On Thu, Oct 17, 2019 at 07:44:14PM +0200, Andrey Konovalov wrote:
> This patch adds kcov_remote_start/kcov_remote_stop annotations to the
> hub_event function, which is responsible for processing events on USB
> buses, in particular events that happen during USB device enumeration.
> Each USB bus gets a unique id, which can be used to attach a kcov device
> to a particular USB bus for coverage collection.
>
> Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> ---
> drivers/usb/core/hub.c | 4 ++++
> include/linux/kcov.h | 1 +
> include/uapi/linux/kcov.h | 7 +++++++
> 3 files changed, 12 insertions(+)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 236313f41f4a..03a40e41b099 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -5374,6 +5374,8 @@ static void hub_event(struct work_struct *work)
> hub_dev = hub->intfdev;
> intf = to_usb_interface(hub_dev);
>
> + kcov_remote_start(kcov_remote_handle_usb(hdev->bus->busnum));
> +
> dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
> hdev->state, hdev->maxchild,
> /* NOTE: expects max 15 ports... */
> @@ -5480,6 +5482,8 @@ static void hub_event(struct work_struct *work)
> /* Balance the stuff in kick_hub_wq() and allow autosuspend */
> usb_autopm_put_interface(intf);
> kref_put(&hub->kref, hub_release);
> +
> + kcov_remote_stop();
> }
>
> static const struct usb_device_id hub_id_table[] = {
> diff --git a/include/linux/kcov.h b/include/linux/kcov.h
> index 702672d98d35..38a47e0b67c2 100644
> --- a/include/linux/kcov.h
> +++ b/include/linux/kcov.h
> @@ -30,6 +30,7 @@ void kcov_task_exit(struct task_struct *t);
> /*
> * Reserved handle ranges:
> * 0000000000000000 - 0000ffffffffffff : common handles
> + * 0001000000000000 - 0001ffffffffffff : USB subsystem handles
So how many bits are you going to have for any in-kernel tasks? Aren't
you going to run out quickly?
> */
> void kcov_remote_start(u64 handle);
> void kcov_remote_stop(void);
> diff --git a/include/uapi/linux/kcov.h b/include/uapi/linux/kcov.h
> index 46f78f716ca9..45c9ae59cebc 100644
> --- a/include/uapi/linux/kcov.h
> +++ b/include/uapi/linux/kcov.h
> @@ -43,4 +43,11 @@ enum {
> #define KCOV_CMP_SIZE(n) ((n) << 1)
> #define KCOV_CMP_MASK KCOV_CMP_SIZE(3)
>
> +#define KCOV_REMOTE_HANDLE_USB 0x0001000000000000ull
> +
> +static inline __u64 kcov_remote_handle_usb(unsigned int bus)
> +{
> + return KCOV_REMOTE_HANDLE_USB + (__u64)bus;
> +}
Why is this function in a uapi .h file? What userspace code would call
this?
thanks,
greg k-h
