arch/mips/kernel/syscall.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
  * Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
  * Copyright (C) 2001 MIPS Technologies, Inc.
  */
 #include <linux/capability.h>
 #include <linux/errno.h>
 #include <linux/linkage.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/smp.h>
 #include <linux/mman.h>
 #include <linux/ptrace.h>
 #include <linux/sched.h>
 #include <linux/string.h>
 #include <linux/syscalls.h>
 #include <linux/file.h>
 #include <linux/slab.h>
 #include <linux/utsname.h>
 #include <linux/unistd.h>
 #include <linux/sem.h>
 #include <linux/msg.h>
 #include <linux/shm.h>
 #include <linux/compiler.h>
 #include <linux/module.h>
 #include <linux/ipc.h>
 #include <linux/uaccess.h>

 #include <asm/asm.h>
 #include <asm/branch.h>
 #include <asm/cachectl.h>
 #include <asm/cacheflush.h>
 #include <asm/asm-offsets.h>
 #include <asm/signal.h>
 #include <asm/sim.h>
 #include <asm/shmparam.h>
 #include <asm/sysmips.h>
 #include <asm/uaccess.h>

 /*
  * For historic reasons the pipe(2) syscall on MIPS has an unusual calling
  * convention.  It returns results in registers $v0 / $v1 which means there
  * is no need for it to do verify the validity of a userspace pointer
  * argument.  Historically that used to be expensive in Linux.  These days
  * the performance advantage is negligible.
  */
 asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
 {
 	int fd[2];
 	int error, res;

 	error = do_pipe_flags(fd, 0);
 	if (error) {
 		res = error;
 		goto out;
 	}
 	regs.regs[3] = fd[1];
 	res = fd[0];
 out:
 	return res;
 }

 unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */

 EXPORT_SYMBOL(shm_align_mask);

 #define COLOUR_ALIGN(addr,pgoff)				\
 	((((addr) + shm_align_mask) & ~shm_align_mask) +	\
 	 (((pgoff) << PAGE_SHIFT) & shm_align_mask))

 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	unsigned long len, unsigned long pgoff, unsigned long flags)
 {
 	struct vm_area_struct * vmm;
 	int do_color_align;
 	unsigned long task_size;

 	task_size = STACK_TOP;

 	if (len > task_size)
 		return -ENOMEM;

 	if (flags & MAP_FIXED) {
 		/* Even MAP_FIXED mappings must reside within task_size.  */
 		if (task_size - len < addr)
 			return -EINVAL;

 		/*
 		 * We do not accept a shared mapping if it would violate
 		 * cache aliasing constraints.
 		 */
 		if ((flags & MAP_SHARED) &&
 		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
 			return -EINVAL;
 		return addr;
 	}

 	do_color_align = 0;
 	if (filp || (flags & MAP_SHARED))
 		do_color_align = 1;
 	if (addr) {
 		if (do_color_align)
 			addr = COLOUR_ALIGN(addr, pgoff);
 		else
 			addr = PAGE_ALIGN(addr);
 		vmm = find_vma(current->mm, addr);
 		if (task_size - len >= addr &&
 		    (!vmm || addr + len <= vmm->vm_start))
 			return addr;
 	}
 	addr = TASK_UNMAPPED_BASE;
 	if (do_color_align)
 		addr = COLOUR_ALIGN(addr, pgoff);
 	else
 		addr = PAGE_ALIGN(addr);

 	for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
 		/* At this point:  (!vmm || addr < vmm->vm_end). */
 		if (task_size - len < addr)
 			return -ENOMEM;
 		if (!vmm || addr + len <= vmm->vm_start)
 			return addr;
 		addr = vmm->vm_end;
 		if (do_color_align)
 			addr = COLOUR_ALIGN(addr, pgoff);
 	}
 }

 SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags, unsigned long,
 	fd, off_t, offset)
 {
 	unsigned long result;

 	result = -EINVAL;
 	if (offset & ~PAGE_MASK)
 		goto out;

 	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);

 out:
 	return result;
 }

 SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
 	unsigned long, prot, unsigned long, flags, unsigned long, fd,
 	unsigned long, pgoff)
 {
 	if (pgoff & (~PAGE_MASK >> 12))
 		return -EINVAL;

 	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
 }

 save_static_function(sys_fork);
 static int __used noinline
 _sys_fork(nabi_no_regargs struct pt_regs regs)
 {
 	return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
 }

 save_static_function(sys_clone);
 static int __used noinline
 _sys_clone(nabi_no_regargs struct pt_regs regs)
 {
 	unsigned long clone_flags;
 	unsigned long newsp;
 	int __user *parent_tidptr, *child_tidptr;

 	clone_flags = regs.regs[4];
 	newsp = regs.regs[5];
 	if (!newsp)
 		newsp = regs.regs[29];
 	parent_tidptr = (int __user *) regs.regs[6];
 #ifdef CONFIG_32BIT
 	/* We need to fetch the fifth argument off the stack.  */
 	child_tidptr = NULL;
 	if (clone_flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) {
 		int __user *__user *usp = (int __user *__user *) regs.regs[29];
 		if (regs.regs[2] == __NR_syscall) {
 			if (get_user (child_tidptr, &usp[5]))
 				return -EFAULT;
 		}
 		else if (get_user (child_tidptr, &usp[4]))
 			return -EFAULT;
 	}
 #else
 	child_tidptr = (int __user *) regs.regs[8];
 #endif
 	return do_fork(clone_flags, newsp, &regs, 0,
 	               parent_tidptr, child_tidptr);
 }

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

 	filename = getname((char __user *) (long)regs.regs[4]);
 	error = PTR_ERR(filename);
 	if (IS_ERR(filename))
 		goto out;
 	error = do_execve(filename, (char __user *__user *) (long)regs.regs[5],
 	                  (char __user *__user *) (long)regs.regs[6], &regs);
 	putname(filename);

 out:
 	return error;
 }

 SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
 {
 	struct thread_info *ti = task_thread_info(current);

 	ti->tp_value = addr;
 	if (cpu_has_userlocal)
 		write_c0_userlocal(addr);

 	return 0;
 }

 static inline int mips_atomic_set(struct pt_regs *regs,
 	unsigned long addr, unsigned long new)
 {
 	unsigned long old, tmp;
 	unsigned int err;

 	if (unlikely(addr & 3))
 		return -EINVAL;

 	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
 		return -EINVAL;

 	if (cpu_has_llsc && R10000_LLSC_WAR) {
 		__asm__ __volatile__ (
 		"	.set	mips3					\n"
 		"	li	%[err], 0				\n"
 		"1:	ll	%[old], (%[addr])			\n"
 		"	move	%[tmp], %[new]				\n"
 		"2:	sc	%[tmp], (%[addr])			\n"
 		"	beqzl	%[tmp], 1b				\n"
 		"3:							\n"
 		"	.section .fixup,\"ax\"				\n"
 		"4:	li	%[err], %[efault]			\n"
 		"	j	3b					\n"
 		"	.previous					\n"
 		"	.section __ex_table,\"a\"			\n"
 		"	"STR(PTR)"	1b, 4b				\n"
 		"	"STR(PTR)"	2b, 4b				\n"
 		"	.previous					\n"
 		"	.set	mips0					\n"
 		: [old] "=&r" (old),
 		  [err] "=&r" (err),
 		  [tmp] "=&r" (tmp)
 		: [addr] "r" (addr),
 		  [new] "r" (new),
 		  [efault] "i" (-EFAULT)
 		: "memory");
 	} else if (cpu_has_llsc) {
 		__asm__ __volatile__ (
 		"	.set	mips3					\n"
 		"	li	%[err], 0				\n"
 		"1:	ll	%[old], (%[addr])			\n"
 		"	move	%[tmp], %[new]				\n"
 		"2:	sc	%[tmp], (%[addr])			\n"
 		"	bnez	%[tmp], 4f				\n"
 		"3:							\n"
 		"	.subsection 2					\n"
 		"4:	b	1b					\n"
 		"	.previous					\n"
 		"							\n"
 		"	.section .fixup,\"ax\"				\n"
 		"5:	li	%[err], %[efault]			\n"
 		"	j	3b					\n"
 		"	.previous					\n"
 		"	.section __ex_table,\"a\"			\n"
 		"	"STR(PTR)"	1b, 5b				\n"
 		"	"STR(PTR)"	2b, 5b				\n"
 		"	.previous					\n"
 		"	.set	mips0					\n"
 		: [old] "=&r" (old),
 		  [err] "=&r" (err),
 		  [tmp] "=&r" (tmp)
 		: [addr] "r" (addr),
 		  [new] "r" (new),
 		  [efault] "i" (-EFAULT)
 		: "memory");
 	} else {
 		do {
 			preempt_disable();
 			ll_bit = 1;
 			ll_task = current;
 			preempt_enable();

 			err = __get_user(old, (unsigned int *) addr);
 			err |= __put_user(new, (unsigned int *) addr);
 			if (err)
 				break;
 			rmb();
 		} while (!ll_bit);
 	}

 	if (unlikely(err))
 		return err;

 	regs->regs[2] = old;
 	regs->regs[7] = 0;	/* No error */

 	/*
 	 * Don't let your children do this ...
 	 */
 	__asm__ __volatile__(
 	"	move	$29, %0						\n"
 	"	j	syscall_exit					\n"
 	: /* no outputs */
 	: "r" (regs));

 	/* unreached.  Honestly.  */
 	while (1);
 }

 save_static_function(sys_sysmips);
 static int __used noinline
 _sys_sysmips(nabi_no_regargs struct pt_regs regs)
 {
 	long cmd, arg1, arg2, arg3;

 	cmd = regs.regs[4];
 	arg1 = regs.regs[5];
 	arg2 = regs.regs[6];
 	arg3 = regs.regs[7];

 	switch (cmd) {
 	case MIPS_ATOMIC_SET:
 		return mips_atomic_set(&regs, arg1, arg2);

 	case MIPS_FIXADE:
 		if (arg1 & ~3)
 			return -EINVAL;

 		if (arg1 & 1)
 			set_thread_flag(TIF_FIXADE);
 		else
 			clear_thread_flag(TIF_FIXADE);
 		if (arg1 & 2)
 			set_thread_flag(TIF_LOGADE);
 		else
 			clear_thread_flag(TIF_FIXADE);

 		return 0;

 	case FLUSH_CACHE:
 		__flush_cache_all();
 		return 0;
 	}

 	return -EINVAL;
 }

 /*
  * No implemented yet ...
  */
 SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
 {
 	return -ENOSYS;
 }

 /*
  * If we ever come here the user sp is bad.  Zap the process right away.
  * Due to the bad stack signaling wouldn't work.
  */
 asmlinkage void bad_stack(void)
 {
 	do_exit(SIGSEGV);
 }

 /*
  * Do a system call from kernel instead of calling sys_execve so we
  * end up with proper pt_regs.
  */
 int kernel_execve(const char *filename, char *const argv[], char *const envp[])
 {
 	register unsigned long __a0 asm("$4") = (unsigned long) filename;
 	register unsigned long __a1 asm("$5") = (unsigned long) argv;
 	register unsigned long __a2 asm("$6") = (unsigned long) envp;
 	register unsigned long __a3 asm("$7");
 	unsigned long __v0;

 	__asm__ volatile ("					\n"
 	"	.set	noreorder				\n"
 	"	li	$2, %5		# __NR_execve		\n"
 	"	syscall						\n"
 	"	move	%0, $2					\n"
 	"	.set	reorder					\n"
 	: "=&r" (__v0), "=r" (__a3)
 	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
 	: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
 	  "memory");

 	if (__a3 == 0)
 		return __v0;

 	return -__v0;
 }
	/*
	* This file is subject to the terms and conditions of the GNU General Public
	* License. See the file "COPYING" in the main directory of this archive
	* for more details.
	*
	* Copyright (C) 1995, 1996, 1997, 2000, 2001, 05 by Ralf Baechle
	* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
	* Copyright (C) 2001 MIPS Technologies, Inc.
	*/
	#include <linux/capability.h>
	#include <linux/errno.h>
	#include <linux/linkage.h>
	#include <linux/mm.h>
	#include <linux/fs.h>
	#include <linux/smp.h>
	#include <linux/mman.h>
	#include <linux/ptrace.h>
	#include <linux/sched.h>
	#include <linux/string.h>
	#include <linux/syscalls.h>
	#include <linux/file.h>
	#include <linux/slab.h>
	#include <linux/utsname.h>
	#include <linux/unistd.h>
	#include <linux/sem.h>
	#include <linux/msg.h>
	#include <linux/shm.h>
	#include <linux/compiler.h>
	#include <linux/module.h>
	#include <linux/ipc.h>
	#include <linux/uaccess.h>

	#include <asm/asm.h>
	#include <asm/branch.h>
	#include <asm/cachectl.h>
	#include <asm/cacheflush.h>
	#include <asm/asm-offsets.h>
	#include <asm/signal.h>
	#include <asm/sim.h>
	#include <asm/shmparam.h>
	#include <asm/sysmips.h>
	#include <asm/uaccess.h>

	/*
	* For historic reasons the pipe(2) syscall on MIPS has an unusual calling
	* convention. It returns results in registers $v0 / $v1 which means there
	* is no need for it to do verify the validity of a userspace pointer
	* argument. Historically that used to be expensive in Linux. These days
	* the performance advantage is negligible.
	*/
	asmlinkage int sysm_pipe(nabi_no_regargs volatile struct pt_regs regs)
	{
	int fd[2];
	int error, res;

	error = do_pipe_flags(fd, 0);
	if (error) {
	res = error;
	goto out;
	}
	regs.regs[3] = fd[1];
	res = fd[0];
	out:
	return res;
	}

	unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */

	EXPORT_SYMBOL(shm_align_mask);

	#define COLOUR_ALIGN(addr,pgoff) \
	((((addr) + shm_align_mask) & ~shm_align_mask) + \
	(((pgoff) << PAGE_SHIFT) & shm_align_mask))

	unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
	unsigned long len, unsigned long pgoff, unsigned long flags)
	{
	struct vm_area_struct * vmm;
	int do_color_align;
	unsigned long task_size;

	task_size = STACK_TOP;

	if (len > task_size)
	return -ENOMEM;

	if (flags & MAP_FIXED) {
	/* Even MAP_FIXED mappings must reside within task_size. */
	if (task_size - len < addr)
	return -EINVAL;

	/*
	* We do not accept a shared mapping if it would violate
	* cache aliasing constraints.
	*/
	if ((flags & MAP_SHARED) &&
	((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
	return -EINVAL;
	return addr;
	}

	do_color_align = 0;
	if (filp \|\| (flags & MAP_SHARED))
	do_color_align = 1;
	if (addr) {
	if (do_color_align)
	addr = COLOUR_ALIGN(addr, pgoff);
	else
	addr = PAGE_ALIGN(addr);
	vmm = find_vma(current->mm, addr);
	if (task_size - len >= addr &&
	(!vmm \|\| addr + len <= vmm->vm_start))
	return addr;
	}
	addr = TASK_UNMAPPED_BASE;
	if (do_color_align)
	addr = COLOUR_ALIGN(addr, pgoff);
	else
	addr = PAGE_ALIGN(addr);

	for (vmm = find_vma(current->mm, addr); ; vmm = vmm->vm_next) {
	/* At this point: (!vmm \|\| addr < vmm->vm_end). */
	if (task_size - len < addr)
	return -ENOMEM;
	if (!vmm \|\| addr + len <= vmm->vm_start)
	return addr;
	addr = vmm->vm_end;
	if (do_color_align)
	addr = COLOUR_ALIGN(addr, pgoff);
	}
	}

	SYSCALL_DEFINE6(mips_mmap, unsigned long, addr, unsigned long, len,
	unsigned long, prot, unsigned long, flags, unsigned long,
	fd, off_t, offset)
	{
	unsigned long result;

	result = -EINVAL;
	if (offset & ~PAGE_MASK)
	goto out;

	result = sys_mmap_pgoff(addr, len, prot, flags, fd, offset >> PAGE_SHIFT);

	out:
	return result;
	}

	SYSCALL_DEFINE6(mips_mmap2, unsigned long, addr, unsigned long, len,
	unsigned long, prot, unsigned long, flags, unsigned long, fd,
	unsigned long, pgoff)
	{
	if (pgoff & (~PAGE_MASK >> 12))
	return -EINVAL;

	return sys_mmap_pgoff(addr, len, prot, flags, fd, pgoff >> (PAGE_SHIFT-12));
	}

	save_static_function(sys_fork);
	static int __used noinline
	_sys_fork(nabi_no_regargs struct pt_regs regs)
	{
	return do_fork(SIGCHLD, regs.regs[29], &regs, 0, NULL, NULL);
	}

	save_static_function(sys_clone);
	static int __used noinline
	_sys_clone(nabi_no_regargs struct pt_regs regs)
	{
	unsigned long clone_flags;
	unsigned long newsp;
	int __user parent_tidptr, child_tidptr;

	clone_flags = regs.regs[4];
	newsp = regs.regs[5];
	if (!newsp)
	newsp = regs.regs[29];
	parent_tidptr = (int __user *) regs.regs[6];
	#ifdef CONFIG_32BIT
	/* We need to fetch the fifth argument off the stack. */
	child_tidptr = NULL;
	if (clone_flags & (CLONE_CHILD_SETTID \| CLONE_CHILD_CLEARTID)) {
	int __user __user usp = (int __user __user ) regs.regs[29];
	if (regs.regs[2] == __NR_syscall) {
	if (get_user (child_tidptr, &usp[5]))
	return -EFAULT;
	}
	else if (get_user (child_tidptr, &usp[4]))
	return -EFAULT;
	}
	#else
	child_tidptr = (int __user *) regs.regs[8];
	#endif
	return do_fork(clone_flags, newsp, &regs, 0,
	parent_tidptr, child_tidptr);
	}

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

	filename = getname((char __user *) (long)regs.regs[4]);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
	goto out;
	error = do_execve(filename, (char __user __user ) (long)regs.regs[5],
	(char __user __user ) (long)regs.regs[6], &regs);
	putname(filename);

	out:
	return error;
	}

	SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
	{
	struct thread_info *ti = task_thread_info(current);

	ti->tp_value = addr;
	if (cpu_has_userlocal)
	write_c0_userlocal(addr);

	return 0;
	}

	static inline int mips_atomic_set(struct pt_regs *regs,
	unsigned long addr, unsigned long new)
	{
	unsigned long old, tmp;
	unsigned int err;

	if (unlikely(addr & 3))
	return -EINVAL;

	if (unlikely(!access_ok(VERIFY_WRITE, addr, 4)))
	return -EINVAL;

	if (cpu_has_llsc && R10000_LLSC_WAR) {
	__asm__ __volatile__ (
	" .set mips3 \n"
	" li %[err], 0 \n"
	"1: ll %[old], (%[addr]) \n"
	" move %[tmp], %[new] \n"
	"2: sc %[tmp], (%[addr]) \n"
	" beqzl %[tmp], 1b \n"
	"3: \n"
	" .section .fixup,\"ax\" \n"
	"4: li %[err], %[efault] \n"
	" j 3b \n"
	" .previous \n"
	" .section __ex_table,\"a\" \n"
	" "STR(PTR)" 1b, 4b \n"
	" "STR(PTR)" 2b, 4b \n"
	" .previous \n"
	" .set mips0 \n"
	: [old] "=&r" (old),
	[err] "=&r" (err),
	[tmp] "=&r" (tmp)
	: [addr] "r" (addr),
	[new] "r" (new),
	[efault] "i" (-EFAULT)
	: "memory");
	} else if (cpu_has_llsc) {
	__asm__ __volatile__ (
	" .set mips3 \n"
	" li %[err], 0 \n"
	"1: ll %[old], (%[addr]) \n"
	" move %[tmp], %[new] \n"
	"2: sc %[tmp], (%[addr]) \n"
	" bnez %[tmp], 4f \n"
	"3: \n"
	" .subsection 2 \n"
	"4: b 1b \n"
	" .previous \n"
	" \n"
	" .section .fixup,\"ax\" \n"
	"5: li %[err], %[efault] \n"
	" j 3b \n"
	" .previous \n"
	" .section __ex_table,\"a\" \n"
	" "STR(PTR)" 1b, 5b \n"
	" "STR(PTR)" 2b, 5b \n"
	" .previous \n"
	" .set mips0 \n"
	: [old] "=&r" (old),
	[err] "=&r" (err),
	[tmp] "=&r" (tmp)
	: [addr] "r" (addr),
	[new] "r" (new),
	[efault] "i" (-EFAULT)
	: "memory");
	} else {
	do {
	preempt_disable();
	ll_bit = 1;
	ll_task = current;
	preempt_enable();

	err = __get_user(old, (unsigned int *) addr);
	err \|= __put_user(new, (unsigned int *) addr);
	if (err)
	break;
	rmb();
	} while (!ll_bit);
	}

	if (unlikely(err))
	return err;

	regs->regs[2] = old;
	regs->regs[7] = 0; /* No error */

	/*
	* Don't let your children do this ...
	*/
	__asm__ __volatile__(
	" move $29, %0 \n"
	" j syscall_exit \n"
	: /* no outputs */
	: "r" (regs));

	/* unreached. Honestly. */
	while (1);
	}

	save_static_function(sys_sysmips);
	static int __used noinline
	_sys_sysmips(nabi_no_regargs struct pt_regs regs)
	{
	long cmd, arg1, arg2, arg3;

	cmd = regs.regs[4];
	arg1 = regs.regs[5];
	arg2 = regs.regs[6];
	arg3 = regs.regs[7];

	switch (cmd) {
	case MIPS_ATOMIC_SET:
	return mips_atomic_set(&regs, arg1, arg2);

	case MIPS_FIXADE:
	if (arg1 & ~3)
	return -EINVAL;

	if (arg1 & 1)
	set_thread_flag(TIF_FIXADE);
	else
	clear_thread_flag(TIF_FIXADE);
	if (arg1 & 2)
	set_thread_flag(TIF_LOGADE);
	else
	clear_thread_flag(TIF_FIXADE);

	return 0;

	case FLUSH_CACHE:
	__flush_cache_all();
	return 0;
	}

	return -EINVAL;
	}

	/*
	* No implemented yet ...
	*/
	SYSCALL_DEFINE3(cachectl, char *, addr, int, nbytes, int, op)
	{
	return -ENOSYS;
	}

	/*
	* If we ever come here the user sp is bad. Zap the process right away.
	* Due to the bad stack signaling wouldn't work.
	*/
	asmlinkage void bad_stack(void)
	{
	do_exit(SIGSEGV);
	}

	/*
	* Do a system call from kernel instead of calling sys_execve so we
	* end up with proper pt_regs.
	*/
	int kernel_execve(const char filename, char const argv[], char *const envp[])
	{
	register unsigned long __a0 asm("$4") = (unsigned long) filename;
	register unsigned long __a1 asm("$5") = (unsigned long) argv;
	register unsigned long __a2 asm("$6") = (unsigned long) envp;
	register unsigned long __a3 asm("$7");
	unsigned long __v0;

	__asm__ volatile (" \n"
	" .set noreorder \n"
	" li $2, %5 # __NR_execve \n"
	" syscall \n"
	" move %0, $2 \n"
	" .set reorder \n"
	: "=&r" (__v0), "=r" (__a3)
	: "r" (__a0), "r" (__a1), "r" (__a2), "i" (__NR_execve)
	: "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",
	"memory");

	if (__a3 == 0)
	return __v0;

	return -__v0;
	}