From 4aad8f51d0672f1c95e2cf0e1bc7b9ab42d8e1ea Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Mon, 25 Oct 2010 10:14:05 -0500 Subject: kdb: Add kdb kernel module sample Add an example of how to add a dynamic kdb shell command via a kernel module. Signed-off-by: Jason Wessel --- Documentation/DocBook/kgdb.tmpl | 13 ++++++++- samples/Kconfig | 7 +++++ samples/Makefile | 2 +- samples/kdb/Makefile | 1 + samples/kdb/kdb_hello.c | 60 +++++++++++++++++++++++++++++++++++++++++ 5 files changed, 81 insertions(+), 2 deletions(-) create mode 100644 samples/kdb/Makefile create mode 100644 samples/kdb/kdb_hello.c diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index 490d862c5f0d..d71b57fcf116 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -710,7 +710,18 @@ Task Addr Pid Parent [*] cpu State Thread Command A simple shell The kdb core command set A registration API to register additional kdb shell commands. - A good example of a self-contained kdb module is the "ftdump" command for dumping the ftrace buffer. See: kernel/trace/trace_kdb.c + + A good example of a self-contained kdb module + is the "ftdump" command for dumping the ftrace buffer. See: + kernel/trace/trace_kdb.c + For an example of how to dynamically register + a new kdb command you can build the kdb_hello.ko kernel module + from samples/kdb/kdb_hello.c. To build this example you can + set CONFIG_SAMPLES=y and CONFIG_SAMPLE_KDB=m in your kernel + config. Later run "modprobe kdb_hello" and the next time you + enter the kdb shell, you can run the "hello" + command. + The implementation for kdb_printf() which emits messages directly to I/O drivers, bypassing the kernel log. diff --git a/samples/Kconfig b/samples/Kconfig index 954a1d550c5f..e03cf0e374d7 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -54,4 +54,11 @@ config SAMPLE_KFIFO If in doubt, say "N" here. +config SAMPLE_KDB + tristate "Build kdb command exmaple -- loadable modules only" + depends on KGDB_KDB && m + help + Build an example of how to dynamically add the hello + command to the kdb shell. + endif # SAMPLES diff --git a/samples/Makefile b/samples/Makefile index 76b3c3455c29..f26c0959fd86 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -1,4 +1,4 @@ # Makefile for Linux samples code obj-$(CONFIG_SAMPLES) += kobject/ kprobes/ tracepoints/ trace_events/ \ - hw_breakpoint/ kfifo/ + hw_breakpoint/ kfifo/ kdb/ diff --git a/samples/kdb/Makefile b/samples/kdb/Makefile new file mode 100644 index 000000000000..fbedf39d9356 --- /dev/null +++ b/samples/kdb/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_SAMPLE_KDB) += kdb_hello.o diff --git a/samples/kdb/kdb_hello.c b/samples/kdb/kdb_hello.c new file mode 100644 index 000000000000..c1c2fa0f62c2 --- /dev/null +++ b/samples/kdb/kdb_hello.c @@ -0,0 +1,60 @@ +/* + * Created by: Jason Wessel + * + * Copyright (c) 2010 Wind River Systems, Inc. All Rights Reserved. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include +#include + +/* + * All kdb shell command call backs receive argc and argv, where + * argv[0] is the command the end user typed + */ +static int kdb_hello_cmd(int argc, const char **argv) +{ + if (argc > 1) + return KDB_ARGCOUNT; + + if (argc) + kdb_printf("Hello %s.\n", argv[1]); + else + kdb_printf("Hello world!\n"); + + return 0; +} + + +static int __init kdb_hello_cmd_init(void) +{ + /* + * Registration of a dynamically added kdb command is done with + * kdb_register() with the arguments being: + * 1: The name of the shell command + * 2: The function that processes the command + * 3: Description of the usage of any arguments + * 4: Descriptive text when you run help + * 5: Number of characters to complete the command + * 0 == type the whole command + * 1 == match both "g" and "go" for example + */ + kdb_register("hello", kdb_hello_cmd, "[string]", + "Say Hello World or Hello [string]", 0); + return 0; +} + +static void __exit kdb_hello_cmd_exit(void) +{ + kdb_unregister("hello"); +} + +module_init(kdb_hello_cmd_init); +module_exit(kdb_hello_cmd_exit); + +MODULE_AUTHOR("WindRiver"); +MODULE_DESCRIPTION("KDB example to add a hello command"); +MODULE_LICENSE("GPL"); -- cgit v1.2.3-70-g09d2