Message ID | 20190321094748.7031-1-felipe.balbi@linux.intel.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | usb: gadget: functions: add ftrace export over USB | expand |
Felipe Balbi <felipe.balbi@linux.intel.com> 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 <felipe.balbi@linux.intel.com> > --- > drivers/usb/gadget/Kconfig | 15 + > drivers/usb/gadget/function/Makefile | 2 + > drivers/usb/gadget/function/f-trace.c | 401 ++++++++++++++++++++++++++ > 3 files changed, 418 insertions(+) > create mode 100644 drivers/usb/gadget/function/f-trace.c > > diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig > index 31cce7805eb2..dfd181e0d717 100644 > --- a/drivers/usb/gadget/Kconfig > +++ b/drivers/usb/gadget/Kconfig > @@ -191,6 +191,9 @@ config USB_F_MASS_STORAGE > config USB_F_FS > tristate > > +config USB_F_TRACE > + tristate > + > config USB_F_UAC1 > tristate > > @@ -368,6 +371,18 @@ 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 5d3a6cf02218..eb851309006c 100644 > --- a/drivers/usb/gadget/function/Makefile > +++ b/drivers/usb/gadget/function/Makefile > @@ -50,3 +50,5 @@ 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..b5941df128a0 > --- /dev/null > +++ b/drivers/usb/gadget/function/f-trace.c > @@ -0,0 +1,401 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * f_trace.c -- USB FTrace Export > + * > + * Copyright (C) 2019 Intel Corporation > + * Author: Felipe Balbi <felipe.balbi@linux.intel.com> > + * > + * 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, We *may* be able to use the USB_DEBUG_CLASS here with a vendor protocol which we define to be Linux Ftrace. If folks think it would be best, then I can go look at the debug class and check whether it would be feasible.
On Thu, Mar 21, 2019 at 11:47:48AM +0200, Felipe Balbi 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. > > Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> > --- > drivers/usb/gadget/Kconfig | 15 + > drivers/usb/gadget/function/Makefile | 2 + > drivers/usb/gadget/function/f-trace.c | 401 ++++++++++++++++++++++++++ > 3 files changed, 418 insertions(+) > create mode 100644 drivers/usb/gadget/function/f-trace.c This is funny, nice work :) Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On Thu, Mar 21, 2019 at 11:50:04AM +0200, Felipe Balbi wrote: > > +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, > > We *may* be able to use the USB_DEBUG_CLASS here with a vendor protocol > which we define to be Linux Ftrace. If folks think it would be best, > then I can go look at the debug class and check whether it would be > feasible. I didn't think that that class allowed vendor protocols, but if it does, sure, that would be nice. I don't have access to usb-if specs since they kicked Linux out of the organization, and because of that, I really don't care about their specs anymore :) thanks, greg k-h
hi, Greg KH <gregkh@linuxfoundation.org> writes: > On Thu, Mar 21, 2019 at 11:50:04AM +0200, Felipe Balbi wrote: >> > +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, >> >> We *may* be able to use the USB_DEBUG_CLASS here with a vendor protocol >> which we define to be Linux Ftrace. If folks think it would be best, >> then I can go look at the debug class and check whether it would be >> feasible. > > I didn't think that that class allowed vendor protocols, but if it does, > sure, that would be nice. I think it does. That spec is public, actually. Came out as part of usb 3.1. I'll review the spec tomorrow and, hopefully, resend this with Diagnostic Class for the interface using DvC.Trace subclass and vendor protocol. cheers
Hi Felipe, I love your patch! Yet something to improve: [auto build test ERROR on balbi-usb/next] [also build test ERROR on v5.1-rc1 next-20190321] [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/20190322-081552 base: https://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git next config: m68k-allyesconfig (attached as .config) compiler: m68k-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree GCC_VERSION=7.2.0 make.cross ARCH=m68k All error/warnings (new ones prefixed by >>): >> drivers/usb/gadget/function/f-trace.c:26:22: error: field 'ftrace' has incomplete type struct trace_export ftrace; ^~~~~~ In file included from include/linux/ioport.h:13:0, from include/linux/device.h:15, from drivers/usb/gadget/function/f-trace.c:13: drivers/usb/gadget/function/f-trace.c: In function 'ftrace_write': >> include/linux/kernel.h:998:32: error: dereferencing pointer to incomplete type 'struct trace_export' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~ include/linux/compiler.h:324:9: note: in definition of macro '__compiletime_assert' if (!(condition)) \ ^~~~~~~~~ include/linux/compiler.h:344:2: note: in expansion of macro '_compiletime_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) ^~~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^~~~~~~~~~~~~~~~~~ include/linux/kernel.h:998:2: note: in expansion of macro 'BUILD_BUG_ON_MSG' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~~~~~~~~~~~ include/linux/kernel.h:998:20: note: in expansion of macro '__same_type' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~~~~~~ >> drivers/usb/gadget/function/f-trace.c:39:29: 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:175:30: 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:295:8: error: implicit declaration of function 'register_ftrace_export'; did you mean 'register_chrdev_region'? [-Werror=implicit-function-declaration] ret = register_ftrace_export(&trace->ftrace); ^~~~~~~~~~~~~~~~~~~~~~ register_chrdev_region drivers/usb/gadget/function/f-trace.c: In function 'ftrace_unbind': >> drivers/usb/gadget/function/f-trace.c:323:2: error: implicit declaration of function 'unregister_ftrace_export'; did you mean 'unregister_chrdev_region'? [-Werror=implicit-function-declaration] unregister_ftrace_export(&trace->ftrace); ^~~~~~~~~~~~~~~~~~~~~~~~ unregister_chrdev_region cc1: some warnings being treated as errors -- drivers/usb//gadget/function/f-trace.c:26:22: error: field 'ftrace' has incomplete type struct trace_export ftrace; ^~~~~~ In file included from include/linux/ioport.h:13:0, from include/linux/device.h:15, from drivers/usb//gadget/function/f-trace.c:13: drivers/usb//gadget/function/f-trace.c: In function 'ftrace_write': >> include/linux/kernel.h:998:32: error: dereferencing pointer to incomplete type 'struct trace_export' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~ include/linux/compiler.h:324:9: note: in definition of macro '__compiletime_assert' if (!(condition)) \ ^~~~~~~~~ include/linux/compiler.h:344:2: note: in expansion of macro '_compiletime_assert' _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) ^~~~~~~~~~~~~~~~~~~ include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert' #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg) ^~~~~~~~~~~~~~~~~~ include/linux/kernel.h:998:2: note: in expansion of macro 'BUILD_BUG_ON_MSG' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~~~~~~~~~~~ include/linux/kernel.h:998:20: note: in expansion of macro '__same_type' BUILD_BUG_ON_MSG(!__same_type(*(ptr), ((type *)0)->member) && \ ^~~~~~~~~~~ drivers/usb//gadget/function/f-trace.c:39:29: 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:175:30: 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:295:8: error: implicit declaration of function 'register_ftrace_export'; did you mean 'register_chrdev_region'? [-Werror=implicit-function-declaration] ret = register_ftrace_export(&trace->ftrace); ^~~~~~~~~~~~~~~~~~~~~~ register_chrdev_region drivers/usb//gadget/function/f-trace.c: In function 'ftrace_unbind': drivers/usb//gadget/function/f-trace.c:323:2: error: implicit declaration of function 'unregister_ftrace_export'; did you mean 'unregister_chrdev_region'? [-Werror=implicit-function-declaration] unregister_ftrace_export(&trace->ftrace); ^~~~~~~~~~~~~~~~~~~~~~~~ unregister_chrdev_region cc1: some warnings being treated as errors vim +/ftrace +26 drivers/usb/gadget/function/f-trace.c 24 25 struct usb_ftrace { > 26 struct trace_export ftrace; 27 struct usb_function function; 28 struct work_struct queue_work; 29 spinlock_t lock; 30 31 struct list_head list; 32 struct list_head pending; 33 struct list_head queued; 34 35 struct usb_ep *in; 36 37 u8 intf_id; 38 }; > 39 #define ftrace_to_trace(f) (container_of((f), struct usb_ftrace, ftrace)) 40 #define work_to_trace(w) (container_of((w), struct usb_ftrace, queue_work)) 41 #define to_trace(f) (container_of((f), struct usb_ftrace, function)) 42 43 #define FTRACE_REQUEST_QUEUE_LENGTH 250 44 45 static inline struct usb_request *next_request(struct list_head *list) 46 { 47 return list_first_entry_or_null(list, struct usb_request, list); 48 } 49 50 struct usb_ftrace_opts { 51 struct usb_function_instance func_inst; 52 }; 53 #define to_opts(fi) (container_of((fi), struct usb_ftrace_opts, func_inst)) 54 55 static struct usb_interface_descriptor ftrace_intf_desc = { 56 .bLength = USB_DT_INTERFACE_SIZE, 57 .bDescriptorType = USB_DT_INTERFACE, 58 59 .bAlternateSetting = 0, 60 .bNumEndpoints = 1, 61 .bInterfaceClass = USB_CLASS_VENDOR_SPEC, 62 .bInterfaceSubClass = USB_SUBCLASS_VENDOR_SPEC, 63 }; 64 65 /* Super-Speed Support */ 66 static struct usb_endpoint_descriptor ftrace_ss_in_desc = { 67 .bLength = USB_DT_ENDPOINT_SIZE, 68 .bDescriptorType = USB_DT_ENDPOINT, 69 70 .bEndpointAddress = USB_DIR_IN, 71 .bmAttributes = USB_ENDPOINT_XFER_BULK, 72 .wMaxPacketSize = cpu_to_le16(1024), 73 }; 74 75 static struct usb_ss_ep_comp_descriptor ftrace_ss_in_comp_desc = { 76 .bLength = USB_DT_SS_EP_COMP_SIZE, 77 .bDescriptorType = USB_DT_SS_ENDPOINT_COMP, 78 79 .bMaxBurst = 15, 80 }; 81 82 static struct usb_descriptor_header *ftrace_ss_function[] = { 83 (struct usb_descriptor_header *) &ftrace_intf_desc, 84 (struct usb_descriptor_header *) &ftrace_ss_in_desc, 85 (struct usb_descriptor_header *) &ftrace_ss_in_comp_desc, 86 NULL, 87 }; 88 89 /* High-Speed Support */ 90 static struct usb_endpoint_descriptor ftrace_hs_in_desc = { 91 .bLength = USB_DT_ENDPOINT_SIZE, 92 .bDescriptorType = USB_DT_ENDPOINT, 93 94 .bEndpointAddress = USB_DIR_IN, 95 .bmAttributes = USB_ENDPOINT_XFER_BULK, 96 .wMaxPacketSize = cpu_to_le16(512), 97 }; 98 99 static struct usb_descriptor_header *ftrace_hs_function[] = { 100 (struct usb_descriptor_header *) &ftrace_intf_desc, 101 (struct usb_descriptor_header *) &ftrace_hs_in_desc, 102 NULL, 103 }; 104 105 /* Full-Speed Support */ 106 static struct usb_endpoint_descriptor ftrace_fs_in_desc = { 107 .bLength = USB_DT_ENDPOINT_SIZE, 108 .bDescriptorType = USB_DT_ENDPOINT, 109 110 .bEndpointAddress = USB_DIR_IN, 111 .bmAttributes = USB_ENDPOINT_XFER_BULK, 112 .wMaxPacketSize = cpu_to_le16(64), 113 }; 114 115 static struct usb_descriptor_header *ftrace_fs_function[] = { 116 (struct usb_descriptor_header *) &ftrace_intf_desc, 117 (struct usb_descriptor_header *) &ftrace_fs_in_desc, 118 NULL, 119 }; 120 121 static struct usb_string ftrace_string_defs[] = { 122 [0].s = "Linux Ftrace Export", 123 { }, 124 }; 125 126 static struct usb_gadget_strings ftrace_string_table = { 127 .language = 0x0409, /* en-US */ 128 .strings = ftrace_string_defs, 129 }; 130 131 static struct usb_gadget_strings *ftrace_strings[] = { 132 &ftrace_string_table, 133 NULL, 134 }; 135 136 /* ------------------------------------------------------------------------ */ 137 138 static void ftrace_complete(struct usb_ep *ep, struct usb_request *req) 139 { 140 struct usb_ftrace *trace = req->context; 141 142 kfree(req->buf); 143 list_move_tail(&req->list, &trace->list); 144 } 145 146 static void ftrace_queue_work(struct work_struct *work) 147 { 148 struct usb_ftrace *trace = work_to_trace(work); 149 struct usb_request *req; 150 struct usb_request *tmp; 151 struct list_head local_list; 152 153 spin_lock_irq(&trace->lock); 154 restart: 155 list_replace_init(&trace->pending, &local_list); 156 spin_unlock_irq(&trace->lock); 157 158 list_for_each_entry_safe(req, tmp, &local_list, list) { 159 int ret; 160 161 ret = usb_ep_queue(trace->in, req, GFP_KERNEL); 162 if (!ret) 163 list_move_tail(&req->list, &trace->queued); 164 } 165 166 spin_lock_irq(&trace->lock); 167 if (!list_empty(&trace->pending)) 168 goto restart; 169 spin_unlock_irq(&trace->lock); 170 } 171 172 static void notrace ftrace_write(struct trace_export *ftrace, const void *buf, 173 unsigned int len) 174 { > 175 struct usb_ftrace *trace = ftrace_to_trace(ftrace); 176 struct usb_request *req = next_request(&trace->list); 177 178 if (!req) 179 return; 180 181 if (!trace->in->enabled) 182 return; 183 184 req->buf = kmemdup(buf, len, GFP_ATOMIC); 185 req->length = len; 186 req->context = trace; 187 req->complete = ftrace_complete; 188 list_move_tail(&req->list, &trace->pending); 189 190 schedule_work(&trace->queue_work); 191 } 192 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig index 31cce7805eb2..dfd181e0d717 100644 --- a/drivers/usb/gadget/Kconfig +++ b/drivers/usb/gadget/Kconfig @@ -191,6 +191,9 @@ config USB_F_MASS_STORAGE config USB_F_FS tristate +config USB_F_TRACE + tristate + config USB_F_UAC1 tristate @@ -368,6 +371,18 @@ 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 5d3a6cf02218..eb851309006c 100644 --- a/drivers/usb/gadget/function/Makefile +++ b/drivers/usb/gadget/function/Makefile @@ -50,3 +50,5 @@ 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..b5941df128a0 --- /dev/null +++ b/drivers/usb/gadget/function/f-trace.c @@ -0,0 +1,401 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * f_trace.c -- USB FTrace Export + * + * Copyright (C) 2019 Intel Corporation + * Author: Felipe Balbi <felipe.balbi@linux.intel.com> + * + * 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 <felipe.balbi@linux.intel.com>"); +MODULE_LICENSE("GPL v2");
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 <felipe.balbi@linux.intel.com> --- drivers/usb/gadget/Kconfig | 15 + drivers/usb/gadget/function/Makefile | 2 + drivers/usb/gadget/function/f-trace.c | 401 ++++++++++++++++++++++++++ 3 files changed, 418 insertions(+) create mode 100644 drivers/usb/gadget/function/f-trace.c