Revert "PCI: Allow drivers to request exclusive config regions"

This reverts commit 3108f7c788 which is
commit 278294798ac9118412c9624a801d3f20f2279363 upstream.

It breaks the Android API and is not needed for any Android-specific
platforms, so it can be dropped for now.  If it is needed in the future,
it can be brought back in an abi-safe way.

Bug: 161946584
Change-Id: Ic1514e1a760e9ac6bb9da232ea895ab4ce42028b
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/pci/pci-sysfs.c

@@ -756,13 +756,6 @@ static ssize_t pci_write_config(struct file *filp, struct kobject *kobj,
 	if (ret)
 		return ret;
 
-	if (resource_is_exclusive(&dev->driver_exclusive_resource, off,
-				  count)) {
-		pci_warn_once(dev, "%s: Unexpected write to kernel-exclusive config offset %llx",
-			      current->comm, off);
-		add_taint(TAINT_USER, LOCKDEP_STILL_OK);
-	}
-
 	if (off > dev->cfg_size)
 		return 0;
 	if (off + count > dev->cfg_size) {

drivers/pci/probe.c

@@ -2307,12 +2307,6 @@ struct pci_dev *pci_alloc_dev(struct pci_bus *bus)
 	INIT_LIST_HEAD(&dev->bus_list);
 	dev->dev.type = &pci_dev_type;
 	dev->bus = pci_bus_get(bus);
-	dev->driver_exclusive_resource = (struct resource) {
-		.name = "PCI Exclusive",
-		.start = 0,
-		.end = -1,
-	};
-
 #ifdef CONFIG_PCI_MSI
 	raw_spin_lock_init(&dev->msi_lock);
 #endif

include/linux/ioport.h

@@ -324,8 +324,6 @@ extern void __devm_release_region(struct device *dev, struct resource *parent,
 				  resource_size_t start, resource_size_t n);
 extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size);
 extern bool iomem_is_exclusive(u64 addr);
-extern bool resource_is_exclusive(struct resource *resource, u64 addr,
-				  resource_size_t size);
 
 extern int
 walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,

include/linux/pci.h

@@ -410,7 +410,6 @@ struct pci_dev {
 	 */
 	unsigned int	irq;
 	struct resource resource[DEVICE_COUNT_RESOURCE]; /* I/O and memory regions + expansion ROMs */
-	struct resource driver_exclusive_resource;	 /* driver exclusive resource ranges */
 
 	bool		match_driver;		/* Skip attaching driver */
 
@@ -1433,21 +1432,6 @@ int pci_request_selected_regions(struct pci_dev *, int, const char *);
 int pci_request_selected_regions_exclusive(struct pci_dev *, int, const char *);
 void pci_release_selected_regions(struct pci_dev *, int);
 
-static inline __must_check struct resource *
-pci_request_config_region_exclusive(struct pci_dev *pdev, unsigned int offset,
-				    unsigned int len, const char *name)
-{
-	return __request_region(&pdev->driver_exclusive_resource, offset, len,
-				name, IORESOURCE_EXCLUSIVE);
-}
-
-static inline void pci_release_config_region(struct pci_dev *pdev,
-					     unsigned int offset,
-					     unsigned int len)
-{
-	__release_region(&pdev->driver_exclusive_resource, offset, len);
-}
-
 /* drivers/pci/bus.c */
 void pci_add_resource(struct list_head *resources, struct resource *res);
 void pci_add_resource_offset(struct list_head *resources, struct resource *res,
@@ -2527,7 +2511,6 @@ void pci_uevent_ers(struct pci_dev *pdev, enum  pci_ers_result err_type);
 #define pci_crit(pdev, fmt, arg...)	dev_crit(&(pdev)->dev, fmt, ##arg)
 #define pci_err(pdev, fmt, arg...)	dev_err(&(pdev)->dev, fmt, ##arg)
 #define pci_warn(pdev, fmt, arg...)	dev_warn(&(pdev)->dev, fmt, ##arg)
-#define pci_warn_once(pdev, fmt, arg...) dev_warn_once(&(pdev)->dev, fmt, ##arg)
 #define pci_notice(pdev, fmt, arg...)	dev_notice(&(pdev)->dev, fmt, ##arg)
 #define pci_info(pdev, fmt, arg...)	dev_info(&(pdev)->dev, fmt, ##arg)
 #define pci_dbg(pdev, fmt, arg...)	dev_dbg(&(pdev)->dev, fmt, ##arg)

kernel/resource.c

@@ -1693,15 +1693,18 @@ static int strict_iomem_checks;
  *
  * Returns true if exclusive to the kernel, otherwise returns false.
  */
-bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size)
+bool iomem_is_exclusive(u64 addr)
 {
 	const unsigned int exclusive_system_ram = IORESOURCE_SYSTEM_RAM |
 						  IORESOURCE_EXCLUSIVE;
 	bool skip_children = false, err = false;
+	int size = PAGE_SIZE;
 	struct resource *p;
 
+	addr = addr & PAGE_MASK;
+
 	read_lock(&resource_lock);
-	for_each_resource(root, p, skip_children) {
+	for_each_resource(&iomem_resource, p, skip_children) {
 		if (p->start >= addr + size)
 			break;
 		if (p->end < addr) {
@@ -1740,12 +1743,6 @@ bool resource_is_exclusive(struct resource *root, u64 addr, resource_size_t size
 	return err;
 }
 
-bool iomem_is_exclusive(u64 addr)
-{
-	return resource_is_exclusive(&iomem_resource, addr & PAGE_MASK,
-				     PAGE_SIZE);
-}
-
 struct resource_entry *resource_list_create_entry(struct resource *res,
 						  size_t extra_size)
 {