5 files changed, 127 insertions, 31 deletions

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 24a76de49f41..2a42add7f563 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -60,3 +60,92 @@ EXPORT_SYMBOL(pci_bus_read_config_dword);
 EXPORT_SYMBOL(pci_bus_write_config_byte);
 EXPORT_SYMBOL(pci_bus_write_config_word);
 EXPORT_SYMBOL(pci_bus_write_config_dword);
+
+static u32 pci_user_cached_config(struct pci_dev *dev, int pos)
+{
+        u32 data;
+
+        data = dev->saved_config_space[pos/sizeof(dev->saved_config_space[0])];
+        data >>= (pos % sizeof(dev->saved_config_space[0])) * 8;
+        return data;
+}
+
+#define PCI_USER_READ_CONFIG(size,type)                                 \
+int pci_user_read_config_##size                                         \
+        (struct pci_dev *dev, int pos, type *val)                       \
+{                                                                       \
+        unsigned long flags;                                            \
+        int ret = 0;                                                    \
+        u32 data = -1;                                                  \
+        if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER;       \
+        spin_lock_irqsave(&pci_lock, flags);                            \
+        if (likely(!dev->block_ucfg_access))                            \
+                ret = dev->bus->ops->read(dev->bus, dev->devfn,         \
+                                        pos, sizeof(type), &data);      \
+        else if (pos < sizeof(dev->saved_config_space))                 \
+                data = pci_user_cached_config(dev, pos);                \
+        spin_unlock_irqrestore(&pci_lock, flags);                       \
+        *val = (type)data;                                              \
+        return ret;                                                     \
+}
+
+#define PCI_USER_WRITE_CONFIG(size,type)                                \
+int pci_user_write_config_##size                                        \
+        (struct pci_dev *dev, int pos, type val)                        \
+{                                                                       \
+        unsigned long flags;                                            \
+        int ret = -EIO;                                                 \
+        if (PCI_##size##_BAD) return PCIBIOS_BAD_REGISTER_NUMBER;       \
+        spin_lock_irqsave(&pci_lock, flags);                            \
+        if (likely(!dev->block_ucfg_access))                            \
+                ret = dev->bus->ops->write(dev->bus, dev->devfn,        \
+                                        pos, sizeof(type), val);        \
+        spin_unlock_irqrestore(&pci_lock, flags);                       \
+        return ret;                                                     \
+}
+
+PCI_USER_READ_CONFIG(byte, u8)
+PCI_USER_READ_CONFIG(word, u16)
+PCI_USER_READ_CONFIG(dword, u32)
+PCI_USER_WRITE_CONFIG(byte, u8)
+PCI_USER_WRITE_CONFIG(word, u16)
+PCI_USER_WRITE_CONFIG(dword, u32)
+
+/**
+ * pci_block_user_cfg_access - Block userspace PCI config reads/writes
+ * @dev:        pci device struct
+ *
+ * This function blocks any userspace PCI config accesses from occurring.
+ * When blocked, any writes will be bit bucketed and reads will return the
+ * data saved using pci_save_state for the first 64 bytes of config
+ * space and return 0xff for all other config reads.
+ **/
+void pci_block_user_cfg_access(struct pci_dev *dev)
+{
+        unsigned long flags;
+
+        pci_save_state(dev);
+
+        /* spinlock to synchronize with anyone reading config space now */
+        spin_lock_irqsave(&pci_lock, flags);
+        dev->block_ucfg_access = 1;
+        spin_unlock_irqrestore(&pci_lock, flags);
+}
+EXPORT_SYMBOL_GPL(pci_block_user_cfg_access);
+
+/**
+ * pci_unblock_user_cfg_access - Unblock userspace PCI config reads/writes
+ * @dev:        pci device struct
+ *
+ * This function allows userspace PCI config accesses to resume.
+ **/
+void pci_unblock_user_cfg_access(struct pci_dev *dev)
+{
+        unsigned long flags;
+
+        /* spinlock to synchronize with anyone reading saved config space */
+        spin_lock_irqsave(&pci_lock, flags);
+        dev->block_ucfg_access = 0;
+        spin_unlock_irqrestore(&pci_lock, flags);
+}
+EXPORT_SYMBOL_GPL(pci_unblock_user_cfg_access);
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 2898830c496f..965a5934623a 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -130,7 +130,7 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 
         if ((off & 1) && size) {
                 u8 val;
-                pci_read_config_byte(dev, off, &val);
+                pci_user_read_config_byte(dev, off, &val);
                 data[off - init_off] = val;
                 off++;
                 size--;
@@ -138,7 +138,7 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 
         if ((off & 3) && size > 2) {
                 u16 val;
-                pci_read_config_word(dev, off, &val);
+                pci_user_read_config_word(dev, off, &val);
                 data[off - init_off] = val & 0xff;
                 data[off - init_off + 1] = (val >> 8) & 0xff;
                 off += 2;
@@ -147,7 +147,7 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 
         while (size > 3) {
                 u32 val;
-                pci_read_config_dword(dev, off, &val);
+                pci_user_read_config_dword(dev, off, &val);
                 data[off - init_off] = val & 0xff;
                 data[off - init_off + 1] = (val >> 8) & 0xff;
                 data[off - init_off + 2] = (val >> 16) & 0xff;
@@ -158,7 +158,7 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 
         if (size >= 2) {
                 u16 val;
-                pci_read_config_word(dev, off, &val);
+                pci_user_read_config_word(dev, off, &val);
                 data[off - init_off] = val & 0xff;
                 data[off - init_off + 1] = (val >> 8) & 0xff;
                 off += 2;
@@ -167,7 +167,7 @@ pci_read_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
 
         if (size > 0) {
                 u8 val;
-                pci_read_config_byte(dev, off, &val);
+                pci_user_read_config_byte(dev, off, &val);
                 data[off - init_off] = val;
                 off++;
                 --size;
@@ -192,7 +192,7 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
         }
         
         if ((off & 1) && size) {
-                pci_write_config_byte(dev, off, data[off - init_off]);
+                pci_user_write_config_byte(dev, off, data[off - init_off]);
                 off++;
                 size--;
         }
@@ -200,7 +200,7 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
         if ((off & 3) && size > 2) {
                 u16 val = data[off - init_off];
                 val |= (u16) data[off - init_off + 1] << 8;
-                pci_write_config_word(dev, off, val);
+                pci_user_write_config_word(dev, off, val);
                 off += 2;
                 size -= 2;
         }
@@ -210,7 +210,7 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
                 val |= (u32) data[off - init_off + 1] << 8;
                 val |= (u32) data[off - init_off + 2] << 16;
                 val |= (u32) data[off - init_off + 3] << 24;
-                pci_write_config_dword(dev, off, val);
+                pci_user_write_config_dword(dev, off, val);
                 off += 4;
                 size -= 4;
         }
@@ -218,13 +218,13 @@ pci_write_config(struct kobject *kobj, char *buf, loff_t off, size_t count)
         if (size >= 2) {
                 u16 val = data[off - init_off];
                 val |= (u16) data[off - init_off + 1] << 8;
-                pci_write_config_word(dev, off, val);
+                pci_user_write_config_word(dev, off, val);
                 off += 2;
                 size -= 2;
         }
 
         if (size) {
-                pci_write_config_byte(dev, off, data[off - init_off]);
+                pci_user_write_config_byte(dev, off, data[off - init_off]);
                 off++;
                 --size;
         }
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index d3f3dd42240d..6527b36c9a61 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -15,6 +15,13 @@ extern int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
 extern int (*platform_pci_choose_state)(struct pci_dev *dev, pm_message_t state);
 extern int (*platform_pci_set_power_state)(struct pci_dev *dev, pci_power_t state);
 
+extern int pci_user_read_config_byte(struct pci_dev *dev, int where, u8 *val);
+extern int pci_user_read_config_word(struct pci_dev *dev, int where, u16 *val);
+extern int pci_user_read_config_dword(struct pci_dev *dev, int where, u32 *val);
+extern int pci_user_write_config_byte(struct pci_dev *dev, int where, u8 val);
+extern int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val);
+extern int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val);
+
 /* PCI /proc functions */
 #ifdef CONFIG_PROC_FS
 extern int pci_proc_attach_device(struct pci_dev *dev);
diff --git a/drivers/pci/proc.c b/drivers/pci/proc.c
index 9613f666c110..9eb465727fce 100644
--- a/drivers/pci/proc.c
+++ b/drivers/pci/proc.c
@@ -80,7 +80,7 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
 
         if ((pos & 1) && cnt) {
                 unsigned char val;
-                pci_read_config_byte(dev, pos, &val);
+                pci_user_read_config_byte(dev, pos, &val);
                 __put_user(val, buf);
                 buf++;
                 pos++;
@@ -89,7 +89,7 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
 
         if ((pos & 3) && cnt > 2) {
                 unsigned short val;
-                pci_read_config_word(dev, pos, &val);
+                pci_user_read_config_word(dev, pos, &val);
                 __put_user(cpu_to_le16(val), (unsigned short __user *) buf);
                 buf += 2;
                 pos += 2;
@@ -98,7 +98,7 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
 
         while (cnt >= 4) {
                 unsigned int val;
-                pci_read_config_dword(dev, pos, &val);
+                pci_user_read_config_dword(dev, pos, &val);
                 __put_user(cpu_to_le32(val), (unsigned int __user *) buf);
                 buf += 4;
                 pos += 4;
@@ -107,7 +107,7 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
 
         if (cnt >= 2) {
                 unsigned short val;
-                pci_read_config_word(dev, pos, &val);
+                pci_user_read_config_word(dev, pos, &val);
                 __put_user(cpu_to_le16(val), (unsigned short __user *) buf);
                 buf += 2;
                 pos += 2;
@@ -116,7 +116,7 @@ proc_bus_pci_read(struct file *file, char __user *buf, size_t nbytes, loff_t *pp
 
         if (cnt) {
                 unsigned char val;
-                pci_read_config_byte(dev, pos, &val);
+                pci_user_read_config_byte(dev, pos, &val);
                 __put_user(val, buf);
                 buf++;
                 pos++;
@@ -151,7 +151,7 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
         if ((pos & 1) && cnt) {
                 unsigned char val;
                 __get_user(val, buf);
-                pci_write_config_byte(dev, pos, val);
+                pci_user_write_config_byte(dev, pos, val);
                 buf++;
                 pos++;
                 cnt--;
@@ -160,7 +160,7 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
         if ((pos & 3) && cnt > 2) {
                 unsigned short val;
                 __get_user(val, (unsigned short __user *) buf);
-                pci_write_config_word(dev, pos, le16_to_cpu(val));
+                pci_user_write_config_word(dev, pos, le16_to_cpu(val));
                 buf += 2;
                 pos += 2;
                 cnt -= 2;
@@ -169,7 +169,7 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
         while (cnt >= 4) {
                 unsigned int val;
                 __get_user(val, (unsigned int __user *) buf);
-                pci_write_config_dword(dev, pos, le32_to_cpu(val));
+                pci_user_write_config_dword(dev, pos, le32_to_cpu(val));
                 buf += 4;
                 pos += 4;
                 cnt -= 4;
@@ -178,7 +178,7 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
         if (cnt >= 2) {
                 unsigned short val;
                 __get_user(val, (unsigned short __user *) buf);
-                pci_write_config_word(dev, pos, le16_to_cpu(val));
+                pci_user_write_config_word(dev, pos, le16_to_cpu(val));
                 buf += 2;
                 pos += 2;
                 cnt -= 2;
@@ -187,7 +187,7 @@ proc_bus_pci_write(struct file *file, const char __user *buf, size_t nbytes, lof
         if (cnt) {
                 unsigned char val;
                 __get_user(val, buf);
-                pci_write_config_byte(dev, pos, val);
+                pci_user_write_config_byte(dev, pos, val);
                 buf++;
                 pos++;
                 cnt--;
@@ -484,10 +484,10 @@ static int show_dev_config(struct seq_file *m, void *v)
 
         drv = pci_dev_driver(dev);
 
-        pci_read_config_dword(dev, PCI_CLASS_REVISION, &class_rev);
-        pci_read_config_byte (dev, PCI_LATENCY_TIMER, &latency);
-        pci_read_config_byte (dev, PCI_MIN_GNT, &min_gnt);
-        pci_read_config_byte (dev, PCI_MAX_LAT, &max_lat);
+        pci_user_read_config_dword(dev, PCI_CLASS_REVISION, &class_rev);
+        pci_user_read_config_byte (dev, PCI_LATENCY_TIMER, &latency);
+        pci_user_read_config_byte (dev, PCI_MIN_GNT, &min_gnt);
+        pci_user_read_config_byte (dev, PCI_MAX_LAT, &max_lat);
         seq_printf(m, "  Bus %2d, device %3d, function %2d:\n",
                dev->bus->number, PCI_SLOT(dev->devfn), PCI_FUNC(dev->devfn));
         seq_printf(m, "    Class %04x", class_rev >> 16);
diff --git a/drivers/pci/syscall.c b/drivers/pci/syscall.c
index c071790cc983..87fafc08cb9d 100644
--- a/drivers/pci/syscall.c
+++ b/drivers/pci/syscall.c
@@ -13,7 +13,7 @@
 #include <linux/smp_lock.h>
 #include <linux/syscalls.h>
 #include <asm/uaccess.h>
-
+#include "pci.h"
 
 asmlinkage long
 sys_pciconfig_read(unsigned long bus, unsigned long dfn,
@@ -38,13 +38,13 @@ sys_pciconfig_read(unsigned long bus, unsigned long dfn,
         lock_kernel();
         switch (len) {
         case 1:
-                cfg_ret = pci_read_config_byte(dev, off, &byte);
+                cfg_ret = pci_user_read_config_byte(dev, off, &byte);
                 break;
         case 2:
-                cfg_ret = pci_read_config_word(dev, off, &word);
+                cfg_ret = pci_user_read_config_word(dev, off, &word);
                 break;
         case 4:
-                cfg_ret = pci_read_config_dword(dev, off, &dword);
+                cfg_ret = pci_user_read_config_dword(dev, off, &dword);
                 break;
         default:
                 err = -EINVAL;
@@ -112,7 +112,7 @@ sys_pciconfig_write(unsigned long bus, unsigned long dfn,
                 err = get_user(byte, (u8 __user *)buf);
                 if (err)
                         break;
-                err = pci_write_config_byte(dev, off, byte);
+                err = pci_user_write_config_byte(dev, off, byte);
                 if (err != PCIBIOS_SUCCESSFUL)
                         err = -EIO;
                 break;
@@ -121,7 +121,7 @@ sys_pciconfig_write(unsigned long bus, unsigned long dfn,
                 err = get_user(word, (u16 __user *)buf);
                 if (err)
                         break;
-                err = pci_write_config_word(dev, off, word);
+                err = pci_user_write_config_word(dev, off, word);
                 if (err != PCIBIOS_SUCCESSFUL)
                         err = -EIO;
                 break;
@@ -130,7 +130,7 @@ sys_pciconfig_write(unsigned long bus, unsigned long dfn,
                 err = get_user(dword, (u32 __user *)buf);
                 if (err)
                         break;
-                err = pci_write_config_dword(dev, off, dword);
+                err = pci_user_write_config_dword(dev, off, dword);
                 if (err != PCIBIOS_SUCCESSFUL)
                         err = -EIO;
                 break;