modules: add modalias file to sysfs for modules.

Message ID	20221111152852.2837363-1-allenwebb@google.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-modules-owner@kernel.org> Date: Fri, 11 Nov 2022 09:28:52 -0600 In-Reply-To: <b2d1004d-4a76-ab0b-d369-a38c2d7c1624@csgroup.eu> Mime-Version: 1.0 References: <b2d1004d-4a76-ab0b-d369-a38c2d7c1624@csgroup.eu> Message-ID: <20221111152852.2837363-1-allenwebb@google.com> Subject: [PATCH] modules: add modalias file to sysfs for modules. From: Allen Webb <allenwebb@google.com> To: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Luis Chamberlain <mcgrof@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, "linux-modules@vger.kernel.org" <linux-modules@vger.kernel.org>, "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>, "Rafael J. Wysocki" <rafael@kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Allen Webb <allenwebb@google.com> Content-Type: text/plain; charset="UTF-8" Precedence: bulk
Series	modules: add modalias file to sysfs for modules. \| expand modules: add modalias file to sysfs for modules.

diff --git a/drivers/base/Makefile b/drivers/base/Makefile index 83217d243c25b..924d46ae987f4 100644 --- a/drivers/base/Makefile +++ b/drivers/base/Makefile @@ -15,7 +15,7 @@ obj-y += firmware_loader/ obj-$(CONFIG_NUMA) += node.o obj-$(CONFIG_MEMORY_HOTPLUG) += memory.o ifeq ($(CONFIG_SYSFS),y) -obj-$(CONFIG_MODULES) += module.o +obj-$(CONFIG_MODULES) += mod_devicetable.o module.o endif obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o obj-$(CONFIG_REGMAP) += regmap/ diff --git a/drivers/base/base.h b/drivers/base/base.h index b3a43a164dcd1..7ac5f7a547be8 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -175,6 +175,14 @@ static inline void module_add_driver(struct module *mod, static inline void module_remove_driver(struct device_driver *drv) { } #endif +#if defined(CONFIG_SYSFS) +ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf, + size_t count); +#else +static inline ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf, + size_t count) { return -ENOSUP; } +#endif + #ifdef CONFIG_DEVTMPFS extern int devtmpfs_init(void); #else diff --git a/drivers/base/bus.c b/drivers/base/bus.c index 7ca47e5b3c1f4..4e0c5925545e5 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -178,6 +178,48 @@ static const struct kset_uevent_ops bus_uevent_ops = { static struct kset *bus_kset; +/** + * bus_for_each - bus iterator. + * @start: bus to start iterating from. + * @data: data for the callback. + * @fn: function to be called for each device. + * + * Iterate over list of buses, and call @fn for each, + * passing it @data. If @start is not NULL, we use that bus to + * begin iterating from. + * + * We check the return of @fn each time. If it returns anything + * other than 0, we break out and return that value. + * + * NOTE: The bus that returns a non-zero value is not retained + * in any way, nor is its refcount incremented. If the caller needs + * to retain this data, it should do so, and increment the reference + * count in the supplied callback. + */ +int bus_for_each(void *data, int (*fn)(struct bus_type *, void *)) +{ + int error = 0; + struct bus_type *bus; + struct subsys_private *bus_prv; + struct kset *subsys; + struct kobject *k; + + spin_lock(&bus_kset->list_lock); + + list_for_each_entry(k, &bus_kset->list, entry) { + subsys = container_of(k, struct kset, kobj); + bus_prv = container_of(subsys, struct subsys_private, subsys); + bus = bus_prv->bus; + error = fn(bus, data); + if (error) + break; + } + + spin_unlock(&bus_kset->list_lock); + return error; +} +EXPORT_SYMBOL_GPL(bus_for_each); + /* Manually detach a device from its associated driver. */ static ssize_t unbind_store(struct device_driver *drv, const char *buf, size_t count) diff --git a/drivers/base/mod_devicetable.c b/drivers/base/mod_devicetable.c new file mode 100644 index 0000000000000..da8d524cdf57a --- /dev/null +++ b/drivers/base/mod_devicetable.c @@ -0,0 +1,241 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * mod_devicetable.c - helpers for displaying modaliases through sysfs. + * + * This borrows a lot from file2alias.c + */ + +#include <linux/device/bus.h> +#include <linux/device.h> +#include <linux/usb.h> + +#include "../usb/core/usb.h" + +#define ADD(buf, count, len, sep, cond, field) \ +do { \ + if (cond) \ + (len) += scnprintf(&(buf)[len], \ + (count) - (len), \ + sizeof(field) == 1 ? (sep "%02X") : \ + sizeof(field) == 2 ? (sep "%04X") : \ + sizeof(field) == 4 ? (sep "%08X") : "", \ + (field)); \ + else \ + (len) += scnprintf(&(buf)[len], (count) - (len), (sep "*")); \ +} while (0) + +/* USB related modaliases can be split because of device number matching, so + * this function handles individual modaliases for one segment of the range. + * + * + */ +static ssize_t usb_id_to_modalias(const struct usb_device_id *id, + unsigned int bcdDevice_initial, + int bcdDevice_initial_digits, + unsigned char range_lo, + unsigned char range_hi, + unsigned char max, const char *mod_name, + char *buf, size_t count) +{ + ssize_t len = 0; + + ADD(buf, count, len, "alias usb:v", + id->match_flags & USB_DEVICE_ID_MATCH_VENDOR, id->idVendor); + ADD(buf, count, len, "p", id->match_flags & USB_DEVICE_ID_MATCH_PRODUCT, + id->idProduct); + + len += scnprintf(&buf[len], count - len, "d"); + if (bcdDevice_initial_digits) + len += scnprintf(&buf[len], count - len, "%0*X", + bcdDevice_initial_digits, bcdDevice_initial); + if (range_lo == range_hi) { + len += scnprintf(&buf[len], count - len, "%X", range_lo); + } else if (range_lo > 0 || range_hi < max) { + if (range_lo > 0x9 || range_hi < 0xA) { + len += scnprintf(&buf[len], count - len, "[%X-%X]", + range_lo, range_hi); + } else { + len += scnprintf(&buf[len], count - len, + range_lo < 0x9 ? "[%X-9" : "[%X", + range_lo); + len += scnprintf(&buf[len], count - len, + range_hi > 0xA ? "A-%X]" : "%X]", + range_hi); + } + } + if (bcdDevice_initial_digits < (sizeof(id->bcdDevice_lo) * 2 - 1)) + len += scnprintf(&buf[len], count - len, "*"); + + ADD(buf, count, len, "dc", + id->match_flags & USB_DEVICE_ID_MATCH_DEV_CLASS, id->bDeviceClass); + ADD(buf, count, len, "dsc", + id->match_flags & USB_DEVICE_ID_MATCH_DEV_SUBCLASS, + id->bDeviceSubClass); + ADD(buf, count, len, "dp", + id->match_flags & USB_DEVICE_ID_MATCH_DEV_PROTOCOL, + id->bDeviceProtocol); + ADD(buf, count, len, "ic", + id->match_flags & USB_DEVICE_ID_MATCH_INT_CLASS, + id->bInterfaceClass); + ADD(buf, count, len, "isc", + id->match_flags & USB_DEVICE_ID_MATCH_INT_SUBCLASS, + id->bInterfaceSubClass); + ADD(buf, count, len, "ip", + id->match_flags & USB_DEVICE_ID_MATCH_INT_PROTOCOL, + id->bInterfaceProtocol); + ADD(buf, count, len, "in", + id->match_flags & USB_DEVICE_ID_MATCH_INT_NUMBER, + id->bInterfaceNumber); + + len += scnprintf(&buf[len], count - len, " %s\n", mod_name); + return len; +} + +/* Handles increment/decrement of BCD formatted integers */ +/* Returns the previous value, so it works like i++ or i-- */ +static unsigned int incbcd(unsigned int *bcd, + int inc, + unsigned char max, + size_t chars) +{ + unsigned int init = *bcd, i, j; + unsigned long long c, dec = 0; + + /* If bcd is not in BCD format, just increment */ + if (max > 0x9) { + *bcd += inc; + return init; + } + + /* Convert BCD to Decimal */ + for (i = 0 ; i < chars ; i++) { + c = (*bcd >> (i << 2)) & 0xf; + c = c > 9 ? 9 : c; /* force to bcd just in case */ + for (j = 0 ; j < i ; j++) + c = c * 10; + dec += c; + } + + /* Do our increment/decrement */ + dec += inc; + *bcd = 0; + + /* Convert back to BCD */ + for (i = 0 ; i < chars ; i++) { + for (c = 1, j = 0 ; j < i ; j++) + c = c * 10; + c = (dec / c) % 10; + *bcd += c << (i << 2); + } + return init; +} + +/* Print the modaliases for the specified struct usb_device_id. + */ +static ssize_t usb_id_to_modalias_multi(const struct usb_device_id *id, + const char *mod_name, char *buf, + size_t count) +{ + ssize_t len = 0; + unsigned int devlo, devhi; + unsigned char chi, clo, max; + int ndigits; + + devlo = id->match_flags & USB_DEVICE_ID_MATCH_DEV_LO ? + id->bcdDevice_lo : 0x0U; + devhi = id->match_flags & USB_DEVICE_ID_MATCH_DEV_HI ? + id->bcdDevice_hi : ~0x0U; + + /* Figure out if this entry is in bcd or hex format */ + max = 0x9; /* Default to decimal format */ + for (ndigits = 0 ; ndigits < sizeof(id->bcdDevice_lo) * 2 ; ndigits++) { + clo = (devlo >> (ndigits << 2)) & 0xf; + chi = ((devhi > 0x9999 ? 0x9999 : devhi) >> + (ndigits << 2)) & 0xf; + if (clo > max || chi > max) { + max = 0xf; + break; + } + } + + /* + * Some modules (visor) have empty slots as placeholder for + * run-time specification that results in catch-all alias + */ + if (!(id->idVendor || id->idProduct || id->bDeviceClass || + id->bInterfaceClass)) + return len; + + /* Convert numeric bcdDevice range into fnmatch-able pattern(s) */ + for (ndigits = sizeof(id->bcdDevice_lo) * 2 - 1; devlo <= devhi; + ndigits--) { + clo = devlo & 0xf; + chi = devhi & 0xf; + /* If we are in bcd mode, truncate if necessary */ + if (chi > max) + chi = max; + devlo >>= 4; + devhi >>= 4; + + if (devlo == devhi || !ndigits) { + len += usb_id_to_modalias(id, devlo, ndigits, clo, chi, + max, mod_name, buf + len, + count - len); + break; + } + + if (clo > 0x0) + len += usb_id_to_modalias(id, + incbcd(&devlo, 1, max, + sizeof(id->bcdDevice_lo) * 2), + ndigits, clo, max, max, mod_name, buf + len, + count - len); + + if (chi < max) + len += usb_id_to_modalias(id, + incbcd(&devhi, -1, max, + sizeof(id->bcdDevice_lo) * 2), + ndigits, 0x0, chi, max, mod_name, buf + len, + count - len); + } + return len; +} + +/* Print the modaliases for the given driver assumed to be an usb_driver or + * usb_device_driver. + * + * "alias" is prepended and the module name is appended to each modalias to + * match the format in modules.aliases. + * + * The modaliases will be written out to @buf with @count being the maximum + * bytes to write. The return value is a negative errno on error or the number + * of bytes written to @buf on success. + */ +ssize_t usb_drv_to_modalias(struct device_driver *drv, char *buf, + size_t count) +{ + ssize_t len = 0; + const struct usb_device_id *id; + const char *mod_name; + + if (drv->bus != &usb_bus_type) + return -EINVAL; + + if (drv->owner) + mod_name = drv->owner->name; + else + mod_name = drv->mod_name; + + if (is_usb_device_driver(drv)) + id = to_usb_device_driver(drv)->id_table; + else + id = to_usb_driver(drv)->id_table; + if (!id) + return len; + + for (; id->match_flags; id++) { + len += usb_id_to_modalias_multi(id, mod_name, buf + len, + count - len); + } + return len; +} diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c index 7e7e119c253fb..fdbc197b64c9c 100644 --- a/drivers/usb/core/driver.c +++ b/drivers/usb/core/driver.c @@ -32,6 +32,7 @@ #include <linux/usb/quirks.h> #include <linux/usb/hcd.h> +#include "../../base/base.h" #include "usb.h" @@ -2030,4 +2031,5 @@ struct bus_type usb_bus_type = { .match = usb_device_match, .uevent = usb_uevent, .need_parent_lock = true, + .drv_to_modalias = usb_drv_to_modalias, }; diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index d8b29ccd07e56..cce0bedec63d9 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -61,6 +61,10 @@ struct fwnode_handle; * this bus. * @dma_cleanup: Called to cleanup DMA configuration on a device on * this bus. + * @drv_to_modalias: Called to convert the matching IDs in a + * struct device_driver to their corresponding modaliases. + * Note that the struct device_driver is expected to belong + * to this bus. * @pm: Power management operations of this bus, callback the specific * device driver's pm-ops. * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU @@ -107,6 +111,9 @@ struct bus_type { int (*dma_configure)(struct device *dev); void (*dma_cleanup)(struct device *dev); + ssize_t (*drv_to_modalias)(struct device_driver *drv, char *buf, + size_t count); + const struct dev_pm_ops *pm; const struct iommu_ops *iommu_ops; @@ -161,6 +168,7 @@ void subsys_dev_iter_init(struct subsys_dev_iter *iter, struct device *subsys_dev_iter_next(struct subsys_dev_iter *iter); void subsys_dev_iter_exit(struct subsys_dev_iter *iter); +int bus_for_each(void *data, int (*fn)(struct bus_type *, void *)); int bus_for_each_dev(struct bus_type *bus, struct device *start, void *data, int (*fn)(struct device *dev, void *data)); struct device *bus_find_device(struct bus_type *bus, struct device *start, diff --git a/include/linux/module.h b/include/linux/module.h index 518296ea7f73a..68fe7bfc38683 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -48,6 +48,7 @@ struct module_kobject { struct kobject *drivers_dir; struct module_param_attrs *mp; struct completion *kobj_completion; + struct bin_attribute modalias_attr; } __randomize_layout; struct module_attribute { diff --git a/kernel/module/internal.h b/kernel/module/internal.h index 680d980a4fb29..63b794cd65df2 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -259,11 +259,13 @@ static inline void add_kallsyms(struct module *mod, const struct load_info *info #endif /* CONFIG_KALLSYMS */ #ifdef CONFIG_SYSFS +void add_modalias_attr(struct module_kobject *mk); int mod_sysfs_setup(struct module *mod, const struct load_info *info, struct kernel_param *kparam, unsigned int num_params); void mod_sysfs_teardown(struct module *mod); void init_param_lock(struct module *mod); #else /* !CONFIG_SYSFS */ +static inline void add_modalias_attr(struct module_kobject *mk) {} static inline int mod_sysfs_setup(struct module *mod, const struct load_info *info, struct kernel_param *kparam, diff --git a/kernel/module/sysfs.c b/kernel/module/sysfs.c index ce68f821dcd12..e80bfa4639765 100644 --- a/kernel/module/sysfs.c +++ b/kernel/module/sysfs.c @@ -5,6 +5,8 @@ * Copyright (C) 2008 Rusty Russell */ +#include <linux/device/bus.h> +#include <linux/device/driver.h> #include <linux/module.h> #include <linux/kernel.h> #include <linux/fs.h> @@ -240,6 +242,102 @@ static inline void add_notes_attrs(struct module *mod, const struct load_info *i static inline void remove_notes_attrs(struct module *mod) { } #endif /* CONFIG_KALLSYMS */ +/* Track of the buffer and module identity in callbacks when walking the list of + * drivers for each bus. + */ +struct modalias_bus_print_state { + struct module_kobject *mk; + char *buf; + size_t count; + ssize_t len; +}; + +static int print_modalias_for_drv(struct device_driver *drv, void *p) +{ + struct modalias_bus_print_state *s = p; + struct module_kobject *mk = s->mk; + ssize_t len; + /* Skip drivers that do not match this module. */ + if (mk->mod) { + if (mk->mod != drv->owner) + return 0; + } else if (!mk->kobj.name || !drv->mod_name || + strcmp(mk->kobj.name, drv->mod_name)) + return 0; + + if (drv->bus && drv->bus->drv_to_modalias) { + len = drv->bus->drv_to_modalias(drv, s->buf + s->len, + s->count - s->len); + if (len < 0) + return len; + s->len += len; + } + + s->len += scnprintf(&s->buf[s->len], s->count - s->len, "driver %s\n", + drv->name); + return 0; +} + +static int print_modalias_for_bus(struct bus_type *type, void *p) +{ + return bus_for_each_drv(type, NULL, p, print_modalias_for_drv); +} + +static ssize_t module_modalias_read(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct module_kobject *mk = container_of(kobj, struct module_kobject, + kobj); + struct modalias_bus_print_state state = {mk, buf, count, 0}; + int error = 0; + + if (pos != 0) + return -EINVAL; + + error = bus_for_each(&state, print_modalias_for_bus); + if (error) + return error; + + if (mk->mod) + state.len += scnprintf(&buf[state.len], count - state.len, + "modalias %s %s\n", kobject_name(kobj), + mk->mod->name); + else + state.len += scnprintf(&buf[state.len], count - state.len, + "modalias %s NULL\n", + kobject_name(kobj)); + + /* + * The caller checked the pos and count against our size. + */ + return state.len; +} + +/* Used in kernel/params.c for builtin modules. + * + * `struct module_kobject` is used instead of `struct module` because for + * builtin modules, the `struct module` is not available when this is called. + */ +void add_modalias_attr(struct module_kobject *mk) +{ + sysfs_bin_attr_init(&mk->modalias_attr); + mk->modalias_attr.attr.name = "modalias"; + mk->modalias_attr.attr.mode = 0444; + mk->modalias_attr.read = module_modalias_read; + if (sysfs_create_bin_file(&mk->kobj, &mk->modalias_attr)) { + /* We shouldn't ignore the return type, but there is nothing to + * do. + */ + return; + } +} + +static void remove_modalias_attr(struct module_kobject *mk) +{ + sysfs_remove_bin_file(&mk->kobj, &mk->modalias_attr); +} + static void del_usage_links(struct module *mod) { #ifdef CONFIG_MODULE_UNLOAD @@ -398,6 +496,7 @@ int mod_sysfs_setup(struct module *mod, add_sect_attrs(mod, info); add_notes_attrs(mod, info); + add_modalias_attr(&mod->mkobj); return 0; @@ -415,6 +514,7 @@ int mod_sysfs_setup(struct module *mod, static void mod_sysfs_fini(struct module *mod) { + remove_modalias_attr(&mod->mkobj); remove_notes_attrs(mod); remove_sect_attrs(mod); mod_kobject_put(mod); diff --git a/kernel/params.c b/kernel/params.c index 5b92310425c50..111024196361a 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -13,6 +13,7 @@ #include <linux/slab.h> #include <linux/ctype.h> #include <linux/security.h> +#include "module/internal.h" #ifdef CONFIG_SYSFS /* Protects all built-in parameters, modules use their own param_lock */ @@ -815,6 +816,7 @@ static void __init kernel_add_sysfs_param(const char *name, BUG_ON(err); kobject_uevent(&mk->kobj, KOBJ_ADD); kobject_put(&mk->kobj); + add_modalias_attr(mk); } /*

modules: add modalias file to sysfs for modules.

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