Allow for ftrace data to be exported over a USB Gadget
Controller. With this, we have a potentially very fast pipe for
transmitting ftrace data to a Host PC for further analysis.
Note that in order to decode the data, one needs access to kernel
symbols in order to convert binary data into function names and what
not.
Signed-off-by: Felipe Balbi <[email protected]>
---
I wanted to take this through the gadget tree, but there is a
dependency with a previous patch of mine adding and extra argument to
the ->write() function. Hoping someone else will take it.
drivers/usb/gadget/Kconfig | 15 ++
drivers/usb/gadget/function/Makefile | 2 +
drivers/usb/gadget/function/f-trace.c | 400 ++++++++++++++++++++++++++++++++++
3 files changed, 417 insertions(+)
create mode 100644 drivers/usb/gadget/function/f-trace.c
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index c164d6b788c3..617921f19b5e 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -188,6 +188,9 @@ config USB_F_MASS_STORAGE
config USB_F_FS
tristate
+config USB_F_TRACE
+ tristate
+
config USB_F_UAC1
tristate
@@ -362,6 +365,18 @@ config USB_CONFIGFS_F_FS
implemented in kernel space (for instance Ethernet, serial or
mass storage) and other are implemented in user space.
+config USB_CONFIGFS_F_TRACE
+ bool "Linux FTrace Export Over USB"
+ depends on USB_CONFIGFS
+ select USB_F_TRACE
+ help
+ The Linux FTrace Export Over USB lets one export ftrace buffer
+ over a USB cable to a host computer for further processing.
+
+ If you want support for that, say Y or M here. Otherwise say N.
+
+ If unsure, say N.
+
config USB_CONFIGFS_F_UAC1
bool "Audio Class 1.0"
depends on USB_CONFIGFS
diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
index cb8c225e8549..1433e8ad7675 100644
--- a/drivers/usb/gadget/function/Makefile
+++ b/drivers/usb/gadget/function/Makefile
@@ -46,3 +46,5 @@ usb_f_printer-y := f_printer.o
obj-$(CONFIG_USB_F_PRINTER) += usb_f_printer.o
usb_f_tcm-y := f_tcm.o
obj-$(CONFIG_USB_F_TCM) += usb_f_tcm.o
+usb_f_trace-y := f-trace.o
+obj-$(CONFIG_USB_F_TRACE) += usb_f_trace.o
diff --git a/drivers/usb/gadget/function/f-trace.c b/drivers/usb/gadget/function/f-trace.c
new file mode 100644
index 000000000000..7de92950c0e7
--- /dev/null
+++ b/drivers/usb/gadget/function/f-trace.c
@@ -0,0 +1,400 @@
+/*
+ * f_trace.c -- USB FTrace Export
+ *
+ * Copyright (C) 2017 Intel Corporation
+ * Author: Felipe Balbi <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License v2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/trace.h>
+#include <linux/usb.h>
+#include <linux/usb/composite.h>
+#include <linux/usb/gadget.h>
+#include <linux/workqueue.h>
+
+struct usb_ftrace {
+ struct trace_export ftrace;
+ struct usb_function function;
+ struct work_struct queue_work;
+ spinlock_t lock;
+
+ struct list_head list;
+ struct list_head pending;
+ struct list_head queued;
+
+ struct usb_ep *in;
+
+ u8 intf_id;
+};
+#define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace))
+#define work_to_trace(w) (container_of((w), struct usb_ftrace, queue_work))
+#define to_trace(f) (container_of((f), struct usb_ftrace, function))
+
+#define FTRACE_REQUEST_QUEUE_LENGTH 250
+
+static inline struct usb_request *next_request(struct list_head *list)
+{
+ return list_first_entry_or_null(list, struct usb_request, list);
+}
+
+struct usb_ftrace_opts {
+ struct usb_function_instance func_inst;
+};
+#define to_opts(fi) (container_of((fi), struct usb_ftrace_opts, func_inst))
+
+static struct usb_interface_descriptor ftrace_intf_desc = {
+ .bLength = USB_DT_INTERFACE_SIZE,
+ .bDescriptorType = USB_DT_INTERFACE,
+
+ .bAlternateSetting = 0,
+ .bNumEndpoints = 1,
+ .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
+ .bInterfaceSubClass = USB_SUBCLASS_VENDOR_SPEC,
+};
+
+/* Super-Speed Support */
+static struct usb_endpoint_descriptor ftrace_ss_in_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(1024),
+};
+
+static struct usb_ss_ep_comp_descriptor ftrace_ss_in_comp_desc = {
+ .bLength = USB_DT_SS_EP_COMP_SIZE,
+ .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
+
+ .bMaxBurst = 15,
+};
+
+static struct usb_descriptor_header *ftrace_ss_function[] = {
+ (struct usb_descriptor_header *) &ftrace_intf_desc,
+ (struct usb_descriptor_header *) &ftrace_ss_in_desc,
+ (struct usb_descriptor_header *) &ftrace_ss_in_comp_desc,
+ NULL,
+};
+
+/* High-Speed Support */
+static struct usb_endpoint_descriptor ftrace_hs_in_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *ftrace_hs_function[] = {
+ (struct usb_descriptor_header *) &ftrace_intf_desc,
+ (struct usb_descriptor_header *) &ftrace_hs_in_desc,
+ NULL,
+};
+
+/* Full-Speed Support */
+static struct usb_endpoint_descriptor ftrace_fs_in_desc = {
+ .bLength = USB_DT_ENDPOINT_SIZE,
+ .bDescriptorType = USB_DT_ENDPOINT,
+
+ .bEndpointAddress = USB_DIR_IN,
+ .bmAttributes = USB_ENDPOINT_XFER_BULK,
+ .wMaxPacketSize = cpu_to_le16(64),
+};
+
+static struct usb_descriptor_header *ftrace_fs_function[] = {
+ (struct usb_descriptor_header *) &ftrace_intf_desc,
+ (struct usb_descriptor_header *) &ftrace_fs_in_desc,
+ NULL,
+};
+
+static struct usb_string ftrace_string_defs[] = {
+ [0].s = "Linux Ftrace Export",
+ { },
+};
+
+static struct usb_gadget_strings ftrace_string_table = {
+ .language = 0x0409, /* en-US */
+ .strings = ftrace_string_defs,
+};
+
+static struct usb_gadget_strings *ftrace_strings[] = {
+ &ftrace_string_table,
+ NULL,
+};
+
+/* ------------------------------------------------------------------------ */
+
+static void ftrace_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct usb_ftrace *trace = req->context;
+
+ kfree(req->buf);
+ list_move_tail(&req->list, &trace->list);
+}
+
+static void ftrace_queue_work(struct work_struct *work)
+{
+ struct usb_ftrace *trace = work_to_trace(work);
+ struct usb_request *req;
+ struct usb_request *tmp;
+ struct list_head local_list;
+
+ spin_lock_irq(&trace->lock);
+restart:
+ list_replace_init(&trace->pending, &local_list);
+ spin_unlock_irq(&trace->lock);
+
+ list_for_each_entry_safe(req, tmp, &local_list, list) {
+ int ret;
+
+ ret = usb_ep_queue(trace->in, req, GFP_KERNEL);
+ if (!ret)
+ list_move_tail(&req->list, &trace->queued);
+ }
+
+ spin_lock_irq(&trace->lock);
+ if (!list_empty(&trace->pending))
+ goto restart;
+ spin_unlock_irq(&trace->lock);
+}
+
+static void notrace ftrace_write(struct trace_export *ftrace, const void *buf,
+ unsigned int len)
+{
+ struct usb_ftrace *trace = ftrace_to_trace(ftrace);
+ struct usb_request *req = next_request(&trace->list);
+
+ if (!req)
+ return;
+
+ if (!trace->in->enabled)
+ return;
+
+ req->buf = kmemdup(buf, len, GFP_ATOMIC);
+ req->length = len;
+ req->context = trace;
+ req->complete = ftrace_complete;
+ list_move_tail(&req->list, &trace->pending);
+
+ schedule_work(&trace->queue_work);
+}
+
+/* ------------------------------------------------------------------------ */
+
+static void ftrace_disable_endpoint(struct usb_ftrace *trace)
+{
+ if (trace->in->enabled)
+ WARN_ON(usb_ep_disable(trace->in));
+}
+
+static int ftrace_enable_endpoint(struct usb_ftrace *trace)
+{
+ if (trace->in->enabled)
+ return 0;
+
+ return usb_ep_enable(trace->in);
+}
+
+static int ftrace_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+ struct usb_ftrace *trace = to_trace(f);
+ struct usb_composite_dev *cdev = f->config->cdev;
+ int ret;
+
+ if (alt != 0)
+ goto fail;
+
+ if (intf != trace->intf_id)
+ goto fail;
+
+ ftrace_disable_endpoint(trace);
+
+ if (!trace->in->desc) {
+ ret = config_ep_by_speed(cdev->gadget, f, trace->in);
+ if (ret) {
+ trace->in->desc = NULL;
+ goto fail;
+ }
+ }
+
+ ret = ftrace_enable_endpoint(trace);
+ if (ret)
+ goto fail;
+
+ return 0;
+
+fail:
+ return -EINVAL;
+}
+
+static int ftrace_bind(struct usb_configuration *c, struct usb_function *f)
+{
+ struct usb_composite_dev *cdev = c->cdev;
+ struct usb_ftrace *trace = to_trace(f);
+ struct usb_string *us;
+ struct usb_ep *ep;
+
+ int ret;
+ int i;
+
+ us = usb_gstrings_attach(cdev, ftrace_strings,
+ ARRAY_SIZE(ftrace_string_defs));
+ if (IS_ERR(us))
+ return PTR_ERR(us);
+
+ ftrace_intf_desc.iInterface = us[0].id;
+
+ ret = usb_interface_id(c, f);
+ if (ret < 0)
+ goto err0;
+ trace->intf_id = ret;
+ ftrace_intf_desc.bInterfaceNumber = ret;
+
+ ep = usb_ep_autoconfig(cdev->gadget, &ftrace_fs_in_desc);
+ if (!ep)
+ goto err0;
+ trace->in = ep;
+
+ ftrace_hs_in_desc.bEndpointAddress = ftrace_fs_in_desc.bEndpointAddress;
+ ftrace_ss_in_desc.bEndpointAddress = ftrace_fs_in_desc.bEndpointAddress;
+
+ trace->ftrace.write = ftrace_write;
+
+ spin_lock_init(&trace->lock);
+ INIT_WORK(&trace->queue_work, ftrace_queue_work);
+ INIT_LIST_HEAD(&trace->list);
+ INIT_LIST_HEAD(&trace->pending);
+ INIT_LIST_HEAD(&trace->queued);
+
+ ret = usb_assign_descriptors(f, ftrace_fs_function, ftrace_hs_function,
+ ftrace_ss_function, NULL);
+ if (ret)
+ goto err0;
+
+ for (i = 0; i < FTRACE_REQUEST_QUEUE_LENGTH; i++) {
+ struct usb_request *req;
+
+ req = usb_ep_alloc_request(trace->in, GFP_KERNEL);
+ if (!req)
+ goto err1;
+
+ list_add_tail(&req->list, &trace->list);
+ }
+
+ ret = register_ftrace_export(&trace->ftrace);
+ if (ret)
+ goto err1;
+
+ return 0;
+
+err1:
+ while (!list_empty(&trace->list)) {
+ struct usb_request *req = next_request(&trace->list);
+
+ usb_ep_free_request(trace->in, req);
+ list_del(&req->list);
+ }
+
+ usb_free_all_descriptors(f);
+
+err0:
+ ERROR(cdev, "%s: can't bind --> err %d\n", f->name, ret);
+
+ return ret;
+}
+
+static void ftrace_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+ struct usb_ftrace *trace = to_trace(f);
+ struct usb_request *req;
+ struct usb_request *tmp;
+
+ unregister_ftrace_export(&trace->ftrace);
+ cancel_work_sync(&trace->queue_work);
+ usb_free_all_descriptors(f);
+
+ list_for_each_entry(req, &trace->queued, list)
+ usb_ep_dequeue(trace->in, req);
+
+ list_for_each_entry_safe(req, tmp, &trace->pending, list) {
+ usb_ep_free_request(trace->in, req);
+ list_del(&req->list);
+ }
+
+ list_for_each_entry_safe(req, tmp, &trace->list, list) {
+ usb_ep_free_request(trace->in, req);
+ list_del(&req->list);
+ }
+}
+
+static void ftrace_disable(struct usb_function *f)
+{
+ struct usb_ftrace *trace = to_trace(f);
+
+ ftrace_disable_endpoint(trace);
+}
+
+static void ftrace_free_func(struct usb_function *f)
+{
+ kfree(to_trace(f));
+}
+
+static struct config_item_type ftrace_func_type = {
+ .ct_owner = THIS_MODULE,
+};
+
+static void ftrace_free_inst(struct usb_function_instance *fi)
+{
+ struct usb_ftrace_opts *opts = to_opts(fi);
+
+ kfree(opts);
+}
+
+static struct usb_function_instance *ftrace_alloc_inst(void)
+{
+ struct usb_ftrace_opts *opts;
+
+ opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+ if (!opts)
+ return ERR_PTR(-ENOMEM);
+
+ opts->func_inst.free_func_inst = ftrace_free_inst;
+
+ config_group_init_type_name(&opts->func_inst.group, "",
+ &ftrace_func_type);
+
+ return &opts->func_inst;
+}
+
+static struct usb_function *ftrace_alloc(struct usb_function_instance *fi)
+{
+ struct usb_ftrace *trace;
+
+ trace = kzalloc(sizeof(*trace), GFP_KERNEL);
+ if (!trace)
+ return NULL;
+
+ trace->function.name = "ftrace";
+ trace->function.bind = ftrace_bind;
+ trace->function.unbind = ftrace_unbind;
+ trace->function.set_alt = ftrace_set_alt;
+ trace->function.disable = ftrace_disable;
+ trace->function.strings = ftrace_strings;
+ trace->function.free_func = ftrace_free_func;
+
+ return &trace->function;
+}
+
+DECLARE_USB_FUNCTION_INIT(ftrace, ftrace_alloc_inst, ftrace_alloc);
+MODULE_AUTHOR("Felipe Balbi <[email protected]>");
+MODULE_LICENSE("GPL v2");
--
2.11.0.295.gd7dffce1ce
Felipe Balbi <[email protected]> writes:
> Allow for ftrace data to be exported over a USB Gadget
> Controller. With this, we have a potentially very fast pipe for
> transmitting ftrace data to a Host PC for further analysis.
>
> Note that in order to decode the data, one needs access to kernel
> symbols in order to convert binary data into function names and what
> not.
>
> Signed-off-by: Felipe Balbi <[email protected]>
> ---
>
> I wanted to take this through the gadget tree, but there is a
> dependency with a previous patch of mine adding and extra argument to
> the ->write() function. Hoping someone else will take it.
just as an extra note here. In order for this to be really useful, it
would be nice to be able to control what is going to be traced over USB
as well, but that means exporting a few extra functions to GPL drivers.
Would that be okay? I could have a set of vendor-specific control
requests to set buffer size and to read/write ftrace filter functions.
The idea is that things like e.g. Android SDK could rely on this on
debug builds and the SDK itself would make sure to keep a copy of
vmlinux around to processing of the data coming through USB.
--
balbi
Felipe Balbi <[email protected]> writes:
> Felipe Balbi <[email protected]> writes:
>
>> Allow for ftrace data to be exported over a USB Gadget
>> Controller. With this, we have a potentially very fast pipe for
>> transmitting ftrace data to a Host PC for further analysis.
>>
>> Note that in order to decode the data, one needs access to kernel
>> symbols in order to convert binary data into function names and what
>> not.
>>
>> Signed-off-by: Felipe Balbi <[email protected]>
>> ---
>>
>> I wanted to take this through the gadget tree, but there is a
>> dependency with a previous patch of mine adding and extra argument to
>> the ->write() function. Hoping someone else will take it.
>
> just as an extra note here. In order for this to be really useful, it
> would be nice to be able to control what is going to be traced over USB
> as well, but that means exporting a few extra functions to GPL drivers.
>
> Would that be okay? I could have a set of vendor-specific control
> requests to set buffer size and to read/write ftrace filter functions.
>
> The idea is that things like e.g. Android SDK could rely on this on
> debug builds and the SDK itself would make sure to keep a copy of
> vmlinux around to processing of the data coming through USB.
something along these lines (although I think trace buffer size doesn't
matter for trace export, but it serves well enough to illustrate a
point):
modified drivers/usb/gadget/function/f-trace.c
@@ -33,6 +33,8 @@ struct usb_ftrace {
struct usb_ep *in;
+ u32 buffer_size;
+ u16 version;
u8 intf_id;
};
#define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace))
@@ -40,6 +42,12 @@ struct usb_ftrace {
#define to_trace(f) (container_of((f), struct usb_ftrace, function))
#define FTRACE_REQUEST_QUEUE_LENGTH 250
+#define FTRACE_VERSION 0x0100 /* bcd 1.00 */
+
+/* FTrace vendor-specific requests */
+#define USB_FTRACE_GET_VERSION 0x00
+#define USB_FTRACE_GET_TRACE_BUF_SIZE 0x01
+#define USB_FTRACE_SET_TRACE_BUF_SIZE 0x02
static inline struct usb_request *next_request(struct list_head *list)
{
@@ -142,6 +150,13 @@ static void ftrace_complete(struct usb_ep *ep, struct usb_request *req)
list_move_tail(&req->list, &trace->list);
}
+static void ftrace_set_trace_buf_size_complete(struct usb_ep *ep, struct usb_request *req)
+{
+ struct usb_ftrace *trace = req->context;
+
+ trace_set_buf_size(le32_to_cpu(trace->buffer_size));
+}
+
static void ftrace_queue_work(struct work_struct *work)
{
struct usb_ftrace *trace = work_to_trace(work);
@@ -237,6 +252,71 @@ static int ftrace_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
return -EINVAL;
}
+extern unsigned long trace_get_buf_size(void);
+
+static int ftrace_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
+{
+ struct usb_configuration *c = f->config;
+ struct usb_request *req = c->cdev->req;
+ struct usb_ftrace *trace = to_trace(f);
+
+ int ret;
+
+ u16 index = le16_to_cpu(ctrl->wIndex);
+ u16 value = le16_to_cpu(ctrl->wValue);
+ u16 length = le16_to_cpu(ctrl->wLength);
+
+ if (value != 0 || index != 0)
+ return -EINVAL;
+
+ switch (ctrl->bRequest) {
+ case USB_FTRACE_GET_VERSION:
+ if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_VENDOR |
+ USB_RECIP_INTERFACE))
+ return -EINVAL;
+
+ if (length != 2)
+ return -EINVAL;
+
+ req->zero = 0;
+ req->length = 2;
+ req->buf = &trace->version;
+ break;
+ case USB_FTRACE_GET_TRACE_BUF_SIZE:
+ if (ctrl->bRequestType != (USB_DIR_IN | USB_TYPE_VENDOR |
+ USB_RECIP_INTERFACE))
+ return -EINVAL;
+
+ if (length != 2)
+ return -EINVAL;
+
+ trace->buffer_size = cpu_to_le32(trace_get_buf_size());
+
+ req->zero = 0;
+ req->length = 2;
+ req->buf = &trace->buffer_size;
+ break;
+ case USB_FTRACE_SET_TRACE_BUF_SIZE:
+ if (ctrl->bRequestType != (USB_DIR_OUT | USB_TYPE_VENDOR |
+ USB_RECIP_INTERFACE))
+ return -EINVAL;
+
+ if (length != 4)
+ return -EINVAL;
+
+ req->zero = 0;
+ req->length = 4;
+ req->context = trace;
+ req->complete = ftrace_set_trace_buf_size_complete;
+ req->buf = &trace->buffer_size;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return usb_ep_queue(c->cdev->gadget->ep0, req, GFP_ATOMIC);
+}
+
static int ftrace_bind(struct usb_configuration *c, struct usb_function *f)
{
struct usb_composite_dev *cdev = c->cdev;
@@ -247,6 +327,8 @@ static int ftrace_bind(struct usb_configuration *c, struct usb_function *f)
int ret;
int i;
+ trace->version = cpu_to_le16(FTRACE_VERSION);
+
us = usb_gstrings_attach(cdev, ftrace_strings,
ARRAY_SIZE(ftrace_string_defs));
if (IS_ERR(us))
modified kernel/trace/trace.c
@@ -618,6 +618,12 @@ int tracing_is_enabled(void)
static unsigned long trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
+unsigned long trace_get_buf_size(void)
+{
+ return trace_buf_size;
+}
+EXPORT_SYMBOL_GPL(trace_get_buf_size);
+
/* trace_types holds a link list of available tracers. */
static struct tracer *trace_types __read_mostly;
--
balbi
On Fri, 9 Jun 2017 09:13:27 +0300
Felipe Balbi <[email protected]> wrote:
> Allow for ftrace data to be exported over a USB Gadget
> Controller. With this, we have a potentially very fast pipe for
> transmitting ftrace data to a Host PC for further analysis.
>
> Note that in order to decode the data, one needs access to kernel
> symbols in order to convert binary data into function names and what
> not.
>
Can you please explain what this is in a bit more detail. I have no
idea what you are trying to accomplish.
Also, do you mean ftrace as the internal Linux tracer (which should
only be called "ftrace" or sometimes "Ftrace" but not "f_trace" or
"FTrace", that just leads to more confusion.
Or is this to do with http://www.ftrace.com/en/gb, a way to trace
produce ;-)
-- Steve
> Signed-off-by: Felipe Balbi <[email protected]>
> ---
>
> I wanted to take this through the gadget tree, but there is a
> dependency with a previous patch of mine adding and extra argument to
> the ->write() function. Hoping someone else will take it.
>
> drivers/usb/gadget/Kconfig | 15 ++
> drivers/usb/gadget/function/Makefile | 2 +
> drivers/usb/gadget/function/f-trace.c | 400 ++++++++++++++++++++++++++++++++++
> 3 files changed, 417 insertions(+)
> create mode 100644 drivers/usb/gadget/function/f-trace.c
>
> diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
> index c164d6b788c3..617921f19b5e 100644
> --- a/drivers/usb/gadget/Kconfig
> +++ b/drivers/usb/gadget/Kconfig
> @@ -188,6 +188,9 @@ config USB_F_MASS_STORAGE
> config USB_F_FS
> tristate
>
> +config USB_F_TRACE
> + tristate
> +
> config USB_F_UAC1
> tristate
>
> @@ -362,6 +365,18 @@ config USB_CONFIGFS_F_FS
> implemented in kernel space (for instance Ethernet, serial or
> mass storage) and other are implemented in user space.
>
> +config USB_CONFIGFS_F_TRACE
> + bool "Linux FTrace Export Over USB"
> + depends on USB_CONFIGFS
> + select USB_F_TRACE
> + help
> + The Linux FTrace Export Over USB lets one export ftrace buffer
> + over a USB cable to a host computer for further processing.
> +
> + If you want support for that, say Y or M here. Otherwise say N.
> +
> + If unsure, say N.
> +
> config USB_CONFIGFS_F_UAC1
> bool "Audio Class 1.0"
> depends on USB_CONFIGFS
> diff --git a/drivers/usb/gadget/function/Makefile b/drivers/usb/gadget/function/Makefile
> index cb8c225e8549..1433e8ad7675 100644
> --- a/drivers/usb/gadget/function/Makefile
> +++ b/drivers/usb/gadget/function/Makefile
> @@ -46,3 +46,5 @@ usb_f_printer-y := f_printer.o
> obj-$(CONFIG_USB_F_PRINTER) += usb_f_printer.o
> usb_f_tcm-y := f_tcm.o
> obj-$(CONFIG_USB_F_TCM) += usb_f_tcm.o
> +usb_f_trace-y := f-trace.o
> +obj-$(CONFIG_USB_F_TRACE) += usb_f_trace.o
> diff --git a/drivers/usb/gadget/function/f-trace.c b/drivers/usb/gadget/function/f-trace.c
> new file mode 100644
> index 000000000000..7de92950c0e7
> --- /dev/null
> +++ b/drivers/usb/gadget/function/f-trace.c
> @@ -0,0 +1,400 @@
> +/*
> + * f_trace.c -- USB FTrace Export
> + *
> + * Copyright (C) 2017 Intel Corporation
> + * Author: Felipe Balbi <[email protected]>
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License v2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/trace.h>
> +#include <linux/usb.h>
> +#include <linux/usb/composite.h>
> +#include <linux/usb/gadget.h>
> +#include <linux/workqueue.h>
> +
> +struct usb_ftrace {
> + struct trace_export ftrace;
> + struct usb_function function;
> + struct work_struct queue_work;
> + spinlock_t lock;
> +
> + struct list_head list;
> + struct list_head pending;
> + struct list_head queued;
> +
> + struct usb_ep *in;
> +
> + u8 intf_id;
> +};
> +#define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace))
> +#define work_to_trace(w) (container_of((w), struct usb_ftrace, queue_work))
> +#define to_trace(f) (container_of((f), struct usb_ftrace, function))
> +
> +#define FTRACE_REQUEST_QUEUE_LENGTH 250
> +
> +static inline struct usb_request *next_request(struct list_head *list)
> +{
> + return list_first_entry_or_null(list, struct usb_request, list);
> +}
> +
> +struct usb_ftrace_opts {
> + struct usb_function_instance func_inst;
> +};
> +#define to_opts(fi) (container_of((fi), struct usb_ftrace_opts, func_inst))
> +
> +static struct usb_interface_descriptor ftrace_intf_desc = {
> + .bLength = USB_DT_INTERFACE_SIZE,
> + .bDescriptorType = USB_DT_INTERFACE,
> +
> + .bAlternateSetting = 0,
> + .bNumEndpoints = 1,
> + .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
> + .bInterfaceSubClass = USB_SUBCLASS_VENDOR_SPEC,
> +};
> +
> +/* Super-Speed Support */
> +static struct usb_endpoint_descriptor ftrace_ss_in_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bEndpointAddress = USB_DIR_IN,
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(1024),
> +};
> +
> +static struct usb_ss_ep_comp_descriptor ftrace_ss_in_comp_desc = {
> + .bLength = USB_DT_SS_EP_COMP_SIZE,
> + .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
> +
> + .bMaxBurst = 15,
> +};
> +
> +static struct usb_descriptor_header *ftrace_ss_function[] = {
> + (struct usb_descriptor_header *) &ftrace_intf_desc,
> + (struct usb_descriptor_header *) &ftrace_ss_in_desc,
> + (struct usb_descriptor_header *) &ftrace_ss_in_comp_desc,
> + NULL,
> +};
> +
> +/* High-Speed Support */
> +static struct usb_endpoint_descriptor ftrace_hs_in_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bEndpointAddress = USB_DIR_IN,
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(512),
> +};
> +
> +static struct usb_descriptor_header *ftrace_hs_function[] = {
> + (struct usb_descriptor_header *) &ftrace_intf_desc,
> + (struct usb_descriptor_header *) &ftrace_hs_in_desc,
> + NULL,
> +};
> +
> +/* Full-Speed Support */
> +static struct usb_endpoint_descriptor ftrace_fs_in_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bEndpointAddress = USB_DIR_IN,
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(64),
> +};
> +
> +static struct usb_descriptor_header *ftrace_fs_function[] = {
> + (struct usb_descriptor_header *) &ftrace_intf_desc,
> + (struct usb_descriptor_header *) &ftrace_fs_in_desc,
> + NULL,
> +};
> +
> +static struct usb_string ftrace_string_defs[] = {
> + [0].s = "Linux Ftrace Export",
> + { },
> +};
> +
> +static struct usb_gadget_strings ftrace_string_table = {
> + .language = 0x0409, /* en-US */
> + .strings = ftrace_string_defs,
> +};
> +
> +static struct usb_gadget_strings *ftrace_strings[] = {
> + &ftrace_string_table,
> + NULL,
> +};
> +
> +/* ------------------------------------------------------------------------ */
> +
> +static void ftrace_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + struct usb_ftrace *trace = req->context;
> +
> + kfree(req->buf);
> + list_move_tail(&req->list, &trace->list);
> +}
> +
> +static void ftrace_queue_work(struct work_struct *work)
> +{
> + struct usb_ftrace *trace = work_to_trace(work);
> + struct usb_request *req;
> + struct usb_request *tmp;
> + struct list_head local_list;
> +
> + spin_lock_irq(&trace->lock);
> +restart:
> + list_replace_init(&trace->pending, &local_list);
> + spin_unlock_irq(&trace->lock);
> +
> + list_for_each_entry_safe(req, tmp, &local_list, list) {
> + int ret;
> +
> + ret = usb_ep_queue(trace->in, req, GFP_KERNEL);
> + if (!ret)
> + list_move_tail(&req->list, &trace->queued);
> + }
> +
> + spin_lock_irq(&trace->lock);
> + if (!list_empty(&trace->pending))
> + goto restart;
> + spin_unlock_irq(&trace->lock);
> +}
> +
> +static void notrace ftrace_write(struct trace_export *ftrace, const void *buf,
> + unsigned int len)
> +{
> + struct usb_ftrace *trace = ftrace_to_trace(ftrace);
> + struct usb_request *req = next_request(&trace->list);
> +
> + if (!req)
> + return;
> +
> + if (!trace->in->enabled)
> + return;
> +
> + req->buf = kmemdup(buf, len, GFP_ATOMIC);
> + req->length = len;
> + req->context = trace;
> + req->complete = ftrace_complete;
> + list_move_tail(&req->list, &trace->pending);
> +
> + schedule_work(&trace->queue_work);
> +}
> +
> +/* ------------------------------------------------------------------------ */
> +
> +static void ftrace_disable_endpoint(struct usb_ftrace *trace)
> +{
> + if (trace->in->enabled)
> + WARN_ON(usb_ep_disable(trace->in));
> +}
> +
> +static int ftrace_enable_endpoint(struct usb_ftrace *trace)
> +{
> + if (trace->in->enabled)
> + return 0;
> +
> + return usb_ep_enable(trace->in);
> +}
> +
> +static int ftrace_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
> +{
> + struct usb_ftrace *trace = to_trace(f);
> + struct usb_composite_dev *cdev = f->config->cdev;
> + int ret;
> +
> + if (alt != 0)
> + goto fail;
> +
> + if (intf != trace->intf_id)
> + goto fail;
> +
> + ftrace_disable_endpoint(trace);
> +
> + if (!trace->in->desc) {
> + ret = config_ep_by_speed(cdev->gadget, f, trace->in);
> + if (ret) {
> + trace->in->desc = NULL;
> + goto fail;
> + }
> + }
> +
> + ret = ftrace_enable_endpoint(trace);
> + if (ret)
> + goto fail;
> +
> + return 0;
> +
> +fail:
> + return -EINVAL;
> +}
> +
> +static int ftrace_bind(struct usb_configuration *c, struct usb_function *f)
> +{
> + struct usb_composite_dev *cdev = c->cdev;
> + struct usb_ftrace *trace = to_trace(f);
> + struct usb_string *us;
> + struct usb_ep *ep;
> +
> + int ret;
> + int i;
> +
> + us = usb_gstrings_attach(cdev, ftrace_strings,
> + ARRAY_SIZE(ftrace_string_defs));
> + if (IS_ERR(us))
> + return PTR_ERR(us);
> +
> + ftrace_intf_desc.iInterface = us[0].id;
> +
> + ret = usb_interface_id(c, f);
> + if (ret < 0)
> + goto err0;
> + trace->intf_id = ret;
> + ftrace_intf_desc.bInterfaceNumber = ret;
> +
> + ep = usb_ep_autoconfig(cdev->gadget, &ftrace_fs_in_desc);
> + if (!ep)
> + goto err0;
> + trace->in = ep;
> +
> + ftrace_hs_in_desc.bEndpointAddress = ftrace_fs_in_desc.bEndpointAddress;
> + ftrace_ss_in_desc.bEndpointAddress = ftrace_fs_in_desc.bEndpointAddress;
> +
> + trace->ftrace.write = ftrace_write;
> +
> + spin_lock_init(&trace->lock);
> + INIT_WORK(&trace->queue_work, ftrace_queue_work);
> + INIT_LIST_HEAD(&trace->list);
> + INIT_LIST_HEAD(&trace->pending);
> + INIT_LIST_HEAD(&trace->queued);
> +
> + ret = usb_assign_descriptors(f, ftrace_fs_function, ftrace_hs_function,
> + ftrace_ss_function, NULL);
> + if (ret)
> + goto err0;
> +
> + for (i = 0; i < FTRACE_REQUEST_QUEUE_LENGTH; i++) {
> + struct usb_request *req;
> +
> + req = usb_ep_alloc_request(trace->in, GFP_KERNEL);
> + if (!req)
> + goto err1;
> +
> + list_add_tail(&req->list, &trace->list);
> + }
> +
> + ret = register_ftrace_export(&trace->ftrace);
> + if (ret)
> + goto err1;
> +
> + return 0;
> +
> +err1:
> + while (!list_empty(&trace->list)) {
> + struct usb_request *req = next_request(&trace->list);
> +
> + usb_ep_free_request(trace->in, req);
> + list_del(&req->list);
> + }
> +
> + usb_free_all_descriptors(f);
> +
> +err0:
> + ERROR(cdev, "%s: can't bind --> err %d\n", f->name, ret);
> +
> + return ret;
> +}
> +
> +static void ftrace_unbind(struct usb_configuration *c, struct usb_function *f)
> +{
> + struct usb_ftrace *trace = to_trace(f);
> + struct usb_request *req;
> + struct usb_request *tmp;
> +
> + unregister_ftrace_export(&trace->ftrace);
> + cancel_work_sync(&trace->queue_work);
> + usb_free_all_descriptors(f);
> +
> + list_for_each_entry(req, &trace->queued, list)
> + usb_ep_dequeue(trace->in, req);
> +
> + list_for_each_entry_safe(req, tmp, &trace->pending, list) {
> + usb_ep_free_request(trace->in, req);
> + list_del(&req->list);
> + }
> +
> + list_for_each_entry_safe(req, tmp, &trace->list, list) {
> + usb_ep_free_request(trace->in, req);
> + list_del(&req->list);
> + }
> +}
> +
> +static void ftrace_disable(struct usb_function *f)
> +{
> + struct usb_ftrace *trace = to_trace(f);
> +
> + ftrace_disable_endpoint(trace);
> +}
> +
> +static void ftrace_free_func(struct usb_function *f)
> +{
> + kfree(to_trace(f));
> +}
> +
> +static struct config_item_type ftrace_func_type = {
> + .ct_owner = THIS_MODULE,
> +};
> +
> +static void ftrace_free_inst(struct usb_function_instance *fi)
> +{
> + struct usb_ftrace_opts *opts = to_opts(fi);
> +
> + kfree(opts);
> +}
> +
> +static struct usb_function_instance *ftrace_alloc_inst(void)
> +{
> + struct usb_ftrace_opts *opts;
> +
> + opts = kzalloc(sizeof(*opts), GFP_KERNEL);
> + if (!opts)
> + return ERR_PTR(-ENOMEM);
> +
> + opts->func_inst.free_func_inst = ftrace_free_inst;
> +
> + config_group_init_type_name(&opts->func_inst.group, "",
> + &ftrace_func_type);
> +
> + return &opts->func_inst;
> +}
> +
> +static struct usb_function *ftrace_alloc(struct usb_function_instance *fi)
> +{
> + struct usb_ftrace *trace;
> +
> + trace = kzalloc(sizeof(*trace), GFP_KERNEL);
> + if (!trace)
> + return NULL;
> +
> + trace->function.name = "ftrace";
> + trace->function.bind = ftrace_bind;
> + trace->function.unbind = ftrace_unbind;
> + trace->function.set_alt = ftrace_set_alt;
> + trace->function.disable = ftrace_disable;
> + trace->function.strings = ftrace_strings;
> + trace->function.free_func = ftrace_free_func;
> +
> + return &trace->function;
> +}
> +
> +DECLARE_USB_FUNCTION_INIT(ftrace, ftrace_alloc_inst, ftrace_alloc);
> +MODULE_AUTHOR("Felipe Balbi <[email protected]>");
> +MODULE_LICENSE("GPL v2");
Hi,
Steven Rostedt <[email protected]> writes:
> On Fri, 9 Jun 2017 09:13:27 +0300
> Felipe Balbi <[email protected]> wrote:
>
>> Allow for ftrace data to be exported over a USB Gadget
>> Controller. With this, we have a potentially very fast pipe for
>> transmitting ftrace data to a Host PC for further analysis.
>>
>> Note that in order to decode the data, one needs access to kernel
>> symbols in order to convert binary data into function names and what
>> not.
>>
>
> Can you please explain what this is in a bit more detail. I have no
> idea what you are trying to accomplish.
this is just another ftrace export. Just like STM
(drivers/hwtracing/stm/ftrace.c), but I'm making use of a USB Peripheral
Controller that may be available.
> Also, do you mean ftrace as the internal Linux tracer (which should
> only be called "ftrace" or sometimes "Ftrace" but not "f_trace" or
> "FTrace", that just leads to more confusion.
heh, internal linux ftrace ;-) The driver name (f-trace.c) is just to
follow the convention of USB functions being name f_*.c or f-*.c. I
could call it f-ftrace.c, but seemed unnecessary.
> Or is this to do with http://www.ftrace.com/en/gb, a way to trace
> produce ;-)
heh :-) unlikely
--
balbi
On Fri, 09 Jun 2017 17:05:52 +0300
Felipe Balbi <[email protected]> wrote:
> Hi,
>
> Steven Rostedt <[email protected]> writes:
> > On Fri, 9 Jun 2017 09:13:27 +0300
> > Felipe Balbi <[email protected]> wrote:
> >
> >> Allow for ftrace data to be exported over a USB Gadget
> >> Controller. With this, we have a potentially very fast pipe for
> >> transmitting ftrace data to a Host PC for further analysis.
> >>
> >> Note that in order to decode the data, one needs access to kernel
> >> symbols in order to convert binary data into function names and what
> >> not.
> >>
> >
> > Can you please explain what this is in a bit more detail. I have no
> > idea what you are trying to accomplish.
>
> this is just another ftrace export. Just like STM
> (drivers/hwtracing/stm/ftrace.c), but I'm making use of a USB Peripheral
> Controller that may be available.
>
> > Also, do you mean ftrace as the internal Linux tracer (which should
> > only be called "ftrace" or sometimes "Ftrace" but not "f_trace" or
> > "FTrace", that just leads to more confusion.
>
> heh, internal linux ftrace ;-) The driver name (f-trace.c) is just to
> follow the convention of USB functions being name f_*.c or f-*.c. I
> could call it f-ftrace.c, but seemed unnecessary.
OK, looking at the other files and functions in
drivers/usb/gadget/function, I see that F there is part of usb process.
OK, although it does make it somewhat confusing.
-- Steve
Hi Felipe,
[auto build test ERROR on balbi-usb/next]
[also build test ERROR on v4.12-rc4 next-20170609]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Felipe-Balbi/usb-gadget-functions-add-ftrace-export-over-USB/20170610-060059
base: https://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git next
config: i386-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
# save the attached .config to linux build tree
make ARCH=i386
All errors (new ones prefixed by >>):
drivers/usb/gadget/function/f-trace.c: In function 'ftrace_bind':
>> drivers/usb/gadget/function/f-trace.c:271:22: error: assignment from incompatible pointer type [-Werror=incompatible-pointer-types]
trace->ftrace.write = ftrace_write;
^
cc1: some warnings being treated as errors
vim +271 drivers/usb/gadget/function/f-trace.c
265 goto err0;
266 trace->in = ep;
267
268 ftrace_hs_in_desc.bEndpointAddress = ftrace_fs_in_desc.bEndpointAddress;
269 ftrace_ss_in_desc.bEndpointAddress = ftrace_fs_in_desc.bEndpointAddress;
270
> 271 trace->ftrace.write = ftrace_write;
272
273 spin_lock_init(&trace->lock);
274 INIT_WORK(&trace->queue_work, ftrace_queue_work);
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Felipe,
[auto build test ERROR on balbi-usb/next]
[also build test ERROR on v4.12-rc4 next-20170609]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Felipe-Balbi/usb-gadget-functions-add-ftrace-export-over-USB/20170610-060059
base: https://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git next
config: alpha-allyesconfig (attached as .config)
compiler: alpha-linux-gnu-gcc (Debian 6.3.0-18) 6.3.0 20170516
reproduce:
wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=alpha
All error/warnings (new ones prefixed by >>):
>> drivers/usb/gadget/function/f-trace.c:25:22: error: field 'ftrace' has incomplete type
struct trace_export ftrace;
^~~~~~
In file included from include/linux/list.h:8:0,
from include/linux/kobject.h:20,
from include/linux/device.h:17,
from drivers/usb/gadget/function/f-trace.c:12:
drivers/usb/gadget/function/f-trace.c: In function 'ftrace_write':
include/linux/kernel.h:854:48: error: initialization from incompatible pointer type [-Werror=incompatible-pointer-types]
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
^
>> drivers/usb/gadget/function/f-trace.c:38:29: note: in expansion of macro 'container_of'
#define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace))
^~~~~~~~~~~~
>> drivers/usb/gadget/function/f-trace.c:174:30: note: in expansion of macro 'ftrace_to_trace'
struct usb_ftrace *trace = ftrace_to_trace(ftrace);
^~~~~~~~~~~~~~~
include/linux/kernel.h:854:48: note: (near initialization for 'trace')
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
^
>> drivers/usb/gadget/function/f-trace.c:38:29: note: in expansion of macro 'container_of'
#define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace))
^~~~~~~~~~~~
>> drivers/usb/gadget/function/f-trace.c:174:30: note: in expansion of macro 'ftrace_to_trace'
struct usb_ftrace *trace = ftrace_to_trace(ftrace);
^~~~~~~~~~~~~~~
drivers/usb/gadget/function/f-trace.c: In function 'ftrace_bind':
>> drivers/usb/gadget/function/f-trace.c:294:8: error: implicit declaration of function 'register_ftrace_export' [-Werror=implicit-function-declaration]
ret = register_ftrace_export(&trace->ftrace);
^~~~~~~~~~~~~~~~~~~~~~
drivers/usb/gadget/function/f-trace.c: In function 'ftrace_unbind':
>> drivers/usb/gadget/function/f-trace.c:322:2: error: implicit declaration of function 'unregister_ftrace_export' [-Werror=implicit-function-declaration]
unregister_ftrace_export(&trace->ftrace);
^~~~~~~~~~~~~~~~~~~~~~~~
cc1: some warnings being treated as errors
vim +/ftrace +25 drivers/usb/gadget/function/f-trace.c
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License v2 as
9 * published by the Free Software Foundation.
10 */
11
> 12 #include <linux/device.h>
13 #include <linux/kernel.h>
14 #include <linux/list.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/spinlock.h>
18 #include <linux/trace.h>
19 #include <linux/usb.h>
20 #include <linux/usb/composite.h>
21 #include <linux/usb/gadget.h>
22 #include <linux/workqueue.h>
23
24 struct usb_ftrace {
> 25 struct trace_export ftrace;
26 struct usb_function function;
27 struct work_struct queue_work;
28 spinlock_t lock;
29
30 struct list_head list;
31 struct list_head pending;
32 struct list_head queued;
33
34 struct usb_ep *in;
35
36 u8 intf_id;
37 };
> 38 #define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace))
39 #define work_to_trace(w) (container_of((w), struct usb_ftrace, queue_work))
40 #define to_trace(f) (container_of((f), struct usb_ftrace, function))
41
42 #define FTRACE_REQUEST_QUEUE_LENGTH 250
43
44 static inline struct usb_request *next_request(struct list_head *list)
45 {
46 return list_first_entry_or_null(list, struct usb_request, list);
47 }
48
49 struct usb_ftrace_opts {
50 struct usb_function_instance func_inst;
51 };
52 #define to_opts(fi) (container_of((fi), struct usb_ftrace_opts, func_inst))
53
54 static struct usb_interface_descriptor ftrace_intf_desc = {
55 .bLength = USB_DT_INTERFACE_SIZE,
56 .bDescriptorType = USB_DT_INTERFACE,
57
58 .bAlternateSetting = 0,
59 .bNumEndpoints = 1,
60 .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
61 .bInterfaceSubClass = USB_SUBCLASS_VENDOR_SPEC,
62 };
63
64 /* Super-Speed Support */
65 static struct usb_endpoint_descriptor ftrace_ss_in_desc = {
66 .bLength = USB_DT_ENDPOINT_SIZE,
67 .bDescriptorType = USB_DT_ENDPOINT,
68
69 .bEndpointAddress = USB_DIR_IN,
70 .bmAttributes = USB_ENDPOINT_XFER_BULK,
71 .wMaxPacketSize = cpu_to_le16(1024),
72 };
73
74 static struct usb_ss_ep_comp_descriptor ftrace_ss_in_comp_desc = {
75 .bLength = USB_DT_SS_EP_COMP_SIZE,
76 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
77
78 .bMaxBurst = 15,
79 };
80
81 static struct usb_descriptor_header *ftrace_ss_function[] = {
82 (struct usb_descriptor_header *) &ftrace_intf_desc,
83 (struct usb_descriptor_header *) &ftrace_ss_in_desc,
84 (struct usb_descriptor_header *) &ftrace_ss_in_comp_desc,
85 NULL,
86 };
87
88 /* High-Speed Support */
89 static struct usb_endpoint_descriptor ftrace_hs_in_desc = {
90 .bLength = USB_DT_ENDPOINT_SIZE,
91 .bDescriptorType = USB_DT_ENDPOINT,
92
93 .bEndpointAddress = USB_DIR_IN,
94 .bmAttributes = USB_ENDPOINT_XFER_BULK,
95 .wMaxPacketSize = cpu_to_le16(512),
96 };
97
98 static struct usb_descriptor_header *ftrace_hs_function[] = {
99 (struct usb_descriptor_header *) &ftrace_intf_desc,
100 (struct usb_descriptor_header *) &ftrace_hs_in_desc,
101 NULL,
102 };
103
104 /* Full-Speed Support */
105 static struct usb_endpoint_descriptor ftrace_fs_in_desc = {
106 .bLength = USB_DT_ENDPOINT_SIZE,
107 .bDescriptorType = USB_DT_ENDPOINT,
108
109 .bEndpointAddress = USB_DIR_IN,
110 .bmAttributes = USB_ENDPOINT_XFER_BULK,
111 .wMaxPacketSize = cpu_to_le16(64),
112 };
113
114 static struct usb_descriptor_header *ftrace_fs_function[] = {
115 (struct usb_descriptor_header *) &ftrace_intf_desc,
116 (struct usb_descriptor_header *) &ftrace_fs_in_desc,
117 NULL,
118 };
119
120 static struct usb_string ftrace_string_defs[] = {
121 [0].s = "Linux Ftrace Export",
122 { },
123 };
124
125 static struct usb_gadget_strings ftrace_string_table = {
126 .language = 0x0409, /* en-US */
127 .strings = ftrace_string_defs,
128 };
129
130 static struct usb_gadget_strings *ftrace_strings[] = {
131 &ftrace_string_table,
132 NULL,
133 };
134
135 /* ------------------------------------------------------------------------ */
136
137 static void ftrace_complete(struct usb_ep *ep, struct usb_request *req)
138 {
139 struct usb_ftrace *trace = req->context;
140
141 kfree(req->buf);
142 list_move_tail(&req->list, &trace->list);
143 }
144
145 static void ftrace_queue_work(struct work_struct *work)
146 {
147 struct usb_ftrace *trace = work_to_trace(work);
148 struct usb_request *req;
149 struct usb_request *tmp;
150 struct list_head local_list;
151
152 spin_lock_irq(&trace->lock);
153 restart:
154 list_replace_init(&trace->pending, &local_list);
155 spin_unlock_irq(&trace->lock);
156
157 list_for_each_entry_safe(req, tmp, &local_list, list) {
158 int ret;
159
160 ret = usb_ep_queue(trace->in, req, GFP_KERNEL);
161 if (!ret)
162 list_move_tail(&req->list, &trace->queued);
163 }
164
165 spin_lock_irq(&trace->lock);
166 if (!list_empty(&trace->pending))
167 goto restart;
168 spin_unlock_irq(&trace->lock);
169 }
170
171 static void notrace ftrace_write(struct trace_export *ftrace, const void *buf,
172 unsigned int len)
173 {
> 174 struct usb_ftrace *trace = ftrace_to_trace(ftrace);
175 struct usb_request *req = next_request(&trace->list);
176
177 if (!req)
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi,
kbuild test robot <[email protected]> writes:
> Hi Felipe,
>
> [auto build test ERROR on balbi-usb/next]
> [also build test ERROR on v4.12-rc4 next-20170609]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
this patch depends on another patch [1] in order to compile properly :-)
[1] https://marc.info/[email protected]
--
balbi
Hi,
Felipe Balbi <[email protected]> writes:
> Allow for ftrace data to be exported over a USB Gadget
> Controller. With this, we have a potentially very fast pipe for
> transmitting ftrace data to a Host PC for further analysis.
>
> Note that in order to decode the data, one needs access to kernel
> symbols in order to convert binary data into function names and what
> not.
>
> Signed-off-by: Felipe Balbi <[email protected]>
> ---
Looks like this and its depedency missed the merge window. Steven, how
do you want me to handle them? Should I rebase them once -rc1 is tagged
and resend?
--
balbi
Hi Felipe,
On Friday 09 June 2017 11:43 AM, Felipe Balbi wrote:
> +static void notrace ftrace_write(struct trace_export *ftrace, const void *buf,
> + unsigned int len)
> +{
> + struct usb_ftrace *trace = ftrace_to_trace(ftrace);
> + struct usb_request *req = next_request(&trace->list);
> +
> + if (!req)
> + return;
> +
> + if (!trace->in->enabled)
> + return;
> +
> + req->buf = kmemdup(buf, len, GFP_ATOMIC);
Probably we can avoid the copy of trace data.
We can make write() call of "struct trace_export" as posted. Can have a
write_complete() callback function implemented in struct trace_export,which
can be called from your ftrace_complete().
We need to execute __buffer_unlock_commit() only in write_complete() in case
of ftrace_export is enabled.
> + req->length = len;
> + req->context = trace;
> + req->complete = ftrace_complete;
> + list_move_tail(&req->list, &trace->pending);
> +
> + schedule_work(&trace->queue_work);
> +}
> +
--
Pratyush
Hi Felipe,
On Friday 09 June 2017 03:58 PM, Felipe Balbi wrote:
> Felipe Balbi <[email protected]> writes:
>
>> Allow for ftrace data to be exported over a USB Gadget
>> Controller. With this, we have a potentially very fast pipe for
>> transmitting ftrace data to a Host PC for further analysis.
>>
>> Note that in order to decode the data, one needs access to kernel
>> symbols in order to convert binary data into function names and what
>> not.
>>
>> Signed-off-by: Felipe Balbi <[email protected]>
>> ---
>>
>> I wanted to take this through the gadget tree, but there is a
>> dependency with a previous patch of mine adding and extra argument to
>> the ->write() function. Hoping someone else will take it.
>
> just as an extra note here. In order for this to be really useful, it
> would be nice to be able to control what is going to be traced over USB
Probably you will also need to export *atleast* symbol information. In future,
if this framework is extended to export tracepoint/kprobe/uprobe event data,
then the information like event format etc will also need to be exported.
What tool do you use on host machine in order to extract information from this
exported target ring buffer data?
IMHO, standard tools like trace-cmd will not be able to use it as it is.
> as well, but that means exporting a few extra functions to GPL drivers.
>
> Would that be okay? I could have a set of vendor-specific control
> requests to set buffer size and to read/write ftrace filter functions.
>
> The idea is that things like e.g. Android SDK could rely on this on
> debug builds and the SDK itself would make sure to keep a copy of
> vmlinux around to processing of the data coming through USB.
>
--
Pratyush
Hi,
Pratyush Anand <[email protected]> writes:
> On Friday 09 June 2017 03:58 PM, Felipe Balbi wrote:
>> Felipe Balbi <[email protected]> writes:
>>
>>> Allow for ftrace data to be exported over a USB Gadget
>>> Controller. With this, we have a potentially very fast pipe for
>>> transmitting ftrace data to a Host PC for further analysis.
>>>
>>> Note that in order to decode the data, one needs access to kernel
>>> symbols in order to convert binary data into function names and what
>>> not.
>>>
>>> Signed-off-by: Felipe Balbi <[email protected]>
>>> ---
>>>
>>> I wanted to take this through the gadget tree, but there is a
>>> dependency with a previous patch of mine adding and extra argument to
>>> the ->write() function. Hoping someone else will take it.
>>
>> just as an extra note here. In order for this to be really useful, it
>> would be nice to be able to control what is going to be traced over USB
>
> Probably you will also need to export *atleast* symbol information. In future,
just keep your vmlinux around. This is not supposed to be shipped on end
products, only debug builds.
> if this framework is extended to export tracepoint/kprobe/uprobe event data,
> then the information like event format etc will also need to be exported.
>
> What tool do you use on host machine in order to extract information from this
> exported target ring buffer data?
> IMHO, standard tools like trace-cmd will not be able to use it as it is.
I hacked something together with libusb for testing. Proper tooling is
needed, indeed.
--
balbi
Hi,
Pratyush Anand <[email protected]> writes:
> Hi Felipe,
>
> On Friday 09 June 2017 11:43 AM, Felipe Balbi wrote:
>> +static void notrace ftrace_write(struct trace_export *ftrace, const void *buf,
>> + unsigned int len)
>> +{
>> + struct usb_ftrace *trace = ftrace_to_trace(ftrace);
>> + struct usb_request *req = next_request(&trace->list);
>> +
>> + if (!req)
>> + return;
>> +
>> + if (!trace->in->enabled)
>> + return;
>> +
>> + req->buf = kmemdup(buf, len, GFP_ATOMIC);
>
> Probably we can avoid the copy of trace data.
not with current setup. I have no control over data's lifetime. If I
did, then this would be zero-copy.
> We can make write() call of "struct trace_export" as posted. Can have a
that would require further patching in trace core which is not part of
$subject. Also, if we turn this into asynchronous calls, we could run
out of trace buffer before the first chunk of data is transferred over
to the other side.
> write_complete() callback function implemented in struct trace_export,which
> can be called from your ftrace_complete().
well, you're welcome to propose a patch :-)
--
balbi
On Fri, 14 Jul 2017 11:22:51 +0530
Pratyush Anand <[email protected]> wrote:
> Hi Felipe,
>
> On Friday 09 June 2017 03:58 PM, Felipe Balbi wrote:
> > Felipe Balbi <[email protected]> writes:
> >
> >> Allow for ftrace data to be exported over a USB Gadget
> >> Controller. With this, we have a potentially very fast pipe for
> >> transmitting ftrace data to a Host PC for further analysis.
> >>
> >> Note that in order to decode the data, one needs access to kernel
> >> symbols in order to convert binary data into function names and what
> >> not.
> >>
> >> Signed-off-by: Felipe Balbi <[email protected]>
> >> ---
> >>
> >> I wanted to take this through the gadget tree, but there is a
> >> dependency with a previous patch of mine adding and extra argument to
> >> the ->write() function. Hoping someone else will take it.
> >
> > just as an extra note here. In order for this to be really useful, it
> > would be nice to be able to control what is going to be traced over USB
>
> Probably you will also need to export *atleast* symbol information. In future,
> if this framework is extended to export tracepoint/kprobe/uprobe event data,
> then the information like event format etc will also need to be exported.
>
> What tool do you use on host machine in order to extract information from this
> exported target ring buffer data?
> IMHO, standard tools like trace-cmd will not be able to use it as it is.
>
Have you looked at how trace-cmd does network transfers? Perhaps this
can do something similar. I'm also working on having trace-cmd work
through sockets for guest to host tracing.
See trace-cmd listen.
-- Steve
Hi,
Felipe Balbi <[email protected]> writes:
> Allow for ftrace data to be exported over a USB Gadget
> Controller. With this, we have a potentially very fast pipe for
> transmitting ftrace data to a Host PC for further analysis.
>
> Note that in order to decode the data, one needs access to kernel
> symbols in order to convert binary data into function names and what
> not.
>
> Signed-off-by: Felipe Balbi <[email protected]>
> ---
>
> I wanted to take this through the gadget tree, but there is a
> dependency with a previous patch of mine adding and extra argument to
> the ->write() function. Hoping someone else will take it.
This is still not upstream, I'll take it through my tree this time around.
--
balbi
On Thu, 21 Mar 2019 11:38:56 +0200
Felipe Balbi <[email protected]> wrote:
> Hi,
>
> Felipe Balbi <[email protected]> writes:
> > Allow for ftrace data to be exported over a USB Gadget
> > Controller. With this, we have a potentially very fast pipe for
> > transmitting ftrace data to a Host PC for further analysis.
> >
> > Note that in order to decode the data, one needs access to kernel
> > symbols in order to convert binary data into function names and what
> > not.
> >
> > Signed-off-by: Felipe Balbi <[email protected]>
> > ---
> >
> > I wanted to take this through the gadget tree, but there is a
> > dependency with a previous patch of mine adding and extra argument to
> > the ->write() function. Hoping someone else will take it.
>
> This is still not upstream, I'll take it through my tree this time around.
>
Can you post the latest to the list one more time. At least to make
sure you got the naming correct ;-)
Not FTrace or f_trace.
-- Steve
Hi,
Steven Rostedt <[email protected]> writes:
>> Felipe Balbi <[email protected]> writes:
>> > Allow for ftrace data to be exported over a USB Gadget
>> > Controller. With this, we have a potentially very fast pipe for
>> > transmitting ftrace data to a Host PC for further analysis.
>> >
>> > Note that in order to decode the data, one needs access to kernel
>> > symbols in order to convert binary data into function names and what
>> > not.
>> >
>> > Signed-off-by: Felipe Balbi <[email protected]>
>> > ---
>> >
>> > I wanted to take this through the gadget tree, but there is a
>> > dependency with a previous patch of mine adding and extra argument to
>> > the ->write() function. Hoping someone else will take it.
>>
>> This is still not upstream, I'll take it through my tree this time around.
>>
>
> Can you post the latest to the list one more time. At least to make
> sure you got the naming correct ;-)
>
> Not FTrace or f_trace.
The reason for the name was discussed already. See [1] and [2]
[1] https://marc.info/[email protected]
[2] https://marc.info/[email protected]
--
balbi
On Fri, 22 Mar 2019 13:49:55 +0200
Felipe Balbi <[email protected]> wrote:
> > Can you post the latest to the list one more time. At least to make
> > sure you got the naming correct ;-)
> >
> > Not FTrace or f_trace.
>
> The reason for the name was discussed already. See [1] and [2]
>
> [1] https://marc.info/[email protected]
> [2] https://marc.info/[email protected]
Ah, I forgot (was two years ago) But not doing FTrace still stands!
-- Steve
Steven Rostedt <[email protected]> writes:
> On Fri, 22 Mar 2019 13:49:55 +0200
> Felipe Balbi <[email protected]> wrote:
>
>> > Can you post the latest to the list one more time. At least to make
>> > sure you got the naming correct ;-)
>> >
>> > Not FTrace or f_trace.
>>
>> The reason for the name was discussed already. See [1] and [2]
>>
>> [1] https://marc.info/[email protected]
>> [2] https://marc.info/[email protected]
>
> Ah, I forgot (was two years ago) But not doing FTrace still stands!
Replaced with ftrace everywhere now. I'll wait a little before a resend
(see [1] for some questions I have)
[1] https://marc.info/[email protected]
--
balbi