osf_sys.c

讲述linux的初始化过程

	down_read(&uts_sem);
	error = -EFAULT;
	if (copy_to_user(name + 0, system_utsname.sysname, 32))
		goto out;
	if (copy_to_user(name + 32, system_utsname.nodename, 32))
		goto out;
	if (copy_to_user(name + 64, system_utsname.release, 32))
		goto out;
	if (copy_to_user(name + 96, system_utsname.version, 32))
		goto out;
	if (copy_to_user(name + 128, system_utsname.machine, 32))
		goto out;

	error = 0;
out:
	up_read(&uts_sem);	
	return error;
}

asmlinkage int osf_swapon(const char *path, int flags, int lowat, int hiwat)
{
	int ret;

	/* for now, simply ignore lowat and hiwat... */
	lock_kernel();
	ret = sys_swapon(path, flags);
	unlock_kernel();
	return ret;
}

asmlinkage unsigned long sys_getpagesize(void)
{
	return PAGE_SIZE;
}

asmlinkage unsigned long sys_getdtablesize(void)
{
	return NR_OPEN;
}

asmlinkage int sys_pipe(int a0, int a1, int a2, int a3, int a4, int a5,
			struct pt_regs regs)
{
	int fd[2];
	int error;

	error = do_pipe(fd);
	if (error)
		goto out;
	(&regs)->r20 = fd[1];
	error = fd[0];
out:
	return error;
}

/*
 * For compatibility with OSF/1 only.  Use utsname(2) instead.
 */
asmlinkage int osf_getdomainname(char *name, int namelen)
{
	unsigned len;
	int i, error;

	error = verify_area(VERIFY_WRITE, name, namelen);
	if (error)
		goto out;

	len = namelen;
	if (namelen > 32)
		len = 32;

	down_read(&uts_sem);
	for (i = 0; i < len; ++i) {
		__put_user(system_utsname.domainname[i], name + i);
		if (system_utsname.domainname[i] == '\0')
			break;
	}
	up_read(&uts_sem);
out:
	return error;
}


asmlinkage long osf_shmat(int shmid, void *shmaddr, int shmflg)
{
	unsigned long raddr;
	long err;

	lock_kernel();
	err = sys_shmat(shmid, shmaddr, shmflg, &raddr);
	if (err)
		goto out;
	/*
	 * This works because all user-level addresses are
	 * non-negative longs!
	 */
	err = raddr;
out:
	unlock_kernel();
	return err;
}


/*
 * The following stuff should move into a header file should it ever
 * be labeled "officially supported."  Right now, there is just enough
 * support to avoid applications (such as tar) printing error
 * messages.  The attributes are not really implemented.
 */

/*
 * Values for Property list entry flag
 */
#define PLE_PROPAGATE_ON_COPY		0x1	/* cp(1) will copy entry
						   by default */
#define PLE_FLAG_MASK			0x1	/* Valid flag values */
#define PLE_FLAG_ALL			-1	/* All flag value */

struct proplistname_args {
	unsigned int pl_mask;
	unsigned int pl_numnames;
	char **pl_names;
};

union pl_args {
	struct setargs {
		char *path;
		long follow;
		long nbytes;
		char *buf;
	} set;
	struct fsetargs {
		long fd;
		long nbytes;
		char *buf;
	} fset;
	struct getargs {
		char *path;
		long follow;
		struct proplistname_args *name_args;
		long nbytes;
		char *buf;
		int *min_buf_size;
	} get;
	struct fgetargs {
		long fd;
		struct proplistname_args *name_args;
		long nbytes;
		char *buf;
		int *min_buf_size;
	} fget;
	struct delargs {
		char *path;
		long follow;
		struct proplistname_args *name_args;
	} del;
	struct fdelargs {
		long fd;
		struct proplistname_args *name_args;
	} fdel;
};

enum pl_code {
	PL_SET = 1, PL_FSET = 2,
	PL_GET = 3, PL_FGET = 4,
	PL_DEL = 5, PL_FDEL = 6
};

asmlinkage long osf_proplist_syscall(enum pl_code code, union pl_args *args)
{
	long error;
	int *min_buf_size_ptr;

	lock_kernel();
	switch (code) {
	case PL_SET:
		error = verify_area(VERIFY_READ, &args->set.nbytes,
				    sizeof(args->set.nbytes));
		if (!error)
			error = args->set.nbytes;
		break;
	case PL_FSET:
		error = verify_area(VERIFY_READ, &args->fset.nbytes,
				    sizeof(args->fset.nbytes));
		if (!error)
			error = args->fset.nbytes;
		break;
	case PL_GET:
		get_user(min_buf_size_ptr, &args->get.min_buf_size);
		error = verify_area(VERIFY_WRITE, min_buf_size_ptr,
				    sizeof(*min_buf_size_ptr));
		if (!error)
			put_user(0, min_buf_size_ptr);
		break;
	case PL_FGET:
		get_user(min_buf_size_ptr, &args->fget.min_buf_size);
		error = verify_area(VERIFY_WRITE, min_buf_size_ptr,
				    sizeof(*min_buf_size_ptr));
		if (!error)
			put_user(0, min_buf_size_ptr);
		break;
	case PL_DEL:
	case PL_FDEL:
		error = 0;
		break;
	default:
		error = -EOPNOTSUPP;
		break;
	};
	unlock_kernel();
	return error;
}

asmlinkage int osf_sigstack(struct sigstack *uss, struct sigstack *uoss)
{
	unsigned long usp = rdusp();
	unsigned long oss_sp = current->sas_ss_sp + current->sas_ss_size;
	unsigned long oss_os = on_sig_stack(usp);
	int error;

	if (uss) {
		void *ss_sp;

		error = -EFAULT;
		if (get_user(ss_sp, &uss->ss_sp))
			goto out;

		/* If the current stack was set with sigaltstack, don't
		   swap stacks while we are on it.  */
		error = -EPERM;
		if (current->sas_ss_sp && on_sig_stack(usp))
			goto out;

		/* Since we don't know the extent of the stack, and we don't
		   track onstack-ness, but rather calculate it, we must 
		   presume a size.  Ho hum this interface is lossy.  */
		current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
		current->sas_ss_size = SIGSTKSZ;
	}

	if (uoss) {
		error = -EFAULT;
		if (! access_ok(VERIFY_WRITE, uoss, sizeof(*uoss))
		    || __put_user(oss_sp, &uoss->ss_sp)
		    || __put_user(oss_os, &uoss->ss_onstack))
			goto out;
	}

	error = 0;
out:
	return error;
}

/*
 * The Linux kernel isn't good at returning values that look
 * like negative longs (they are mistaken as error values).
 * Until that is fixed, we need this little workaround for
 * create_module() because it's one of the few system calls
 * that return kernel addresses (which are negative).
 */
asmlinkage unsigned long alpha_create_module(char *module_name, unsigned long size,
					  int a3, int a4, int a5, int a6,
					     struct pt_regs regs)
{
	asmlinkage unsigned long sys_create_module(char *, unsigned long);
	long retval;

	lock_kernel();
	retval = sys_create_module(module_name, size);
	/*
	 * we get either a module address or an error number,
	 * and we know the error number is a small negative
	 * number, while the address is always negative but
	 * much larger.
	 */
	if (retval + 1000 > 0)
		goto out;

	/* tell entry.S:syscall_error that this is NOT an error: */
	regs.r0 = 0;
out:
	unlock_kernel();
	return retval;
}

asmlinkage long osf_sysinfo(int command, char *buf, long count)
{
	static char * sysinfo_table[] = {
		system_utsname.sysname,
		system_utsname.nodename,
		system_utsname.release,
		system_utsname.version,
		system_utsname.machine,
		"alpha",	/* instruction set architecture */
		"dummy",	/* hardware serial number */
		"dummy",	/* hardware manufacturer */
		"dummy",	/* secure RPC domain */
	};
	unsigned long offset;
	char *res;
	long len, err = -EINVAL;

	offset = command-1;
	if (offset >= sizeof(sysinfo_table)/sizeof(char *)) {
		/* Digital UNIX has a few unpublished interfaces here */
		printk("sysinfo(%d)", command);
		goto out;
	}
	
	down_read(&uts_sem);
	res = sysinfo_table[offset];
	len = strlen(res)+1;
	if (len > count)
		len = count;
	if (copy_to_user(buf, res, len))
		err = -EFAULT;
	else
		err = 0;
	up_read(&uts_sem);
out:
	return err;
}

asmlinkage unsigned long osf_getsysinfo(unsigned long op, void *buffer,
					unsigned long nbytes,
					int *start, void *arg)
{
	unsigned long w;
	struct percpu_struct *cpu;

	switch (op) {
	case GSI_IEEE_FP_CONTROL:
		/* Return current software fp control & status bits.  */
		/* Note that DU doesn't verify available space here.  */

 		w = current->thread.flags & IEEE_SW_MASK;
 		w = swcr_update_status(w, rdfpcr());
		if (put_user(w, (unsigned long *) buffer))
			return -EFAULT;
		return 0;

	case GSI_IEEE_STATE_AT_SIGNAL:
		/*
		 * Not sure anybody will ever use this weird stuff.  These
		 * ops can be used (under OSF/1) to set the fpcr that should
		 * be used when a signal handler starts executing.
		 */
		break;

 	case GSI_UACPROC:
		if (nbytes < sizeof(unsigned int))
			return -EINVAL;
 		w = (current->thread.flags >> UAC_SHIFT) & UAC_BITMASK;
 		if (put_user(w, (unsigned int *)buffer))
 			return -EFAULT;
 		return 1;

	case GSI_PROC_TYPE:
		if (nbytes < sizeof(unsigned long))
			return -EINVAL;
		cpu = (struct percpu_struct*)
		  ((char*)hwrpb + hwrpb->processor_offset);
		w = cpu->type;
		if (put_user(w, (unsigned long *)buffer))
			return -EFAULT;
		return 1;

	case GSI_GET_HWRPB:
		if (nbytes < sizeof(*hwrpb))
			return -EINVAL;
		if (copy_to_user(buffer, hwrpb, nbytes) != 0)
			return -EFAULT;
		return 1;

	default:
		break;
	}

	return -EOPNOTSUPP;
}

asmlinkage unsigned long osf_setsysinfo(unsigned long op, void *buffer,
					unsigned long nbytes,
					int *start, void *arg)
{
	switch (op) {
	case SSI_IEEE_FP_CONTROL: {
		unsigned long swcr, fpcr;

		/* 
		 * Alpha Architecture Handbook 4.7.7.3:
		 * To be fully IEEE compiant, we must track the current IEEE
		 * exception state in software, because spurrious bits can be
		 * set in the trap shadow of a software-complete insn.
		 */

		/* Update softare trap enable bits.  */
		if (get_user(swcr, (unsigned long *)buffer))
			return -EFAULT;
		current->thread.flags &= ~IEEE_SW_MASK;
		current->thread.flags |= swcr & IEEE_SW_MASK;

		/* Update the real fpcr.  */
		fpcr = rdfpcr();
		fpcr &= FPCR_DYN_MASK;
		fpcr |= ieee_swcr_to_fpcr(swcr);
		wrfpcr(fpcr);

 		/* If any exceptions are now unmasked, send a signal.  */
 		if (((swcr & IEEE_STATUS_MASK)
 		     >> IEEE_STATUS_TO_EXCSUM_SHIFT) & swcr) {
 			send_sig(SIGFPE, current, 1);
 		}

		return 0;
	}

	case SSI_IEEE_STATE_AT_SIGNAL:
	case SSI_IEEE_IGNORE_STATE_AT_SIGNAL:
		/*
		 * Not sure anybody will ever use this weird stuff.  These
		 * ops can be used (under OSF/1) to set the fpcr that should
		 * be used when a signal handler starts executing.
		 */
		break;

 	case SSI_NVPAIRS: {
		unsigned long v, w, i;
		
 		for (i = 0; i < nbytes; ++i) {
 			if (get_user(v, 2*i + (unsigned int *)buffer))
 				return -EFAULT;
 			if (get_user(w, 2*i + 1 + (unsigned int *)buffer))
 				return -EFAULT;
 			switch (v) {
 			case SSIN_UACPROC:
 				current->thread.flags &=
 					~(UAC_BITMASK << UAC_SHIFT);
 				current->thread.flags |=
 					(w & UAC_BITMASK) << UAC_SHIFT;