Merge tag 'char-misc-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver updates from Greg KH:
 "Here is the large set of char/misc driver patches for 5.8-rc1

  Included in here are:

   - habanalabs driver updates, loads

   - mhi bus driver updates

   - extcon driver updates

   - clk driver updates (approved by the clock maintainer)

   - firmware driver updates

   - fpga driver updates

   - gnss driver updates

   - coresight driver updates

   - interconnect driver updates

   - parport driver updates (it's still alive!)

   - nvmem driver updates

   - soundwire driver updates

   - visorbus driver updates

   - w1 driver updates

   - various misc driver updates

  In short, loads of different driver subsystem updates along with the
  drivers as well.

  All have been in linux-next for a while with no reported issues"

* tag 'char-misc-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (233 commits)
  habanalabs: correctly cast u64 to void*
  habanalabs: initialize variable to default value
  extcon: arizona: Fix runtime PM imbalance on error
  extcon: max14577: Add proper dt-compatible strings
  extcon: adc-jack: Fix an error handling path in 'adc_jack_probe()'
  extcon: remove redundant assignment to variable idx
  w1: omap-hdq: print dev_err if irq flags are not cleared
  w1: omap-hdq: fix interrupt handling which did show spurious timeouts
  w1: omap-hdq: fix return value to be -1 if there is a timeout
  w1: omap-hdq: cleanup to add missing newline for some dev_dbg
  /dev/mem: Revoke mappings when a driver claims the region
  misc: xilinx-sdfec: convert get_user_pages() --> pin_user_pages()
  misc: xilinx-sdfec: cleanup return value in xsdfec_table_write()
  misc: xilinx-sdfec: improve get_user_pages_fast() error handling
  nvmem: qfprom: remove incorrect write support
  habanalabs: handle MMU cache invalidation timeout
  habanalabs: don't allow hard reset with open processes
  habanalabs: GAUDI does not support soft-reset
  habanalabs: add print for soft reset due to event
  habanalabs: improve MMU cache invalidation code
  ...

1 files changed, 99 insertions, 2 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 43dd0891ca1e..31cae88a730b 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -31,11 +31,15 @@
 #include <linux/uio.h>
 #include <linux/uaccess.h>
 #include <linux/security.h>
+#include <linux/pseudo_fs.h>
+#include <uapi/linux/magic.h>
+#include <linux/mount.h>
 
 #ifdef CONFIG_IA64
 # include <linux/efi.h>
 #endif
 
+#define DEVMEM_MINOR	1
 #define DEVPORT_MINOR	4
 
 static inline unsigned long size_inside_page(unsigned long start,
@@ -805,12 +809,64 @@ static loff_t memory_lseek(struct file *file, loff_t offset, int orig)
 	return ret;
 }
 
+static struct inode *devmem_inode;
+
+#ifdef CONFIG_IO_STRICT_DEVMEM
+void revoke_devmem(struct resource *res)
+{
+	struct inode *inode = READ_ONCE(devmem_inode);
+
+	/*
+	 * Check that the initialization has completed. Losing the race
+	 * is ok because it means drivers are claiming resources before
+	 * the fs_initcall level of init and prevent /dev/mem from
+	 * establishing mappings.
+	 */
+	if (!inode)
+		return;
+
+	/*
+	 * The expectation is that the driver has successfully marked
+	 * the resource busy by this point, so devmem_is_allowed()
+	 * should start returning false, however for performance this
+	 * does not iterate the entire resource range.
+	 */
+	if (devmem_is_allowed(PHYS_PFN(res->start)) &&
+	    devmem_is_allowed(PHYS_PFN(res->end))) {
+		/*
+		 * *cringe* iomem=relaxed says "go ahead, what's the
+		 * worst that can happen?"
+		 */
+		return;
+	}
+
+	unmap_mapping_range(inode->i_mapping, res->start, resource_size(res), 1);
+}
+#endif
+
 static int open_port(struct inode *inode, struct file *filp)
 {
+	int rc;
+
 	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
-	return security_locked_down(LOCKDOWN_DEV_MEM);
+	rc = security_locked_down(LOCKDOWN_DEV_MEM);
+	if (rc)
+		return rc;
+
+	if (iminor(inode) != DEVMEM_MINOR)
+		return 0;
+
+	/*
+	 * Use a unified address space to have a single point to manage
+	 * revocations when drivers want to take over a /dev/mem mapped
+	 * range.
+	 */
+	inode->i_mapping = devmem_inode->i_mapping;
+	filp->f_mapping = inode->i_mapping;
+
+	return 0;
 }
 
 #define zero_lseek	null_lseek
@@ -885,7 +941,7 @@ static const struct memdev {
 	fmode_t fmode;
 } devlist[] = {
 #ifdef CONFIG_DEVMEM
-	 [1] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
+	 [DEVMEM_MINOR] = { "mem", 0, &mem_fops, FMODE_UNSIGNED_OFFSET },
 #endif
 #ifdef CONFIG_DEVKMEM
 	 [2] = { "kmem", 0, &kmem_fops, FMODE_UNSIGNED_OFFSET },
@@ -939,6 +995,45 @@ static char *mem_devnode(struct device *dev, umode_t *mode)
 
 static struct class *mem_class;
 
+static int devmem_fs_init_fs_context(struct fs_context *fc)
+{
+	return init_pseudo(fc, DEVMEM_MAGIC) ? 0 : -ENOMEM;
+}
+
+static struct file_system_type devmem_fs_type = {
+	.name		= "devmem",
+	.owner		= THIS_MODULE,
+	.init_fs_context = devmem_fs_init_fs_context,
+	.kill_sb	= kill_anon_super,
+};
+
+static int devmem_init_inode(void)
+{
+	static struct vfsmount *devmem_vfs_mount;
+	static int devmem_fs_cnt;
+	struct inode *inode;
+	int rc;
+
+	rc = simple_pin_fs(&devmem_fs_type, &devmem_vfs_mount, &devmem_fs_cnt);
+	if (rc < 0) {
+		pr_err("Cannot mount /dev/mem pseudo filesystem: %d\n", rc);
+		return rc;
+	}
+
+	inode = alloc_anon_inode(devmem_vfs_mount->mnt_sb);
+	if (IS_ERR(inode)) {
+		rc = PTR_ERR(inode);
+		pr_err("Cannot allocate inode for /dev/mem: %d\n", rc);
+		simple_release_fs(&devmem_vfs_mount, &devmem_fs_cnt);
+		return rc;
+	}
+
+	/* publish /dev/mem initialized */
+	WRITE_ONCE(devmem_inode, inode);
+
+	return 0;
+}
+
 static int __init chr_dev_init(void)
 {
 	int minor;
@@ -960,6 +1055,8 @@ static int __init chr_dev_init(void)
 		 */
 		if ((minor == DEVPORT_MINOR) && !arch_has_dev_port())
 			continue;
+		if ((minor == DEVMEM_MINOR) && devmem_init_inode() != 0)
+			continue;
 
 		device_create(mem_class, NULL, MKDEV(MEM_MAJOR, minor),
 			      NULL, devlist[minor].name);