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author | Timothy Pearson <tpearson@raptorengineering.com> | 2017-08-23 14:45:25 -0500 |
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committer | Timothy Pearson <tpearson@raptorengineering.com> | 2017-08-23 14:45:25 -0500 |
commit | fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204 (patch) | |
tree | 22962a4387943edc841c72a4e636a068c66d58fd /drivers/firmware/efivars.c | |
download | ast2050-linux-kernel-fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204.zip ast2050-linux-kernel-fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204.tar.gz |
Initial import of modified Linux 2.6.28 tree
Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y
Diffstat (limited to 'drivers/firmware/efivars.c')
-rw-r--r-- | drivers/firmware/efivars.c | 761 |
1 files changed, 761 insertions, 0 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c new file mode 100644 index 0000000..f4f709d --- /dev/null +++ b/drivers/firmware/efivars.c @@ -0,0 +1,761 @@ +/* + * EFI Variables - efivars.c + * + * Copyright (C) 2001,2003,2004 Dell <Matt_Domsch@dell.com> + * Copyright (C) 2004 Intel Corporation <matthew.e.tolentino@intel.com> + * + * This code takes all variables accessible from EFI runtime and + * exports them via sysfs + * + * 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 + * + * Changelog: + * + * 17 May 2004 - Matt Domsch <Matt_Domsch@dell.com> + * remove check for efi_enabled in exit + * add MODULE_VERSION + * + * 26 Apr 2004 - Matt Domsch <Matt_Domsch@dell.com> + * minor bug fixes + * + * 21 Apr 2004 - Matt Tolentino <matthew.e.tolentino@intel.com) + * converted driver to export variable information via sysfs + * and moved to drivers/firmware directory + * bumped revision number to v0.07 to reflect conversion & move + * + * 10 Dec 2002 - Matt Domsch <Matt_Domsch@dell.com> + * fix locking per Peter Chubb's findings + * + * 25 Mar 2002 - Matt Domsch <Matt_Domsch@dell.com> + * move uuid_unparse() to include/asm-ia64/efi.h:efi_guid_unparse() + * + * 12 Feb 2002 - Matt Domsch <Matt_Domsch@dell.com> + * use list_for_each_safe when deleting vars. + * remove ifdef CONFIG_SMP around include <linux/smp.h> + * v0.04 release to linux-ia64@linuxia64.org + * + * 20 April 2001 - Matt Domsch <Matt_Domsch@dell.com> + * Moved vars from /proc/efi to /proc/efi/vars, and made + * efi.c own the /proc/efi directory. + * v0.03 release to linux-ia64@linuxia64.org + * + * 26 March 2001 - Matt Domsch <Matt_Domsch@dell.com> + * At the request of Stephane, moved ownership of /proc/efi + * to efi.c, and now efivars lives under /proc/efi/vars. + * + * 12 March 2001 - Matt Domsch <Matt_Domsch@dell.com> + * Feedback received from Stephane Eranian incorporated. + * efivar_write() checks copy_from_user() return value. + * efivar_read/write() returns proper errno. + * v0.02 release to linux-ia64@linuxia64.org + * + * 26 February 2001 - Matt Domsch <Matt_Domsch@dell.com> + * v0.01 release to linux-ia64@linuxia64.org + */ + +#include <linux/capability.h> +#include <linux/types.h> +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/string.h> +#include <linux/smp.h> +#include <linux/efi.h> +#include <linux/sysfs.h> +#include <linux/kobject.h> +#include <linux/device.h> + +#include <asm/uaccess.h> + +#define EFIVARS_VERSION "0.08" +#define EFIVARS_DATE "2004-May-17" + +MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>"); +MODULE_DESCRIPTION("sysfs interface to EFI Variables"); +MODULE_LICENSE("GPL"); +MODULE_VERSION(EFIVARS_VERSION); + +/* + * efivars_lock protects two things: + * 1) efivar_list - adds, removals, reads, writes + * 2) efi.[gs]et_variable() calls. + * It must not be held when creating sysfs entries or calling kmalloc. + * efi.get_next_variable() is only called from efivars_init(), + * which is protected by the BKL, so that path is safe. + */ +static DEFINE_SPINLOCK(efivars_lock); +static LIST_HEAD(efivar_list); + +/* + * The maximum size of VariableName + Data = 1024 + * Therefore, it's reasonable to save that much + * space in each part of the structure, + * and we use a page for reading/writing. + */ + +struct efi_variable { + efi_char16_t VariableName[1024/sizeof(efi_char16_t)]; + efi_guid_t VendorGuid; + unsigned long DataSize; + __u8 Data[1024]; + efi_status_t Status; + __u32 Attributes; +} __attribute__((packed)); + + +struct efivar_entry { + struct efi_variable var; + struct list_head list; + struct kobject kobj; +}; + +struct efivar_attribute { + struct attribute attr; + ssize_t (*show) (struct efivar_entry *entry, char *buf); + ssize_t (*store)(struct efivar_entry *entry, const char *buf, size_t count); +}; + + +#define EFIVAR_ATTR(_name, _mode, _show, _store) \ +struct efivar_attribute efivar_attr_##_name = { \ + .attr = {.name = __stringify(_name), .mode = _mode}, \ + .show = _show, \ + .store = _store, \ +}; + +#define to_efivar_attr(_attr) container_of(_attr, struct efivar_attribute, attr) +#define to_efivar_entry(obj) container_of(obj, struct efivar_entry, kobj) + +/* + * Prototype for sysfs creation function + */ +static int +efivar_create_sysfs_entry(unsigned long variable_name_size, + efi_char16_t *variable_name, + efi_guid_t *vendor_guid); + +/* Return the number of unicode characters in data */ +static unsigned long +utf8_strlen(efi_char16_t *data, unsigned long maxlength) +{ + unsigned long length = 0; + + while (*data++ != 0 && length < maxlength) + length++; + return length; +} + +/* + * Return the number of bytes is the length of this string + * Note: this is NOT the same as the number of unicode characters + */ +static inline unsigned long +utf8_strsize(efi_char16_t *data, unsigned long maxlength) +{ + return utf8_strlen(data, maxlength/sizeof(efi_char16_t)) * sizeof(efi_char16_t); +} + +static efi_status_t +get_var_data(struct efi_variable *var) +{ + efi_status_t status; + + spin_lock(&efivars_lock); + var->DataSize = 1024; + status = efi.get_variable(var->VariableName, + &var->VendorGuid, + &var->Attributes, + &var->DataSize, + var->Data); + spin_unlock(&efivars_lock); + if (status != EFI_SUCCESS) { + printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n", + status); + } + return status; +} + +static ssize_t +efivar_guid_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + char *str = buf; + + if (!entry || !buf) + return 0; + + efi_guid_unparse(&var->VendorGuid, str); + str += strlen(str); + str += sprintf(str, "\n"); + + return str - buf; +} + +static ssize_t +efivar_attr_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + char *str = buf; + efi_status_t status; + + if (!entry || !buf) + return -EINVAL; + + status = get_var_data(var); + if (status != EFI_SUCCESS) + return -EIO; + + if (var->Attributes & 0x1) + str += sprintf(str, "EFI_VARIABLE_NON_VOLATILE\n"); + if (var->Attributes & 0x2) + str += sprintf(str, "EFI_VARIABLE_BOOTSERVICE_ACCESS\n"); + if (var->Attributes & 0x4) + str += sprintf(str, "EFI_VARIABLE_RUNTIME_ACCESS\n"); + return str - buf; +} + +static ssize_t +efivar_size_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + char *str = buf; + efi_status_t status; + + if (!entry || !buf) + return -EINVAL; + + status = get_var_data(var); + if (status != EFI_SUCCESS) + return -EIO; + + str += sprintf(str, "0x%lx\n", var->DataSize); + return str - buf; +} + +static ssize_t +efivar_data_read(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + efi_status_t status; + + if (!entry || !buf) + return -EINVAL; + + status = get_var_data(var); + if (status != EFI_SUCCESS) + return -EIO; + + memcpy(buf, var->Data, var->DataSize); + return var->DataSize; +} +/* + * We allow each variable to be edited via rewriting the + * entire efi variable structure. + */ +static ssize_t +efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count) +{ + struct efi_variable *new_var, *var = &entry->var; + efi_status_t status = EFI_NOT_FOUND; + + if (count != sizeof(struct efi_variable)) + return -EINVAL; + + new_var = (struct efi_variable *)buf; + /* + * If only updating the variable data, then the name + * and guid should remain the same + */ + if (memcmp(new_var->VariableName, var->VariableName, sizeof(var->VariableName)) || + efi_guidcmp(new_var->VendorGuid, var->VendorGuid)) { + printk(KERN_ERR "efivars: Cannot edit the wrong variable!\n"); + return -EINVAL; + } + + if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){ + printk(KERN_ERR "efivars: DataSize & Attributes must be valid!\n"); + return -EINVAL; + } + + spin_lock(&efivars_lock); + status = efi.set_variable(new_var->VariableName, + &new_var->VendorGuid, + new_var->Attributes, + new_var->DataSize, + new_var->Data); + + spin_unlock(&efivars_lock); + + if (status != EFI_SUCCESS) { + printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n", + status); + return -EIO; + } + + memcpy(&entry->var, new_var, count); + return count; +} + +static ssize_t +efivar_show_raw(struct efivar_entry *entry, char *buf) +{ + struct efi_variable *var = &entry->var; + efi_status_t status; + + if (!entry || !buf) + return 0; + + status = get_var_data(var); + if (status != EFI_SUCCESS) + return -EIO; + + memcpy(buf, var, sizeof(*var)); + return sizeof(*var); +} + +/* + * Generic read/write functions that call the specific functions of + * the atttributes... + */ +static ssize_t efivar_attr_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct efivar_entry *var = to_efivar_entry(kobj); + struct efivar_attribute *efivar_attr = to_efivar_attr(attr); + ssize_t ret = -EIO; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (efivar_attr->show) { + ret = efivar_attr->show(var, buf); + } + return ret; +} + +static ssize_t efivar_attr_store(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + struct efivar_entry *var = to_efivar_entry(kobj); + struct efivar_attribute *efivar_attr = to_efivar_attr(attr); + ssize_t ret = -EIO; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + if (efivar_attr->store) + ret = efivar_attr->store(var, buf, count); + + return ret; +} + +static struct sysfs_ops efivar_attr_ops = { + .show = efivar_attr_show, + .store = efivar_attr_store, +}; + +static void efivar_release(struct kobject *kobj) +{ + struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj); + kfree(var); +} + +static EFIVAR_ATTR(guid, 0400, efivar_guid_read, NULL); +static EFIVAR_ATTR(attributes, 0400, efivar_attr_read, NULL); +static EFIVAR_ATTR(size, 0400, efivar_size_read, NULL); +static EFIVAR_ATTR(data, 0400, efivar_data_read, NULL); +static EFIVAR_ATTR(raw_var, 0600, efivar_show_raw, efivar_store_raw); + +static struct attribute *def_attrs[] = { + &efivar_attr_guid.attr, + &efivar_attr_size.attr, + &efivar_attr_attributes.attr, + &efivar_attr_data.attr, + &efivar_attr_raw_var.attr, + NULL, +}; + +static struct kobj_type efivar_ktype = { + .release = efivar_release, + .sysfs_ops = &efivar_attr_ops, + .default_attrs = def_attrs, +}; + +static inline void +efivar_unregister(struct efivar_entry *var) +{ + kobject_put(&var->kobj); +} + + +static ssize_t efivar_create(struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct efi_variable *new_var = (struct efi_variable *)buf; + struct efivar_entry *search_efivar, *n; + unsigned long strsize1, strsize2; + efi_status_t status = EFI_NOT_FOUND; + int found = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + spin_lock(&efivars_lock); + + /* + * Does this variable already exist? + */ + list_for_each_entry_safe(search_efivar, n, &efivar_list, list) { + strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024); + strsize2 = utf8_strsize(new_var->VariableName, 1024); + if (strsize1 == strsize2 && + !memcmp(&(search_efivar->var.VariableName), + new_var->VariableName, strsize1) && + !efi_guidcmp(search_efivar->var.VendorGuid, + new_var->VendorGuid)) { + found = 1; + break; + } + } + if (found) { + spin_unlock(&efivars_lock); + return -EINVAL; + } + + /* now *really* create the variable via EFI */ + status = efi.set_variable(new_var->VariableName, + &new_var->VendorGuid, + new_var->Attributes, + new_var->DataSize, + new_var->Data); + + if (status != EFI_SUCCESS) { + printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n", + status); + spin_unlock(&efivars_lock); + return -EIO; + } + spin_unlock(&efivars_lock); + + /* Create the entry in sysfs. Locking is not required here */ + status = efivar_create_sysfs_entry(utf8_strsize(new_var->VariableName, + 1024), new_var->VariableName, &new_var->VendorGuid); + if (status) { + printk(KERN_WARNING "efivars: variable created, but sysfs entry wasn't.\n"); + } + return count; +} + +static ssize_t efivar_delete(struct kobject *kobj, + struct bin_attribute *bin_attr, + char *buf, loff_t pos, size_t count) +{ + struct efi_variable *del_var = (struct efi_variable *)buf; + struct efivar_entry *search_efivar, *n; + unsigned long strsize1, strsize2; + efi_status_t status = EFI_NOT_FOUND; + int found = 0; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + + spin_lock(&efivars_lock); + + /* + * Does this variable already exist? + */ + list_for_each_entry_safe(search_efivar, n, &efivar_list, list) { + strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024); + strsize2 = utf8_strsize(del_var->VariableName, 1024); + if (strsize1 == strsize2 && + !memcmp(&(search_efivar->var.VariableName), + del_var->VariableName, strsize1) && + !efi_guidcmp(search_efivar->var.VendorGuid, + del_var->VendorGuid)) { + found = 1; + break; + } + } + if (!found) { + spin_unlock(&efivars_lock); + return -EINVAL; + } + /* force the Attributes/DataSize to 0 to ensure deletion */ + del_var->Attributes = 0; + del_var->DataSize = 0; + + status = efi.set_variable(del_var->VariableName, + &del_var->VendorGuid, + del_var->Attributes, + del_var->DataSize, + del_var->Data); + + if (status != EFI_SUCCESS) { + printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n", + status); + spin_unlock(&efivars_lock); + return -EIO; + } + list_del(&search_efivar->list); + /* We need to release this lock before unregistering. */ + spin_unlock(&efivars_lock); + efivar_unregister(search_efivar); + + /* It's dead Jim.... */ + return count; +} + +static struct bin_attribute var_subsys_attr_new_var = { + .attr = {.name = "new_var", .mode = 0200}, + .write = efivar_create, +}; + +static struct bin_attribute var_subsys_attr_del_var = { + .attr = {.name = "del_var", .mode = 0200}, + .write = efivar_delete, +}; + +/* + * Let's not leave out systab information that snuck into + * the efivars driver + */ +static ssize_t systab_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + char *str = buf; + + if (!kobj || !buf) + return -EINVAL; + + if (efi.mps != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "MPS=0x%lx\n", efi.mps); + if (efi.acpi20 != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "ACPI20=0x%lx\n", efi.acpi20); + if (efi.acpi != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "ACPI=0x%lx\n", efi.acpi); + if (efi.smbios != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "SMBIOS=0x%lx\n", efi.smbios); + if (efi.hcdp != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "HCDP=0x%lx\n", efi.hcdp); + if (efi.boot_info != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "BOOTINFO=0x%lx\n", efi.boot_info); + if (efi.uga != EFI_INVALID_TABLE_ADDR) + str += sprintf(str, "UGA=0x%lx\n", efi.uga); + + return str - buf; +} + +static struct kobj_attribute efi_attr_systab = + __ATTR(systab, 0400, systab_show, NULL); + +static struct attribute *efi_subsys_attrs[] = { + &efi_attr_systab.attr, + NULL, /* maybe more in the future? */ +}; + +static struct attribute_group efi_subsys_attr_group = { + .attrs = efi_subsys_attrs, +}; + + +static struct kset *vars_kset; +static struct kobject *efi_kobj; + +/* + * efivar_create_sysfs_entry() + * Requires: + * variable_name_size = number of bytes required to hold + * variable_name (not counting the NULL + * character at the end. + * efivars_lock is not held on entry or exit. + * Returns 1 on failure, 0 on success + */ +static int +efivar_create_sysfs_entry(unsigned long variable_name_size, + efi_char16_t *variable_name, + efi_guid_t *vendor_guid) +{ + int i, short_name_size = variable_name_size / sizeof(efi_char16_t) + 38; + char *short_name; + struct efivar_entry *new_efivar; + + short_name = kzalloc(short_name_size + 1, GFP_KERNEL); + new_efivar = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL); + + if (!short_name || !new_efivar) { + kfree(short_name); + kfree(new_efivar); + return 1; + } + + memcpy(new_efivar->var.VariableName, variable_name, + variable_name_size); + memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t)); + + /* Convert Unicode to normal chars (assume top bits are 0), + ala UTF-8 */ + for (i=0; i < (int)(variable_name_size / sizeof(efi_char16_t)); i++) { + short_name[i] = variable_name[i] & 0xFF; + } + /* This is ugly, but necessary to separate one vendor's + private variables from another's. */ + + *(short_name + strlen(short_name)) = '-'; + efi_guid_unparse(vendor_guid, short_name + strlen(short_name)); + + new_efivar->kobj.kset = vars_kset; + i = kobject_init_and_add(&new_efivar->kobj, &efivar_ktype, NULL, + "%s", short_name); + if (i) { + kfree(short_name); + kfree(new_efivar); + return 1; + } + + kobject_uevent(&new_efivar->kobj, KOBJ_ADD); + kfree(short_name); + short_name = NULL; + + spin_lock(&efivars_lock); + list_add(&new_efivar->list, &efivar_list); + spin_unlock(&efivars_lock); + + return 0; +} +/* + * For now we register the efi subsystem with the firmware subsystem + * and the vars subsystem with the efi subsystem. In the future, it + * might make sense to split off the efi subsystem into its own + * driver, but for now only efivars will register with it, so just + * include it here. + */ + +static int __init +efivars_init(void) +{ + efi_status_t status = EFI_NOT_FOUND; + efi_guid_t vendor_guid; + efi_char16_t *variable_name; + unsigned long variable_name_size = 1024; + int error = 0; + + if (!efi_enabled) + return -ENODEV; + + variable_name = kzalloc(variable_name_size, GFP_KERNEL); + if (!variable_name) { + printk(KERN_ERR "efivars: Memory allocation failed.\n"); + return -ENOMEM; + } + + printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION, + EFIVARS_DATE); + + /* For now we'll register the efi directory at /sys/firmware/efi */ + efi_kobj = kobject_create_and_add("efi", firmware_kobj); + if (!efi_kobj) { + printk(KERN_ERR "efivars: Firmware registration failed.\n"); + error = -ENOMEM; + goto out_free; + } + + vars_kset = kset_create_and_add("vars", NULL, efi_kobj); + if (!vars_kset) { + printk(KERN_ERR "efivars: Subsystem registration failed.\n"); + error = -ENOMEM; + goto out_firmware_unregister; + } + + /* + * Per EFI spec, the maximum storage allocated for both + * the variable name and variable data is 1024 bytes. + */ + + do { + variable_name_size = 1024; + + status = efi.get_next_variable(&variable_name_size, + variable_name, + &vendor_guid); + switch (status) { + case EFI_SUCCESS: + efivar_create_sysfs_entry(variable_name_size, + variable_name, + &vendor_guid); + break; + case EFI_NOT_FOUND: + break; + default: + printk(KERN_WARNING "efivars: get_next_variable: status=%lx\n", + status); + status = EFI_NOT_FOUND; + break; + } + } while (status != EFI_NOT_FOUND); + + /* + * Now add attributes to allow creation of new vars + * and deletion of existing ones... + */ + error = sysfs_create_bin_file(&vars_kset->kobj, + &var_subsys_attr_new_var); + if (error) + printk(KERN_ERR "efivars: unable to create new_var sysfs file" + " due to error %d\n", error); + error = sysfs_create_bin_file(&vars_kset->kobj, + &var_subsys_attr_del_var); + if (error) + printk(KERN_ERR "efivars: unable to create del_var sysfs file" + " due to error %d\n", error); + + /* Don't forget the systab entry */ + error = sysfs_create_group(efi_kobj, &efi_subsys_attr_group); + if (error) + printk(KERN_ERR "efivars: Sysfs attribute export failed with error %d.\n", error); + else + goto out_free; + + kset_unregister(vars_kset); + +out_firmware_unregister: + kobject_put(efi_kobj); + +out_free: + kfree(variable_name); + + return error; +} + +static void __exit +efivars_exit(void) +{ + struct efivar_entry *entry, *n; + + list_for_each_entry_safe(entry, n, &efivar_list, list) { + spin_lock(&efivars_lock); + list_del(&entry->list); + spin_unlock(&efivars_lock); + efivar_unregister(entry); + } + + kset_unregister(vars_kset); + kobject_put(efi_kobj); +} + +module_init(efivars_init); +module_exit(efivars_exit); + |