test: add standalone btusb ZLP quirk module

2026-09-26 17:44:16 +00:00 · 2026-07-25 15:40:59 +08:00
parent 268c4f7122
commit 6550131e18
6 changed files with 604 additions and 0 deletions
@@ -0,0 +1,228 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/atomic.h>
+#include <linux/kernel.h>
+#include <linux/kprobes.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/ptrace.h>
+#include <linux/usb.h>
+
+#define AIC_USB_VENDOR_ID	0x368b
+#define AIC_USB_PRODUCT_ID	0x8d81
+#define USB_BT_SUBCLASS		0x01
+#define USB_BT_PROTOCOL		0x01
+
+static atomic64_t injection_count = ATOMIC64_INIT(0);
+static const char *hook_name = "none";
+
+static int injections_get(char *buffer, const struct kernel_param *kp)
+{
+	(void)kp;
+
+	return scnprintf(buffer, PAGE_SIZE, "%lld\n",
+			 (long long)atomic64_read(&injection_count));
+}
+
+static const struct kernel_param_ops injections_ops = {
+	.get = injections_get,
+};
+
+module_param_cb(injections, &injections_ops, NULL, 0444);
+MODULE_PARM_DESC(injections, "Number of AIC ACL bulk OUT URBs modified");
+
+static int hook_get(char *buffer, const struct kernel_param *kp)
+{
+	(void)kp;
+
+	return scnprintf(buffer, PAGE_SIZE, "%s\n", hook_name);
+}
+
+static const struct kernel_param_ops hook_ops = {
+	.get = hook_get,
+};
+
+module_param_cb(hook, &hook_ops, NULL, 0444);
+MODULE_PARM_DESC(hook, "Active injection hook");
+
+#if IS_ENABLED(CONFIG_KPROBES)
+
+enum aic_zlp_hook {
+	AIC_ZLP_HOOK_NONE,
+	AIC_ZLP_HOOK_BTUSB_RETURN,
+	AIC_ZLP_HOOK_USB_SUBMIT,
+};
+
+static enum aic_zlp_hook active_hook;
+
+static bool is_aic_bulk_out(const struct urb *urb)
+{
+	const struct usb_device *udev;
+
+	if (!urb)
+		return false;
+
+	udev = urb->dev;
+	if (!udev)
+		return false;
+
+	if (le16_to_cpu(udev->descriptor.idVendor) != AIC_USB_VENDOR_ID ||
+	    le16_to_cpu(udev->descriptor.idProduct) != AIC_USB_PRODUCT_ID)
+		return false;
+
+	return usb_pipetype(urb->pipe) == PIPE_BULK &&
+	       usb_pipeout(urb->pipe);
+}
+
+static bool is_bluetooth_acl_endpoint(const struct urb *urb)
+{
+	const struct usb_endpoint_descriptor *ep;
+	struct usb_host_interface *alt;
+	struct usb_interface *intf;
+	unsigned int endpoint;
+	int i;
+
+	if (!is_aic_bulk_out(urb))
+		return false;
+
+	intf = usb_ifnum_to_if(urb->dev, 0);
+	if (!intf)
+		return false;
+
+	alt = READ_ONCE(intf->cur_altsetting);
+	if (!alt ||
+	    alt->desc.bInterfaceClass != USB_CLASS_WIRELESS_CONTROLLER ||
+	    alt->desc.bInterfaceSubClass != USB_BT_SUBCLASS ||
+	    alt->desc.bInterfaceProtocol != USB_BT_PROTOCOL)
+		return false;
+
+	endpoint = usb_pipeendpoint(urb->pipe);
+	for (i = 0; i < alt->desc.bNumEndpoints; i++) {
+		ep = &alt->endpoint[i].desc;
+		if (usb_endpoint_is_bulk_out(ep) &&
+		    usb_endpoint_num(ep) == endpoint)
+			return true;
+	}
+
+	return false;
+}
+
+static void enable_zlp(struct urb *urb)
+{
+	long long count;
+
+	if (urb->transfer_flags & URB_ZERO_PACKET)
+		return;
+
+	urb->transfer_flags |= URB_ZERO_PACKET;
+	count = atomic64_inc_return(&injection_count);
+
+	if (count == 1)
+		pr_info("enabled ZLP on the first 368b:8d81 ACL bulk OUT URB\n");
+}
+
+static int alloc_bulk_urb_ret_handler(struct kretprobe_instance *ri,
+				      struct pt_regs *regs)
+{
+	struct urb *urb;
+
+	(void)ri;
+
+	urb = (struct urb *)regs_return_value(regs);
+	if (!is_aic_bulk_out(urb))
+		return 0;
+
+	enable_zlp(urb);
+	return 0;
+}
+
+static struct kretprobe alloc_bulk_urb_probe = {
+	.kp.symbol_name = "btusb:alloc_bulk_urb",
+	.handler = alloc_bulk_urb_ret_handler,
+};
+
+static int usb_submit_urb_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+	struct urb *urb;
+
+	(void)p;
+
+	urb = (struct urb *)regs_get_kernel_argument(regs, 0);
+	if (is_bluetooth_acl_endpoint(urb))
+		enable_zlp(urb);
+
+	return 0;
+}
+
+static struct kprobe usb_submit_urb_probe = {
+	.symbol_name = "usb_submit_urb",
+	.pre_handler = usb_submit_urb_pre_handler,
+};
+
+static int __init aic_zlp_quirk_init(void)
+{
+	int ret;
+
+	ret = register_kretprobe(&alloc_bulk_urb_probe);
+	if (!ret) {
+		active_hook = AIC_ZLP_HOOK_BTUSB_RETURN;
+		hook_name = "btusb:alloc_bulk_urb";
+		pr_info("attached to system btusb for USB device 368b:8d81\n");
+		return 0;
+	}
+
+	pr_warn("btusb return hook unavailable (%d), trying USB submit fallback\n",
+		ret);
+
+	ret = register_kprobe(&usb_submit_urb_probe);
+	if (ret) {
+		pr_err("cannot attach to usb_submit_urb: %d\n", ret);
+		return ret;
+	}
+
+	active_hook = AIC_ZLP_HOOK_USB_SUBMIT;
+	hook_name = "usb_submit_urb";
+	pr_info("attached USB submit fallback for device 368b:8d81 interface 0\n");
+	return 0;
+}
+
+static void __exit aic_zlp_quirk_exit(void)
+{
+	unsigned long missed = 0;
+
+	if (active_hook == AIC_ZLP_HOOK_BTUSB_RETURN) {
+		unregister_kretprobe(&alloc_bulk_urb_probe);
+		missed = alloc_bulk_urb_probe.nmissed;
+	} else if (active_hook == AIC_ZLP_HOOK_USB_SUBMIT) {
+		unregister_kprobe(&usb_submit_urb_probe);
+		missed = usb_submit_urb_probe.nmissed;
+	}
+
+	pr_info("detached %s after %lld injections (%lu missed hits)\n",
+		hook_name, (long long)atomic64_read(&injection_count), missed);
+}
+
+#else
+
+static int __init aic_zlp_quirk_init(void)
+{
+	pr_err("CONFIG_KPROBES is disabled in this kernel\n");
+	return -EOPNOTSUPP;
+}
+
+static void __exit aic_zlp_quirk_exit(void)
+{
+}
+
+#endif
+
+module_init(aic_zlp_quirk_init);
+module_exit(aic_zlp_quirk_exit);
+
+MODULE_AUTHOR("Shen Mintao <cx330.shen@autocore.ai>");
+MODULE_DESCRIPTION("AIC 8800D80 standard btusb ACL bulk TX ZLP quirk");
+MODULE_LICENSE("GPL");
+MODULE_VERSION("0.1");
+MODULE_SOFTDEP("pre: btusb");