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/*  $Id: setup.c,v 1.72 2002/02/09 19:49:30 davem Exp $
 *  linux/arch/sparc64/kernel/setup.c
 *
 *  Copyright (C) 1995,1996  David S. Miller (davem@caip.rutgers.edu)
 *  Copyright (C) 1997       Jakub Jelinek (jj@sunsite.mff.cuni.cz)
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <asm/smp.h>
#include <linux/user.h>
#include <linux/a.out.h>
#include <linux/tty.h>
#include <linux/delay.h>
#include <linux/config.h>
#include <linux/fs.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/kdev_t.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/inet.h>
#include <linux/console.h>
#include <linux/root_dev.h>
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/initrd.h>

#include <asm/segment.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/oplib.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/idprom.h>
#include <asm/head.h>
#include <asm/starfire.h>
#include <asm/mmu_context.h>
#include <asm/timer.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/mmu.h>

#ifdef CONFIG_IP_PNP
#include <net/ipconfig.h>
#endif

struct screen_info screen_info = {
	0, 0,			/* orig-x, orig-y */
	0,			/* unused */
	0,			/* orig-video-page */
	0,			/* orig-video-mode */
	128,			/* orig-video-cols */
	0, 0, 0,		/* unused, ega_bx, unused */
	54,			/* orig-video-lines */
	0,                      /* orig-video-isVGA */
	16                      /* orig-video-points */
};

/* Typing sync at the prom prompt calls the function pointed to by
 * the sync callback which I set to the following function.
 * This should sync all filesystems and return, for now it just
 * prints out pretty messages and returns.
 */

void (*prom_palette)(int);
void (*prom_keyboard)(void);

static void
prom_console_write(struct console *con, const char *s, unsigned n)
{
	prom_write(s, n);
}

static struct console prom_console = {
	.name =		"prom",
	.write =	prom_console_write,
	.flags =	CON_CONSDEV | CON_ENABLED,
	.index =	-1,
};

#define PROM_TRUE	-1
#define PROM_FALSE	0

/* Pretty sick eh? */
int prom_callback(long *args)
{
	struct console *cons, *saved_console = NULL;
	unsigned long flags;
	char *cmd;
	extern spinlock_t prom_entry_lock;

	if (!args)
		return -1;
	if (!(cmd = (char *)args[0]))
		return -1;

	/*
	 * The callback can be invoked on the cpu that first dropped 
	 * into prom_cmdline after taking the serial interrupt, or on 
	 * a slave processor that was smp_captured() if the 
	 * administrator has done a switch-cpu inside obp. In either 
	 * case, the cpu is marked as in-interrupt. Drop IRQ locks.
	 */
	irq_exit();

	/* XXX Revisit the locking here someday.  This is a debugging
	 * XXX feature so it isnt all that critical.  -DaveM
	 */
	local_irq_save(flags);

	spin_unlock(&prom_entry_lock);
	cons = console_drivers;
	while (cons) {
		unregister_console(cons);
		cons->flags &= ~(CON_PRINTBUFFER);
		cons->next = saved_console;
		saved_console = cons;
		cons = console_drivers;
	}
	register_console(&prom_console);
	if (!strcmp(cmd, "sync")) {
		prom_printf("PROM `%s' command...\n", cmd);
		show_free_areas();
		if (current->pid != 0) {
			local_irq_enable();
			sys_sync();
			local_irq_disable();
		}
		args[2] = 0;
		args[args[1] + 3] = -1;
		prom_printf("Returning to PROM\n");
	} else if (!strcmp(cmd, "va>tte-data")) {
		unsigned long ctx, va;
		unsigned long tte = 0;
		long res = PROM_FALSE;

		ctx = args[3];
		va = args[4];
		if (ctx) {
			/*
			 * Find process owning ctx, lookup mapping.
			 */
			struct task_struct *p;
			struct mm_struct *mm = NULL;
			pgd_t *pgdp;
			pud_t *pudp;
			pmd_t *pmdp;
			pte_t *ptep;

			for_each_process(p) {
				mm = p->mm;
				if (CTX_NRBITS(mm->context) == ctx)
					break;
			}
			if (!mm ||
			    CTX_NRBITS(mm->context) != ctx)
				goto done;

			pgdp = pgd_offset(mm, va);
			if (pgd_none(*pgdp))
				goto done;
			pudp = pud_offset(pgdp, va);
			if (pud_none(*pudp))
				goto done;
			pmdp = pmd_offset(pudp, va);
			if (pmd_none(*pmdp))
				goto done;

			/* Preemption implicitly disabled by virtue of
			 * being called from inside OBP.
			 */
			ptep = pte_offset_map(pmdp, va);
			if (pte_present(*ptep)) {
				tte = pte_val(*ptep);
				res = PROM_TRUE;
			}
			pte_unmap(ptep);
			goto done;
		}

		if ((va >= KERNBASE) && (va < (KERNBASE + (4 * 1024 * 1024)))) {
			unsigned long kernel_pctx = 0;

			if (tlb_type == cheetah_plus)
				kernel_pctx |= (CTX_CHEETAH_PLUS_NUC |
						CTX_CHEETAH_PLUS_CTX0);

			/* Spitfire Errata #32 workaround */
			__asm__ __volatile__("stxa	%0, [%1] %2\n\t"
					     "flush	%%g6"
					     : /* No outputs */
					     : "r" (kernel_pctx),
					       "r" (PRIMARY_CONTEXT),
					       "i" (ASI_DMMU));

			/*
			 * Locked down tlb entry.
			 */

			if (tlb_type == spitfire)
				tte = spitfire_get_dtlb_data(SPITFIRE_HIGHEST_LOCKED_TLBENT);
			else if (tlb_type == cheetah || tlb_type == cheetah_plus)
				tte = cheetah_get_ldtlb_data(CHEETAH_HIGHEST_LOCKED_TLBENT);

			res = PROM_TRUE;
			goto done;
		}

		if (va < PGDIR_SIZE) {
			/*
			 * vmalloc or prom_inherited mapping.
			 */
			pgd_t *pgdp;
			pud_t *pudp;
			pmd_t *pmdp;
			pte_t *ptep;
			int error;

			if ((va >= LOW_OBP_ADDRESS) && (va < HI_OBP_ADDRESS)) {
				tte = prom_virt_to_phys(va, &error);
				if (!error)
					res = PROM_TRUE;
				goto done;
			}
			pgdp = pgd_offset_k(va);
			if (pgd_none(*pgdp))
				goto done;
			pudp = pud_offset(pgdp, va);
			if (pud_none(*pudp))
				goto done;
			pmdp = pmd_offset(pudp, va);
			if (pmd_none(*pmdp))
				goto done;

			/* Preemption implicitly disabled by virtue of
			 * being called from inside OBP.
			 */
			ptep = pte_offset_kernel(pmdp, va);
			if (pte_present(*ptep)) {
				tte = pte_val(*ptep);
				res = PROM_TRUE;
			}
			goto done;
		}

		if (va < PAGE_OFFSET) {
			/*
			 * No mappings here.
			 */
			goto done;
		}

		if (va & (1UL << 40)) {
			/*
			 * I/O page.
			 */

			tte = (__pa(va) & _PAGE_PADDR) |
			      _PAGE_VALID | _PAGE_SZ4MB |
			      _PAGE_E | _PAGE_P | _PAGE_W;
			res = PROM_TRUE;
			goto done;
		}

		/*
		 * Normal page.
		 */
		tte = (__pa(va) & _PAGE_PADDR) |
		      _PAGE_VALID | _PAGE_SZ4MB |
		      _PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_W;
		res = PROM_TRUE;

	done:
		if (res == PROM_TRUE) {
			args[2] = 3;
			args[args[1] + 3] = 0;
			args[args[1] + 4] = res;
			args[args[1] + 5] = tte;
		} else {
			args[2] = 2;
			args[args[1] + 3] = 0;
			args[args[1] + 4] = res;
		}
	} else if (!strcmp(cmd, ".soft1")) {
		unsigned long tte;

		tte = args[3];
		prom_printf("%lx:\"%s%s%s%s%s\" ",
			    (tte & _PAGE_SOFT) >> 7,
			    tte & _PAGE_MODIFIED ? "M" : "-",
			    tte & _PAGE_ACCESSED ? "A" : "-",
			    tte & _PAGE_READ     ? "W" : "-",
			    tte & _PAGE_WRITE    ? "R" : "-",
			    tte & _PAGE_PRESENT  ? "P" : "-");

		args[2] = 2;
		args[args[1] + 3] = 0;
		args[args[1] + 4] = PROM_TRUE;
	} else if (!strcmp(cmd, ".soft2")) {
		unsigned long tte;

		tte = args[3];
		prom_printf("%lx ", (tte & 0x07FC000000000000UL) >> 50);

		args[2] = 2;
		args[args[1] + 3] = 0;
		args[args[1] + 4] = PROM_TRUE;
	} else {
		prom_printf("unknown PROM `%s' command...\n", cmd);
	}
	unregister_console(&prom_console);
	while (saved_console) {
		cons = saved_console;
		saved_console = cons->next;
		register_console(cons);
	}
	spin_lock(&prom_entry_lock);
	local_irq_restore(flags);

	/*
	 * Restore in-interrupt status for a resume from obp.
	 */
	irq_enter();
	return 0;
}

unsigned int boot_flags = 0;
#define BOOTME_DEBUG  0x1
#define BOOTME_SINGLE 0x2

/* Exported for mm/init.c:paging_init. */
unsigned long cmdline_memory_size = 0;

static struct console prom_debug_console = {
	.name =		"debug",
	.write =	prom_console_write,
	.flags =	CON_PRINTBUFFER,
	.index =	-1,
};

/* XXX Implement this at some point... */
void kernel_enter_debugger(void)
{
}

int obp_system_intr(void)
{
	if (boot_flags & BOOTME_DEBUG) {
		printk("OBP: system interrupted\n");
		prom_halt();
		return 1;
	}
	return 0;
}

/* 
 * Process kernel command line switches that are specific to the
 * SPARC or that require special low-level processing.
 */
static void __init process_switch(char c)
{
	switch (c) {
	case 'd':
		boot_flags |= BOOTME_DEBUG;
		break;
	case 's':
		boot_flags |= BOOTME_SINGLE;
		break;
	case 'h':
		prom_printf("boot_flags_init: Halt!\n");
		prom_halt();
		break;
	case 'p':
		/* Use PROM debug console. */
		register_console(&prom_debug_console);
		break;
	default:
		printk("Unknown boot switch (-%c)\n", c);
		break;
	}
}

static void __init process_console(char *commands)
{
	serial_console = 0;
	commands += 8;
	/* Linux-style serial */
	if (!strncmp(commands, "ttyS", 4))
		serial_console = simple_strtoul(commands + 4, NULL, 10) + 1;
	else if (!strncmp(commands, "tty", 3)) {
		char c = *(commands + 3);
		/* Solaris-style serial */
		if (c == 'a' || c == 'b') {
			serial_console = c - 'a' + 1;
			prom_printf ("Using /dev/tty%c as console.\n", c);
		}
		/* else Linux-style fbcon, not serial */
	}
#if defined(CONFIG_PROM_CONSOLE)
	if (!strncmp(commands, "prom", 4)) {
		char *p;

		for (p = commands - 8; *p && *p != ' '; p++)
			*p = ' ';
		conswitchp = &prom_con;
	}
#endif
}

static void __init boot_flags_init(char *commands)
{
	while (*commands) {
		/* Move to the start of the next "argument". */
		while (*commands && *commands == ' ')
			commands++;

		/* Process any command switches, otherwise skip it. */
		if (*commands == '\0')
			break;
		if (*commands == '-') {
			commands++;
			while (*commands && *commands != ' ')
				process_switch(*commands++);
			continue;
		}
		if (!strncmp(commands, "console=", 8)) {
			process_console(commands);
		} else if (!strncmp(commands, "mem=", 4)) {
			/*
			 * "mem=XXX[kKmM]" overrides the PROM-reported
			 * memory size.
			 */
			cmdline_memory_size = simple_strtoul(commands + 4,
							     &commands, 0);
			if (*commands == 'K' || *commands == 'k') {
				cmdline_memory_size <<= 10;
				commands++;
			} else if (*commands=='M' || *commands=='m') {
				cmdline_memory_size <<= 20;
				commands++;
			}
		}
		while (*commands && *commands != ' ')
			commands++;
	}
}

extern int prom_probe_memory(void);
extern unsigned long start, end;
extern void panic_setup(char *, int *);

extern unsigned short root_flags;
extern unsigned short root_dev;
extern unsigned short ram_flags;
#define RAMDISK_IMAGE_START_MASK	0x07FF
#define RAMDISK_PROMPT_FLAG		0x8000
#define RAMDISK_LOAD_FLAG		0x4000

extern int root_mountflags;

char reboot_command[COMMAND_LINE_SIZE];

static struct pt_regs fake_swapper_regs = { { 0, }, 0, 0, 0, 0 };

void register_prom_callbacks(void)
{
	prom_setcallback(prom_callback);
	prom_feval(": linux-va>tte-data 2 \" va>tte-data\" $callback drop ; "
		   "' linux-va>tte-data to va>tte-data");
	prom_feval(": linux-.soft1 1 \" .soft1\" $callback 2drop ; "
		   "' linux-.soft1 to .soft1");
	prom_feval(": linux-.soft2 1 \" .soft2\" $callback 2drop ; "
		   "' linux-.soft2 to .soft2");
}

extern void paging_init(void);

void __init setup_arch(char **cmdline_p)
{
	unsigned long highest_paddr;
	int i;

	/* Initialize PROM console and command line. */
	*cmdline_p = prom_getbootargs();
	strcpy(saved_command_line, *cmdline_p);

	printk("ARCH: SUN4U\n");

#ifdef CONFIG_DUMMY_CONSOLE
	conswitchp = &dummy_con;
#elif defined(CONFIG_PROM_CONSOLE)
	conswitchp = &prom_con;
#endif

#ifdef CONFIG_SMP
	i = (unsigned long)&irq_stat[1] - (unsigned long)&irq_stat[0];
	if ((i == SMP_CACHE_BYTES) || (i == (2 * SMP_CACHE_BYTES))) {
		extern unsigned int irqsz_patchme[1];
		irqsz_patchme[0] |= ((i == SMP_CACHE_BYTES) ? SMP_CACHE_BYTES_SHIFT : \
							SMP_CACHE_BYTES_SHIFT + 1);
		flushi((long)&irqsz_patchme[0]);
	} else {
		prom_printf("Unexpected size of irq_stat[] elements\n");
		prom_halt();
	}
#endif
	/* Work out if we are starfire early on */
	check_if_starfire();

	boot_flags_init(*cmdline_p);

	idprom_init();
	(void) prom_probe_memory();

	/* In paging_init() we tip off this value to see if we need
	 * to change init_mm.pgd to point to the real alias mapping.
	 */
	phys_base = 0xffffffffffffffffUL;
	highest_paddr = 0UL;
	for (i = 0; sp_banks[i].num_bytes != 0; i++) {
		unsigned long top;

		if (sp_banks[i].base_addr < phys_base)
			phys_base = sp_banks[i].base_addr;
		top = sp_banks[i].base_addr +
			sp_banks[i].num_bytes;
		if (highest_paddr < top)
			highest_paddr = top;
	}
	pfn_base = phys_base >> PAGE_SHIFT;

	switch (tlb_type) {
	default:
	case spitfire:
		kern_base = spitfire_get_itlb_data(sparc64_highest_locked_tlbent());
		kern_base &= _PAGE_PADDR_SF;
		break;

	case cheetah:
	case cheetah_plus:
		kern_base = cheetah_get_litlb_data(sparc64_highest_locked_tlbent());
		kern_base &= _PAGE_PADDR;
		break;
	};

	kern_size = (unsigned long)&_end - (unsigned long)KERNBASE;

	if (!root_flags)
		root_mountflags &= ~MS_RDONLY;
	ROOT_DEV = old_decode_dev(root_dev);
#ifdef CONFIG_BLK_DEV_INITRD
	rd_image_start = ram_flags & RAMDISK_IMAGE_START_MASK;
	rd_prompt = ((ram_flags & RAMDISK_PROMPT_FLAG) != 0);
	rd_doload = ((ram_flags & RAMDISK_LOAD_FLAG) != 0);	
#endif

	init_task.thread_info->kregs = &fake_swapper_regs;

#ifdef CONFIG_IP_PNP
	if (!ic_set_manually) {
		int chosen = prom_finddevice ("/chosen");
		u32 cl, sv, gw;
		
		cl = prom_getintdefault (chosen, "client-ip", 0);
		sv = prom_getintdefault (chosen, "server-ip", 0);
		gw = prom_getintdefault (chosen, "gateway-ip", 0);
		if (cl && sv) {
			ic_myaddr = cl;
			ic_servaddr = sv;
			if (gw)
				ic_gateway = gw;
#if defined(CONFIG_IP_PNP_BOOTP) || defined(CONFIG_IP_PNP_RARP)
			ic_proto_enabled = 0;
#endif
		}
	}
#endif

	paging_init();
}

static int __init set_preferred_console(void)
{
	int idev, odev;

	/* The user has requested a console so this is already set up. */
	if (serial_console >= 0)
		return -EBUSY;

	idev = prom_query_input_device();
	odev = prom_query_output_device();
	if (idev == PROMDEV_IKBD && odev == PROMDEV_OSCREEN) {
		serial_console = 0;
	} else if (idev == PROMDEV_ITTYA && odev == PROMDEV_OTTYA) {
		serial_console = 1;
	} else if (idev == PROMDEV_ITTYB && odev == PROMDEV_OTTYB) {
		serial_console = 2;
	} else {
		prom_printf("Inconsistent console: "
			    "input %d, output %d\n",
			    idev, odev);
		prom_halt();
	}

	if (serial_console)
		return add_preferred_console("ttyS", serial_console - 1, NULL);

	return -ENODEV;
}
console_initcall(set_preferred_console);

/* BUFFER is PAGE_SIZE bytes long. */

extern char *sparc_cpu_type;
extern char *sparc_fpu_type;

extern void smp_info(struct seq_file *);
extern void smp_bogo(struct seq_file *);
extern void mmu_info(struct seq_file *);

static int show_cpuinfo(struct seq_file *m, void *__unused)
{
	seq_printf(m, 
		   "cpu\t\t: %s\n"
		   "fpu\t\t: %s\n"
		   "promlib\t\t: Version 3 Revision %d\n"
		   "prom\t\t: %d.%d.%d\n"
		   "type\t\t: sun4u\n"
		   "ncpus probed\t: %ld\n"
		   "ncpus active\t: %ld\n"
#ifndef CONFIG_SMP
		   "Cpu0Bogo\t: %lu.%02lu\n"
		   "Cpu0ClkTck\t: %016lx\n"
#endif
		   ,
		   sparc_cpu_type,
		   sparc_fpu_type,
		   prom_rev,
		   prom_prev >> 16,
		   (prom_prev >> 8) & 0xff,
		   prom_prev & 0xff,
		   (long)num_possible_cpus(),
		   (long)num_online_cpus()
#ifndef CONFIG_SMP
		   , cpu_data(0).udelay_val/(500000/HZ),
		   (cpu_data(0).udelay_val/(5000/HZ)) % 100,
		   cpu_data(0).clock_tick
#endif
		);
#ifdef CONFIG_SMP
	smp_bogo(m);
#endif
	mmu_info(m);
#ifdef CONFIG_SMP
	smp_info(m);
#endif
	return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	/* The pointer we are returning is arbitrary,
	 * it just has to be non-NULL and not IS_ERR
	 * in the success case.
	 */
	return *pos == 0 ? &c_start : NULL;
}

static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
	++*pos;
	return c_start(m, pos);
}

static void c_stop(struct seq_file *m, void *v)
{
}

struct seq_operations cpuinfo_op = {
	.start =c_start,
	.next =	c_next,
	.stop =	c_stop,
	.show =	show_cpuinfo,
};

extern int stop_a_enabled;

void sun_do_break(void)
{
	if (!stop_a_enabled)
		return;

	prom_printf("\n");
	flush_user_windows();

	prom_cmdline();
}

int serial_console = -1;
int stop_a_enabled = 1;

static int __init topology_init(void)
{
	int i, err;

	err = -ENOMEM;
	for (i = 0; i < NR_CPUS; i++) {
		if (cpu_possible(i)) {
			struct cpu *p = kmalloc(sizeof(*p), GFP_KERNEL);

			if (p) {
				memset(p, 0, sizeof(*p));
				register_cpu(p, i, NULL);
				err = 0;
			}
		}
	}

	return err;
}

subsys_initcall(topology_init);
ommit/kernel/fork.c?id=17406b82d621930cca8ccc1272cdac9a7dae8e40'>17406b82d62
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/*
 *  linux/kernel/fork.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

/*
 *  'fork.c' contains the help-routines for the 'fork' system call
 * (see also entry.S and others).
 * Fork is rather simple, once you get the hang of it, but the memory
 * management can be a bitch. See 'mm/memory.c': 'copy_page_range()'
 */

#include <linux/slab.h>
#include <linux/init.h>
#include <linux/unistd.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/completion.h>
#include <linux/personality.h>
#include <linux/mempolicy.h>
#include <linux/sem.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/iocontext.h>
#include <linux/key.h>
#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/mmu_notifier.h>
#include <linux/fs.h>
#include <linux/nsproxy.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/cgroup.h>
#include <linux/security.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/syscalls.h>
#include <linux/jiffies.h>
#include <linux/tracehook.h>
#include <linux/futex.h>
#include <linux/compat.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/rcupdate.h>
#include <linux/ptrace.h>
#include <linux/mount.h>
#include <linux/audit.h>
#include <linux/memcontrol.h>
#include <linux/ftrace.h>
#include <linux/profile.h>
#include <linux/rmap.h>
#include <linux/ksm.h>
#include <linux/acct.h>
#include <linux/tsacct_kern.h>
#include <linux/cn_proc.h>
#include <linux/freezer.h>
#include <linux/delayacct.h>
#include <linux/taskstats_kern.h>
#include <linux/random.h>
#include <linux/tty.h>
#include <linux/proc_fs.h>
#include <linux/blkdev.h>
#include <linux/fs_struct.h>
#include <linux/magic.h>
#include <linux/perf_event.h>
#include <linux/posix-timers.h>
#include <linux/user-return-notifier.h>
#include <linux/oom.h>
#include <linux/khugepaged.h>

#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>

#include <trace/events/sched.h>

/*
 * Protected counters by write_lock_irq(&tasklist_lock)
 */
unsigned long total_forks;	/* Handle normal Linux uptimes. */
int nr_threads; 		/* The idle threads do not count.. */

int max_threads;		/* tunable limit on nr_threads */

DEFINE_PER_CPU(unsigned long, process_counts) = 0;

__cacheline_aligned DEFINE_RWLOCK(tasklist_lock);  /* outer */

#ifdef CONFIG_PROVE_RCU
int lockdep_tasklist_lock_is_held(void)
{
	return lockdep_is_held(&tasklist_lock);
}
EXPORT_SYMBOL_GPL(lockdep_tasklist_lock_is_held);
#endif /* #ifdef CONFIG_PROVE_RCU */

int nr_processes(void)
{
	int cpu;
	int total = 0;

	for_each_possible_cpu(cpu)
		total += per_cpu(process_counts, cpu);

	return total;
}

#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
# define alloc_task_struct()	kmem_cache_alloc(task_struct_cachep, GFP_KERNEL)
# define free_task_struct(tsk)	kmem_cache_free(task_struct_cachep, (tsk))
static struct kmem_cache *task_struct_cachep;
#endif

#ifndef __HAVE_ARCH_THREAD_INFO_ALLOCATOR
static inline struct thread_info *alloc_thread_info(struct task_struct *tsk)
{
#ifdef CONFIG_DEBUG_STACK_USAGE
	gfp_t mask = GFP_KERNEL | __GFP_ZERO;
#else
	gfp_t mask = GFP_KERNEL;
#endif
	return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER);
}

static inline void free_thread_info(struct thread_info *ti)
{
	free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
}
#endif

/* SLAB cache for signal_struct structures (tsk->signal) */
static struct kmem_cache *signal_cachep;

/* SLAB cache for sighand_struct structures (tsk->sighand) */
struct kmem_cache *sighand_cachep;

/* SLAB cache for files_struct structures (tsk->files) */
struct kmem_cache *files_cachep;

/* SLAB cache for fs_struct structures (tsk->fs) */
struct kmem_cache *fs_cachep;

/* SLAB cache for vm_area_struct structures */
struct kmem_cache *vm_area_cachep;

/* SLAB cache for mm_struct structures (tsk->mm) */
static struct kmem_cache *mm_cachep;

static void account_kernel_stack(struct thread_info *ti, int account)
{
	struct zone *zone = page_zone(virt_to_page(ti));

	mod_zone_page_state(zone, NR_KERNEL_STACK, account);
}

void free_task(struct task_struct *tsk)
{
	prop_local_destroy_single(&tsk->dirties);
	account_kernel_stack(tsk->stack, -1);
	free_thread_info(tsk->stack);
	rt_mutex_debug_task_free(tsk);
	ftrace_graph_exit_task(tsk);
	free_task_struct(tsk);
}
EXPORT_SYMBOL(free_task);

static inline void free_signal_struct(struct signal_struct *sig)
{
	taskstats_tgid_free(sig);
	sched_autogroup_exit(sig);
	kmem_cache_free(signal_cachep, sig);
}

static inline void put_signal_struct(struct signal_struct *sig)
{
	if (atomic_dec_and_test(&sig->sigcnt))
		free_signal_struct(sig);
}

void __put_task_struct(struct task_struct *tsk)
{
	WARN_ON(!tsk->exit_state);
	WARN_ON(atomic_read(&tsk->usage));
	WARN_ON(tsk == current);

	exit_creds(tsk);
	delayacct_tsk_free(tsk);
	put_signal_struct(tsk->signal);

	if (!profile_handoff_task(tsk))
		free_task(tsk);
}

/*
 * macro override instead of weak attribute alias, to workaround
 * gcc 4.1.0 and 4.1.1 bugs with weak attribute and empty functions.
 */
#ifndef arch_task_cache_init
#define arch_task_cache_init()
#endif

void __init fork_init(unsigned long mempages)
{
#ifndef __HAVE_ARCH_TASK_STRUCT_ALLOCATOR
#ifndef ARCH_MIN_TASKALIGN
#define ARCH_MIN_TASKALIGN	L1_CACHE_BYTES
#endif
	/* create a slab on which task_structs can be allocated */
	task_struct_cachep =
		kmem_cache_create("task_struct", sizeof(struct task_struct),
			ARCH_MIN_TASKALIGN, SLAB_PANIC | SLAB_NOTRACK, NULL);
#endif

	/* do the arch specific task caches init */
	arch_task_cache_init();

	/*
	 * The default maximum number of threads is set to a safe
	 * value: the thread structures can take up at most half
	 * of memory.
	 */
	max_threads = mempages / (8 * THREAD_SIZE / PAGE_SIZE);

	/*
	 * we need to allow at least 20 threads to boot a system
	 */
	if(max_threads < 20)
		max_threads = 20;

	init_task.signal->rlim[RLIMIT_NPROC].rlim_cur = max_threads/2;
	init_task.signal->rlim[RLIMIT_NPROC].rlim_max = max_threads/2;
	init_task.signal->rlim[RLIMIT_SIGPENDING] =
		init_task.signal->rlim[RLIMIT_NPROC];
}

int __attribute__((weak)) arch_dup_task_struct(struct task_struct *dst,
					       struct task_struct *src)
{
	*dst = *src;
	return 0;
}

static struct task_struct *dup_task_struct(struct task_struct *orig)
{
	struct task_struct *tsk;
	struct thread_info *ti;
	unsigned long *stackend;

	int err;

	prepare_to_copy(orig);

	tsk = alloc_task_struct();
	if (!tsk)
		return NULL;

	ti = alloc_thread_info(tsk);
	if (!ti) {
		free_task_struct(tsk);
		return NULL;
	}

 	err = arch_dup_task_struct(tsk, orig);
	if (err)
		goto out;

	tsk->stack = ti;

	err = prop_local_init_single(&tsk->dirties);
	if (err)
		goto out;

	setup_thread_stack(tsk, orig);
	clear_user_return_notifier(tsk);
	clear_tsk_need_resched(tsk);
	stackend = end_of_stack(tsk);
	*stackend = STACK_END_MAGIC;	/* for overflow detection */

#ifdef CONFIG_CC_STACKPROTECTOR
	tsk->stack_canary = get_random_int();
#endif

	/* One for us, one for whoever does the "release_task()" (usually parent) */
	atomic_set(&tsk->usage,2);
	atomic_set(&tsk->fs_excl, 0);
#ifdef CONFIG_BLK_DEV_IO_TRACE
	tsk->btrace_seq = 0;
#endif
	tsk->splice_pipe = NULL;

	account_kernel_stack(ti, 1);

	return tsk;

out:
	free_thread_info(ti);
	free_task_struct(tsk);
	return NULL;
}

#ifdef CONFIG_MMU
static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
{
	struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
	struct rb_node **rb_link, *rb_parent;
	int retval;
	unsigned long charge;
	struct mempolicy *pol;

	down_write(&oldmm->mmap_sem);
	flush_cache_dup_mm(oldmm);
	/*
	 * Not linked in yet - no deadlock potential:
	 */
	down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING);

	mm->locked_vm = 0;
	mm->mmap = NULL;
	mm->mmap_cache = NULL;
	mm->free_area_cache = oldmm->mmap_base;
	mm->cached_hole_size = ~0UL;
	mm->map_count = 0;
	cpumask_clear(mm_cpumask(mm));
	mm->mm_rb = RB_ROOT;
	rb_link = &mm->mm_rb.rb_node;
	rb_parent = NULL;
	pprev = &mm->mmap;
	retval = ksm_fork(mm, oldmm);
	if (retval)
		goto out;
	retval = khugepaged_fork(mm, oldmm);
	if (retval)
		goto out;

	prev = NULL;
	for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
		struct file *file;

		if (mpnt->vm_flags & VM_DONTCOPY) {
			long pages = vma_pages(mpnt);
			mm->total_vm -= pages;
			vm_stat_account(mm, mpnt->vm_flags, mpnt->vm_file,
								-pages);
			continue;
		}
		charge = 0;
		if (mpnt->vm_flags & VM_ACCOUNT) {
			unsigned int len = (mpnt->vm_end - mpnt->vm_start) >> PAGE_SHIFT;
			if (security_vm_enough_memory(len))
				goto fail_nomem;
			charge = len;
		}
		tmp = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
		if (!tmp)
			goto fail_nomem;
		*tmp = *mpnt;
		INIT_LIST_HEAD(&tmp->anon_vma_chain);
		pol = mpol_dup(vma_policy(mpnt));
		retval = PTR_ERR(pol);
		if (IS_ERR(pol))
			goto fail_nomem_policy;
		vma_set_policy(tmp, pol);
		tmp->vm_mm = mm;
		if (anon_vma_fork(tmp, mpnt))
			goto fail_nomem_anon_vma_fork;
		tmp->vm_flags &= ~VM_LOCKED;
		tmp->vm_next = tmp->vm_prev = NULL;
		file = tmp->vm_file;
		if (file) {
			struct inode *inode = file->f_path.dentry->d_inode;
			struct address_space *mapping = file->f_mapping;

			get_file(file);
			if (tmp->vm_flags & VM_DENYWRITE)
				atomic_dec(&inode->i_writecount);
			spin_lock(&mapping->i_mmap_lock);
			if (tmp->vm_flags & VM_SHARED)
				mapping->i_mmap_writable++;
			tmp->vm_truncate_count = mpnt->vm_truncate_count;
			flush_dcache_mmap_lock(mapping);
			/* insert tmp into the share list, just after mpnt */
			vma_prio_tree_add(tmp, mpnt);
			flush_dcache_mmap_unlock(mapping);
			spin_unlock(&mapping->i_mmap_lock);
		}

		/*
		 * Clear hugetlb-related page reserves for children. This only
		 * affects MAP_PRIVATE mappings. Faults generated by the child
		 * are not guaranteed to succeed, even if read-only
		 */
		if (is_vm_hugetlb_page(tmp))
			reset_vma_resv_huge_pages(tmp);

		/*
		 * Link in the new vma and copy the page table entries.
		 */
		*pprev = tmp;
		pprev = &tmp->vm_next;
		tmp->vm_prev = prev;
		prev = tmp;

		__vma_link_rb(mm, tmp, rb_link, rb_parent);
		rb_link = &tmp->vm_rb.rb_right;
		rb_parent = &tmp->vm_rb;

		mm->map_count++;
		retval = copy_page_range(mm, oldmm, mpnt);

		if (tmp->vm_ops && tmp->vm_ops->open)
			tmp->vm_ops->open(tmp);

		if (retval)
			goto out;
	}
	/* a new mm has just been created */
	arch_dup_mmap(oldmm, mm);
	retval = 0;
out:
	up_write(&mm->mmap_sem);
	flush_tlb_mm(oldmm);
	up_write(&oldmm->mmap_sem);
	return retval;
fail_nomem_anon_vma_fork:
	mpol_put(pol);
fail_nomem_policy:
	kmem_cache_free(vm_area_cachep, tmp);
fail_nomem:
	retval = -ENOMEM;
	vm_unacct_memory(charge);
	goto out;
}

static inline int mm_alloc_pgd(struct mm_struct * mm)
{
	mm->pgd = pgd_alloc(mm);
	if (unlikely(!mm->pgd))
		return -ENOMEM;
	return 0;
}

static inline void mm_free_pgd(struct mm_struct * mm)
{
	pgd_free(mm, mm->pgd);
}
#else
#define dup_mmap(mm, oldmm)	(0)
#define mm_alloc_pgd(mm)	(0)
#define mm_free_pgd(mm)
#endif /* CONFIG_MMU */

__cacheline_aligned_in_smp DEFINE_SPINLOCK(mmlist_lock);

#define allocate_mm()	(kmem_cache_alloc(mm_cachep, GFP_KERNEL))
#define free_mm(mm)	(kmem_cache_free(mm_cachep, (mm)))

static unsigned long default_dump_filter = MMF_DUMP_FILTER_DEFAULT;

static int __init coredump_filter_setup(char *s)
{
	default_dump_filter =
		(simple_strtoul(s, NULL, 0) << MMF_DUMP_FILTER_SHIFT) &
		MMF_DUMP_FILTER_MASK;
	return 1;
}

__setup("coredump_filter=", coredump_filter_setup);

#include <linux/init_task.h>

static void mm_init_aio(struct mm_struct *mm)
{
#ifdef CONFIG_AIO
	spin_lock_init(&mm->ioctx_lock);
	INIT_HLIST_HEAD(&mm->ioctx_list);
#endif
}

static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
{
	atomic_set(&mm->mm_users, 1);
	atomic_set(&mm->mm_count, 1);
	init_rwsem(&mm->mmap_sem);
	INIT_LIST_HEAD(&mm->mmlist);
	mm->flags = (current->mm) ?
		(current->mm->flags & MMF_INIT_MASK) : default_dump_filter;
	mm->core_state = NULL;
	mm->nr_ptes = 0;
	memset(&mm->rss_stat, 0, sizeof(mm->rss_stat));
	spin_lock_init(&mm->page_table_lock);
	mm->free_area_cache = TASK_UNMAPPED_BASE;
	mm->cached_hole_size = ~0UL;
	mm_init_aio(mm);
	mm_init_owner(mm, p);
	atomic_set(&mm->oom_disable_count, 0);

	if (likely(!mm_alloc_pgd(mm))) {
		mm->def_flags = 0;
		mmu_notifier_mm_init(mm);
		return mm;
	}

	free_mm(mm);
	return NULL;
}

/*
 * Allocate and initialize an mm_struct.
 */
struct mm_struct * mm_alloc(void)
{
	struct mm_struct * mm;

	mm = allocate_mm();
	if (mm) {
		memset(mm, 0, sizeof(*mm));
		mm = mm_init(mm, current);
	}
	return mm;
}

/*
 * Called when the last reference to the mm
 * is dropped: either by a lazy thread or by
 * mmput. Free the page directory and the mm.
 */
void __mmdrop(struct mm_struct *mm)
{
	BUG_ON(mm == &init_mm);
	mm_free_pgd(mm);
	destroy_context(mm);
	mmu_notifier_mm_destroy(mm);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	VM_BUG_ON(mm->pmd_huge_pte);
#endif
	free_mm(mm);
}
EXPORT_SYMBOL_GPL(__mmdrop);

/*
 * Decrement the use count and release all resources for an mm.
 */
void mmput(struct mm_struct *mm)
{
	might_sleep();

	if (atomic_dec_and_test(&mm->mm_users)) {
		exit_aio(mm);
		ksm_exit(mm);
		khugepaged_exit(mm); /* must run before exit_mmap */
		exit_mmap(mm);
		set_mm_exe_file(mm, NULL);
		if (!list_empty(&mm->mmlist)) {
			spin_lock(&mmlist_lock);
			list_del(&mm->mmlist);
			spin_unlock(&mmlist_lock);
		}
		put_swap_token(mm);
		if (mm->binfmt)
			module_put(mm->binfmt->module);
		mmdrop(mm);
	}
}
EXPORT_SYMBOL_GPL(mmput);

/**
 * get_task_mm - acquire a reference to the task's mm
 *
 * Returns %NULL if the task has no mm.  Checks PF_KTHREAD (meaning
 * this kernel workthread has transiently adopted a user mm with use_mm,
 * to do its AIO) is not set and if so returns a reference to it, after
 * bumping up the use count.  User must release the mm via mmput()
 * after use.  Typically used by /proc and ptrace.
 */
struct mm_struct *get_task_mm(struct task_struct *task)
{
	struct mm_struct *mm;

	task_lock(task);
	mm = task->mm;
	if (mm) {
		if (task->flags & PF_KTHREAD)
			mm = NULL;
		else
			atomic_inc(&mm->mm_users);
	}
	task_unlock(task);
	return mm;
}
EXPORT_SYMBOL_GPL(get_task_mm);

/* Please note the differences between mmput and mm_release.
 * mmput is called whenever we stop holding onto a mm_struct,
 * error success whatever.
 *
 * mm_release is called after a mm_struct has been removed
 * from the current process.
 *
 * This difference is important for error handling, when we
 * only half set up a mm_struct for a new process and need to restore
 * the old one.  Because we mmput the new mm_struct before
 * restoring the old one. . .
 * Eric Biederman 10 January 1998
 */
void mm_release(struct task_struct *tsk, struct mm_struct *mm)
{
	struct completion *vfork_done = tsk->vfork_done;

	/* Get rid of any futexes when releasing the mm */
#ifdef CONFIG_FUTEX
	if (unlikely(tsk->robust_list)) {
		exit_robust_list(tsk);
		tsk->robust_list = NULL;
	}
#ifdef CONFIG_COMPAT
	if (unlikely(tsk->compat_robust_list)) {
		compat_exit_robust_list(tsk);
		tsk->compat_robust_list = NULL;
	}
#endif
	if (unlikely(!list_empty(&tsk->pi_state_list)))
		exit_pi_state_list(tsk);
#endif

	/* Get rid of any cached register state */
	deactivate_mm(tsk, mm);

	/* notify parent sleeping on vfork() */
	if (vfork_done) {
		tsk->vfork_done = NULL;
		complete(vfork_done);
	}

	/*
	 * If we're exiting normally, clear a user-space tid field if
	 * requested.  We leave this alone when dying by signal, to leave
	 * the value intact in a core dump, and to save the unnecessary
	 * trouble otherwise.  Userland only wants this done for a sys_exit.
	 */
	if (tsk->clear_child_tid) {
		if (!(tsk->flags & PF_SIGNALED) &&
		    atomic_read(&mm->mm_users) > 1) {
			/*
			 * We don't check the error code - if userspace has
			 * not set up a proper pointer then tough luck.
			 */
			put_user(0, tsk->clear_child_tid);
			sys_futex(tsk->clear_child_tid, FUTEX_WAKE,
					1, NULL, NULL, 0);
		}
		tsk->clear_child_tid = NULL;
	}
}

/*
 * Allocate a new mm structure and copy contents from the
 * mm structure of the passed in task structure.
 */
struct mm_struct *dup_mm(struct task_struct *tsk)
{
	struct mm_struct *mm, *oldmm = current->mm;
	int err;

	if (!oldmm)
		return NULL;

	mm = allocate_mm();
	if (!mm)
		goto fail_nomem;

	memcpy(mm, oldmm, sizeof(*mm));

	/* Initializing for Swap token stuff */
	mm->token_priority = 0;
	mm->last_interval = 0;

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	mm->pmd_huge_pte = NULL;
#endif

	if (!mm_init(mm, tsk))
		goto fail_nomem;

	if (init_new_context(tsk, mm))
		goto fail_nocontext;

	dup_mm_exe_file(oldmm, mm);

	err = dup_mmap(mm, oldmm);
	if (err)
		goto free_pt;

	mm->hiwater_rss = get_mm_rss(mm);
	mm->hiwater_vm = mm->total_vm;

	if (mm->binfmt && !try_module_get(mm->binfmt->module))
		goto free_pt;

	return mm;

free_pt:
	/* don't put binfmt in mmput, we haven't got module yet */
	mm->binfmt = NULL;
	mmput(mm);

fail_nomem:
	return NULL;

fail_nocontext:
	/*
	 * If init_new_context() failed, we cannot use mmput() to free the mm
	 * because it calls destroy_context()
	 */
	mm_free_pgd(mm);
	free_mm(mm);
	return NULL;
}

static int copy_mm(unsigned long clone_flags, struct task_struct * tsk)
{
	struct mm_struct * mm, *oldmm;
	int retval;

	tsk->min_flt = tsk->maj_flt = 0;
	tsk->nvcsw = tsk->nivcsw = 0;
#ifdef CONFIG_DETECT_HUNG_TASK
	tsk->last_switch_count = tsk->nvcsw + tsk->nivcsw;
#endif

	tsk->mm = NULL;
	tsk->active_mm = NULL;

	/*
	 * Are we cloning a kernel thread?
	 *
	 * We need to steal a active VM for that..
	 */
	oldmm = current->mm;
	if (!oldmm)
		return 0;

	if (clone_flags & CLONE_VM) {
		atomic_inc(&oldmm->mm_users);
		mm = oldmm;
		goto good_mm;
	}

	retval = -ENOMEM;
	mm = dup_mm(tsk);
	if (!mm)
		goto fail_nomem;

good_mm:
	/* Initializing for Swap token stuff */
	mm->token_priority = 0;
	mm->last_interval = 0;
	if (tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
		atomic_inc(&mm->oom_disable_count);

	tsk->mm = mm;
	tsk->active_mm = mm;
	return 0;

fail_nomem:
	return retval;
}

static int copy_fs(unsigned long clone_flags, struct task_struct *tsk)
{
	struct fs_struct *fs = current->fs;
	if (clone_flags & CLONE_FS) {
		/* tsk->fs is already what we want */
		spin_lock(&fs->lock);
		if (fs->in_exec) {
			spin_unlock(&fs->lock);
			return -EAGAIN;
		}
		fs->users++;
		spin_unlock(&fs->lock);
		return 0;
	}
	tsk->fs = copy_fs_struct(fs);
	if (!tsk->fs)
		return -ENOMEM;
	return 0;
}

static int copy_files(unsigned long clone_flags, struct task_struct * tsk)
{
	struct files_struct *oldf, *newf;
	int error = 0;

	/*
	 * A background process may not have any files ...
	 */
	oldf = current->files;
	if (!oldf)
		goto out;

	if (clone_flags & CLONE_FILES) {
		atomic_inc(&oldf->count);
		goto out;
	}

	newf = dup_fd(oldf, &error);
	if (!newf)
		goto out;

	tsk->files = newf;
	error = 0;
out:
	return error;
}

static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
{
#ifdef CONFIG_BLOCK
	struct io_context *ioc = current->io_context;

	if (!ioc)
		return 0;
	/*
	 * Share io context with parent, if CLONE_IO is set
	 */
	if (clone_flags & CLONE_IO) {
		tsk->io_context = ioc_task_link(ioc);
		if (unlikely(!tsk->io_context))
			return -ENOMEM;
	} else if (ioprio_valid(ioc->ioprio)) {
		tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
		if (unlikely(!tsk->io_context))
			return -ENOMEM;

		tsk->io_context->ioprio = ioc->ioprio;
	}
#endif
	return 0;
}

static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
{
	struct sighand_struct *sig;

	if (clone_flags & CLONE_SIGHAND) {
		atomic_inc(&current->sighand->count);
		return 0;
	}
	sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
	rcu_assign_pointer(tsk->sighand, sig);
	if (!sig)
		return -ENOMEM;
	atomic_set(&sig->count, 1);
	memcpy(sig->action, current->sighand->action, sizeof(sig->action));
	return 0;
}

void __cleanup_sighand(struct sighand_struct *sighand)
{
	if (atomic_dec_and_test(&sighand->count))
		kmem_cache_free(sighand_cachep, sighand);
}


/*
 * Initialize POSIX timer handling for a thread group.
 */
static void posix_cpu_timers_init_group(struct signal_struct *sig)
{
	unsigned long cpu_limit;

	/* Thread group counters. */
	thread_group_cputime_init(sig);

	cpu_limit = ACCESS_ONCE(sig->rlim[RLIMIT_CPU].rlim_cur);
	if (cpu_limit != RLIM_INFINITY) {
		sig->cputime_expires.prof_exp = secs_to_cputime(cpu_limit);
		sig->cputimer.running = 1;
	}

	/* The timer lists. */
	INIT_LIST_HEAD(&sig->cpu_timers[0]);
	INIT_LIST_HEAD(&sig->cpu_timers[1]);
	INIT_LIST_HEAD(&sig->cpu_timers[2]);
}

static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
{
	struct signal_struct *sig;

	if (clone_flags & CLONE_THREAD)
		return 0;

	sig = kmem_cache_zalloc(signal_cachep, GFP_KERNEL);
	tsk->signal = sig;
	if (!sig)
		return -ENOMEM;

	sig->nr_threads = 1;
	atomic_set(&sig->live, 1);
	atomic_set(&sig->sigcnt, 1);
	init_waitqueue_head(&sig->wait_chldexit);
	if (clone_flags & CLONE_NEWPID)
		sig->flags |= SIGNAL_UNKILLABLE;
	sig->curr_target = tsk;
	init_sigpending(&sig->shared_pending);
	INIT_LIST_HEAD(&sig->posix_timers);

	hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	sig->real_timer.function = it_real_fn;

	task_lock(current->group_leader);
	memcpy(sig->rlim, current->signal->rlim, sizeof sig->rlim);
	task_unlock(current->group_leader);

	posix_cpu_timers_init_group(sig);

	tty_audit_fork(sig);
	sched_autogroup_fork(sig);

	sig->oom_adj = current->signal->oom_adj;
	sig->oom_score_adj = current->signal->oom_score_adj;
	sig->oom_score_adj_min = current->signal->oom_score_adj_min;

	mutex_init(&sig->cred_guard_mutex);

	return 0;
}

static void copy_flags(unsigned long clone_flags, struct task_struct *p)
{
	unsigned long new_flags = p->flags;

	new_flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER);
	new_flags |= PF_FORKNOEXEC;
	new_flags |= PF_STARTING;
	p->flags = new_flags;
	clear_freeze_flag(p);
}

SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
{
	current->clear_child_tid = tidptr;

	return task_pid_vnr(current);
}

static void rt_mutex_init_task(struct task_struct *p)
{
	raw_spin_lock_init(&p->pi_lock);
#ifdef CONFIG_RT_MUTEXES
	plist_head_init_raw(&p->pi_waiters, &p->pi_lock);
	p->pi_blocked_on = NULL;
#endif
}

#ifdef CONFIG_MM_OWNER
void mm_init_owner(struct mm_struct *mm, struct task_struct *p)
{
	mm->owner = p;
}
#endif /* CONFIG_MM_OWNER */

/*
 * Initialize POSIX timer handling for a single task.
 */
static void posix_cpu_timers_init(struct task_struct *tsk)
{
	tsk->cputime_expires.prof_exp = cputime_zero;
	tsk->cputime_expires.virt_exp = cputime_zero;
	tsk->cputime_expires.sched_exp = 0;
	INIT_LIST_HEAD(&tsk->cpu_timers[0]);
	INIT_LIST_HEAD(&tsk->cpu_timers[1]);
	INIT_LIST_HEAD(&tsk->cpu_timers[2]);
}

/*
 * This creates a new process as a copy of the old one,
 * but does not actually start it yet.
 *
 * It copies the registers, and all the appropriate
 * parts of the process environment (as per the clone
 * flags). The actual kick-off is left to the caller.
 */
static struct task_struct *copy_process(unsigned long clone_flags,
					unsigned long stack_start,
					struct pt_regs *regs,
					unsigned long stack_size,
					int __user *child_tidptr,
					struct pid *pid,
					int trace)
{
	int retval;
	struct task_struct *p;
	int cgroup_callbacks_done = 0;

	if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
		return ERR_PTR(-EINVAL);

	/*
	 * Thread groups must share signals as well, and detached threads
	 * can only be started up within the thread group.
	 */
	if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
		return ERR_PTR(-EINVAL);

	/*
	 * Shared signal handlers imply shared VM. By way of the above,
	 * thread groups also imply shared VM. Blocking this case allows
	 * for various simplifications in other code.
	 */
	if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
		return ERR_PTR(-EINVAL);

	/*
	 * Siblings of global init remain as zombies on exit since they are
	 * not reaped by their parent (swapper). To solve this and to avoid
	 * multi-rooted process trees, prevent global and container-inits
	 * from creating siblings.
	 */
	if ((clone_flags & CLONE_PARENT) &&
				current->signal->flags & SIGNAL_UNKILLABLE)
		return ERR_PTR(-EINVAL);

	retval = security_task_create(clone_flags);
	if (retval)
		goto fork_out;

	retval = -ENOMEM;
	p = dup_task_struct(current);
	if (!p)
		goto fork_out;

	ftrace_graph_init_task(p);

	rt_mutex_init_task(p);

#ifdef CONFIG_PROVE_LOCKING
	DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
	DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
	retval = -EAGAIN;
	if (atomic_read(&p->real_cred->user->processes) >=
			task_rlimit(p, RLIMIT_NPROC)) {
		if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
		    p->real_cred->user != INIT_USER)
			goto bad_fork_free;
	}

	retval = copy_creds(p, clone_flags);
	if (retval < 0)
		goto bad_fork_free;

	/*
	 * If multiple threads are within copy_process(), then this check
	 * triggers too late. This doesn't hurt, the check is only there
	 * to stop root fork bombs.
	 */
	retval = -EAGAIN;
	if (nr_threads >= max_threads)
		goto bad_fork_cleanup_count;

	if (!try_module_get(task_thread_info(p)->exec_domain->module))
		goto bad_fork_cleanup_count;

	p->did_exec = 0;
	delayacct_tsk_init(p);	/* Must remain after dup_task_struct() */
	copy_flags(clone_flags, p);
	INIT_LIST_HEAD(&p->children);
	INIT_LIST_HEAD(&p->sibling);
	rcu_copy_process(p);
	p->vfork_done = NULL;
	spin_lock_init(&p->alloc_lock);

	init_sigpending(&p->pending);

	p->utime = cputime_zero;
	p->stime = cputime_zero;
	p->gtime = cputime_zero;
	p->utimescaled = cputime_zero;
	p->stimescaled = cputime_zero;
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
	p->prev_utime = cputime_zero;
	p->prev_stime = cputime_zero;
#endif
#if defined(SPLIT_RSS_COUNTING)
	memset(&p->rss_stat, 0, sizeof(p->rss_stat));
#endif

	p->default_timer_slack_ns = current->timer_slack_ns;

	task_io_accounting_init(&p->ioac);
	acct_clear_integrals(p);

	posix_cpu_timers_init(p);

	p->lock_depth = -1;		/* -1 = no lock */
	do_posix_clock_monotonic_gettime(&p->start_time);
	p->real_start_time = p->start_time;
	monotonic_to_bootbased(&p->real_start_time);
	p->io_context = NULL;
	p->audit_context = NULL;
	cgroup_fork(p);
#ifdef CONFIG_NUMA
	p->mempolicy = mpol_dup(p->mempolicy);
 	if (IS_ERR(p->mempolicy)) {
 		retval = PTR_ERR(p->mempolicy);
 		p->mempolicy = NULL;
 		goto bad_fork_cleanup_cgroup;
 	}
	mpol_fix_fork_child_flag(p);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS
	p->irq_events = 0;
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
	p->hardirqs_enabled = 1;
#else
	p->hardirqs_enabled = 0;
#endif
	p->hardirq_enable_ip = 0;
	p->hardirq_enable_event = 0;
	p->hardirq_disable_ip = _THIS_IP_;
	p->hardirq_disable_event = 0;
	p->softirqs_enabled = 1;
	p->softirq_enable_ip = _THIS_IP_;
	p->softirq_enable_event = 0;
	p->softirq_disable_ip = 0;
	p->softirq_disable_event = 0;
	p->hardirq_context = 0;
	p->softirq_context = 0;
#endif
#ifdef CONFIG_LOCKDEP
	p->lockdep_depth = 0; /* no locks held yet */
	p->curr_chain_key = 0;
	p->lockdep_recursion = 0;
#endif

#ifdef CONFIG_DEBUG_MUTEXES
	p->blocked_on = NULL; /* not blocked yet */
#endif
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
	p->memcg_batch.do_batch = 0;
	p->memcg_batch.memcg = NULL;
#endif

	/* Perform scheduler related setup. Assign this task to a CPU. */
	sched_fork(p, clone_flags);

	retval = perf_event_init_task(p);
	if (retval)
		goto bad_fork_cleanup_policy;

	if ((retval = audit_alloc(p)))
		goto bad_fork_cleanup_policy;
	/* copy all the process information */
	if ((retval = copy_semundo(clone_flags, p)))
		goto bad_fork_cleanup_audit;
	if ((retval = copy_files(clone_flags, p)))
		goto bad_fork_cleanup_semundo;
	if ((retval = copy_fs(clone_flags, p)))
		goto bad_fork_cleanup_files;
	if ((retval = copy_sighand(clone_flags, p)))
		goto bad_fork_cleanup_fs;
	if ((retval = copy_signal(clone_flags, p)))
		goto bad_fork_cleanup_sighand;
	if ((retval = copy_mm(clone_flags, p)))
		goto bad_fork_cleanup_signal;
	if ((retval = copy_namespaces(clone_flags, p)))
		goto bad_fork_cleanup_mm;
	if ((retval = copy_io(clone_flags, p)))
		goto bad_fork_cleanup_namespaces;
	retval = copy_thread(clone_flags, stack_start, stack_size, p, regs);
	if (retval)
		goto bad_fork_cleanup_io;

	if (pid != &init_struct_pid) {
		retval = -ENOMEM;
		pid = alloc_pid(p->nsproxy->pid_ns);
		if (!pid)
			goto bad_fork_cleanup_io;

		if (clone_flags & CLONE_NEWPID) {
			retval = pid_ns_prepare_proc(p->nsproxy->pid_ns);
			if (retval < 0)
				goto bad_fork_free_pid;
		}
	}

	p->pid = pid_nr(pid);
	p->tgid = p->pid;
	if (clone_flags & CLONE_THREAD)
		p->tgid = current->tgid;

	if (current->nsproxy != p->nsproxy) {
		retval = ns_cgroup_clone(p, pid);
		if (retval)
			goto bad_fork_free_pid;
	}

	p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
	/*
	 * Clear TID on mm_release()?
	 */
	p->clear_child_tid = (clone_flags & CLONE_CHILD_CLEARTID) ? child_tidptr: NULL;
#ifdef CONFIG_FUTEX
	p->robust_list = NULL;
#ifdef CONFIG_COMPAT
	p->compat_robust_list = NULL;
#endif
	INIT_LIST_HEAD(&p->pi_state_list);
	p->pi_state_cache = NULL;
#endif
	/*
	 * sigaltstack should be cleared when sharing the same VM
	 */
	if ((clone_flags & (CLONE_VM|CLONE_VFORK)) == CLONE_VM)
		p->sas_ss_sp = p->sas_ss_size = 0;

	/*
	 * Syscall tracing and stepping should be turned off in the
	 * child regardless of CLONE_PTRACE.
	 */
	user_disable_single_step(p);
	clear_tsk_thread_flag(p, TIF_SYSCALL_TRACE);
#ifdef TIF_SYSCALL_EMU
	clear_tsk_thread_flag(p, TIF_SYSCALL_EMU);
#endif
	clear_all_latency_tracing(p);

	/* ok, now we should be set up.. */
	p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
	p->pdeath_signal = 0;
	p->exit_state = 0;

	/*
	 * Ok, make it visible to the rest of the system.
	 * We dont wake it up yet.
	 */
	p->group_leader = p;
	INIT_LIST_HEAD(&p->thread_group);

	/* Now that the task is set up, run cgroup callbacks if
	 * necessary. We need to run them before the task is visible
	 * on the tasklist. */
	cgroup_fork_callbacks(p);
	cgroup_callbacks_done = 1;

	/* Need tasklist lock for parent etc handling! */
	write_lock_irq(&tasklist_lock);

	/* CLONE_PARENT re-uses the old parent */
	if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
		p->real_parent = current->real_parent;
		p->parent_exec_id = current->parent_exec_id;
	} else {
		p->real_parent = current;
		p->parent_exec_id = current->self_exec_id;
	}

	spin_lock(&current->sighand->siglock);

	/*
	 * Process group and session signals need to be delivered to just the
	 * parent before the fork or both the parent and the child after the
	 * fork. Restart if a signal comes in before we add the new process to
	 * it's process group.
	 * A fatal signal pending means that current will exit, so the new
	 * thread can't slip out of an OOM kill (or normal SIGKILL).
 	 */
	recalc_sigpending();
	if (signal_pending(current)) {
		spin_unlock(&current->sighand->siglock);
		write_unlock_irq(&tasklist_lock);
		retval = -ERESTARTNOINTR;
		goto bad_fork_free_pid;
	}

	if (clone_flags & CLONE_THREAD) {
		current->signal->nr_threads++;
		atomic_inc(&current->signal->live);
		atomic_inc(&current->signal->sigcnt);
		p->group_leader = current->group_leader;
		list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
	}

	if (likely(p->pid)) {
		tracehook_finish_clone(p, clone_flags, trace);

		if (thread_group_leader(p)) {
			if (clone_flags & CLONE_NEWPID)
				p->nsproxy->pid_ns->child_reaper = p;

			p->signal->leader_pid = pid;
			p->signal->tty = tty_kref_get(current->signal->tty);
			attach_pid(p, PIDTYPE_PGID, task_pgrp(current));
			attach_pid(p, PIDTYPE_SID, task_session(current));
			list_add_tail(&p->sibling, &p->real_parent->children);
			list_add_tail_rcu(&p->tasks, &init_task.tasks);
			__this_cpu_inc(process_counts);
		}
		attach_pid(p, PIDTYPE_PID, pid);
		nr_threads++;
	}

	total_forks++;
	spin_unlock(&current->sighand->siglock);
	write_unlock_irq(&tasklist_lock);
	proc_fork_connector(p);
	cgroup_post_fork(p);
	perf_event_fork(p);
	return p;

bad_fork_free_pid:
	if (pid != &init_struct_pid)
		free_pid(pid);
bad_fork_cleanup_io:
	if (p->io_context)
		exit_io_context(p);
bad_fork_cleanup_namespaces:
	exit_task_namespaces(p);
bad_fork_cleanup_mm:
	if (p->mm) {
		task_lock(p);
		if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
			atomic_dec(&p->mm->oom_disable_count);
		task_unlock(p);
		mmput(p->mm);
	}
bad_fork_cleanup_signal:
	if (!(clone_flags & CLONE_THREAD))
		free_signal_struct(p->signal);
bad_fork_cleanup_sighand:
	__cleanup_sighand(p->sighand);
bad_fork_cleanup_fs:
	exit_fs(p); /* blocking */
bad_fork_cleanup_files:
	exit_files(p); /* blocking */
bad_fork_cleanup_semundo:
	exit_sem(p);
bad_fork_cleanup_audit:
	audit_free(p);
bad_fork_cleanup_policy:
	perf_event_free_task(p);
#ifdef CONFIG_NUMA
	mpol_put(p->mempolicy);
bad_fork_cleanup_cgroup:
#endif
	cgroup_exit(p, cgroup_callbacks_done);
	delayacct_tsk_free(p);
	module_put(task_thread_info(p)->exec_domain->module);
bad_fork_cleanup_count:
	atomic_dec(&p->cred->user->processes);
	exit_creds(p);
bad_fork_free:
	free_task(p);
fork_out:
	return ERR_PTR(retval);
}

noinline struct pt_regs * __cpuinit __attribute__((weak)) idle_regs(struct pt_regs *regs)
{
	memset(regs, 0, sizeof(struct pt_regs));
	return regs;
}

static inline void init_idle_pids(struct pid_link *links)
{
	enum pid_type type;

	for (type = PIDTYPE_PID; type < PIDTYPE_MAX; ++type) {
		INIT_HLIST_NODE(&links[type].node); /* not really needed */
		links[type].pid = &init_struct_pid;
	}
}

struct task_struct * __cpuinit fork_idle(int cpu)
{
	struct task_struct *task;
	struct pt_regs regs;

	task = copy_process(CLONE_VM, 0, idle_regs(&regs), 0, NULL,
			    &init_struct_pid, 0);
	if (!IS_ERR(task)) {
		init_idle_pids(task->pids);
		init_idle(task, cpu);
	}

	return task;
}

/*
 *  Ok, this is the main fork-routine.
 *
 * It copies the process, and if successful kick-starts
 * it and waits for it to finish using the VM if required.
 */
long do_fork(unsigned long clone_flags,
	      unsigned long stack_start,
	      struct pt_regs *regs,
	      unsigned long stack_size,
	      int __user *parent_tidptr,
	      int __user *child_tidptr)
{
	struct task_struct *p;
	int trace = 0;
	long nr;

	/*
	 * Do some preliminary argument and permissions checking before we
	 * actually start allocating stuff
	 */
	if (clone_flags & CLONE_NEWUSER) {
		if (clone_flags & CLONE_THREAD)
			return -EINVAL;
		/* hopefully this check will go away when userns support is
		 * complete
		 */
		if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) ||
				!capable(CAP_SETGID))
			return -EPERM;
	}

	/*
	 * When called from kernel_thread, don't do user tracing stuff.
	 */
	if (likely(user_mode(regs)))
		trace = tracehook_prepare_clone(clone_flags);

	p = copy_process(clone_flags, stack_start, regs, stack_size,
			 child_tidptr, NULL, trace);
	/*
	 * Do this prior waking up the new thread - the thread pointer
	 * might get invalid after that point, if the thread exits quickly.
	 */
	if (!IS_ERR(p)) {
		struct completion vfork;

		trace_sched_process_fork(current, p);

		nr = task_pid_vnr(p);

		if (clone_flags & CLONE_PARENT_SETTID)
			put_user(nr, parent_tidptr);

		if (clone_flags & CLONE_VFORK) {
			p->vfork_done = &vfork;
			init_completion(&vfork);
		}

		audit_finish_fork(p);
		tracehook_report_clone(regs, clone_flags, nr, p);

		/*
		 * We set PF_STARTING at creation in case tracing wants to
		 * use this to distinguish a fully live task from one that
		 * hasn't gotten to tracehook_report_clone() yet.  Now we
		 * clear it and set the child going.
		 */
		p->flags &= ~PF_STARTING;

		wake_up_new_task(p, clone_flags);

		tracehook_report_clone_complete(trace, regs,
						clone_flags, nr, p);

		if (clone_flags & CLONE_VFORK) {
			freezer_do_not_count();
			wait_for_completion(&vfork);
			freezer_count();
			tracehook_report_vfork_done(p, nr);
		}
	} else {
		nr = PTR_ERR(p);
	}
	return nr;
}

#ifndef ARCH_MIN_MMSTRUCT_ALIGN
#define ARCH_MIN_MMSTRUCT_ALIGN 0
#endif

static void sighand_ctor(void *data)
{
	struct sighand_struct *sighand = data;

	spin_lock_init(&sighand->siglock);
	init_waitqueue_head(&sighand->signalfd_wqh);
}

void __init proc_caches_init(void)
{
	sighand_cachep = kmem_cache_create("sighand_cache",
			sizeof(struct sighand_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_DESTROY_BY_RCU|
			SLAB_NOTRACK, sighand_ctor);
	signal_cachep = kmem_cache_create("signal_cache",
			sizeof(struct signal_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
	files_cachep = kmem_cache_create("files_cache",
			sizeof(struct files_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
	fs_cachep = kmem_cache_create("fs_cache",
			sizeof(struct fs_struct), 0,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
	mm_cachep = kmem_cache_create("mm_struct",
			sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
			SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
	vm_area_cachep = KMEM_CACHE(vm_area_struct, SLAB_PANIC);
	mmap_init();
}

/*
 * Check constraints on flags passed to the unshare system call and
 * force unsharing of additional process context as appropriate.
 */
static void check_unshare_flags(unsigned long *flags_ptr)
{
	/*
	 * If unsharing a thread from a thread group, must also
	 * unshare vm.
	 */
	if (*flags_ptr & CLONE_THREAD)
		*flags_ptr |= CLONE_VM;

	/*
	 * If unsharing vm, must also unshare signal handlers.
	 */
	if (*flags_ptr & CLONE_VM)
		*flags_ptr |= CLONE_SIGHAND;

	/*
	 * If unsharing namespace, must also unshare filesystem information.
	 */
	if (*flags_ptr & CLONE_NEWNS)
		*flags_ptr |= CLONE_FS;
}

/*
 * Unsharing of tasks created with CLONE_THREAD is not supported yet
 */
static int unshare_thread(unsigned long unshare_flags)
{
	if (unshare_flags & CLONE_THREAD)
		return -EINVAL;

	return 0;
}

/*
 * Unshare the filesystem structure if it is being shared
 */
static int unshare_fs(unsigned long unshare_flags, struct fs_struct **new_fsp)
{
	struct fs_struct *fs = current->fs;

	if (!(unshare_flags & CLONE_FS) || !fs)
		return 0;

	/* don't need lock here; in the worst case we'll do useless copy */
	if (fs->users == 1)
		return 0;

	*new_fsp = copy_fs_struct(fs);
	if (!*new_fsp)
		return -ENOMEM;

	return 0;
}

/*
 * Unsharing of sighand is not supported yet
 */
static int unshare_sighand(unsigned long unshare_flags, struct sighand_struct **new_sighp)
{
	struct sighand_struct *sigh = current->sighand;

	if ((unshare_flags & CLONE_SIGHAND) && atomic_read(&sigh->count) > 1)
		return -EINVAL;
	else
		return 0;
}

/*
 * Unshare vm if it is being shared
 */
static int unshare_vm(unsigned long unshare_flags, struct mm_struct **new_mmp)
{
	struct mm_struct *mm = current->mm;

	if ((unshare_flags & CLONE_VM) &&
	    (mm && atomic_read(&mm->mm_users) > 1)) {
		return -EINVAL;
	}

	return 0;
}

/*
 * Unshare file descriptor table if it is being shared
 */
static int unshare_fd(unsigned long unshare_flags, struct files_struct **new_fdp)
{
	struct files_struct *fd = current->files;
	int error = 0;

	if ((unshare_flags & CLONE_FILES) &&
	    (fd && atomic_read(&fd->count) > 1)) {
		*new_fdp = dup_fd(fd, &error);
		if (!*new_fdp)
			return error;
	}

	return 0;
}

/*
 * unshare allows a process to 'unshare' part of the process
 * context which was originally shared using clone.  copy_*
 * functions used by do_fork() cannot be used here directly
 * because they modify an inactive task_struct that is being
 * constructed. Here we are modifying the current, active,
 * task_struct.
 */
SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags)
{
	int err = 0;
	struct fs_struct *fs, *new_fs = NULL;
	struct sighand_struct *new_sigh = NULL;
	struct mm_struct *mm, *new_mm = NULL, *active_mm = NULL;
	struct files_struct *fd, *new_fd = NULL;
	struct nsproxy *new_nsproxy = NULL;
	int do_sysvsem = 0;

	check_unshare_flags(&unshare_flags);

	/* Return -EINVAL for all unsupported flags */
	err = -EINVAL;
	if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
				CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
				CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET))
		goto bad_unshare_out;

	/*
	 * CLONE_NEWIPC must also detach from the undolist: after switching
	 * to a new ipc namespace, the semaphore arrays from the old
	 * namespace are unreachable.
	 */
	if (unshare_flags & (CLONE_NEWIPC|CLONE_SYSVSEM))
		do_sysvsem = 1;
	if ((err = unshare_thread(unshare_flags)))
		goto bad_unshare_out;
	if ((err = unshare_fs(unshare_flags, &new_fs)))
		goto bad_unshare_cleanup_thread;
	if ((err = unshare_sighand(unshare_flags, &new_sigh)))
		goto bad_unshare_cleanup_fs;
	if ((err = unshare_vm(unshare_flags, &new_mm)))
		goto bad_unshare_cleanup_sigh;
	if ((err = unshare_fd(unshare_flags, &new_fd)))
		goto bad_unshare_cleanup_vm;
	if ((err = unshare_nsproxy_namespaces(unshare_flags, &new_nsproxy,
			new_fs)))
		goto bad_unshare_cleanup_fd;

	if (new_fs ||  new_mm || new_fd || do_sysvsem || new_nsproxy) {
		if (do_sysvsem) {
			/*
			 * CLONE_SYSVSEM is equivalent to sys_exit().
			 */
			exit_sem(current);
		}

		if (new_nsproxy) {
			switch_task_namespaces(current, new_nsproxy);
			new_nsproxy = NULL;
		}

		task_lock(current);

		if (new_fs) {
			fs = current->fs;
			spin_lock(&fs->lock);
			current->fs = new_fs;
			if (--fs->users)
				new_fs = NULL;
			else
				new_fs = fs;
			spin_unlock(&fs->lock);
		}

		if (new_mm) {
			mm = current->mm;
			active_mm = current->active_mm;
			current->mm = new_mm;
			current->active_mm = new_mm;
			if (current->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
				atomic_dec(&mm->oom_disable_count);
				atomic_inc(&new_mm->oom_disable_count);
			}
			activate_mm(active_mm, new_mm);
			new_mm = mm;
		}

		if (new_fd) {
			fd = current->files;
			current->files = new_fd;
			new_fd = fd;
		}

		task_unlock(current);
	}

	if (new_nsproxy)
		put_nsproxy(new_nsproxy);

bad_unshare_cleanup_fd:
	if (new_fd)
		put_files_struct(new_fd);

bad_unshare_cleanup_vm:
	if (new_mm)
		mmput(new_mm);

bad_unshare_cleanup_sigh:
	if (new_sigh)
		if (atomic_dec_and_test(&new_sigh->count))
			kmem_cache_free(sighand_cachep, new_sigh);

bad_unshare_cleanup_fs:
	if (new_fs)
		free_fs_struct(new_fs);

bad_unshare_cleanup_thread:
bad_unshare_out:
	return err;
}

/*
 *	Helper to unshare the files of the current task.
 *	We don't want to expose copy_files internals to
 *	the exec layer of the kernel.
 */

int unshare_files(struct files_struct **displaced)
{
	struct task_struct *task = current;
	struct files_struct *copy = NULL;
	int error;

	error = unshare_fd(CLONE_FILES, &copy);
	if (error || !copy) {
		*displaced = NULL;
		return error;
	}
	*displaced = task->files;
	task_lock(task);
	task->files = copy;
	task_unlock(task);
	return 0;
}