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Subject[PATCH] /proc/bus/pci* changes
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Date
The existing /proc/bus/pci/*/* files are a
hack involving ioctl and out-of-bounds mmap.
The following patch starts a transition to
something sane while keeping compatibility.
Typical user-space drivers for polled devices
should be easy to port to the new interface.
The X server will need some per-arch enhancements
to handle write-combining (non-x86 lack MTRRs)
and the use of multiple VGA-style devices.

In the new interface, pci/00/00.0 is a symbolic
link to a ../../pci*/bus0/dev0/fn0/config-space
file, where the '*' is typically 0. (PCI domain)
Simple and direct per-resource mmap() is provided,
via pci0/bus0/dev0/fn0/bar0 and so on.


diff -Naurd old/drivers/pci/proc.c new/drivers/pci/proc.c
--- old/drivers/pci/proc.c 2003-07-13 23:10:29.000000000 -0400
+++ new/drivers/pci/proc.c 2003-07-13 23:09:06.000000000 -0400
@@ -199,6 +199,14 @@
int write_combine;
};

+
+/*
+ * 2001-05-20 Alexander Viro "BTW, -pre4 got new bunch of ioctls. On
procfs, no less."
+ * 2001-05-20 Linus Torvalds "This particular braindamage is not too
late to fix.."
+ * 2003-06-30 Matthew Wilcox "The current fugly ioctl really has to
go."
+ *
+ * Damn, this lives in 2.6.xx, but at least a new interface is in
place.
+ */
static int proc_bus_pci_ioctl(struct inode *inode, struct file *file,
unsigned int cmd, unsigned long arg)
{
const struct proc_dir_entry *dp = PDE(inode);
@@ -240,6 +248,7 @@
}

#ifdef HAVE_PCI_MMAP
+/* old interface */
static int proc_bus_pci_mmap(struct file *file, struct vm_area_struct
*vma)
{
struct inode *inode = file->f_dentry->d_inode;
@@ -379,43 +388,215 @@

struct proc_dir_entry *proc_bus_pci_dir;

+
+#ifdef HAVE_PCI_MMAP
+
+struct pci_bar_private {
+ struct pci_dev *pdev;
+ int bar;
+};
+
+
+/* For now, a wrapper. Next fixes: do a proper per-arch version of
this, plus mmap flags. */
+static int pci_bar_mmap_page_range(struct pci_dev *pdev, struct
vm_area_struct *vma, int bar)
+{
+ enum pci_mmap_state type; /* which PCI address space, MMIO or IO
ports? */
+ unsigned busaddr;
+ unsigned npages;
+ int ret;
+
+ type = pci_resource_flags(pdev,bar) & IORESOURCE_MEM ? pci_mmap_mem :
pci_mmap_io;
+
+ /* check size limit */
+ npages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ if(npages + vma->vm_pgoff > pci_resource_len(pdev,bar) >> PAGE_SHIFT)
+ return -EINVAL;
+
+ /* Eeew. Make the old per-arch interface happy. */
+ /* Too bad "busaddr = pci_resource_start(pdev,bar)" only works on
i386 */
+ pci_read_config_dword(pdev, PCI_BASE_ADDRESS_0 + bar * 4, &busaddr);
+ vma->vm_pgoff += busaddr >> PAGE_SHIFT;
+
+ /* vma ought to choose: uncache, write-combine, write-back... */
+ ret = pci_mmap_page_range(pdev, vma, type, 0);
+ if (ret<0)
+ return ret;
+ return 0;
+}
+
+
+static int proc_pci_bar_mmap(struct file *file, struct vm_area_struct
*vma)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ const struct proc_dir_entry *dp = PDE(inode);
+ struct pci_bar_private *private = dp->data;
+
+ int ret;
+
+ if (!capable(CAP_SYS_RAWIO))
+ return -EPERM;
+
+ ret = pci_bar_mmap_page_range(private->pdev, vma, private->bar);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+static int proc_pci_bar_open(struct inode *inode, struct file *file)
+{
+ return 0;
+}
+
+static int proc_pci_bar_release(struct inode *inode, struct file *file)
+{
+ kfree(file->private_data);
+ file->private_data = NULL;
+
+ return 0;
+}
+#endif /* HAVE_PCI_MMAP */
+
+static struct file_operations proc_pci_bar_operations = {
+#ifdef HAVE_PCI_MMAP
+ .open = proc_pci_bar_open,
+ .release = proc_pci_bar_release,
+ .mmap = proc_pci_bar_mmap,
+#ifdef HAVE_ARCH_PCI_GET_UNMAPPED_AREA
+ .get_unmapped_area = get_pci_unmapped_area,
+#endif /* HAVE_ARCH_PCI_GET_UNMAPPED_AREA */
+#endif /* HAVE_PCI_MMAP */
+};
+
+/* TODO: per-arch way to hang a proc_dir_entry off of a pci domain */
+#ifdef CONFIG_PCI_DOMAINS
+static struct proc_dir_entry *procdom[0x10000];
+#else
+static struct proc_dir_entry *procdom[1];
+#endif
+
int pci_proc_attach_device(struct pci_dev *dev)
{
struct pci_bus *bus = dev->bus;
struct proc_dir_entry *de, *e;
char name[16];
+ char target[48]; /* sized for
../../pci65535/bus255/dev31/fn7/config-space */
+ int i;

if (!proc_initialized)
return -EACCES;

- if (!(de = bus->procdir)) {
- if (pci_name_bus(name, bus))
- return -EEXIST;
- de = bus->procdir = proc_mkdir(name, proc_bus_pci_dir);
+ /* Create new-style /proc/bus/pci65535/bus255/dev31/fn7/config-space &
friends. */
+ if (!(de = bus->procbus)) {
+ if (!( de = procdom[pci_domain_nr(bus)] )) {
+ sprintf(name, "pci%u", pci_domain_nr(bus));
+ de = procdom[pci_domain_nr(bus)] = proc_mkdir(name, proc_bus);
+ if (!de)
+ return -ENOMEM;
+ }
+ sprintf(name, "bus%u", bus->number);
+ de = bus->procbus = proc_mkdir(name, de);
if (!de)
return -ENOMEM;
}
- sprintf(name, "%02x.%x", PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn));
- e = dev->procent = create_proc_entry(name, S_IFREG | S_IRUGO |
S_IWUSR, de);
+
+ if (!( de = bus->procdevs[PCI_SLOT(dev->devfn)] )) {
+ sprintf(name, "dev%u", PCI_SLOT(dev->devfn));
+ de = bus->procdevs[PCI_SLOT(dev->devfn)] = proc_mkdir(name,
bus->procbus);
+ if (!de)
+ return -ENOMEM;
+ }
+
+ sprintf(name, "fn%u", PCI_FUNC(dev->devfn));
+ de = dev->procfn = proc_mkdir(name, de);
+ if (!de)
+ return -ENOMEM;
+
+ e = dev->proccfg = create_proc_entry("config-space", S_IFREG | S_IRUGO
| S_IWUSR, de);
if (!e)
return -ENOMEM;
e->proc_fops = &proc_bus_pci_operations;
e->data = dev;
e->size = PCI_CFG_SPACE_SIZE;

+ /* one entry per resource */
+ for (i = 0; i < DEVICE_COUNT_RESOURCE && pci_resource_start(dev,i);
i++) {
+ struct pci_bar_private *private;
+ private = kmalloc(sizeof(*private), GFP_KERNEL);
+ if (!private)
+ return -ENOMEM;
+ private->pdev = dev;
+ private->bar = i;
+ sprintf(name, "bar%u", i);
+ e = dev->procbar[i] = create_proc_entry(name, S_IFREG | S_IRUGO |
S_IWUSR, dev->procfn);
+ if (!e)
+ return -ENOMEM;
+ e->proc_fops = &proc_pci_bar_operations;
+ e->data = private;
+ e->size = pci_resource_len(dev,i);
+ }
+
+ /* Create old-style /proc/bus/pci/ff/1f.7 entry as a symlink. */
+ if (!(de = bus->procdir)) {
+ if (pci_name_bus(name, bus))
+ return -EEXIST; /* fail if name taken by some other PCI domain
*/
+ de = bus->procdir = proc_mkdir(name, proc_bus_pci_dir);
+ if (!de)
+ return -ENOMEM;
+ }
+ sprintf(name, "%02x.%x", PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn));
+ sprintf(target, "../../pci%d/bus%d/dev%d/fn%d/config-space",
pci_domain_nr(bus), bus->number, PCI_SLOT(dev->devfn),
PCI_FUNC(dev->devfn));
+ dev->procent = proc_symlink(name, de, target);
+ if (!dev->procent)
+ return -ENOMEM;
+
return 0;
}

int pci_proc_detach_device(struct pci_dev *dev)
{
struct proc_dir_entry *e;
+ int i;

+ /* old-style */
if ((e = dev->procent)) {
if (atomic_read(&e->count))
return -EBUSY;
remove_proc_entry(e->name, dev->bus->procdir);
dev->procent = NULL;
}
+ /* the config-space file */
+ if ((e = dev->proccfg)) {
+ if (atomic_read(&e->count))
+ return -EBUSY;
+ remove_proc_entry(e->name, dev->procfn);
+ dev->proccfg = NULL;
+ }
+ /* one entry per resource */
+ for (i = 0; i < DEVICE_COUNT_RESOURCE && pci_resource_start(dev,i);
i++) {
+ e = dev->procbar[i];
+ if(!e)
+ continue;
+ if(atomic_read(&e->count))
+ return -EBUSY;
+ remove_proc_entry(e->name, dev->procfn);
+ dev->procbar[i] = NULL;
+ }
+ /* the per-fn directory */
+ if ((e = dev->procfn)) {
+ if (atomic_read(&e->count))
+ return -EBUSY;
+ kfree(e->data);
+ remove_proc_entry(e->name, dev->bus->procdevs[PCI_SLOT(dev->devfn)]);
+ dev->procfn = NULL;
+ }
+ /* the per-dev directory */
+ if ((e = dev->bus->procdevs[PCI_SLOT(dev->devfn)])) {
+ if (atomic_read(&e->count))
+ return -EBUSY;
+ remove_proc_entry(e->name, dev->bus->procbus);
+ dev->bus->procdevs[PCI_SLOT(dev->devfn)] = NULL;
+ }
return 0;
}

@@ -441,6 +622,9 @@
struct proc_dir_entry *de = bus->procdir;
if (de)
remove_proc_entry(de->name, proc_bus_pci_dir);
+ de = bus->procbus;
+ if (de)
+ remove_proc_entry(de->name, procdom[pci_domain_nr(bus)]);
return 0;
}

diff -Naurd old/include/linux/pci.h new/include/linux/pci.h
--- old/include/linux/pci.h 2003-07-13 23:09:45.000000000 -0400
+++ new/include/linux/pci.h 2003-07-13 23:09:17.000000000 -0400
@@ -371,7 +371,10 @@
struct pci_bus *subordinate; /* bus this device bridges to */

void *sysdata; /* hook for sys-specific extension */
- struct proc_dir_entry *procent; /* device entry in /proc/bus/pci */
+ struct proc_dir_entry *procent; /* in /proc/bus/pci (old-style) */
+ struct proc_dir_entry *procfn; /* in /proc/bus/pci* (new-style) */
+ struct proc_dir_entry *proccfg; /* config-space (new-style) */
+ struct proc_dir_entry *procbar[DEVICE_COUNT_RESOURCE]; /* per-bar
entries */

unsigned int devfn; /* encoded device & function index */
unsigned short vendor;
@@ -454,7 +457,9 @@

struct pci_ops *ops; /* configuration access functions */
void *sysdata; /* hook for sys-specific extension */
- struct proc_dir_entry *procdir; /* directory entry in /proc/bus/pci */
+ struct proc_dir_entry *procdir; /* old-style /proc/bus/pci entry */
+ struct proc_dir_entry *procbus; /* new-style /proc/bus/pci* entry */
+ struct proc_dir_entry *procdevs[32]; /* new-style /proc/bus/pci*
per-slot */

unsigned char number; /* bus number */
unsigned char primary; /* number of primary bridge */


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