Ohoy,
Another one to go on top of do_no_pfn() - no changes here either.
Cheers,
Jes
This patch implements the special memory driver (mspec) based on the
do_no_pfn approach. The driver is currently used only on SN2 hardware
with special fetchop support but could be beneficial on other
architectures using the uncached mode.
Signed-off-by: Jes Sorensen <[email protected]>
----
drivers/char/Kconfig | 8
drivers/char/Makefile | 1
drivers/char/mspec.c | 421 ++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 430 insertions(+)
Index: linux-2.6/drivers/char/Kconfig
===================================================================
--- linux-2.6.orig/drivers/char/Kconfig
+++ linux-2.6/drivers/char/Kconfig
@@ -439,6 +439,14 @@ config SGI_MBCS
If you have an SGI Altix with an attached SABrick
say Y or M here, otherwise say N.
+config MSPEC
+ tristate "Memory special operations driver"
+ depends on IA64
+ help
+ If you have an ia64 and you want to enable memory special
+ operations support (formerly known as fetchop), say Y here,
+ otherwise say N.
+
source "drivers/serial/Kconfig"
config UNIX98_PTYS
Index: linux-2.6/drivers/char/Makefile
===================================================================
--- linux-2.6.orig/drivers/char/Makefile
+++ linux-2.6/drivers/char/Makefile
@@ -51,6 +51,7 @@ obj-$(CONFIG_VIOCONS) += viocons.o
obj-$(CONFIG_VIOTAPE) += viotape.o
obj-$(CONFIG_HVCS) += hvcs.o
obj-$(CONFIG_SGI_MBCS) += mbcs.o
+obj-$(CONFIG_MSPEC) += mspec.o
obj-$(CONFIG_PRINTER) += lp.o
obj-$(CONFIG_TIPAR) += tipar.o
Index: linux-2.6/drivers/char/mspec.c
===================================================================
--- /dev/null
+++ linux-2.6/drivers/char/mspec.c
@@ -0,0 +1,421 @@
+/*
+ * 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/config.h>
+#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/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_FETCHOP = 1,
+ MSPEC_CACHED,
+ MSPEC_UNCACHED
+};
+
+static int is_sn2;
+
+/*
+ * 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.
+ */
+struct vma_data {
+ atomic_t refcnt; /* Number of vmas sharing the data. */
+ spinlock_t lock; /* Serialize access to the vma. */
+ int count; /* Number of pages allocated. */
+ int type; /* Type of pages allocated. */
+ unsigned long maddr[0]; /* Array of MSPEC addresses. */
+};
+
+/* 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, 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 the vma.
+ */
+static void
+mspec_close(struct vm_area_struct *vma)
+{
+ struct vma_data *vdata;
+ int i, pages, result, vdata_size;
+
+ vdata = vma->vm_private_data;
+ if (!atomic_dec_and_test(&vdata->refcnt))
+ return;
+
+ pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
+ for (i = 0; i < pages; i++) {
+ if (vdata->maddr[i] == 0)
+ continue;
+ /*
+ * Clear the page before sticking it back
+ * into the pool.
+ */
+ result = mspec_zero_block(vdata->maddr[i], PAGE_SIZE);
+ if (!result)
+ uncached_free_page(vdata->maddr[i]);
+ else
+ printk(KERN_WARNING "mspec_close(): "
+ "failed to zero page %i\n",
+ result);
+ }
+
+ if (vdata_size <= PAGE_SIZE)
+ kfree(vdata);
+ else
+ vfree(vdata);
+}
+
+
+/*
+ * mspec_nopfn
+ *
+ * Creates a mspec page and maps it to user space.
+ */
+static unsigned long
+mspec_nopfn(struct vm_area_struct *vma, unsigned long address)
+{
+ unsigned long paddr, maddr;
+ unsigned long pfn;
+ int index;
+ struct vma_data *vdata = vma->vm_private_data;
+
+ index = (address - vma->vm_start) >> PAGE_SHIFT;
+ maddr = (volatile unsigned long) vdata->maddr[index];
+ if (maddr == 0) {
+ maddr = uncached_alloc_page(numa_node_id());
+ if (maddr == 0)
+ return NOPFN_OOM;
+
+ spin_lock(&vdata->lock);
+ if (vdata->maddr[index] == 0) {
+ vdata->count++;
+ vdata->maddr[index] = maddr;
+ } else {
+ uncached_free_page(maddr);
+ maddr = vdata->maddr[index];
+ }
+ spin_unlock(&vdata->lock);
+ }
+
+ if (vdata->type == MSPEC_FETCHOP)
+ paddr = TO_AMO(maddr);
+ else
+ paddr = __pa(TO_CAC(maddr));
+
+ pfn = paddr >> PAGE_SHIFT;
+
+ return pfn;
+}
+
+static struct vm_operations_struct mspec_vm_ops = {
+ .open = mspec_open,
+ .close = mspec_close,
+ .nopfn = mspec_nopfn
+};
+
+/*
+ * 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, int type)
+{
+ struct vma_data *vdata;
+ int pages, vdata_size;
+
+ 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);
+ if (!vdata)
+ return -ENOMEM;
+ memset(vdata, 0, vdata_size);
+
+ vdata->type = type;
+ spin_lock_init(&vdata->lock);
+ vdata->refcnt = ATOMIC_INIT(1);
+ vma->vm_private_data = vdata;
+
+ vma->vm_flags |= (VM_IO | VM_LOCKED | VM_RESERVED | VM_PFNMAP);
+ 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 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 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 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
+ */
+ if (ia64_platform_is("sn2")) {
+ is_sn2 = 1;
+ if (is_shub2()) {
+ ret = -ENOMEM;
+ for_each_online_node(nid) {
+ int actual_nid;
+ int nasid;
+ unsigned long phys;
+
+ scratch_page[nid] = uncached_alloc_page(nid);
+ 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;
+ }
+ }
+ 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]);
+ }
+ 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]);
+ }
+ }
+}
+
+module_init(mspec_init);
+module_exit(mspec_exit);
+
+MODULE_AUTHOR("Silicon Graphics, Inc. <[email protected]>");
+MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
+MODULE_LICENSE("GPL");
On 20 Sep 2006 03:26:53 -0400 Jes Sorensen wrote:
Ahoy.
> drivers/char/Kconfig | 8
> drivers/char/Makefile | 1
> drivers/char/mspec.c | 421 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 430 insertions(+)
>
> Index: linux-2.6/drivers/char/Kconfig
> ===================================================================
> --- linux-2.6.orig/drivers/char/Kconfig
> +++ linux-2.6/drivers/char/Kconfig
> @@ -439,6 +439,14 @@ config SGI_MBCS
> If you have an SGI Altix with an attached SABrick
> say Y or M here, otherwise say N.
>
> +config MSPEC
> + tristate "Memory special operations driver"
> + depends on IA64
> + help
> + If you have an ia64 and you want to enable memory special
> + operations support (formerly known as fetchop), say Y here,
> + otherwise say N.
If the answers are {Y, N}, then it should be bool instead of tristate.
If tristate, M can be an answer....
> source "drivers/serial/Kconfig"
>
> config UNIX98_PTYS
> Index: linux-2.6/drivers/char/mspec.c
> ===================================================================
> --- /dev/null
> +++ linux-2.6/drivers/char/mspec.c
> @@ -0,0 +1,421 @@
> +#include <linux/config.h>
Don't need to include config.h (it's done by build system).
(well, actually autoconf.h is)
> +static struct vm_operations_struct mspec_vm_ops = {
> + .open = mspec_open,
> + .close = mspec_close,
> + .nopfn = mspec_nopfn
> +};
These interfaces create a userspace interface, eh?
So those 3 functions could stand to have kernel-doc function
comments and have documentation in Documentation/ABI/ (see its
README file for more details). Maybe check all of
Documentation/SubmitChecklist for other items...
> +/*
> + * mspec_init
> + *
> + * Called at boot time to initialize the mspec facility.
> + */
> +static int __init
> +mspec_init(void)
ugh, matey. All on one line.
> +{
> +}
> +
> +static void __exit
> +mspec_exit(void)
Ditto.
> +{
> +}
---
~Randy
Randy.Dunlap wrote:
> On 20 Sep 2006 03:26:53 -0400 Jes Sorensen wrote:
>> @@ -439,6 +439,14 @@ config SGI_MBCS
>> If you have an SGI Altix with an attached SABrick
>> say Y or M here, otherwise say N.
>>
>> +config MSPEC
>> + tristate "Memory special operations driver"
>> + depends on IA64
>> + help
>> + If you have an ia64 and you want to enable memory special
>> + operations support (formerly known as fetchop), say Y here,
>> + otherwise say N.
>
> If the answers are {Y, N}, then it should be bool instead of tristate.
> If tristate, M can be an answer....
True, will look into that.
>> +#include <linux/config.h>
>
> Don't need to include config.h (it's done by build system).
> (well, actually autoconf.h is)
True, I remember that changing - what happens when the code sits around
for too long. Personally I prefer it is included explicitly, but I'll
change it anyway.
>> +static struct vm_operations_struct mspec_vm_ops = {
>> + .open = mspec_open,
>> + .close = mspec_close,
>> + .nopfn = mspec_nopfn
>> +};
>
> These interfaces create a userspace interface, eh?
> So those 3 functions could stand to have kernel-doc function
> comments and have documentation in Documentation/ABI/ (see its
> README file for more details). Maybe check all of
> Documentation/SubmitChecklist for other items...
Mmmmmmm, I'd need someone else to write that up, might take a little
longer to get done. Robin know any volunteers?
>> +/*
>> + * mspec_init
>> + *
>> + * Called at boot time to initialize the mspec facility.
>> + */
>> +static int __init
>> +mspec_init(void)
>
> ugh, matey. All on one line.
Sorry, but I think that one falls under personal preference. It's short
than 80, which is what really matters.
Cheers,
Jes
> >These interfaces create a userspace interface, eh?
> >So those 3 functions could stand to have kernel-doc function
> >comments and have documentation in Documentation/ABI/ (see its
> >README file for more details). Maybe check all of
> >Documentation/SubmitChecklist for other items...
>
> Mmmmmmm, I'd need someone else to write that up, might take a little
> longer to get done. Robin know any volunteers?
Am I reading this right? Jes, are you looking for a volunteer or a
"volunteer" :)
Sure, I can grab this and see about the documentation. I assume you
want me to give you the blurb and your will add it to your patch?
If that assumption is wrong, please let me know.
Thanks,
Robin
Robin Holt wrote:
> Am I reading this right? Jes, are you looking for a volunteer or a
> "volunteer" :)
>
> Sure, I can grab this and see about the documentation. I assume you
> want me to give you the blurb and your will add it to your patch?
> If that assumption is wrong, please let me know.
Hi Robin,
Well if you are volunteering, that would be great :) Problem is I still
don't understand quite what is going on, so it's a bit harder for me to
write it and having it actually be correct.
If you have the time to write it up, then I'll be happy to add it to my
patch and push it all upstream.
Cheers,
Jes