drivers/char/mspec.c - maze/linux - Git at Google

 /*
  * Copyright (C) 2001-2006 Silicon Graphics, Inc.  All rights
  * reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of version 2 of the GNU General Public License
  * as published by the Free Software Foundation.
  */

 /*
  * SN Platform Special Memory (mspec) Support
  *
  * This driver exports the SN special memory (mspec) facility to user
  * processes.
  * There are three types of memory made available thru this driver:
  * fetchops, uncached and cached.
  *
  * Fetchops are atomic memory operations that are implemented in the
  * memory controller on SGI SN hardware.
  *
  * Uncached are used for memory write combining feature of the ia64
  * cpu.
  *
  * Cached are used for areas of memory that are used as cached addresses
  * on our partition and used as uncached addresses from other partitions.
  * Due to a design constraint of the SN2 Shub, you can not have processors
  * on the same FSB perform both a cached and uncached reference to the
  * same cache line.  These special memory cached regions prevent the
  * kernel from ever dropping in a TLB entry and therefore prevent the
  * processor from ever speculating a cache line from this page.
  */

 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/miscdevice.h>
 #include <linux/spinlock.h>
 #include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/vmalloc.h>
 #include <linux/string.h>
 #include <linux/slab.h>
 #include <linux/numa.h>
 #include <asm/page.h>
 #include <asm/system.h>
 #include <asm/pgtable.h>
 #include <asm/atomic.h>
 #include <asm/tlbflush.h>
 #include <asm/uncached.h>
 #include <asm/sn/addrs.h>
 #include <asm/sn/arch.h>
 #include <asm/sn/mspec.h>
 #include <asm/sn/sn_cpuid.h>
 #include <asm/sn/io.h>
 #include <asm/sn/bte.h>
 #include <asm/sn/shubio.h>


 #define FETCHOP_ID	"SGI Fetchop,"
 #define CACHED_ID	"Cached,"
 #define UNCACHED_ID	"Uncached"
 #define REVISION	"4.0"
 #define MSPEC_BASENAME	"mspec"

 /*
  * Page types allocated by the device.
  */
 enum mspec_page_type {
 	MSPEC_FETCHOP = 1,
 	MSPEC_CACHED,
 	MSPEC_UNCACHED
 };

 #ifdef CONFIG_SGI_SN
 static int is_sn2;
 #else
 #define is_sn2		0
 #endif

 /*
  * One of these structures is allocated when an mspec region is mmaped. The
  * structure is pointed to by the vma->vm_private_data field in the vma struct.
  * This structure is used to record the addresses of the mspec pages.
  * This structure is shared by all vma's that are split off from the
  * original vma when split_vma()'s are done.
  *
  * The refcnt is incremented atomically because mm->mmap_sem does not
  * protect in fork case where multiple tasks share the vma_data.
  */
 struct vma_data {
 	atomic_t refcnt;	/* Number of vmas sharing the data. */
 	spinlock_t lock;	/* Serialize access to this structure. */
 	int count;		/* Number of pages allocated. */
 	enum mspec_page_type type; /* Type of pages allocated. */
 	int flags;		/* See VMD_xxx below. */
 	unsigned long vm_start;	/* Original (unsplit) base. */
 	unsigned long vm_end;	/* Original (unsplit) end. */
 	unsigned long maddr[0];	/* Array of MSPEC addresses. */
 };

 #define VMD_VMALLOCED 0x1	/* vmalloc'd rather than kmalloc'd */

 /* used on shub2 to clear FOP cache in the HUB */
 static unsigned long scratch_page[MAX_NUMNODES];
 #define SH2_AMO_CACHE_ENTRIES	4

 static inline int
 mspec_zero_block(unsigned long addr, int len)
 {
 	int status;

 	if (is_sn2) {
 		if (is_shub2()) {
 			int nid;
 			void *p;
 			int i;

 			nid = nasid_to_cnodeid(get_node_number(__pa(addr)));
 			p = (void *)TO_AMO(scratch_page[nid]);

 			for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) {
 				FETCHOP_LOAD_OP(p, FETCHOP_LOAD);
 				p += FETCHOP_VAR_SIZE;
 			}
 		}

 		status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len,
 				  BTE_WACQUIRE | BTE_ZERO_FILL, NULL);
 	} else {
 		memset((char *) addr, 0, len);
 		status = 0;
 	}
 	return status;
 }

 /*
  * mspec_open
  *
  * Called when a device mapping is created by a means other than mmap
  * (via fork, munmap, etc.).  Increments the reference count on the
  * underlying mspec data so it is not freed prematurely.
  */
 static void
 mspec_open(struct vm_area_struct *vma)
 {
 	struct vma_data *vdata;

 	vdata = vma->vm_private_data;
 	atomic_inc(&vdata->refcnt);
 }

 /*
  * mspec_close
  *
  * Called when unmapping a device mapping. Frees all mspec pages
  * belonging to all the vma's sharing this vma_data structure.
  */
 static void
 mspec_close(struct vm_area_struct *vma)
 {
 	struct vma_data *vdata;
 	int index, last_index;
 	unsigned long my_page;

 	vdata = vma->vm_private_data;

 	if (!atomic_dec_and_test(&vdata->refcnt))
 		return;

 	last_index = (vdata->vm_end - vdata->vm_start) >> PAGE_SHIFT;
 	for (index = 0; index < last_index; index++) {
 		if (vdata->maddr[index] == 0)
 			continue;
 		/*
 		 * Clear the page before sticking it back
 		 * into the pool.
 		 */
 		my_page = vdata->maddr[index];
 		vdata->maddr[index] = 0;
 		if (!mspec_zero_block(my_page, PAGE_SIZE))
 			uncached_free_page(my_page, 1);
 		else
 			printk(KERN_WARNING "mspec_close(): "
 			       "failed to zero page %ld\n", my_page);
 	}

 	if (vdata->flags & VMD_VMALLOCED)
 		vfree(vdata);
 	else
 		kfree(vdata);
 }

 /*
  * mspec_fault
  *
  * Creates a mspec page and maps it to user space.
  */
 static int
 mspec_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
 	unsigned long paddr, maddr;
 	unsigned long pfn;
 	pgoff_t index = vmf->pgoff;
 	struct vma_data *vdata = vma->vm_private_data;

 	maddr = (volatile unsigned long) vdata->maddr[index];
 	if (maddr == 0) {
 		maddr = uncached_alloc_page(numa_node_id(), 1);
 		if (maddr == 0)
 			return VM_FAULT_OOM;

 		spin_lock(&vdata->lock);
 		if (vdata->maddr[index] == 0) {
 			vdata->count++;
 			vdata->maddr[index] = maddr;
 		} else {
 			uncached_free_page(maddr, 1);
 			maddr = vdata->maddr[index];
 		}
 		spin_unlock(&vdata->lock);
 	}

 	if (vdata->type == MSPEC_FETCHOP)
 		paddr = TO_AMO(maddr);
 	else
 		paddr = maddr & ~__IA64_UNCACHED_OFFSET;

 	pfn = paddr >> PAGE_SHIFT;

 	/*
 	 * vm_insert_pfn can fail with -EBUSY, but in that case it will
 	 * be because another thread has installed the pte first, so it
 	 * is no problem.
 	 */
 	vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);

 	return VM_FAULT_NOPAGE;
 }

 static struct vm_operations_struct mspec_vm_ops = {
 	.open = mspec_open,
 	.close = mspec_close,
 	.fault = mspec_fault,
 };

 /*
  * mspec_mmap
  *
  * Called when mmaping the device.  Initializes the vma with a fault handler
  * and private data structure necessary to allocate, track, and free the
  * underlying pages.
  */
 static int
 mspec_mmap(struct file *file, struct vm_area_struct *vma,
 					enum mspec_page_type type)
 {
 	struct vma_data *vdata;
 	int pages, vdata_size, flags = 0;

 	if (vma->vm_pgoff != 0)
 		return -EINVAL;

 	if ((vma->vm_flags & VM_SHARED) == 0)
 		return -EINVAL;

 	if ((vma->vm_flags & VM_WRITE) == 0)
 		return -EPERM;

 	pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
 	vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
 	if (vdata_size <= PAGE_SIZE)
 		vdata = kmalloc(vdata_size, GFP_KERNEL);
 	else {
 		vdata = vmalloc(vdata_size);
 		flags = VMD_VMALLOCED;
 	}
 	if (!vdata)
 		return -ENOMEM;
 	memset(vdata, 0, vdata_size);

 	vdata->vm_start = vma->vm_start;
 	vdata->vm_end = vma->vm_end;
 	vdata->flags = flags;
 	vdata->type = type;
 	spin_lock_init(&vdata->lock);
 	vdata->refcnt = ATOMIC_INIT(1);
 	vma->vm_private_data = vdata;

 	vma->vm_flags |= (VM_IO | VM_RESERVED | VM_PFNMAP | VM_DONTEXPAND);
 	if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED)
 		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	vma->vm_ops = &mspec_vm_ops;

 	return 0;
 }

 static int
 fetchop_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	return mspec_mmap(file, vma, MSPEC_FETCHOP);
 }

 static int
 cached_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	return mspec_mmap(file, vma, MSPEC_CACHED);
 }

 static int
 uncached_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	return mspec_mmap(file, vma, MSPEC_UNCACHED);
 }

 static const struct file_operations fetchop_fops = {
 	.owner = THIS_MODULE,
 	.mmap = fetchop_mmap
 };

 static struct miscdevice fetchop_miscdev = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "sgi_fetchop",
 	.fops = &fetchop_fops
 };

 static const struct file_operations cached_fops = {
 	.owner = THIS_MODULE,
 	.mmap = cached_mmap
 };

 static struct miscdevice cached_miscdev = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "mspec_cached",
 	.fops = &cached_fops
 };

 static const struct file_operations uncached_fops = {
 	.owner = THIS_MODULE,
 	.mmap = uncached_mmap
 };

 static struct miscdevice uncached_miscdev = {
 	.minor = MISC_DYNAMIC_MINOR,
 	.name = "mspec_uncached",
 	.fops = &uncached_fops
 };

 /*
  * mspec_init
  *
  * Called at boot time to initialize the mspec facility.
  */
 static int __init
 mspec_init(void)
 {
 	int ret;
 	int nid;

 	/*
 	 * The fetchop device only works on SN2 hardware, uncached and cached
 	 * memory drivers should both be valid on all ia64 hardware
 	 */
 #ifdef CONFIG_SGI_SN
 	if (ia64_platform_is("sn2")) {
 		is_sn2 = 1;
 		if (is_shub2()) {
 			ret = -ENOMEM;
 			for_each_node_state(nid, N_ONLINE) {
 				int actual_nid;
 				int nasid;
 				unsigned long phys;

 				scratch_page[nid] = uncached_alloc_page(nid, 1);
 				if (scratch_page[nid] == 0)
 					goto free_scratch_pages;
 				phys = __pa(scratch_page[nid]);
 				nasid = get_node_number(phys);
 				actual_nid = nasid_to_cnodeid(nasid);
 				if (actual_nid != nid)
 					goto free_scratch_pages;
 			}
 		}

 		ret = misc_register(&fetchop_miscdev);
 		if (ret) {
 			printk(KERN_ERR
 			       "%s: failed to register device %i\n",
 			       FETCHOP_ID, ret);
 			goto free_scratch_pages;
 		}
 	}
 #endif
 	ret = misc_register(&cached_miscdev);
 	if (ret) {
 		printk(KERN_ERR "%s: failed to register device %i\n",
 		       CACHED_ID, ret);
 		if (is_sn2)
 			misc_deregister(&fetchop_miscdev);
 		goto free_scratch_pages;
 	}
 	ret = misc_register(&uncached_miscdev);
 	if (ret) {
 		printk(KERN_ERR "%s: failed to register device %i\n",
 		       UNCACHED_ID, ret);
 		misc_deregister(&cached_miscdev);
 		if (is_sn2)
 			misc_deregister(&fetchop_miscdev);
 		goto free_scratch_pages;
 	}

 	printk(KERN_INFO "%s %s initialized devices: %s %s %s\n",
 	       MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "",
 	       CACHED_ID, UNCACHED_ID);

 	return 0;

  free_scratch_pages:
 	for_each_node(nid) {
 		if (scratch_page[nid] != 0)
 			uncached_free_page(scratch_page[nid], 1);
 	}
 	return ret;
 }

 static void __exit
 mspec_exit(void)
 {
 	int nid;

 	misc_deregister(&uncached_miscdev);
 	misc_deregister(&cached_miscdev);
 	if (is_sn2) {
 		misc_deregister(&fetchop_miscdev);

 		for_each_node(nid) {
 			if (scratch_page[nid] != 0)
 				uncached_free_page(scratch_page[nid], 1);
 		}
 	}
 }

 module_init(mspec_init);
 module_exit(mspec_exit);

 MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>");
 MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
 MODULE_LICENSE("GPL");
	/*
	* Copyright (C) 2001-2006 Silicon Graphics, Inc. All rights
	* reserved.
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of version 2 of the GNU General Public License
	* as published by the Free Software Foundation.
	*/

	/*
	* SN Platform Special Memory (mspec) Support
	*
	* This driver exports the SN special memory (mspec) facility to user
	* processes.
	* There are three types of memory made available thru this driver:
	* fetchops, uncached and cached.
	*
	* Fetchops are atomic memory operations that are implemented in the
	* memory controller on SGI SN hardware.
	*
	* Uncached are used for memory write combining feature of the ia64
	* cpu.
	*
	* Cached are used for areas of memory that are used as cached addresses
	* on our partition and used as uncached addresses from other partitions.
	* Due to a design constraint of the SN2 Shub, you can not have processors
	* on the same FSB perform both a cached and uncached reference to the
	* same cache line. These special memory cached regions prevent the
	* kernel from ever dropping in a TLB entry and therefore prevent the
	* processor from ever speculating a cache line from this page.
	*/

	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/errno.h>
	#include <linux/miscdevice.h>
	#include <linux/spinlock.h>
	#include <linux/mm.h>
	#include <linux/fs.h>
	#include <linux/vmalloc.h>
	#include <linux/string.h>
	#include <linux/slab.h>
	#include <linux/numa.h>
	#include <asm/page.h>
	#include <asm/system.h>
	#include <asm/pgtable.h>
	#include <asm/atomic.h>
	#include <asm/tlbflush.h>
	#include <asm/uncached.h>
	#include <asm/sn/addrs.h>
	#include <asm/sn/arch.h>
	#include <asm/sn/mspec.h>
	#include <asm/sn/sn_cpuid.h>
	#include <asm/sn/io.h>
	#include <asm/sn/bte.h>
	#include <asm/sn/shubio.h>


	#define FETCHOP_ID "SGI Fetchop,"
	#define CACHED_ID "Cached,"
	#define UNCACHED_ID "Uncached"
	#define REVISION "4.0"
	#define MSPEC_BASENAME "mspec"

	/*
	* Page types allocated by the device.
	*/
	enum mspec_page_type {
	MSPEC_FETCHOP = 1,
	MSPEC_CACHED,
	MSPEC_UNCACHED
	};

	#ifdef CONFIG_SGI_SN
	static int is_sn2;
	#else
	#define is_sn2 0
	#endif

	/*
	* One of these structures is allocated when an mspec region is mmaped. The
	* structure is pointed to by the vma->vm_private_data field in the vma struct.
	* This structure is used to record the addresses of the mspec pages.
	* This structure is shared by all vma's that are split off from the
	* original vma when split_vma()'s are done.
	*
	* The refcnt is incremented atomically because mm->mmap_sem does not
	* protect in fork case where multiple tasks share the vma_data.
	*/
	struct vma_data {
	atomic_t refcnt; /* Number of vmas sharing the data. */
	spinlock_t lock; /* Serialize access to this structure. */
	int count; /* Number of pages allocated. */
	enum mspec_page_type type; /* Type of pages allocated. */
	int flags; /* See VMD_xxx below. */
	unsigned long vm_start; /* Original (unsplit) base. */
	unsigned long vm_end; /* Original (unsplit) end. */
	unsigned long maddr[0]; /* Array of MSPEC addresses. */
	};

	#define VMD_VMALLOCED 0x1 /* vmalloc'd rather than kmalloc'd */

	/* used on shub2 to clear FOP cache in the HUB */
	static unsigned long scratch_page[MAX_NUMNODES];
	#define SH2_AMO_CACHE_ENTRIES 4

	static inline int
	mspec_zero_block(unsigned long addr, int len)
	{
	int status;

	if (is_sn2) {
	if (is_shub2()) {
	int nid;
	void *p;
	int i;

	nid = nasid_to_cnodeid(get_node_number(__pa(addr)));
	p = (void *)TO_AMO(scratch_page[nid]);

	for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) {
	FETCHOP_LOAD_OP(p, FETCHOP_LOAD);
	p += FETCHOP_VAR_SIZE;
	}
	}

	status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len,
	BTE_WACQUIRE \| BTE_ZERO_FILL, NULL);
	} else {
	memset((char *) addr, 0, len);
	status = 0;
	}
	return status;
	}

	/*
	* mspec_open
	*
	* Called when a device mapping is created by a means other than mmap
	* (via fork, munmap, etc.). Increments the reference count on the
	* underlying mspec data so it is not freed prematurely.
	*/
	static void
	mspec_open(struct vm_area_struct *vma)
	{
	struct vma_data *vdata;

	vdata = vma->vm_private_data;
	atomic_inc(&vdata->refcnt);
	}

	/*
	* mspec_close
	*
	* Called when unmapping a device mapping. Frees all mspec pages
	* belonging to all the vma's sharing this vma_data structure.
	*/
	static void
	mspec_close(struct vm_area_struct *vma)
	{
	struct vma_data *vdata;
	int index, last_index;
	unsigned long my_page;

	vdata = vma->vm_private_data;

	if (!atomic_dec_and_test(&vdata->refcnt))
	return;

	last_index = (vdata->vm_end - vdata->vm_start) >> PAGE_SHIFT;
	for (index = 0; index < last_index; index++) {
	if (vdata->maddr[index] == 0)
	continue;
	/*
	* Clear the page before sticking it back
	* into the pool.
	*/
	my_page = vdata->maddr[index];
	vdata->maddr[index] = 0;
	if (!mspec_zero_block(my_page, PAGE_SIZE))
	uncached_free_page(my_page, 1);
	else
	printk(KERN_WARNING "mspec_close(): "
	"failed to zero page %ld\n", my_page);
	}

	if (vdata->flags & VMD_VMALLOCED)
	vfree(vdata);
	else
	kfree(vdata);
	}

	/*
	* mspec_fault
	*
	* Creates a mspec page and maps it to user space.
	*/
	static int
	mspec_fault(struct vm_area_struct vma, struct vm_fault vmf)
	{
	unsigned long paddr, maddr;
	unsigned long pfn;
	pgoff_t index = vmf->pgoff;
	struct vma_data *vdata = vma->vm_private_data;

	maddr = (volatile unsigned long) vdata->maddr[index];
	if (maddr == 0) {
	maddr = uncached_alloc_page(numa_node_id(), 1);
	if (maddr == 0)
	return VM_FAULT_OOM;

	spin_lock(&vdata->lock);
	if (vdata->maddr[index] == 0) {
	vdata->count++;
	vdata->maddr[index] = maddr;
	} else {
	uncached_free_page(maddr, 1);
	maddr = vdata->maddr[index];
	}
	spin_unlock(&vdata->lock);
	}

	if (vdata->type == MSPEC_FETCHOP)
	paddr = TO_AMO(maddr);
	else
	paddr = maddr & ~__IA64_UNCACHED_OFFSET;

	pfn = paddr >> PAGE_SHIFT;

	/*
	* vm_insert_pfn can fail with -EBUSY, but in that case it will
	* be because another thread has installed the pte first, so it
	* is no problem.
	*/
	vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);

	return VM_FAULT_NOPAGE;
	}

	static struct vm_operations_struct mspec_vm_ops = {
	.open = mspec_open,
	.close = mspec_close,
	.fault = mspec_fault,
	};

	/*
	* mspec_mmap
	*
	* Called when mmaping the device. Initializes the vma with a fault handler
	* and private data structure necessary to allocate, track, and free the
	* underlying pages.
	*/
	static int
	mspec_mmap(struct file file, struct vm_area_struct vma,
	enum mspec_page_type type)
	{
	struct vma_data *vdata;
	int pages, vdata_size, flags = 0;

	if (vma->vm_pgoff != 0)
	return -EINVAL;

	if ((vma->vm_flags & VM_SHARED) == 0)
	return -EINVAL;

	if ((vma->vm_flags & VM_WRITE) == 0)
	return -EPERM;

	pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
	vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
	if (vdata_size <= PAGE_SIZE)
	vdata = kmalloc(vdata_size, GFP_KERNEL);
	else {
	vdata = vmalloc(vdata_size);
	flags = VMD_VMALLOCED;
	}
	if (!vdata)
	return -ENOMEM;
	memset(vdata, 0, vdata_size);

	vdata->vm_start = vma->vm_start;
	vdata->vm_end = vma->vm_end;
	vdata->flags = flags;
	vdata->type = type;
	spin_lock_init(&vdata->lock);
	vdata->refcnt = ATOMIC_INIT(1);
	vma->vm_private_data = vdata;

	vma->vm_flags \|= (VM_IO \| VM_RESERVED \| VM_PFNMAP \| VM_DONTEXPAND);
	if (vdata->type == MSPEC_FETCHOP \|\| vdata->type == MSPEC_UNCACHED)
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
	vma->vm_ops = &mspec_vm_ops;

	return 0;
	}

	static int
	fetchop_mmap(struct file file, struct vm_area_struct vma)
	{
	return mspec_mmap(file, vma, MSPEC_FETCHOP);
	}

	static int
	cached_mmap(struct file file, struct vm_area_struct vma)
	{
	return mspec_mmap(file, vma, MSPEC_CACHED);
	}

	static int
	uncached_mmap(struct file file, struct vm_area_struct vma)
	{
	return mspec_mmap(file, vma, MSPEC_UNCACHED);
	}

	static const struct file_operations fetchop_fops = {
	.owner = THIS_MODULE,
	.mmap = fetchop_mmap
	};

	static struct miscdevice fetchop_miscdev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "sgi_fetchop",
	.fops = &fetchop_fops
	};

	static const struct file_operations cached_fops = {
	.owner = THIS_MODULE,
	.mmap = cached_mmap
	};

	static struct miscdevice cached_miscdev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "mspec_cached",
	.fops = &cached_fops
	};

	static const struct file_operations uncached_fops = {
	.owner = THIS_MODULE,
	.mmap = uncached_mmap
	};

	static struct miscdevice uncached_miscdev = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "mspec_uncached",
	.fops = &uncached_fops
	};

	/*
	* mspec_init
	*
	* Called at boot time to initialize the mspec facility.
	*/
	static int __init
	mspec_init(void)
	{
	int ret;
	int nid;

	/*
	* The fetchop device only works on SN2 hardware, uncached and cached
	* memory drivers should both be valid on all ia64 hardware
	*/
	#ifdef CONFIG_SGI_SN
	if (ia64_platform_is("sn2")) {
	is_sn2 = 1;
	if (is_shub2()) {
	ret = -ENOMEM;
	for_each_node_state(nid, N_ONLINE) {
	int actual_nid;
	int nasid;
	unsigned long phys;

	scratch_page[nid] = uncached_alloc_page(nid, 1);
	if (scratch_page[nid] == 0)
	goto free_scratch_pages;
	phys = __pa(scratch_page[nid]);
	nasid = get_node_number(phys);
	actual_nid = nasid_to_cnodeid(nasid);
	if (actual_nid != nid)
	goto free_scratch_pages;
	}
	}

	ret = misc_register(&fetchop_miscdev);
	if (ret) {
	printk(KERN_ERR
	"%s: failed to register device %i\n",
	FETCHOP_ID, ret);
	goto free_scratch_pages;
	}
	}
	#endif
	ret = misc_register(&cached_miscdev);
	if (ret) {
	printk(KERN_ERR "%s: failed to register device %i\n",
	CACHED_ID, ret);
	if (is_sn2)
	misc_deregister(&fetchop_miscdev);
	goto free_scratch_pages;
	}
	ret = misc_register(&uncached_miscdev);
	if (ret) {
	printk(KERN_ERR "%s: failed to register device %i\n",
	UNCACHED_ID, ret);
	misc_deregister(&cached_miscdev);
	if (is_sn2)
	misc_deregister(&fetchop_miscdev);
	goto free_scratch_pages;
	}

	printk(KERN_INFO "%s %s initialized devices: %s %s %s\n",
	MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "",
	CACHED_ID, UNCACHED_ID);

	return 0;

	free_scratch_pages:
	for_each_node(nid) {
	if (scratch_page[nid] != 0)
	uncached_free_page(scratch_page[nid], 1);
	}
	return ret;
	}

	static void __exit
	mspec_exit(void)
	{
	int nid;

	misc_deregister(&uncached_miscdev);
	misc_deregister(&cached_miscdev);
	if (is_sn2) {
	misc_deregister(&fetchop_miscdev);

	for_each_node(nid) {
	if (scratch_page[nid] != 0)
	uncached_free_page(scratch_page[nid], 1);
	}
	}
	}

	module_init(mspec_init);
	module_exit(mspec_exit);

	MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>");
	MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
	MODULE_LICENSE("GPL");