diff options
Diffstat (limited to 'samples')
24 files changed, 1947 insertions, 0 deletions
diff --git a/samples/Kconfig b/samples/Kconfig new file mode 100644 index 00000000..954a1d55 --- /dev/null +++ b/samples/Kconfig @@ -0,0 +1,57 @@ +menuconfig SAMPLES + bool "Sample kernel code" + help + You can build and test sample kernel code here. + +if SAMPLES + +config SAMPLE_TRACEPOINTS + tristate "Build tracepoints examples -- loadable modules only" + depends on TRACEPOINTS && m + help + This build tracepoints example modules. + +config SAMPLE_TRACE_EVENTS + tristate "Build trace_events examples -- loadable modules only" + depends on EVENT_TRACING && m + help + This build trace event example modules. + +config SAMPLE_KOBJECT + tristate "Build kobject examples -- loadable modules only" + depends on m + help + This config option will allow you to build a number of + different kobject sample modules showing how to use kobjects, + ksets, and ktypes properly. + + If in doubt, say "N" here. + +config SAMPLE_KPROBES + tristate "Build kprobes examples -- loadable modules only" + depends on KPROBES && m + help + This build several kprobes example modules. + +config SAMPLE_KRETPROBES + tristate "Build kretprobes example -- loadable modules only" + default m + depends on SAMPLE_KPROBES && KRETPROBES + +config SAMPLE_HW_BREAKPOINT + tristate "Build kernel hardware breakpoint examples -- loadable module only" + depends on HAVE_HW_BREAKPOINT && m + help + This builds kernel hardware breakpoint example modules. + +config SAMPLE_KFIFO + tristate "Build kfifo examples -- loadable modules only" + depends on m + help + This config option will allow you to build a number of + different kfifo sample modules showing how to use the + generic kfifo API. + + If in doubt, say "N" here. + +endif # SAMPLES diff --git a/samples/Makefile b/samples/Makefile new file mode 100644 index 00000000..76b3c345 --- /dev/null +++ b/samples/Makefile @@ -0,0 +1,4 @@ +# Makefile for Linux samples code + +obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ tracepoints/ trace_events/ \ + hw_breakpoint/ kfifo/ diff --git a/samples/hw_breakpoint/Makefile b/samples/hw_breakpoint/Makefile new file mode 100644 index 00000000..0f5c31c2 --- /dev/null +++ b/samples/hw_breakpoint/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_HW_BREAKPOINT) += data_breakpoint.o diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c new file mode 100644 index 00000000..bd0f337a --- /dev/null +++ b/samples/hw_breakpoint/data_breakpoint.c @@ -0,0 +1,90 @@ +/* + * data_breakpoint.c - Sample HW Breakpoint file to watch kernel data address + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * usage: insmod data_breakpoint.ko ksym=<ksym_name> + * + * This file is a kernel module that places a breakpoint over ksym_name kernel + * variable using Hardware Breakpoint register. The corresponding handler which + * prints a backtrace is invoked everytime a write operation is performed on + * that variable. + * + * Copyright (C) IBM Corporation, 2009 + * + * Author: K.Prasad <prasad@linux.vnet.ibm.com> + */ +#include <linux/module.h> /* Needed by all modules */ +#include <linux/kernel.h> /* Needed for KERN_INFO */ +#include <linux/init.h> /* Needed for the macros */ +#include <linux/kallsyms.h> + +#include <linux/perf_event.h> +#include <linux/hw_breakpoint.h> + +struct perf_event * __percpu *sample_hbp; + +static char ksym_name[KSYM_NAME_LEN] = "pid_max"; +module_param_string(ksym, ksym_name, KSYM_NAME_LEN, S_IRUGO); +MODULE_PARM_DESC(ksym, "Kernel symbol to monitor; this module will report any" + " write operations on the kernel symbol"); + +static void sample_hbp_handler(struct perf_event *bp, int nmi, + struct perf_sample_data *data, + struct pt_regs *regs) +{ + printk(KERN_INFO "%s value is changed\n", ksym_name); + dump_stack(); + printk(KERN_INFO "Dump stack from sample_hbp_handler\n"); +} + +static int __init hw_break_module_init(void) +{ + int ret; + struct perf_event_attr attr; + + hw_breakpoint_init(&attr); + attr.bp_addr = kallsyms_lookup_name(ksym_name); + attr.bp_len = HW_BREAKPOINT_LEN_4; + attr.bp_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R; + + sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler); + if (IS_ERR((void __force *)sample_hbp)) { + ret = PTR_ERR((void __force *)sample_hbp); + goto fail; + } + + printk(KERN_INFO "HW Breakpoint for %s write installed\n", ksym_name); + + return 0; + +fail: + printk(KERN_INFO "Breakpoint registration failed\n"); + + return ret; +} + +static void __exit hw_break_module_exit(void) +{ + unregister_wide_hw_breakpoint(sample_hbp); + printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name); +} + +module_init(hw_break_module_init); +module_exit(hw_break_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("K.Prasad"); +MODULE_DESCRIPTION("ksym breakpoint"); diff --git a/samples/kfifo/Makefile b/samples/kfifo/Makefile new file mode 100644 index 00000000..bcc9484a --- /dev/null +++ b/samples/kfifo/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_KFIFO) += bytestream-example.o dma-example.o inttype-example.o record-example.o diff --git a/samples/kfifo/bytestream-example.c b/samples/kfifo/bytestream-example.c new file mode 100644 index 00000000..178061e8 --- /dev/null +++ b/samples/kfifo/bytestream-example.c @@ -0,0 +1,193 @@ +/* + * Sample kfifo byte stream implementation + * + * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net> + * + * Released under the GPL version 2 only. + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/proc_fs.h> +#include <linux/mutex.h> +#include <linux/kfifo.h> + +/* + * This module shows how to create a byte stream fifo. + */ + +/* fifo size in elements (bytes) */ +#define FIFO_SIZE 32 + +/* name of the proc entry */ +#define PROC_FIFO "bytestream-fifo" + +/* lock for procfs read access */ +static DEFINE_MUTEX(read_lock); + +/* lock for procfs write access */ +static DEFINE_MUTEX(write_lock); + +/* + * define DYNAMIC in this example for a dynamically allocated fifo. + * + * Otherwise the fifo storage will be a part of the fifo structure. + */ +#if 0 +#define DYNAMIC +#endif + +#ifdef DYNAMIC +static struct kfifo test; +#else +static DECLARE_KFIFO(test, unsigned char, FIFO_SIZE); +#endif + +static const unsigned char expected_result[FIFO_SIZE] = { + 3, 4, 5, 6, 7, 8, 9, 0, + 1, 20, 21, 22, 23, 24, 25, 26, + 27, 28, 29, 30, 31, 32, 33, 34, + 35, 36, 37, 38, 39, 40, 41, 42, +}; + +static int __init testfunc(void) +{ + unsigned char buf[6]; + unsigned char i, j; + unsigned int ret; + + printk(KERN_INFO "byte stream fifo test start\n"); + + /* put string into the fifo */ + kfifo_in(&test, "hello", 5); + + /* put values into the fifo */ + for (i = 0; i != 10; i++) + kfifo_put(&test, &i); + + /* show the number of used elements */ + printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test)); + + /* get max of 5 bytes from the fifo */ + i = kfifo_out(&test, buf, 5); + printk(KERN_INFO "buf: %.*s\n", i, buf); + + /* get max of 2 elements from the fifo */ + ret = kfifo_out(&test, buf, 2); + printk(KERN_INFO "ret: %d\n", ret); + /* and put it back to the end of the fifo */ + ret = kfifo_in(&test, buf, ret); + printk(KERN_INFO "ret: %d\n", ret); + + /* skip first element of the fifo */ + printk(KERN_INFO "skip 1st element\n"); + kfifo_skip(&test); + + /* put values into the fifo until is full */ + for (i = 20; kfifo_put(&test, &i); i++) + ; + + printk(KERN_INFO "queue len: %u\n", kfifo_len(&test)); + + /* show the first value without removing from the fifo */ + if (kfifo_peek(&test, &i)) + printk(KERN_INFO "%d\n", i); + + /* check the correctness of all values in the fifo */ + j = 0; + while (kfifo_get(&test, &i)) { + printk(KERN_INFO "item = %d\n", i); + if (i != expected_result[j++]) { + printk(KERN_WARNING "value mismatch: test failed\n"); + return -EIO; + } + } + if (j != ARRAY_SIZE(expected_result)) { + printk(KERN_WARNING "size mismatch: test failed\n"); + return -EIO; + } + printk(KERN_INFO "test passed\n"); + + return 0; +} + +static ssize_t fifo_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&write_lock)) + return -ERESTARTSYS; + + ret = kfifo_from_user(&test, buf, count, &copied); + + mutex_unlock(&write_lock); + + return ret ? ret : copied; +} + +static ssize_t fifo_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&read_lock)) + return -ERESTARTSYS; + + ret = kfifo_to_user(&test, buf, count, &copied); + + mutex_unlock(&read_lock); + + return ret ? ret : copied; +} + +static const struct file_operations fifo_fops = { + .owner = THIS_MODULE, + .read = fifo_read, + .write = fifo_write, +}; + +static int __init example_init(void) +{ +#ifdef DYNAMIC + int ret; + + ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL); + if (ret) { + printk(KERN_ERR "error kfifo_alloc\n"); + return ret; + } +#else + INIT_KFIFO(test); +#endif + if (testfunc() < 0) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -EIO; + } + + if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -ENOMEM; + } + return 0; +} + +static void __exit example_exit(void) +{ + remove_proc_entry(PROC_FIFO, NULL); +#ifdef DYNAMIC + kfifo_free(&test); +#endif +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>"); diff --git a/samples/kfifo/dma-example.c b/samples/kfifo/dma-example.c new file mode 100644 index 00000000..06473791 --- /dev/null +++ b/samples/kfifo/dma-example.c @@ -0,0 +1,143 @@ +/* + * Sample fifo dma implementation + * + * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net> + * + * Released under the GPL version 2 only. + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kfifo.h> + +/* + * This module shows how to handle fifo dma operations. + */ + +/* fifo size in elements (bytes) */ +#define FIFO_SIZE 32 + +static struct kfifo fifo; + +static int __init example_init(void) +{ + int i; + unsigned int ret; + unsigned int nents; + struct scatterlist sg[10]; + + printk(KERN_INFO "DMA fifo test start\n"); + + if (kfifo_alloc(&fifo, FIFO_SIZE, GFP_KERNEL)) { + printk(KERN_WARNING "error kfifo_alloc\n"); + return -ENOMEM; + } + + printk(KERN_INFO "queue size: %u\n", kfifo_size(&fifo)); + + kfifo_in(&fifo, "test", 4); + + for (i = 0; i != 9; i++) + kfifo_put(&fifo, &i); + + /* kick away first byte */ + kfifo_skip(&fifo); + + printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); + + /* + * Configure the kfifo buffer to receive data from DMA input. + * + * .--------------------------------------. + * | 0 | 1 | 2 | ... | 12 | 13 | ... | 31 | + * |---|------------------|---------------| + * \_/ \________________/ \_____________/ + * \ \ \ + * \ \_allocated data \ + * \_*free space* \_*free space* + * + * We need two different SG entries: one for the free space area at the + * end of the kfifo buffer (19 bytes) and another for the first free + * byte at the beginning, after the kfifo_skip(). + */ + sg_init_table(sg, ARRAY_SIZE(sg)); + nents = kfifo_dma_in_prepare(&fifo, sg, ARRAY_SIZE(sg), FIFO_SIZE); + printk(KERN_INFO "DMA sgl entries: %d\n", nents); + if (!nents) { + /* fifo is full and no sgl was created */ + printk(KERN_WARNING "error kfifo_dma_in_prepare\n"); + return -EIO; + } + + /* receive data */ + printk(KERN_INFO "scatterlist for receive:\n"); + for (i = 0; i < nents; i++) { + printk(KERN_INFO + "sg[%d] -> " + "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n", + i, sg[i].page_link, sg[i].offset, sg[i].length); + + if (sg_is_last(&sg[i])) + break; + } + + /* put here your code to setup and exectute the dma operation */ + /* ... */ + + /* example: zero bytes received */ + ret = 0; + + /* finish the dma operation and update the received data */ + kfifo_dma_in_finish(&fifo, ret); + + /* Prepare to transmit data, example: 8 bytes */ + nents = kfifo_dma_out_prepare(&fifo, sg, ARRAY_SIZE(sg), 8); + printk(KERN_INFO "DMA sgl entries: %d\n", nents); + if (!nents) { + /* no data was available and no sgl was created */ + printk(KERN_WARNING "error kfifo_dma_out_prepare\n"); + return -EIO; + } + + printk(KERN_INFO "scatterlist for transmit:\n"); + for (i = 0; i < nents; i++) { + printk(KERN_INFO + "sg[%d] -> " + "page_link 0x%.8lx offset 0x%.8x length 0x%.8x\n", + i, sg[i].page_link, sg[i].offset, sg[i].length); + + if (sg_is_last(&sg[i])) + break; + } + + /* put here your code to setup and exectute the dma operation */ + /* ... */ + + /* example: 5 bytes transmitted */ + ret = 5; + + /* finish the dma operation and update the transmitted data */ + kfifo_dma_out_finish(&fifo, ret); + + ret = kfifo_len(&fifo); + printk(KERN_INFO "queue len: %u\n", kfifo_len(&fifo)); + + if (ret != 7) { + printk(KERN_WARNING "size mismatch: test failed"); + return -EIO; + } + printk(KERN_INFO "test passed\n"); + + return 0; +} + +static void __exit example_exit(void) +{ + kfifo_free(&fifo); +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>"); diff --git a/samples/kfifo/inttype-example.c b/samples/kfifo/inttype-example.c new file mode 100644 index 00000000..71b2aabc --- /dev/null +++ b/samples/kfifo/inttype-example.c @@ -0,0 +1,184 @@ +/* + * Sample kfifo int type implementation + * + * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net> + * + * Released under the GPL version 2 only. + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/proc_fs.h> +#include <linux/mutex.h> +#include <linux/kfifo.h> + +/* + * This module shows how to create a int type fifo. + */ + +/* fifo size in elements (ints) */ +#define FIFO_SIZE 32 + +/* name of the proc entry */ +#define PROC_FIFO "int-fifo" + +/* lock for procfs read access */ +static DEFINE_MUTEX(read_lock); + +/* lock for procfs write access */ +static DEFINE_MUTEX(write_lock); + +/* + * define DYNAMIC in this example for a dynamically allocated fifo. + * + * Otherwise the fifo storage will be a part of the fifo structure. + */ +#if 0 +#define DYNAMIC +#endif + +#ifdef DYNAMIC +static DECLARE_KFIFO_PTR(test, int); +#else +static DEFINE_KFIFO(test, int, FIFO_SIZE); +#endif + +static const int expected_result[FIFO_SIZE] = { + 3, 4, 5, 6, 7, 8, 9, 0, + 1, 20, 21, 22, 23, 24, 25, 26, + 27, 28, 29, 30, 31, 32, 33, 34, + 35, 36, 37, 38, 39, 40, 41, 42, +}; + +static int __init testfunc(void) +{ + int buf[6]; + int i, j; + unsigned int ret; + + printk(KERN_INFO "int fifo test start\n"); + + /* put values into the fifo */ + for (i = 0; i != 10; i++) + kfifo_put(&test, &i); + + /* show the number of used elements */ + printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test)); + + /* get max of 2 elements from the fifo */ + ret = kfifo_out(&test, buf, 2); + printk(KERN_INFO "ret: %d\n", ret); + /* and put it back to the end of the fifo */ + ret = kfifo_in(&test, buf, ret); + printk(KERN_INFO "ret: %d\n", ret); + + /* skip first element of the fifo */ + printk(KERN_INFO "skip 1st element\n"); + kfifo_skip(&test); + + /* put values into the fifo until is full */ + for (i = 20; kfifo_put(&test, &i); i++) + ; + + printk(KERN_INFO "queue len: %u\n", kfifo_len(&test)); + + /* show the first value without removing from the fifo */ + if (kfifo_peek(&test, &i)) + printk(KERN_INFO "%d\n", i); + + /* check the correctness of all values in the fifo */ + j = 0; + while (kfifo_get(&test, &i)) { + printk(KERN_INFO "item = %d\n", i); + if (i != expected_result[j++]) { + printk(KERN_WARNING "value mismatch: test failed\n"); + return -EIO; + } + } + if (j != ARRAY_SIZE(expected_result)) { + printk(KERN_WARNING "size mismatch: test failed\n"); + return -EIO; + } + printk(KERN_INFO "test passed\n"); + + return 0; +} + +static ssize_t fifo_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&write_lock)) + return -ERESTARTSYS; + + ret = kfifo_from_user(&test, buf, count, &copied); + + mutex_unlock(&write_lock); + + return ret ? ret : copied; +} + +static ssize_t fifo_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&read_lock)) + return -ERESTARTSYS; + + ret = kfifo_to_user(&test, buf, count, &copied); + + mutex_unlock(&read_lock); + + return ret ? ret : copied; +} + +static const struct file_operations fifo_fops = { + .owner = THIS_MODULE, + .read = fifo_read, + .write = fifo_write, +}; + +static int __init example_init(void) +{ +#ifdef DYNAMIC + int ret; + + ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL); + if (ret) { + printk(KERN_ERR "error kfifo_alloc\n"); + return ret; + } +#endif + if (testfunc() < 0) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -EIO; + } + + if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -ENOMEM; + } + return 0; +} + +static void __exit example_exit(void) +{ + remove_proc_entry(PROC_FIFO, NULL); +#ifdef DYNAMIC + kfifo_free(&test); +#endif +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>"); diff --git a/samples/kfifo/record-example.c b/samples/kfifo/record-example.c new file mode 100644 index 00000000..e68bd16a --- /dev/null +++ b/samples/kfifo/record-example.c @@ -0,0 +1,200 @@ +/* + * Sample dynamic sized record fifo implementation + * + * Copyright (C) 2010 Stefani Seibold <stefani@seibold.net> + * + * Released under the GPL version 2 only. + * + */ + +#include <linux/init.h> +#include <linux/module.h> +#include <linux/proc_fs.h> +#include <linux/mutex.h> +#include <linux/kfifo.h> + +/* + * This module shows how to create a variable sized record fifo. + */ + +/* fifo size in elements (bytes) */ +#define FIFO_SIZE 128 + +/* name of the proc entry */ +#define PROC_FIFO "record-fifo" + +/* lock for procfs read access */ +static DEFINE_MUTEX(read_lock); + +/* lock for procfs write access */ +static DEFINE_MUTEX(write_lock); + +/* + * define DYNAMIC in this example for a dynamically allocated fifo. + * + * Otherwise the fifo storage will be a part of the fifo structure. + */ +#if 0 +#define DYNAMIC +#endif + +/* + * struct kfifo_rec_ptr_1 and STRUCT_KFIFO_REC_1 can handle records of a + * length between 0 and 255 bytes. + * + * struct kfifo_rec_ptr_2 and STRUCT_KFIFO_REC_2 can handle records of a + * length between 0 and 65535 bytes. + */ + +#ifdef DYNAMIC +struct kfifo_rec_ptr_1 test; + +#else +typedef STRUCT_KFIFO_REC_1(FIFO_SIZE) mytest; + +static mytest test; +#endif + +static const char *expected_result[] = { + "a", + "bb", + "ccc", + "dddd", + "eeeee", + "ffffff", + "ggggggg", + "hhhhhhhh", + "iiiiiiiii", + "jjjjjjjjjj", +}; + +static int __init testfunc(void) +{ + char buf[100]; + unsigned int i; + unsigned int ret; + struct { unsigned char buf[6]; } hello = { "hello" }; + + printk(KERN_INFO "record fifo test start\n"); + + kfifo_in(&test, &hello, sizeof(hello)); + + /* show the size of the next record in the fifo */ + printk(KERN_INFO "fifo peek len: %u\n", kfifo_peek_len(&test)); + + /* put in variable length data */ + for (i = 0; i < 10; i++) { + memset(buf, 'a' + i, i + 1); + kfifo_in(&test, buf, i + 1); + } + + /* skip first element of the fifo */ + printk(KERN_INFO "skip 1st element\n"); + kfifo_skip(&test); + + printk(KERN_INFO "fifo len: %u\n", kfifo_len(&test)); + + /* show the first record without removing from the fifo */ + ret = kfifo_out_peek(&test, buf, sizeof(buf)); + if (ret) + printk(KERN_INFO "%.*s\n", ret, buf); + + /* check the correctness of all values in the fifo */ + i = 0; + while (!kfifo_is_empty(&test)) { + ret = kfifo_out(&test, buf, sizeof(buf)); + buf[ret] = '\0'; + printk(KERN_INFO "item = %.*s\n", ret, buf); + if (strcmp(buf, expected_result[i++])) { + printk(KERN_WARNING "value mismatch: test failed\n"); + return -EIO; + } + } + if (i != ARRAY_SIZE(expected_result)) { + printk(KERN_WARNING "size mismatch: test failed\n"); + return -EIO; + } + printk(KERN_INFO "test passed\n"); + + return 0; +} + +static ssize_t fifo_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&write_lock)) + return -ERESTARTSYS; + + ret = kfifo_from_user(&test, buf, count, &copied); + + mutex_unlock(&write_lock); + + return ret ? ret : copied; +} + +static ssize_t fifo_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + int ret; + unsigned int copied; + + if (mutex_lock_interruptible(&read_lock)) + return -ERESTARTSYS; + + ret = kfifo_to_user(&test, buf, count, &copied); + + mutex_unlock(&read_lock); + + return ret ? ret : copied; +} + +static const struct file_operations fifo_fops = { + .owner = THIS_MODULE, + .read = fifo_read, + .write = fifo_write, +}; + +static int __init example_init(void) +{ +#ifdef DYNAMIC + int ret; + + ret = kfifo_alloc(&test, FIFO_SIZE, GFP_KERNEL); + if (ret) { + printk(KERN_ERR "error kfifo_alloc\n"); + return ret; + } +#else + INIT_KFIFO(test); +#endif + if (testfunc() < 0) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -EIO; + } + + if (proc_create(PROC_FIFO, 0, NULL, &fifo_fops) == NULL) { +#ifdef DYNAMIC + kfifo_free(&test); +#endif + return -ENOMEM; + } + return 0; +} + +static void __exit example_exit(void) +{ + remove_proc_entry(PROC_FIFO, NULL); +#ifdef DYNAMIC + kfifo_free(&test); +#endif +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Stefani Seibold <stefani@seibold.net>"); diff --git a/samples/kobject/Makefile b/samples/kobject/Makefile new file mode 100644 index 00000000..4a194203 --- /dev/null +++ b/samples/kobject/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_KOBJECT) += kobject-example.o kset-example.o diff --git a/samples/kobject/kobject-example.c b/samples/kobject/kobject-example.c new file mode 100644 index 00000000..86ea0c3a --- /dev/null +++ b/samples/kobject/kobject-example.c @@ -0,0 +1,137 @@ +/* + * Sample kobject implementation + * + * Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (C) 2007 Novell Inc. + * + * Released under the GPL version 2 only. + * + */ +#include <linux/kobject.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include <linux/module.h> +#include <linux/init.h> + +/* + * This module shows how to create a simple subdirectory in sysfs called + * /sys/kernel/kobject-example In that directory, 3 files are created: + * "foo", "baz", and "bar". If an integer is written to these files, it can be + * later read out of it. + */ + +static int foo; +static int baz; +static int bar; + +/* + * The "foo" file where a static variable is read from and written to. + */ +static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + return sprintf(buf, "%d\n", foo); +} + +static ssize_t foo_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + sscanf(buf, "%du", &foo); + return count; +} + +static struct kobj_attribute foo_attribute = + __ATTR(foo, 0666, foo_show, foo_store); + +/* + * More complex function where we determine which variable is being accessed by + * looking at the attribute for the "baz" and "bar" files. + */ +static ssize_t b_show(struct kobject *kobj, struct kobj_attribute *attr, + char *buf) +{ + int var; + + if (strcmp(attr->attr.name, "baz") == 0) + var = baz; + else + var = bar; + return sprintf(buf, "%d\n", var); +} + +static ssize_t b_store(struct kobject *kobj, struct kobj_attribute *attr, + const char *buf, size_t count) +{ + int var; + + sscanf(buf, "%du", &var); + if (strcmp(attr->attr.name, "baz") == 0) + baz = var; + else + bar = var; + return count; +} + +static struct kobj_attribute baz_attribute = + __ATTR(baz, 0666, b_show, b_store); +static struct kobj_attribute bar_attribute = + __ATTR(bar, 0666, b_show, b_store); + + +/* + * Create a group of attributes so that we can create and destroy them all + * at once. + */ +static struct attribute *attrs[] = { + &foo_attribute.attr, + &baz_attribute.attr, + &bar_attribute.attr, + NULL, /* need to NULL terminate the list of attributes */ +}; + +/* + * An unnamed attribute group will put all of the attributes directly in + * the kobject directory. If we specify a name, a subdirectory will be + * created for the attributes with the directory being the name of the + * attribute group. + */ +static struct attribute_group attr_group = { + .attrs = attrs, +}; + +static struct kobject *example_kobj; + +static int __init example_init(void) +{ + int retval; + + /* + * Create a simple kobject with the name of "kobject_example", + * located under /sys/kernel/ + * + * As this is a simple directory, no uevent will be sent to + * userspace. That is why this function should not be used for + * any type of dynamic kobjects, where the name and number are + * not known ahead of time. + */ + example_kobj = kobject_create_and_add("kobject_example", kernel_kobj); + if (!example_kobj) + return -ENOMEM; + + /* Create the files associated with this kobject */ + retval = sysfs_create_group(example_kobj, &attr_group); + if (retval) + kobject_put(example_kobj); + + return retval; +} + +static void __exit example_exit(void) +{ + kobject_put(example_kobj); +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>"); diff --git a/samples/kobject/kset-example.c b/samples/kobject/kset-example.c new file mode 100644 index 00000000..d0c687fd --- /dev/null +++ b/samples/kobject/kset-example.c @@ -0,0 +1,279 @@ +/* + * Sample kset and ktype implementation + * + * Copyright (C) 2004-2007 Greg Kroah-Hartman <greg@kroah.com> + * Copyright (C) 2007 Novell Inc. + * + * Released under the GPL version 2 only. + * + */ +#include <linux/kobject.h> +#include <linux/string.h> +#include <linux/sysfs.h> +#include <linux/slab.h> +#include <linux/module.h> +#include <linux/init.h> + +/* + * This module shows how to create a kset in sysfs called + * /sys/kernel/kset-example + * Then tree kobjects are created and assigned to this kset, "foo", "baz", + * and "bar". In those kobjects, attributes of the same name are also + * created and if an integer is written to these files, it can be later + * read out of it. + */ + + +/* + * This is our "object" that we will create a few of and register them with + * sysfs. + */ +struct foo_obj { + struct kobject kobj; + int foo; + int baz; + int bar; +}; +#define to_foo_obj(x) container_of(x, struct foo_obj, kobj) + +/* a custom attribute that works just for a struct foo_obj. */ +struct foo_attribute { + struct attribute attr; + ssize_t (*show)(struct foo_obj *foo, struct foo_attribute *attr, char *buf); + ssize_t (*store)(struct foo_obj *foo, struct foo_attribute *attr, const char *buf, size_t count); +}; +#define to_foo_attr(x) container_of(x, struct foo_attribute, attr) + +/* + * The default show function that must be passed to sysfs. This will be + * called by sysfs for whenever a show function is called by the user on a + * sysfs file associated with the kobjects we have registered. We need to + * transpose back from a "default" kobject to our custom struct foo_obj and + * then call the show function for that specific object. + */ +static ssize_t foo_attr_show(struct kobject *kobj, + struct attribute *attr, + char *buf) +{ + struct foo_attribute *attribute; + struct foo_obj *foo; + + attribute = to_foo_attr(attr); + foo = to_foo_obj(kobj); + + if (!attribute->show) + return -EIO; + + return attribute->show(foo, attribute, buf); +} + +/* + * Just like the default show function above, but this one is for when the + * sysfs "store" is requested (when a value is written to a file.) + */ +static ssize_t foo_attr_store(struct kobject *kobj, + struct attribute *attr, + const char *buf, size_t len) +{ + struct foo_attribute *attribute; + struct foo_obj *foo; + + attribute = to_foo_attr(attr); + foo = to_foo_obj(kobj); + + if (!attribute->store) + return -EIO; + + return attribute->store(foo, attribute, buf, len); +} + +/* Our custom sysfs_ops that we will associate with our ktype later on */ +static const struct sysfs_ops foo_sysfs_ops = { + .show = foo_attr_show, + .store = foo_attr_store, +}; + +/* + * The release function for our object. This is REQUIRED by the kernel to + * have. We free the memory held in our object here. + * + * NEVER try to get away with just a "blank" release function to try to be + * smarter than the kernel. Turns out, no one ever is... + */ +static void foo_release(struct kobject *kobj) +{ + struct foo_obj *foo; + + foo = to_foo_obj(kobj); + kfree(foo); +} + +/* + * The "foo" file where the .foo variable is read from and written to. + */ +static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr, + char *buf) +{ + return sprintf(buf, "%d\n", foo_obj->foo); +} + +static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr, + const char *buf, size_t count) +{ + sscanf(buf, "%du", &foo_obj->foo); + return count; +} + +static struct foo_attribute foo_attribute = + __ATTR(foo, 0666, foo_show, foo_store); + +/* + * More complex function where we determine which variable is being accessed by + * looking at the attribute for the "baz" and "bar" files. + */ +static ssize_t b_show(struct foo_obj *foo_obj, struct foo_attribute *attr, + char *buf) +{ + int var; + + if (strcmp(attr->attr.name, "baz") == 0) + var = foo_obj->baz; + else + var = foo_obj->bar; + return sprintf(buf, "%d\n", var); +} + +static ssize_t b_store(struct foo_obj *foo_obj, struct foo_attribute *attr, + const char *buf, size_t count) +{ + int var; + + sscanf(buf, "%du", &var); + if (strcmp(attr->attr.name, "baz") == 0) + foo_obj->baz = var; + else + foo_obj->bar = var; + return count; +} + +static struct foo_attribute baz_attribute = + __ATTR(baz, 0666, b_show, b_store); +static struct foo_attribute bar_attribute = + __ATTR(bar, 0666, b_show, b_store); + +/* + * Create a group of attributes so that we can create and destroy them all + * at once. + */ +static struct attribute *foo_default_attrs[] = { + &foo_attribute.attr, + &baz_attribute.attr, + &bar_attribute.attr, + NULL, /* need to NULL terminate the list of attributes */ +}; + +/* + * Our own ktype for our kobjects. Here we specify our sysfs ops, the + * release function, and the set of default attributes we want created + * whenever a kobject of this type is registered with the kernel. + */ +static struct kobj_type foo_ktype = { + .sysfs_ops = &foo_sysfs_ops, + .release = foo_release, + .default_attrs = foo_default_attrs, +}; + +static struct kset *example_kset; +static struct foo_obj *foo_obj; +static struct foo_obj *bar_obj; +static struct foo_obj *baz_obj; + +static struct foo_obj *create_foo_obj(const char *name) +{ + struct foo_obj *foo; + int retval; + + /* allocate the memory for the whole object */ + foo = kzalloc(sizeof(*foo), GFP_KERNEL); + if (!foo) + return NULL; + + /* + * As we have a kset for this kobject, we need to set it before calling + * the kobject core. + */ + foo->kobj.kset = example_kset; + + /* + * Initialize and add the kobject to the kernel. All the default files + * will be created here. As we have already specified a kset for this + * kobject, we don't have to set a parent for the kobject, the kobject + * will be placed beneath that kset automatically. + */ + retval = kobject_init_and_add(&foo->kobj, &foo_ktype, NULL, "%s", name); + if (retval) { + kobject_put(&foo->kobj); + return NULL; + } + + /* + * We are always responsible for sending the uevent that the kobject + * was added to the system. + */ + kobject_uevent(&foo->kobj, KOBJ_ADD); + + return foo; +} + +static void destroy_foo_obj(struct foo_obj *foo) +{ + kobject_put(&foo->kobj); +} + +static int __init example_init(void) +{ + /* + * Create a kset with the name of "kset_example", + * located under /sys/kernel/ + */ + example_kset = kset_create_and_add("kset_example", NULL, kernel_kobj); + if (!example_kset) + return -ENOMEM; + + /* + * Create three objects and register them with our kset + */ + foo_obj = create_foo_obj("foo"); + if (!foo_obj) + goto foo_error; + + bar_obj = create_foo_obj("bar"); + if (!bar_obj) + goto bar_error; + + baz_obj = create_foo_obj("baz"); + if (!baz_obj) + goto baz_error; + + return 0; + +baz_error: + destroy_foo_obj(bar_obj); +bar_error: + destroy_foo_obj(foo_obj); +foo_error: + return -EINVAL; +} + +static void __exit example_exit(void) +{ + destroy_foo_obj(baz_obj); + destroy_foo_obj(bar_obj); + destroy_foo_obj(foo_obj); + kset_unregister(example_kset); +} + +module_init(example_init); +module_exit(example_exit); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>"); diff --git a/samples/kprobes/Makefile b/samples/kprobes/Makefile new file mode 100644 index 00000000..68739bc4 --- /dev/null +++ b/samples/kprobes/Makefile @@ -0,0 +1,5 @@ +# builds the kprobes example kernel modules; +# then to use one (as root): insmod <module_name.ko> + +obj-$(CONFIG_SAMPLE_KPROBES) += kprobe_example.o jprobe_example.o +obj-$(CONFIG_SAMPLE_KRETPROBES) += kretprobe_example.o diff --git a/samples/kprobes/jprobe_example.c b/samples/kprobes/jprobe_example.c new file mode 100644 index 00000000..b7541355 --- /dev/null +++ b/samples/kprobes/jprobe_example.c @@ -0,0 +1,68 @@ +/* + * Here's a sample kernel module showing the use of jprobes to dump + * the arguments of do_fork(). + * + * For more information on theory of operation of jprobes, see + * Documentation/kprobes.txt + * + * Build and insert the kernel module as done in the kprobe example. + * You will see the trace data in /var/log/messages and on the + * console whenever do_fork() is invoked to create a new process. + * (Some messages may be suppressed if syslogd is configured to + * eliminate duplicate messages.) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/kprobes.h> + +/* + * Jumper probe for do_fork. + * Mirror principle enables access to arguments of the probed routine + * from the probe handler. + */ + +/* Proxy routine having the same arguments as actual do_fork() routine */ +static long jdo_fork(unsigned long clone_flags, unsigned long stack_start, + struct pt_regs *regs, unsigned long stack_size, + int __user *parent_tidptr, int __user *child_tidptr) +{ + printk(KERN_INFO "jprobe: clone_flags = 0x%lx, stack_size = 0x%lx," + " regs = 0x%p\n", + clone_flags, stack_size, regs); + + /* Always end with a call to jprobe_return(). */ + jprobe_return(); + return 0; +} + +static struct jprobe my_jprobe = { + .entry = jdo_fork, + .kp = { + .symbol_name = "do_fork", + }, +}; + +static int __init jprobe_init(void) +{ + int ret; + + ret = register_jprobe(&my_jprobe); + if (ret < 0) { + printk(KERN_INFO "register_jprobe failed, returned %d\n", ret); + return -1; + } + printk(KERN_INFO "Planted jprobe at %p, handler addr %p\n", + my_jprobe.kp.addr, my_jprobe.entry); + return 0; +} + +static void __exit jprobe_exit(void) +{ + unregister_jprobe(&my_jprobe); + printk(KERN_INFO "jprobe at %p unregistered\n", my_jprobe.kp.addr); +} + +module_init(jprobe_init) +module_exit(jprobe_exit) +MODULE_LICENSE("GPL"); diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c new file mode 100644 index 00000000..ebf5e0c3 --- /dev/null +++ b/samples/kprobes/kprobe_example.c @@ -0,0 +1,100 @@ +/* + * NOTE: This example is works on x86 and powerpc. + * Here's a sample kernel module showing the use of kprobes to dump a + * stack trace and selected registers when do_fork() is called. + * + * For more information on theory of operation of kprobes, see + * Documentation/kprobes.txt + * + * You will see the trace data in /var/log/messages and on the console + * whenever do_fork() is invoked to create a new process. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/kprobes.h> + +/* For each probe you need to allocate a kprobe structure */ +static struct kprobe kp = { + .symbol_name = "do_fork", +}; + +/* kprobe pre_handler: called just before the probed instruction is executed */ +static int handler_pre(struct kprobe *p, struct pt_regs *regs) +{ +#ifdef CONFIG_X86 + printk(KERN_INFO "pre_handler: p->addr = 0x%p, ip = %lx," + " flags = 0x%lx\n", + p->addr, regs->ip, regs->flags); +#endif +#ifdef CONFIG_PPC + printk(KERN_INFO "pre_handler: p->addr = 0x%p, nip = 0x%lx," + " msr = 0x%lx\n", + p->addr, regs->nip, regs->msr); +#endif +#ifdef CONFIG_MIPS + printk(KERN_INFO "pre_handler: p->addr = 0x%p, epc = 0x%lx," + " status = 0x%lx\n", + p->addr, regs->cp0_epc, regs->cp0_status); +#endif + + /* A dump_stack() here will give a stack backtrace */ + return 0; +} + +/* kprobe post_handler: called after the probed instruction is executed */ +static void handler_post(struct kprobe *p, struct pt_regs *regs, + unsigned long flags) +{ +#ifdef CONFIG_X86 + printk(KERN_INFO "post_handler: p->addr = 0x%p, flags = 0x%lx\n", + p->addr, regs->flags); +#endif +#ifdef CONFIG_PPC + printk(KERN_INFO "post_handler: p->addr = 0x%p, msr = 0x%lx\n", + p->addr, regs->msr); +#endif +#ifdef CONFIG_MIPS + printk(KERN_INFO "post_handler: p->addr = 0x%p, status = 0x%lx\n", + p->addr, regs->cp0_status); +#endif +} + +/* + * fault_handler: this is called if an exception is generated for any + * instruction within the pre- or post-handler, or when Kprobes + * single-steps the probed instruction. + */ +static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr) +{ + printk(KERN_INFO "fault_handler: p->addr = 0x%p, trap #%dn", + p->addr, trapnr); + /* Return 0 because we don't handle the fault. */ + return 0; +} + +static int __init kprobe_init(void) +{ + int ret; + kp.pre_handler = handler_pre; + kp.post_handler = handler_post; + kp.fault_handler = handler_fault; + + ret = register_kprobe(&kp); + if (ret < 0) { + printk(KERN_INFO "register_kprobe failed, returned %d\n", ret); + return ret; + } + printk(KERN_INFO "Planted kprobe at %p\n", kp.addr); + return 0; +} + +static void __exit kprobe_exit(void) +{ + unregister_kprobe(&kp); + printk(KERN_INFO "kprobe at %p unregistered\n", kp.addr); +} + +module_init(kprobe_init) +module_exit(kprobe_exit) +MODULE_LICENSE("GPL"); diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c new file mode 100644 index 00000000..1041b673 --- /dev/null +++ b/samples/kprobes/kretprobe_example.c @@ -0,0 +1,107 @@ +/* + * kretprobe_example.c + * + * Here's a sample kernel module showing the use of return probes to + * report the return value and total time taken for probed function + * to run. + * + * usage: insmod kretprobe_example.ko func=<func_name> + * + * If no func_name is specified, do_fork is instrumented + * + * For more information on theory of operation of kretprobes, see + * Documentation/kprobes.txt + * + * Build and insert the kernel module as done in the kprobe example. + * You will see the trace data in /var/log/messages and on the console + * whenever the probed function returns. (Some messages may be suppressed + * if syslogd is configured to eliminate duplicate messages.) + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/kprobes.h> +#include <linux/ktime.h> +#include <linux/limits.h> +#include <linux/sched.h> + +static char func_name[NAME_MAX] = "do_fork"; +module_param_string(func, func_name, NAME_MAX, S_IRUGO); +MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the" + " function's execution time"); + +/* per-instance private data */ +struct my_data { + ktime_t entry_stamp; +}; + +/* Here we use the entry_hanlder to timestamp function entry */ +static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + struct my_data *data; + + if (!current->mm) + return 1; /* Skip kernel threads */ + + data = (struct my_data *)ri->data; + data->entry_stamp = ktime_get(); + return 0; +} + +/* + * Return-probe handler: Log the return value and duration. Duration may turn + * out to be zero consistently, depending upon the granularity of time + * accounting on the platform. + */ +static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs) +{ + int retval = regs_return_value(regs); + struct my_data *data = (struct my_data *)ri->data; + s64 delta; + ktime_t now; + + now = ktime_get(); + delta = ktime_to_ns(ktime_sub(now, data->entry_stamp)); + printk(KERN_INFO "%s returned %d and took %lld ns to execute\n", + func_name, retval, (long long)delta); + return 0; +} + +static struct kretprobe my_kretprobe = { + .handler = ret_handler, + .entry_handler = entry_handler, + .data_size = sizeof(struct my_data), + /* Probe up to 20 instances concurrently. */ + .maxactive = 20, +}; + +static int __init kretprobe_init(void) +{ + int ret; + + my_kretprobe.kp.symbol_name = func_name; + ret = register_kretprobe(&my_kretprobe); + if (ret < 0) { + printk(KERN_INFO "register_kretprobe failed, returned %d\n", + ret); + return -1; + } + printk(KERN_INFO "Planted return probe at %s: %p\n", + my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr); + return 0; +} + +static void __exit kretprobe_exit(void) +{ + unregister_kretprobe(&my_kretprobe); + printk(KERN_INFO "kretprobe at %p unregistered\n", + my_kretprobe.kp.addr); + + /* nmissed > 0 suggests that maxactive was set too low. */ + printk(KERN_INFO "Missed probing %d instances of %s\n", + my_kretprobe.nmissed, my_kretprobe.kp.symbol_name); +} + +module_init(kretprobe_init) +module_exit(kretprobe_exit) +MODULE_LICENSE("GPL"); diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile new file mode 100644 index 00000000..0f8d9212 --- /dev/null +++ b/samples/trace_events/Makefile @@ -0,0 +1,14 @@ +# builds the trace events example kernel modules; +# then to use one (as root): insmod <module_name.ko> + +# If you include a trace header outside of include/trace/events +# then the file that does the #define CREATE_TRACE_POINTS must +# have that tracer file in its main search path. This is because +# define_trace.h will include it, and must be able to find it from +# the include/trace directory. +# +# Here trace-events-sample.c does the CREATE_TRACE_POINTS. +# +CFLAGS_trace-events-sample.o := -I$(src) + +obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o diff --git a/samples/trace_events/trace-events-sample.c b/samples/trace_events/trace-events-sample.c new file mode 100644 index 00000000..aabc4e97 --- /dev/null +++ b/samples/trace_events/trace-events-sample.c @@ -0,0 +1,52 @@ +#include <linux/module.h> +#include <linux/kthread.h> + +/* + * Any file that uses trace points, must include the header. + * But only one file, must include the header by defining + * CREATE_TRACE_POINTS first. This will make the C code that + * creates the handles for the trace points. + */ +#define CREATE_TRACE_POINTS +#include "trace-events-sample.h" + + +static void simple_thread_func(int cnt) +{ + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(HZ); + trace_foo_bar("hello", cnt); +} + +static int simple_thread(void *arg) +{ + int cnt = 0; + + while (!kthread_should_stop()) + simple_thread_func(cnt++); + + return 0; +} + +static struct task_struct *simple_tsk; + +static int __init trace_event_init(void) +{ + simple_tsk = kthread_run(simple_thread, NULL, "event-sample"); + if (IS_ERR(simple_tsk)) + return -1; + + return 0; +} + +static void __exit trace_event_exit(void) +{ + kthread_stop(simple_tsk); +} + +module_init(trace_event_init); +module_exit(trace_event_exit); + +MODULE_AUTHOR("Steven Rostedt"); +MODULE_DESCRIPTION("trace-events-sample"); +MODULE_LICENSE("GPL"); diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h new file mode 100644 index 00000000..6af37323 --- /dev/null +++ b/samples/trace_events/trace-events-sample.h @@ -0,0 +1,137 @@ +/* + * If TRACE_SYSTEM is defined, that will be the directory created + * in the ftrace directory under /sys/kernel/debug/tracing/events/<system> + * + * The define_trace.h below will also look for a file name of + * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. + * In this case, it would look for sample.h + * + * If the header name will be different than the system name + * (as in this case), then you can override the header name that + * define_trace.h will look up by defining TRACE_INCLUDE_FILE + * + * This file is called trace-events-sample.h but we want the system + * to be called "sample". Therefore we must define the name of this + * file: + * + * #define TRACE_INCLUDE_FILE trace-events-sample + * + * As we do an the bottom of this file. + * + * Notice that TRACE_SYSTEM should be defined outside of #if + * protection, just like TRACE_INCLUDE_FILE. + */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM sample + +/* + * Notice that this file is not protected like a normal header. + * We also must allow for rereading of this file. The + * + * || defined(TRACE_HEADER_MULTI_READ) + * + * serves this purpose. + */ +#if !defined(_TRACE_EVENT_SAMPLE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_EVENT_SAMPLE_H + +/* + * All trace headers should include tracepoint.h, until we finally + * make it into a standard header. + */ +#include <linux/tracepoint.h> + +/* + * The TRACE_EVENT macro is broken up into 5 parts. + * + * name: name of the trace point. This is also how to enable the tracepoint. + * A function called trace_foo_bar() will be created. + * + * proto: the prototype of the function trace_foo_bar() + * Here it is trace_foo_bar(char *foo, int bar). + * + * args: must match the arguments in the prototype. + * Here it is simply "foo, bar". + * + * struct: This defines the way the data will be stored in the ring buffer. + * There are currently two types of elements. __field and __array. + * a __field is broken up into (type, name). Where type can be any + * type but an array. + * For an array. there are three fields. (type, name, size). The + * type of elements in the array, the name of the field and the size + * of the array. + * + * __array( char, foo, 10) is the same as saying char foo[10]. + * + * fast_assign: This is a C like function that is used to store the items + * into the ring buffer. + * + * printk: This is a way to print out the data in pretty print. This is + * useful if the system crashes and you are logging via a serial line, + * the data can be printed to the console using this "printk" method. + * + * Note, that for both the assign and the printk, __entry is the handler + * to the data structure in the ring buffer, and is defined by the + * TP_STRUCT__entry. + */ +TRACE_EVENT(foo_bar, + + TP_PROTO(char *foo, int bar), + + TP_ARGS(foo, bar), + + TP_STRUCT__entry( + __array( char, foo, 10 ) + __field( int, bar ) + ), + + TP_fast_assign( + strncpy(__entry->foo, foo, 10); + __entry->bar = bar; + ), + + TP_printk("foo %s %d", __entry->foo, __entry->bar) +); +#endif + +/***** NOTICE! The #if protection ends here. *****/ + + +/* + * There are several ways I could have done this. If I left out the + * TRACE_INCLUDE_PATH, then it would default to the kernel source + * include/trace/events directory. + * + * I could specify a path from the define_trace.h file back to this + * file. + * + * #define TRACE_INCLUDE_PATH ../../samples/trace_events + * + * But the safest and easiest way to simply make it use the directory + * that the file is in is to add in the Makefile: + * + * CFLAGS_trace-events-sample.o := -I$(src) + * + * This will make sure the current path is part of the include + * structure for our file so that define_trace.h can find it. + * + * I could have made only the top level directory the include: + * + * CFLAGS_trace-events-sample.o := -I$(PWD) + * + * And then let the path to this directory be the TRACE_INCLUDE_PATH: + * + * #define TRACE_INCLUDE_PATH samples/trace_events + * + * But then if something defines "samples" or "trace_events" as a macro + * then we could risk that being converted too, and give us an unexpected + * result. + */ +#undef TRACE_INCLUDE_PATH +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_PATH . +/* + * TRACE_INCLUDE_FILE is not needed if the filename and TRACE_SYSTEM are equal + */ +#define TRACE_INCLUDE_FILE trace-events-sample +#include <trace/define_trace.h> diff --git a/samples/tracepoints/Makefile b/samples/tracepoints/Makefile new file mode 100644 index 00000000..36479ad9 --- /dev/null +++ b/samples/tracepoints/Makefile @@ -0,0 +1,6 @@ +# builds the tracepoint example kernel modules; +# then to use one (as root): insmod <module_name.ko> + +obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-sample.o +obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample.o +obj-$(CONFIG_SAMPLE_TRACEPOINTS) += tracepoint-probe-sample2.o diff --git a/samples/tracepoints/tp-samples-trace.h b/samples/tracepoints/tp-samples-trace.h new file mode 100644 index 00000000..4d46be96 --- /dev/null +++ b/samples/tracepoints/tp-samples-trace.h @@ -0,0 +1,11 @@ +#ifndef _TP_SAMPLES_TRACE_H +#define _TP_SAMPLES_TRACE_H + +#include <linux/proc_fs.h> /* for struct inode and struct file */ +#include <linux/tracepoint.h> + +DECLARE_TRACE(subsys_event, + TP_PROTO(struct inode *inode, struct file *file), + TP_ARGS(inode, file)); +DECLARE_TRACE_NOARGS(subsys_eventb); +#endif diff --git a/samples/tracepoints/tracepoint-probe-sample.c b/samples/tracepoints/tracepoint-probe-sample.c new file mode 100644 index 00000000..744c0b96 --- /dev/null +++ b/samples/tracepoints/tracepoint-probe-sample.c @@ -0,0 +1,57 @@ +/* + * tracepoint-probe-sample.c + * + * sample tracepoint probes. + */ + +#include <linux/module.h> +#include <linux/file.h> +#include <linux/dcache.h> +#include "tp-samples-trace.h" + +/* + * Here the caller only guarantees locking for struct file and struct inode. + * Locking must therefore be done in the probe to use the dentry. + */ +static void probe_subsys_event(void *ignore, + struct inode *inode, struct file *file) +{ + path_get(&file->f_path); + dget(file->f_path.dentry); + printk(KERN_INFO "Event is encountered with filename %s\n", + file->f_path.dentry->d_name.name); + dput(file->f_path.dentry); + path_put(&file->f_path); +} + +static void probe_subsys_eventb(void *ignore) +{ + printk(KERN_INFO "Event B is encountered\n"); +} + +static int __init tp_sample_trace_init(void) +{ + int ret; + + ret = register_trace_subsys_event(probe_subsys_event, NULL); + WARN_ON(ret); + ret = register_trace_subsys_eventb(probe_subsys_eventb, NULL); + WARN_ON(ret); + + return 0; +} + +module_init(tp_sample_trace_init); + +static void __exit tp_sample_trace_exit(void) +{ + unregister_trace_subsys_eventb(probe_subsys_eventb, NULL); + unregister_trace_subsys_event(probe_subsys_event, NULL); + tracepoint_synchronize_unregister(); +} + +module_exit(tp_sample_trace_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Mathieu Desnoyers"); +MODULE_DESCRIPTION("Tracepoint Probes Samples"); diff --git a/samples/tracepoints/tracepoint-probe-sample2.c b/samples/tracepoints/tracepoint-probe-sample2.c new file mode 100644 index 00000000..9fcf990e --- /dev/null +++ b/samples/tracepoints/tracepoint-probe-sample2.c @@ -0,0 +1,44 @@ +/* + * tracepoint-probe-sample2.c + * + * 2nd sample tracepoint probes. + */ + +#include <linux/module.h> +#include <linux/fs.h> +#include "tp-samples-trace.h" + +/* + * Here the caller only guarantees locking for struct file and struct inode. + * Locking must therefore be done in the probe to use the dentry. + */ +static void probe_subsys_event(void *ignore, + struct inode *inode, struct file *file) +{ + printk(KERN_INFO "Event is encountered with inode number %lu\n", + inode->i_ino); +} + +static int __init tp_sample_trace_init(void) +{ + int ret; + + ret = register_trace_subsys_event(probe_subsys_event, NULL); + WARN_ON(ret); + + return 0; +} + +module_init(tp_sample_trace_init); + +static void __exit tp_sample_trace_exit(void) +{ + unregister_trace_subsys_event(probe_subsys_event, NULL); + tracepoint_synchronize_unregister(); +} + +module_exit(tp_sample_trace_exit); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Mathieu Desnoyers"); +MODULE_DESCRIPTION("Tracepoint Probes Samples"); diff --git a/samples/tracepoints/tracepoint-sample.c b/samples/tracepoints/tracepoint-sample.c new file mode 100644 index 00000000..26fab33f --- /dev/null +++ b/samples/tracepoints/tracepoint-sample.c @@ -0,0 +1,56 @@ +/* tracepoint-sample.c + * + * Executes a tracepoint when /proc/tracepoint-sample is opened. + * + * (C) Copyright 2007 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> + * + * This file is released under the GPLv2. + * See the file COPYING for more details. + */ + +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/proc_fs.h> +#include "tp-samples-trace.h" + +DEFINE_TRACE(subsys_event); +DEFINE_TRACE(subsys_eventb); + +struct proc_dir_entry *pentry_sample; + +static int my_open(struct inode *inode, struct file *file) +{ + int i; + + trace_subsys_event(inode, file); + for (i = 0; i < 10; i++) + trace_subsys_eventb(); + return -EPERM; +} + +static const struct file_operations mark_ops = { + .open = my_open, +}; + +static int __init sample_init(void) +{ + printk(KERN_ALERT "sample init\n"); + pentry_sample = proc_create("tracepoint-sample", 0444, NULL, + &mark_ops); + if (!pentry_sample) + return -EPERM; + return 0; +} + +static void __exit sample_exit(void) +{ + printk(KERN_ALERT "sample exit\n"); + remove_proc_entry("tracepoint-sample", NULL); +} + +module_init(sample_init) +module_exit(sample_exit) + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Mathieu Desnoyers"); +MODULE_DESCRIPTION("Tracepoint sample"); |