模塊的符號導出后其他模塊不能調用求解

www1862

其實就是LDD的例子，其中作者自己實現(xiàn)了一個簡單的總線 ldd_bus 代碼如下：

ldd_bus.h MODULE_LICENSE("GPL"); extern struct bus_type ldd_bus_type; /*  * The LDD driver type.  */ struct ldd_driver {     char *version;     struct module *module;     struct device_driver driver;     struct driver_attribute version_attr; }; #define to_ldd_driver(drv) container_of(drv, struct ldd_driver, driver); /*  * A device type for things "plugged" into the LDD bus.  */ struct ldd_device {     char *name;     struct ldd_driver *driver;     struct device dev; }; #define to_ldd_device(dev) container_of(dev, struct ldd_device, dev); extern int register_ldd_device(struct ldd_device *); extern void unregister_ldd_device(struct ldd_device *); extern int register_ldd_driver(struct ldd_driver *); extern void unregister_ldd_driver(struct ldd_driver *);

ldd_bus.c #include <linux/device.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/string.h> #include "lddbus.h" MODULE_AUTHOR("Jonathan Corbet"); MODULE_LICENSE("GPL"); static char *Version = "$Revision: 1.9 $"; /*  * Respond to hotplug events.  */ //static int ldd_hotplug(struct device *dev, char **envp, int num_envp, //        char *buffer, int buffer_size) static int ldd_uevent(struct device *dev, struct kobj_uevent_env *env) {     struct ldd_device *pdev;     if (!dev)         return -ENODEV;          pdev = to_ldd_device(dev);          if (!pdev)         return -ENODEV;          if (add_uevent_var(env, "LDDBUS_VERSION=%s", Version))         return -ENOMEM;         /*         envp[0] = buffer;     if (snprintf(buffer, buffer_size, "LDDBUS_VERSION=%s",                 Version) >= buffer_size)         return -ENOMEM;     envp[1] = NULL;     */          return 0; } /*  * Match LDD devices to drivers.  Just do a simple name test.  */ static int ldd_match(struct device *dev, struct device_driver *driver) {     return !strncmp(dev->bus_id, driver->name, strlen(driver->name)); } /*  * The LDD bus device.  */ static void ldd_bus_release(struct device *dev) {     printk(KERN_DEBUG "lddbus release\n"); }      struct device ldd_bus = {     .bus_id   = "ldd0",     .release  = ldd_bus_release }; /*  * And the bus type.  */ struct bus_type ldd_bus_type = {     .name = "ldd",     .match = ldd_match,     //.hotplug  = ldd_hotplug,     .uevent = ldd_uevent, }; /*  * Export a simple attribute.  */ static ssize_t show_bus_version(struct bus_type *bus, char *buf) {     return snprintf(buf, PAGE_SIZE, "%s\n", Version); } static BUS_ATTR(version, S_IRUGO, show_bus_version, NULL); /*  * LDD devices.  */ /*  * For now, no references to LDDbus devices go out which are not  * tracked via the module reference count, so we use a no-op  * release function.  */ static void ldd_dev_release(struct device *dev) { } int register_ldd_device(struct ldd_device *ldddev) {     ldddev->dev.bus = &ldd_bus_type;     ldddev->dev.parent = &ldd_bus;     ldddev->dev.release = ldd_dev_release;     strncpy(ldddev->dev.bus_id, ldddev->name, BUS_ID_SIZE);     return device_register(&ldddev->dev); } EXPORT_SYMBOL(register_ldd_device); void unregister_ldd_device(struct ldd_device *ldddev) {     device_unregister(&ldddev->dev); } EXPORT_SYMBOL(unregister_ldd_device);

int sculld_init(void) { &nbsp;&nbsp;&nbsp;&nbsp;int result, i; &nbsp;&nbsp;&nbsp;&nbsp;dev_t dev = MKDEV(sculld_major, 0); &nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;/* &nbsp;&nbsp;&nbsp;&nbsp; * Register your major, and accept a dynamic number. &nbsp;&nbsp;&nbsp;&nbsp; */ &nbsp;&nbsp;&nbsp;&nbsp;if (sculld_major) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;result = register_chrdev_region(dev, sculld_devs, "sculld"); &nbsp;&nbsp;&nbsp;&nbsp;else { &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;result = alloc_chrdev_region(&dev, 0, sculld_devs, "sculld"); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sculld_major = MAJOR(dev); &nbsp;&nbsp;&nbsp;&nbsp;} &nbsp;&nbsp;&nbsp;&nbsp;if (result < 0) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return result; &nbsp;&nbsp;&nbsp;&nbsp;/* &nbsp;&nbsp;&nbsp;&nbsp; * Register with the driver core. &nbsp;&nbsp;&nbsp;&nbsp; */ &nbsp;&nbsp;&nbsp;&nbsp;register_ldd_driver(&sculld_driver); &nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;/* &nbsp;&nbsp;&nbsp;&nbsp; * allocate the devices -- we can't have them static, as the number &nbsp;&nbsp;&nbsp;&nbsp; * can be specified at load time &nbsp;&nbsp;&nbsp;&nbsp; */ &nbsp;&nbsp;&nbsp;&nbsp;sculld_devices = kmalloc(sculld_devs*sizeof (struct sculld_dev), GFP_KERNEL); &nbsp;&nbsp;&nbsp;&nbsp;if (!sculld_devices) { &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;result = -ENOMEM; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;goto fail_malloc; &nbsp;&nbsp;&nbsp;&nbsp;} &nbsp;&nbsp;&nbsp;&nbsp;memset(sculld_devices, 0, sculld_devs*sizeof (struct sculld_dev)); &nbsp;&nbsp;&nbsp;&nbsp;for (i = 0; i < sculld_devs; i++) { &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sculld_devices[i].order = sculld_order; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sculld_devices[i].qset = sculld_qset; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sema_init (&sculld_devices[i].sem, 1); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sculld_setup_cdev(sculld_devices + i, i); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;sculld_register_dev(sculld_devices + i, i); &nbsp;&nbsp;&nbsp;&nbsp;} //#ifdef SCULLD_USE_PROC /* only when available */ &nbsp;&nbsp;&nbsp;&nbsp;create_proc_read_entry("sculldmem", 0, NULL, sculld_read_procmem, NULL); //#endif &nbsp;&nbsp;&nbsp;&nbsp;return 0; /* succeed */ &nbsp;&nbsp;fail_malloc: &nbsp;&nbsp;&nbsp;&nbsp;unregister_chrdev_region(dev, sculld_devs); &nbsp;&nbsp;&nbsp;&nbsp;return result; }

在另一個模塊里調用EXPORT的函數，編譯的時候 WARNING: "register_ldd_driver" [/sculld/sculld.ko] undefined! insmod 的時候出錯 Unknown symbol in module

cat /proc/kallsyms | grep register_ldd_driver

ffffffffa0493310 r __ksymtab_unregister_ldd_driver        [lddbus] ffffffffa0493370 r __kstrtab_unregister_ldd_driver        [lddbus] ffffffffa0493350 r __kcrctab_unregister_ldd_driver        [lddbus] ffffffffa0493320 r __ksymtab_register_ldd_driver        [lddbus] ffffffffa0493386 r __kstrtab_register_ldd_driver        [lddbus] ffffffffa0493358 r __kcrctab_register_ldd_driver        [lddbus] ffffffffa0493330 r __ksymtab_unregister_ldd_device        [lddbus] ffffffffa049339a r __kstrtab_unregister_ldd_device        [lddbus] ffffffffa0493360 r __kcrctab_unregister_ldd_device        [lddbus] ffffffffa0493130 t unregister_ldd_driver        [lddbus] 00000000cea62aa1 a __crc_unregister_ldd_device        [lddbus] 00000000750790d6 a __crc_register_ldd_device        [lddbus] ffffffffa04931f0 t register_ldd_device        [lddbus] 0000000073ce301d a __crc_unregister_ldd_driver        [lddbus] ffffffffa04930d0 t unregister_ldd_device        [lddbus] 000000002db493e5 a __crc_register_ldd_driver        [lddbus] ffffffffa0493140 t register_ldd_driver        [lddbus]

[ 本帖最后由 www1862 于 2009-4-29 21:45 編輯 ]

dreamice

前面有個哥們說，符號表里面要是類型u的才能被調用

www1862

你的問題解決了嗎？不是已經用EXPORT_SYMBOL(fun) 導出了嗎？為什么還不能用？

www1862

看了一下，ssb b43 的代碼，發(fā)現(xiàn)沒什么不一樣，不過SSB B43都在內核樹里。關于2樓的說法，我的理解是U 是調用者 USE的意思，因為b43 依賴ssb模塊，且ssb_device_enable 是ssb模塊里的 函數。

cat /proc/kallsyms | grep ssb_device_enable ffffffffa0033310 u ssb_device_enable        [b43] ffffffffa0037c60 r __ksymtab_ssb_device_enable        [ssb] ffffffffa0037e79 r __kstrtab_ssb_device_enable        [ssb] ffffffffa0037d68 r __kcrctab_ssb_device_enable        [ssb] ffffffffa0033310 T ssb_device_enable        [ssb] 00000000654ba824 a __crc_ssb_device_enable        [ssb]

[ 本帖最后由 www1862 于 2009-4-29 23:13 編輯 ]

accessory

.H文件里：
extern int register_ldd_device(struct ldd_device *);
extern void unregister_ldd_device(struct ldd_device *);
extern int register_ldd_driver(struct ldd_driver *);
extern void unregister_ldd_driver(struct ldd_driver *);

上面前2行和后面2行一樣的�。苛硗�，EXTERN似乎可以去掉吧？因為在.C里面實現(xiàn)了啊。又不是在其他地方實現(xiàn)的。

還有，你調用 register_ldd_driver 的模塊是怎么寫的？ 應該加了 extern int register_ldd_driver(struct ldd_driver *); 這句吧？

www1862

不一樣，一個是device 一個是driver。
解決了，原來是lddbus.c 頭文件的引用問題。

[ 本帖最后由 www1862 于 2009-4-30 16:43 編輯 ]

emmoblin

不錯，學習了。

linco_gp

回復 1# www1862


    樓主能再具體說下怎么解決的嗎？ 我看lddbus.c頭文件的引用 找不到問題��？

eaglexmw

u的意思是undefined吧