USB fixes for 6.4-rc5

Here are some USB driver and core fixes for 6.4-rc5.  Most of these are
 tiny driver fixes, including:
   - udc driver bugfix
   - f_fs gadget driver bugfix
   - cdns3 driver bugfix
   - typec bugfixes
 
 But the "big" thing in here is a fix yet-again for how the USB buffers
 are handled from userspace when dealing with DMA issues.  The changes
 were discussed a lot, and tested a lot, on the list, and acked by the
 relevant mm maintainers and have been in linux-next all this past week
 with no reported problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 -----BEGIN PGP SIGNATURE-----
 
 iG0EABECAC0WIQT0tgzFv3jCIUoxPcsxR9QN2y37KQUCZHxFGA8cZ3JlZ0Brcm9h
 aC5jb20ACgkQMUfUDdst+ykd0wCgwHMYaXa8jJCGgG+e4o/rFvBucK8AoJdmHc8M
 hoeLOGdBuxJItXNOnMac
 =uUEx
 -----END PGP SIGNATURE-----

Merge tag 'usb-6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

Pull USB fixes from Greg KH:
 "Here are some USB driver and core fixes for 6.4-rc5. Most of these are
  tiny driver fixes, including:

   - udc driver bugfix

   - f_fs gadget driver bugfix

   - cdns3 driver bugfix

   - typec bugfixes

  But the "big" thing in here is a fix yet-again for how the USB buffers
  are handled from userspace when dealing with DMA issues. The changes
  were discussed a lot, and tested a lot, on the list, and acked by the
  relevant mm maintainers and have been in linux-next all this past week
  with no reported problems"

* tag 'usb-6.4-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: tps6598x: Fix broken polling mode after system suspend/resume
  mm: page_table_check: Ensure user pages are not slab pages
  mm: page_table_check: Make it dependent on EXCLUSIVE_SYSTEM_RAM
  usb: usbfs: Use consistent mmap functions
  usb: usbfs: Enforce page requirements for mmap
  dt-bindings: usb: snps,dwc3: Fix "snps,hsphy_interface" type
  usb: gadget: udc: fix NULL dereference in remove()
  usb: gadget: f_fs: Add unbind event before functionfs_unbind
  usb: cdns3: fix NCM gadget RX speed 20x slow than expection at iMX8QM

Documentation/devicetree/bindings/usb/snps,dwc3.yaml

@@ -287,7 +287,7 @@ properties:
     description:
       High-Speed PHY interface selection between UTMI+ and ULPI when the
       DWC_USB3_HSPHY_INTERFACE has value 3.
-    $ref: /schemas/types.yaml#/definitions/uint8
+    $ref: /schemas/types.yaml#/definitions/string
     enum: [utmi, ulpi]
 
   snps,quirk-frame-length-adjustment:

Documentation/mm/page_table_check.rst

@@ -52,3 +52,22 @@ Build kernel with:
 
 Optionally, build kernel with PAGE_TABLE_CHECK_ENFORCED in order to have page
 table support without extra kernel parameter.
+
+Implementation notes
+====================
+
+We specifically decided not to use VMA information in order to avoid relying on
+MM states (except for limited "struct page" info). The page table check is a
+separate from Linux-MM state machine that verifies that the user accessible
+pages are not falsely shared.
+
+PAGE_TABLE_CHECK depends on EXCLUSIVE_SYSTEM_RAM. The reason is that without
+EXCLUSIVE_SYSTEM_RAM, users are allowed to map arbitrary physical memory
+regions into the userspace via /dev/mem. At the same time, pages may change
+their properties (e.g., from anonymous pages to named pages) while they are
+still being mapped in the userspace, leading to "corruption" detected by the
+page table check.
+
+Even with EXCLUSIVE_SYSTEM_RAM, I/O pages may be still allowed to be mapped via
+/dev/mem. However, these pages are always considered as named pages, so they
+won't break the logic used in the page table check.

drivers/usb/cdns3/cdns3-gadget.c

@@ -2097,6 +2097,19 @@ int cdns3_ep_config(struct cdns3_endpoint *priv_ep, bool enable)
 	else
 		priv_ep->trb_burst_size = 16;
 
+	/*
+	 * In versions preceding DEV_VER_V2, for example, iMX8QM, there exit the bugs
+	 * in the DMA. These bugs occur when the trb_burst_size exceeds 16 and the
+	 * address is not aligned to 128 Bytes (which is a product of the 64-bit AXI
+	 * and AXI maximum burst length of 16 or 0xF+1, dma_axi_ctrl0[3:0]). This
+	 * results in data corruption when it crosses the 4K border. The corruption
+	 * specifically occurs from the position (4K - (address & 0x7F)) to 4K.
+	 *
+	 * So force trb_burst_size to 16 at such platform.
+	 */
+	if (priv_dev->dev_ver < DEV_VER_V2)
+		priv_ep->trb_burst_size = 16;
+
 	mult = min_t(u8, mult, EP_CFG_MULT_MAX);
 	buffering = min_t(u8, buffering, EP_CFG_BUFFERING_MAX);
 	maxburst = min_t(u8, maxburst, EP_CFG_MAXBURST_MAX);

drivers/usb/core/buffer.c

@@ -172,3 +172,44 @@ void hcd_buffer_free(
 	}
 	dma_free_coherent(hcd->self.sysdev, size, addr, dma);
 }
+
+void *hcd_buffer_alloc_pages(struct usb_hcd *hcd,
+		size_t size, gfp_t mem_flags, dma_addr_t *dma)
+{
+	if (size == 0)
+		return NULL;
+
+	if (hcd->localmem_pool)
+		return gen_pool_dma_alloc_align(hcd->localmem_pool,
+				size, dma, PAGE_SIZE);
+
+	/* some USB hosts just use PIO */
+	if (!hcd_uses_dma(hcd)) {
+		*dma = DMA_MAPPING_ERROR;
+		return (void *)__get_free_pages(mem_flags,
+				get_order(size));
+	}
+
+	return dma_alloc_coherent(hcd->self.sysdev,
+			size, dma, mem_flags);
+}
+
+void hcd_buffer_free_pages(struct usb_hcd *hcd,
+		size_t size, void *addr, dma_addr_t dma)
+{
+	if (!addr)
+		return;
+
+	if (hcd->localmem_pool) {
+		gen_pool_free(hcd->localmem_pool,
+				(unsigned long)addr, size);
+		return;
+	}
+
+	if (!hcd_uses_dma(hcd)) {
+		free_pages((unsigned long)addr, get_order(size));
+		return;
+	}
+
+	dma_free_coherent(hcd->self.sysdev, size, addr, dma);
+}

drivers/usb/core/devio.c

@@ -186,6 +186,7 @@ static int connected(struct usb_dev_state *ps)
 static void dec_usb_memory_use_count(struct usb_memory *usbm, int *count)
 {
 	struct usb_dev_state *ps = usbm->ps;
+	struct usb_hcd *hcd = bus_to_hcd(ps->dev->bus);
 	unsigned long flags;
 
 	spin_lock_irqsave(&ps->lock, flags);
@@ -194,8 +195,8 @@ static void dec_usb_memory_use_count(struct usb_memory *usbm, int *count)
 		list_del(&usbm->memlist);
 		spin_unlock_irqrestore(&ps->lock, flags);
 
-		usb_free_coherent(ps->dev, usbm->size, usbm->mem,
-				usbm->dma_handle);
+		hcd_buffer_free_pages(hcd, usbm->size,
+				usbm->mem, usbm->dma_handle);
 		usbfs_decrease_memory_usage(
 			usbm->size + sizeof(struct usb_memory));
 		kfree(usbm);
@@ -234,7 +235,7 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
 	size_t size = vma->vm_end - vma->vm_start;
 	void *mem;
 	unsigned long flags;
-	dma_addr_t dma_handle;
+	dma_addr_t dma_handle = DMA_MAPPING_ERROR;
 	int ret;
 
 	ret = usbfs_increase_memory_usage(size + sizeof(struct usb_memory));
@@ -247,8 +248,8 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
 		goto error_decrease_mem;
 	}
 
-	mem = usb_alloc_coherent(ps->dev, size, GFP_USER | __GFP_NOWARN,
-			&dma_handle);
+	mem = hcd_buffer_alloc_pages(hcd,
+			size, GFP_USER | __GFP_NOWARN, &dma_handle);
 	if (!mem) {
 		ret = -ENOMEM;
 		goto error_free_usbm;
@@ -264,7 +265,14 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma)
 	usbm->vma_use_count = 1;
 	INIT_LIST_HEAD(&usbm->memlist);
 
-	if (hcd->localmem_pool || !hcd_uses_dma(hcd)) {
+	/*
+	 * In DMA-unavailable cases, hcd_buffer_alloc_pages allocates
+	 * normal pages and assigns DMA_MAPPING_ERROR to dma_handle. Check
+	 * whether we are in such cases, and then use remap_pfn_range (or
+	 * dma_mmap_coherent) to map normal (or DMA) pages into the user
+	 * space, respectively.
+	 */
+	if (dma_handle == DMA_MAPPING_ERROR) {
 		if (remap_pfn_range(vma, vma->vm_start,
 				    virt_to_phys(usbm->mem) >> PAGE_SHIFT,
 				    size, vma->vm_page_prot) < 0) {

drivers/usb/gadget/function/f_fs.c

@@ -3535,6 +3535,7 @@ static void ffs_func_unbind(struct usb_configuration *c,
 	/* Drain any pending AIO completions */
 	drain_workqueue(ffs->io_completion_wq);
 
+	ffs_event_add(ffs, FUNCTIONFS_UNBIND);
 	if (!--opts->refcnt)
 		functionfs_unbind(ffs);
 
@@ -3559,7 +3560,6 @@ static void ffs_func_unbind(struct usb_configuration *c,
 	func->function.ssp_descriptors = NULL;
 	func->interfaces_nums = NULL;
 
-	ffs_event_add(ffs, FUNCTIONFS_UNBIND);
 }
 
 static struct usb_function *ffs_alloc(struct usb_function_instance *fi)

drivers/usb/gadget/udc/amd5536udc_pci.c

@@ -170,6 +170,9 @@ static int udc_pci_probe(
 		retval = -ENODEV;
 		goto err_probe;
 	}
+
+	udc = dev;
+
 	return 0;
 
 err_probe:

drivers/usb/typec/tipd/core.c

@@ -920,7 +920,7 @@ static int __maybe_unused tps6598x_resume(struct device *dev)
 		enable_irq(client->irq);
 	}
 
-	if (client->irq)
+	if (!client->irq)
 		queue_delayed_work(system_power_efficient_wq, &tps->wq_poll,
 				   msecs_to_jiffies(POLL_INTERVAL));
 

include/linux/page-flags.h

@@ -617,6 +617,12 @@ PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted)
  * Please note that, confusingly, "page_mapping" refers to the inode
  * address_space which maps the page from disk; whereas "page_mapped"
  * refers to user virtual address space into which the page is mapped.
+ *
+ * For slab pages, since slab reuses the bits in struct page to store its
+ * internal states, the page->mapping does not exist as such, nor do these
+ * flags below.  So in order to avoid testing non-existent bits, please
+ * make sure that PageSlab(page) actually evaluates to false before calling
+ * the following functions (e.g., PageAnon).  See mm/slab.h.
  */
 #define PAGE_MAPPING_ANON	0x1
 #define PAGE_MAPPING_MOVABLE	0x2

include/linux/usb/hcd.h

@@ -501,6 +501,11 @@ void *hcd_buffer_alloc(struct usb_bus *bus, size_t size,
 void hcd_buffer_free(struct usb_bus *bus, size_t size,
 	void *addr, dma_addr_t dma);
 
+void *hcd_buffer_alloc_pages(struct usb_hcd *hcd,
+		size_t size, gfp_t mem_flags, dma_addr_t *dma);
+void hcd_buffer_free_pages(struct usb_hcd *hcd,
+		size_t size, void *addr, dma_addr_t dma);
+
 /* generic bus glue, needed for host controllers that don't use PCI */
 extern irqreturn_t usb_hcd_irq(int irq, void *__hcd);
 

mm/Kconfig.debug

@@ -98,6 +98,7 @@ config PAGE_OWNER
 config PAGE_TABLE_CHECK
 	bool "Check for invalid mappings in user page tables"
 	depends on ARCH_SUPPORTS_PAGE_TABLE_CHECK
+	depends on EXCLUSIVE_SYSTEM_RAM
 	select PAGE_EXTENSION
 	help
 	  Check that anonymous page is not being mapped twice with read write

mm/page_table_check.c

@@ -71,6 +71,8 @@ static void page_table_check_clear(struct mm_struct *mm, unsigned long addr,
 
 	page = pfn_to_page(pfn);
 	page_ext = page_ext_get(page);
+
+	BUG_ON(PageSlab(page));
 	anon = PageAnon(page);
 
 	for (i = 0; i < pgcnt; i++) {
@@ -107,6 +109,8 @@ static void page_table_check_set(struct mm_struct *mm, unsigned long addr,
 
 	page = pfn_to_page(pfn);
 	page_ext = page_ext_get(page);
+
+	BUG_ON(PageSlab(page));
 	anon = PageAnon(page);
 
 	for (i = 0; i < pgcnt; i++) {
@@ -133,6 +137,8 @@ void __page_table_check_zero(struct page *page, unsigned int order)
 	struct page_ext *page_ext;
 	unsigned long i;
 
+	BUG_ON(PageSlab(page));
+
 	page_ext = page_ext_get(page);
 	BUG_ON(!page_ext);
 	for (i = 0; i < (1ul << order); i++) {