From 7664c5a1da4711bb6383117f51b94c8dc8f3f1cd Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Fri, 8 Dec 2006 02:36:19 -0800 Subject: [PATCH] Generic BUG implementation This patch adds common handling for kernel BUGs, for use by architectures as they wish. The code is derived from arch/powerpc. The advantages of having common BUG handling are: - consistent BUG reporting across architectures - shared implementation of out-of-line file/line data - implement CONFIG_DEBUG_BUGVERBOSE consistently This means that in inline impact of BUG is just the illegal instruction itself, which is an improvement for i386 and x86-64. A BUG is represented in the instruction stream as an illegal instruction, which has file/line information associated with it. This extra information is stored in the __bug_table section in the ELF file. When the kernel gets an illegal instruction, it first confirms it might possibly be from a BUG (ie, in kernel mode, the right illegal instruction). It then calls report_bug(). This searches __bug_table for a matching instruction pointer, and if found, prints the corresponding file/line information. If report_bug() determines that it wasn't a BUG which caused the trap, it returns BUG_TRAP_TYPE_NONE. Some architectures (powerpc) implement WARN using the same mechanism; if the illegal instruction was the result of a WARN, then report_bug(Q) returns CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG. lib/bug.c keeps a list of loaded modules which can be searched for __bug_table entries. The architecture must call module_bug_finalize()/module_bug_cleanup() from its corresponding module_finalize/cleanup functions. Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount. At the very least, filename and line information will not be recorded for each but, but architectures may decide to store no extra information per BUG at all. Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so architectures will generally have to include an infinite loop (or similar) in the BUG code, so that gcc knows execution won't continue beyond that point. gcc does have a __builtin_trap() operator which may be useful to achieve the same effect, unfortunately it cannot be used to actually implement the BUG itself, because there's no way to get the instruction's address for use in generating the __bug_table entry. [randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors] [bunk@stusta.de: include/linux/bug.h must always #include Cc: Andi Kleen Cc: Hugh Dickens Cc: Michael Ellerman Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Rusty Russell Signed-off-by: Adrian Bunk Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/module.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index d33df2408e05..10f771a49997 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -319,6 +319,13 @@ struct module unsigned int taints; /* same bits as kernel:tainted */ +#ifdef CONFIG_GENERIC_BUG + /* Support for BUG */ + struct list_head bug_list; + struct bug_entry *bug_table; + unsigned num_bugs; +#endif + #ifdef CONFIG_MODULE_UNLOAD /* Reference counts */ struct module_ref ref[NR_CPUS]; -- cgit v1.2.3 From f30c53a873d0d227493197064b8886af2d57bbd6 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Mon, 15 Jan 2007 20:22:02 +0100 Subject: MODULES: add the module name for built in kernel drivers Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- include/linux/device.h | 1 + include/linux/module.h | 2 +- kernel/module.c | 33 ++++++++++++++++++++++++--------- kernel/params.c | 12 +++++------- 4 files changed, 31 insertions(+), 17 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/device.h b/include/linux/device.h index f44247fe8135..da7221913114 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -126,6 +126,7 @@ struct device_driver { struct klist_node knode_bus; struct module * owner; + const char * mod_name; /* used for built-in modules */ int (*probe) (struct device * dev); int (*remove) (struct device * dev); diff --git a/include/linux/module.h b/include/linux/module.h index 10f771a49997..90dc2542978c 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -58,6 +58,7 @@ struct module_kobject { struct kobject kobj; struct module *mod; + struct kobject *drivers_dir; }; /* These are either module local, or the kernel's dummy ones. */ @@ -263,7 +264,6 @@ struct module struct module_attribute *modinfo_attrs; const char *version; const char *srcversion; - struct kobject *drivers_dir; /* Exported symbols */ const struct kernel_symbol *syms; diff --git a/kernel/module.c b/kernel/module.c index d0f2260a0210..0f4489af3e29 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1131,8 +1131,8 @@ static int mod_sysfs_setup(struct module *mod, if (err) goto out; - mod->drivers_dir = kobject_add_dir(&mod->mkobj.kobj, "drivers"); - if (!mod->drivers_dir) { + mod->mkobj.drivers_dir = kobject_add_dir(&mod->mkobj.kobj, "drivers"); + if (!mod->mkobj.drivers_dir) { err = -ENOMEM; goto out_unreg; } @@ -1151,7 +1151,7 @@ static int mod_sysfs_setup(struct module *mod, out_unreg_param: module_param_sysfs_remove(mod); out_unreg_drivers: - kobject_unregister(mod->drivers_dir); + kobject_unregister(mod->mkobj.drivers_dir); out_unreg: kobject_del(&mod->mkobj.kobj); kobject_put(&mod->mkobj.kobj); @@ -1163,7 +1163,7 @@ static void mod_kobject_remove(struct module *mod) { module_remove_modinfo_attrs(mod); module_param_sysfs_remove(mod); - kobject_unregister(mod->drivers_dir); + kobject_unregister(mod->mkobj.drivers_dir); kobject_unregister(&mod->mkobj.kobj); } @@ -2344,15 +2344,30 @@ void module_add_driver(struct module *mod, struct device_driver *drv) { char *driver_name; int no_warn; + struct module_kobject *mk = NULL; - if (!mod || !drv) + if (!drv) + return; + + if (mod) + mk = &mod->mkobj; + else if (drv->mod_name) { + struct kobject *mkobj; + + /* Lookup built-in module entry in /sys/modules */ + mkobj = kset_find_obj(&module_subsys.kset, drv->mod_name); + if (mkobj) + mk = container_of(mkobj, struct module_kobject, kobj); + } + + if (!mk) return; /* Don't check return codes; these calls are idempotent */ - no_warn = sysfs_create_link(&drv->kobj, &mod->mkobj.kobj, "module"); + no_warn = sysfs_create_link(&drv->kobj, &mk->kobj, "module"); driver_name = make_driver_name(drv); if (driver_name) { - no_warn = sysfs_create_link(mod->drivers_dir, &drv->kobj, + no_warn = sysfs_create_link(mk->drivers_dir, &drv->kobj, driver_name); kfree(driver_name); } @@ -2367,10 +2382,10 @@ void module_remove_driver(struct device_driver *drv) return; sysfs_remove_link(&drv->kobj, "module"); - if (drv->owner && drv->owner->drivers_dir) { + if (drv->owner && drv->owner->mkobj.drivers_dir) { driver_name = make_driver_name(drv); if (driver_name) { - sysfs_remove_link(drv->owner->drivers_dir, + sysfs_remove_link(drv->owner->mkobj.drivers_dir, driver_name); kfree(driver_name); } diff --git a/kernel/params.c b/kernel/params.c index 718945da8f58..737b7c5e93aa 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -561,14 +561,12 @@ static void __init kernel_param_sysfs_setup(const char *name, mk->mod = THIS_MODULE; kobj_set_kset_s(mk, module_subsys); kobject_set_name(&mk->kobj, name); - ret = kobject_register(&mk->kobj); + kobject_init(&mk->kobj); + ret = kobject_add(&mk->kobj); BUG_ON(ret < 0); - - /* no need to keep the kobject if no parameter is exported */ - if (!param_sysfs_setup(mk, kparam, num_params, name_skip)) { - kobject_unregister(&mk->kobj); - kfree(mk); - } + param_sysfs_setup(mk, kparam, num_params, name_skip); + mk->drivers_dir = kobject_add_dir(&mk->kobj, "drivers"); + kobject_uevent(&mk->kobj, KOBJ_ADD); } /* -- cgit v1.2.3 From 270a6c4cad809e92d7b81adde92d0b3d94eeb8ee Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Thu, 18 Jan 2007 13:26:15 +0100 Subject: /sys/modules/*/holders /sys/module/usbcore/ |-- drivers | |-- usb:hub -> ../../../subsystem/usb/drivers/hub | |-- usb:usb -> ../../../subsystem/usb/drivers/usb | `-- usb:usbfs -> ../../../subsystem/usb/drivers/usbfs |-- holders | |-- ehci_hcd -> ../../../module/ehci_hcd | |-- uhci_hcd -> ../../../module/uhci_hcd | |-- usb_storage -> ../../../module/usb_storage | `-- usbhid -> ../../../module/usbhid |-- initstate Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- include/linux/module.h | 1 + kernel/module.c | 37 +++++++++++++++++++++++++++++++------ kernel/params.c | 17 ++++++++++++++++- 3 files changed, 48 insertions(+), 7 deletions(-) (limited to 'include/linux/module.h') diff --git a/include/linux/module.h b/include/linux/module.h index 90dc2542978c..419d3ef293dd 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -264,6 +264,7 @@ struct module struct module_attribute *modinfo_attrs; const char *version; const char *srcversion; + struct kobject *holders_dir; /* Exported symbols */ const struct kernel_symbol *syms; diff --git a/kernel/module.c b/kernel/module.c index 9de4209f6a67..8a94e054230c 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -537,6 +537,8 @@ static int already_uses(struct module *a, struct module *b) static int use_module(struct module *a, struct module *b) { struct module_use *use; + int no_warn; + if (b == NULL || already_uses(a, b)) return 1; if (!strong_try_module_get(b)) @@ -552,6 +554,7 @@ static int use_module(struct module *a, struct module *b) use->module_which_uses = a; list_add(&use->list, &b->modules_which_use_me); + no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name); return 1; } @@ -569,6 +572,7 @@ static void module_unload_free(struct module *mod) module_put(i); list_del(&use->list); kfree(use); + sysfs_remove_link(i->holders_dir, mod->name); /* There can be at most one match. */ break; } @@ -1106,9 +1110,7 @@ static void module_remove_modinfo_attrs(struct module *mod) kfree(mod->modinfo_attrs); } -static int mod_sysfs_setup(struct module *mod, - struct kernel_param *kparam, - unsigned int num_params) +static int mod_sysfs_init(struct module *mod) { int err; @@ -1125,15 +1127,30 @@ static int mod_sysfs_setup(struct module *mod, kobj_set_kset_s(&mod->mkobj, module_subsys); mod->mkobj.mod = mod; - /* delay uevent until full sysfs population */ kobject_init(&mod->mkobj.kobj); + +out: + return err; +} + +static int mod_sysfs_setup(struct module *mod, + struct kernel_param *kparam, + unsigned int num_params) +{ + int err; + + /* delay uevent until full sysfs population */ err = kobject_add(&mod->mkobj.kobj); if (err) goto out; + mod->holders_dir = kobject_add_dir(&mod->mkobj.kobj, "holders"); + if (!mod->holders_dir) + goto out_unreg; + err = module_param_sysfs_setup(mod, kparam, num_params); if (err) - goto out_unreg_drivers; + goto out_unreg_holders; err = module_add_modinfo_attrs(mod); if (err) @@ -1144,7 +1161,9 @@ static int mod_sysfs_setup(struct module *mod, out_unreg_param: module_param_sysfs_remove(mod); -out_unreg_drivers: +out_unreg_holders: + kobject_unregister(mod->holders_dir); +out_unreg: kobject_del(&mod->mkobj.kobj); kobject_put(&mod->mkobj.kobj); out: @@ -1157,6 +1176,8 @@ static void mod_kobject_remove(struct module *mod) module_param_sysfs_remove(mod); if (mod->mkobj.drivers_dir) kobject_unregister(mod->mkobj.drivers_dir); + if (mod->holders_dir) + kobject_unregister(mod->holders_dir); kobject_unregister(&mod->mkobj.kobj); } @@ -1761,6 +1782,10 @@ static struct module *load_module(void __user *umod, /* Now we've moved module, initialize linked lists, etc. */ module_unload_init(mod); + /* Initialize kobject, so we can reference it. */ + if (mod_sysfs_init(mod) != 0) + goto cleanup; + /* Set up license info based on the info section */ set_license(mod, get_modinfo(sechdrs, infoindex, "license")); diff --git a/kernel/params.c b/kernel/params.c index cbaac85942d5..553cf7d6a4be 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -30,6 +30,8 @@ #define DEBUGP(fmt, a...) #endif +static struct kobj_type module_ktype; + static inline char dash2underscore(char c) { if (c == '-') @@ -671,6 +673,19 @@ static struct sysfs_ops module_sysfs_ops = { .store = module_attr_store, }; +static int uevent_filter(struct kset *kset, struct kobject *kobj) +{ + struct kobj_type *ktype = get_ktype(kobj); + + if (ktype == &module_ktype) + return 1; + return 0; +} + +static struct kset_uevent_ops module_uevent_ops = { + .filter = uevent_filter, +}; + #else static struct sysfs_ops module_sysfs_ops = { .show = NULL, @@ -682,7 +697,7 @@ static struct kobj_type module_ktype = { .sysfs_ops = &module_sysfs_ops, }; -decl_subsys(module, &module_ktype, NULL); +decl_subsys(module, &module_ktype, &module_uevent_ops); /* * param_sysfs_init - wrapper for built-in params support -- cgit v1.2.3