectly */

Linus Torvalds's avatar
Linus Torvalds committed
715 716 717 718 719 720 721
	unlazy_fpu(prev_p);

	/*
	 * Reload esp0, LDT and the page table pointer:
	 */
	tss->esp0 = next->esp0;

722 723 724
	/*
	 * Load the per-thread Thread-Local Storage descriptor.
	 */
Ingo Molnar's avatar
Ingo Molnar committed
725
	load_TLS(next, cpu);
726

Linus Torvalds's avatar
Linus Torvalds committed
727 728 729 730 731 732 733 734
	/*
	 * Save away %fs and %gs. No need to save %es and %ds, as
	 * those are always kernel segments while inside the kernel.
	 */
	asm volatile("movl %%fs,%0":"=m" (*(int *)&prev->fs));
	asm volatile("movl %%gs,%0":"=m" (*(int *)&prev->gs));

	/*
Linus Torvalds's avatar
Linus Torvalds committed
735
	 * Restore %fs and %gs if needed.
Linus Torvalds's avatar
Linus Torvalds committed
736
	 */
Linus Torvalds's avatar
Linus Torvalds committed
737 738 739 740
	if (unlikely(prev->fs | prev->gs | next->fs | next->gs)) {
		loadsegment(fs, next->fs);
		loadsegment(gs, next->gs);
	}
Linus Torvalds's avatar
Linus Torvalds committed
741 742 743 744

	/*
	 * Now maybe reload the debug registers
	 */
Linus Torvalds's avatar
Linus Torvalds committed
745
	if (unlikely(next->debugreg[7])) {
Linus Torvalds's avatar
Linus Torvalds committed
746 747 748 749 750 751 752 753 754
		loaddebug(next, 0);
		loaddebug(next, 1);
		loaddebug(next, 2);
		loaddebug(next, 3);
		/* no 4 and 5 */
		loaddebug(next, 6);
		loaddebug(next, 7);
	}

755 756
	if (unlikely(prev->ts_io_bitmap || next->ts_io_bitmap)) {
		if (next->ts_io_bitmap) {
Linus Torvalds's avatar
Linus Torvalds committed
757 758 759 760 761 762 763 764
			/*
			 * 4 cachelines copy ... not good, but not that
			 * bad either. Anyone got something better?
			 * This only affects processes which use ioperm().
			 * [Putting the TSSs into 4k-tlb mapped regions
			 * and playing VM tricks to switch the IO bitmap
			 * is not really acceptable.]
			 */
765 766
			memcpy(tss->io_bitmap, next->ts_io_bitmap,
				IO_BITMAP_BYTES);
Linus Torvalds's avatar
Linus Torvalds committed
767 768 769 770 771 772 773 774 775 776 777 778 779 780
			tss->bitmap = IO_BITMAP_OFFSET;
		} else
			/*
			 * a bitmap offset pointing outside of the TSS limit
			 * causes a nicely controllable SIGSEGV if a process
			 * tries to use a port IO instruction. The first
			 * sys_ioperm() call sets up the bitmap properly.
			 */
			tss->bitmap = INVALID_IO_BITMAP_OFFSET;
	}
}

asmlinkage int sys_fork(struct pt_regs regs)
{
Rusty Russell's avatar
Rusty Russell committed
781 782 783 784
	struct task_struct *p;

	p = do_fork(SIGCHLD, regs.esp, &regs, 0);
	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
Linus Torvalds's avatar
Linus Torvalds committed
785 786 787 788
}

asmlinkage int sys_clone(struct pt_regs regs)
{
Rusty Russell's avatar
Rusty Russell committed
789
	struct task_struct *p;
Linus Torvalds's avatar
Linus Torvalds committed
790 791 792 793 794 795 796
	unsigned long clone_flags;
	unsigned long newsp;

	clone_flags = regs.ebx;
	newsp = regs.ecx;
	if (!newsp)
		newsp = regs.esp;
Rusty Russell's avatar
Rusty Russell committed
797 798
	p = do_fork(clone_flags & ~CLONE_IDLETASK, newsp, &regs, 0);
	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
Linus Torvalds's avatar
Linus Torvalds committed
799 800 801 802 803 804 805 806 807 808 809 810 811 812
}

/*
 * This is trivial, and on the face of it looks like it
 * could equally well be done in user mode.
 *
 * Not so, for quite unobvious reasons - register pressure.
 * In user mode vfork() cannot have a stack frame, and if
 * done by calling the "clone()" system call directly, you
 * do not have enough call-clobbered registers to hold all
 * the information you need.
 */
asmlinkage int sys_vfork(struct pt_regs regs)
{
Rusty Russell's avatar
Rusty Russell committed
813 814 815 816
	struct task_struct *p;

	p = do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.esp, &regs, 0);
	return IS_ERR(p) ? PTR_ERR(p) : p->pid;
Linus Torvalds's avatar
Linus Torvalds committed
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853
}

/*
 * sys_execve() executes a new program.
 */
asmlinkage int sys_execve(struct pt_regs regs)
{
	int error;
	char * filename;

	filename = getname((char *) regs.ebx);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	error = do_execve(filename, (char **) regs.ecx, (char **) regs.edx, &regs);
	if (error == 0)
		current->ptrace &= ~PT_DTRACE;
	putname(filename);
out:
	return error;
}

/*
 * These bracket the sleeping functions..
 */
extern void scheduling_functions_start_here(void);
extern void scheduling_functions_end_here(void);
#define first_sched	((unsigned long) scheduling_functions_start_here)
#define last_sched	((unsigned long) scheduling_functions_end_here)

unsigned long get_wchan(struct task_struct *p)
{
	unsigned long ebp, esp, eip;
	unsigned long stack_page;
	int count = 0;
	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;
854
	stack_page = (unsigned long)p->thread_info;
Linus Torvalds's avatar
Linus Torvalds committed
855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871
	esp = p->thread.esp;
	if (!stack_page || esp < stack_page || esp > 8188+stack_page)
		return 0;
	/* include/asm-i386/system.h:switch_to() pushes ebp last. */
	ebp = *(unsigned long *) esp;
	do {
		if (ebp < stack_page || ebp > 8184+stack_page)
			return 0;
		eip = *(unsigned long *) (ebp+4);
		if (eip < first_sched || eip >= last_sched)
			return eip;
		ebp = *(unsigned long *) ebp;
	} while (count++ < 16);
	return 0;
}
#undef last_sched
#undef first_sched
872 873

/*
Ingo Molnar's avatar
Ingo Molnar committed
874
 * sys_alloc_thread_area: get a yet unused TLS descriptor index.
875
 */
Ingo Molnar's avatar
Ingo Molnar committed
876
static int get_free_idx(void)
877 878
{
	struct thread_struct *t = &current->thread;
Ingo Molnar's avatar
Ingo Molnar committed
879
	int idx;
880

Ingo Molnar's avatar
Ingo Molnar committed
881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913
	for (idx = 0; idx < GDT_ENTRY_TLS_ENTRIES; idx++)
		if (desc_empty(t->tls_array + idx))
			return idx + GDT_ENTRY_TLS_MIN;
	return -ESRCH;
}

/*
 * Set a given TLS descriptor:
 */
asmlinkage int sys_set_thread_area(struct user_desc *u_info)
{
	struct thread_struct *t = &current->thread;
	struct user_desc info;
	struct desc_struct *desc;
	int cpu, idx;

	if (copy_from_user(&info, u_info, sizeof(info)))
		return -EFAULT;
	idx = info.entry_number;

	/*
	 * index -1 means the kernel should try to find and
	 * allocate an empty descriptor:
	 */
	if (idx == -1) {
		idx = get_free_idx();
		if (idx < 0)
			return idx;
		if (put_user(idx, &u_info->entry_number))
			return -EFAULT;
	}

	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
914 915
		return -EINVAL;

Ingo Molnar's avatar
Ingo Molnar committed
916
	desc = t->tls_array + idx - GDT_ENTRY_TLS_MIN;
917 918 919 920 921 922

	/*
	 * We must not get preempted while modifying the TLS.
	 */
	cpu = get_cpu();

Ingo Molnar's avatar
Ingo Molnar committed
923 924 925 926 927 928 929 930
	if (LDT_empty(&info)) {
		desc->a = 0;
		desc->b = 0;
	} else {
		desc->a = LDT_entry_a(&info);
		desc->b = LDT_entry_b(&info);
	}
	load_TLS(t, cpu);
931 932 933

	put_cpu();

Ingo Molnar's avatar
Ingo Molnar committed
934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982
	return 0;
}

/*
 * Get the current Thread-Local Storage area:
 */

#define GET_BASE(desc) ( \
	(((desc)->a >> 16) & 0x0000ffff) | \
	(((desc)->b << 16) & 0x00ff0000) | \
	( (desc)->b        & 0xff000000)   )

#define GET_LIMIT(desc) ( \
	((desc)->a & 0x0ffff) | \
	 ((desc)->b & 0xf0000) )
	
#define GET_32BIT(desc)		(((desc)->b >> 23) & 1)
#define GET_CONTENTS(desc)	(((desc)->b >> 10) & 3)
#define GET_WRITABLE(desc)	(((desc)->b >>  9) & 1)
#define GET_LIMIT_PAGES(desc)	(((desc)->b >> 23) & 1)
#define GET_PRESENT(desc)	(((desc)->b >> 15) & 1)
#define GET_USEABLE(desc)	(((desc)->b >> 20) & 1)

asmlinkage int sys_get_thread_area(struct user_desc *u_info)
{
	struct user_desc info;
	struct desc_struct *desc;
	int idx;

	if (get_user(idx, &u_info->entry_number))
		return -EFAULT;
	if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
		return -EINVAL;

	desc = current->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;

	info.entry_number = idx;
	info.base_addr = GET_BASE(desc);
	info.limit = GET_LIMIT(desc);
	info.seg_32bit = GET_32BIT(desc);
	info.contents = GET_CONTENTS(desc);
	info.read_exec_only = !GET_WRITABLE(desc);
	info.limit_in_pages = GET_LIMIT_PAGES(desc);
	info.seg_not_present = !GET_PRESENT(desc);
	info.useable = GET_USEABLE(desc);

	if (copy_to_user(u_info, &info, sizeof(info)))
		return -EFAULT;
	return 0;
983 984
}