[PATCH] efivars update

From: Matt Tolentino <metolent_at_snoqualmie.dp.intel.com>
Date: 2003-08-30 07:24:12
Hi,

A while back I posted a patch that moved the EFI variable services driver (efivars) to a new drivers/efi directory.  As EFI driver are typically platform/architecturally independent, it seems like a good idea to collect them in a common place.  Pat suggested the efivars driver should be converted to use sysfs rather than proc....so here you go.  As such, this patch does several things:

+ Adds a new driver directory drivers/efi.
+ Adds a new generic config option for EFI drivers - CONFIG_EFI
+ Moves efivars from arch/ia64/kernel to drivers/efi
+ Allows EFI variables to be read/created/deleted/modified via sysfs
+ Bumps the driver revision level up to 0.07 to reflect these changes

Within the sysfs hierarchy, I've created an efi subsystem under which future
EFI related information might be exported.  I've also created another subsystem vars that manages/exports EFI variable information.  

Note, this patch relies upon the kobject_set_name() call recently introduced by Pat Mochel in order to export the long gvariable name-guid combinations needed to accurately identify variables of the same name.  

The patch is against 2.6.0-test4.  Please apply.  

thanks,
matt









diff -urN linux-2.6.0-test4/arch/ia64/defconfig linux-2.6.0-test4-all/arch/ia64/defconfig
--- linux-2.6.0-test4/arch/ia64/defconfig	2003-08-22 16:51:44.000000000 -0700
+++ linux-2.6.0-test4-all/arch/ia64/defconfig	2003-08-29 11:45:12.000000000 -0700
@@ -76,6 +76,7 @@
 CONFIG_COMPAT=y
 CONFIG_PERFMON=y
 CONFIG_IA64_PALINFO=y
+CONFIG_EFI=y
 CONFIG_EFI_VARS=y
 CONFIG_NR_CPUS=16
 CONFIG_BINFMT_ELF=y
diff -urN linux-2.6.0-test4/arch/ia64/Kconfig linux-2.6.0-test4-all/arch/ia64/Kconfig
--- linux-2.6.0-test4/arch/ia64/Kconfig	2003-08-22 17:00:49.000000000 -0700
+++ linux-2.6.0-test4-all/arch/ia64/Kconfig	2003-08-29 11:45:12.000000000 -0700
@@ -433,15 +433,7 @@
 	  To use this option, you have to ensure that the "/proc file system
 	  support" (CONFIG_PROC_FS) is enabled, too.
 
-config EFI_VARS
-	tristate "/proc/efi/vars support"
-	help
-	  If you say Y here, you are able to get EFI (Extensible Firmware
-	  Interface) variable information in /proc/efi/vars.  You may read,
-	  write, create, and destroy EFI variables through this interface.
-
-	  To use this option, you have to check that the "/proc file system
-	  support" (CONFIG_PROC_FS) is enabled, too.
+source "drivers/efi/Kconfig"
 
 config NR_CPUS
 	int "Maximum number of CPUs (2-64)"
diff -urN linux-2.6.0-test4/arch/ia64/kernel/efivars.c linux-2.6.0-test4-all/arch/ia64/kernel/efivars.c
--- linux-2.6.0-test4/arch/ia64/kernel/efivars.c	2003-08-22 16:55:33.000000000 -0700
+++ linux-2.6.0-test4-all/arch/ia64/kernel/efivars.c	1969-12-31 16:00:00.000000000 -0800
@@ -1,508 +0,0 @@
-/*
- * EFI Variables - efivars.c
- *
- * Copyright (C) 2001 Dell Computer Corporation <Matt_Domsch@dell.com>
- *
- * This code takes all variables accessible from EFI runtime and
- *  exports them via /proc
- *
- * Reads to /proc/efi/vars/varname return an efi_variable_t structure.
- * Writes to /proc/efi/vars/varname must be an efi_variable_t structure.
- * Writes with DataSize = 0 or Attributes = 0 deletes the variable.
- * Writes with a new value in VariableName+VendorGuid creates
- * a new variable.
- *
- *
- *  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:
- *
- *  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/config.h>
-#include <linux/types.h>
-#include <linux/errno.h>
-#include <linux/init.h>
-#include <linux/proc_fs.h>
-#include <linux/sched.h>		/* for capable() */
-#include <linux/mm.h>
-#include <linux/module.h>
-#include <linux/smp.h>
-#include <linux/efi.h>
-
-#include <asm/uaccess.h>
-
-MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
-MODULE_DESCRIPTION("/proc interface to EFI Variables");
-MODULE_LICENSE("GPL");
-
-#define EFIVARS_VERSION "0.06 2002-Dec-10"
-
-static int
-efivar_read(char *page, char **start, off_t off,
-	    int count, int *eof, void *data);
-static int
-efivar_write(struct file *file, const char *buffer,
-	     unsigned long count, void *data);
-
-
-/*
- * 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.
- */
-
-typedef struct _efi_variable_t {
-	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)) efi_variable_t;
-
-
-typedef struct _efivar_entry_t {
-	efi_variable_t          var;
-	struct proc_dir_entry   *entry;
-	struct list_head        list;
-} efivar_entry_t;
-
-/*
-  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 proc 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 spinlock_t efivars_lock = SPIN_LOCK_UNLOCKED;
-static LIST_HEAD(efivar_list);
-static struct proc_dir_entry *efi_vars_dir;
-
-#define efivar_entry(n) list_entry(n, efivar_entry_t, list)
-
-/* 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 int
-proc_calc_metrics(char *page, char **start, off_t off,
-		  int count, int *eof, int len)
-{
-	if (len <= off+count) *eof = 1;
-	*start = page + off;
-	len -= off;
-	if (len>count) len = count;
-	if (len<0) len = 0;
-	return len;
-}
-
-/*
- * efivar_create_proc_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_proc_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;
-	efivar_entry_t *new_efivar;
-
-	short_name = kmalloc(short_name_size+1, GFP_KERNEL);
-	new_efivar = kmalloc(sizeof(efivar_entry_t), GFP_KERNEL);
-
-	if (!short_name || !new_efivar)  {
-		if (short_name)        kfree(short_name);
-		if (new_efivar)        kfree(new_efivar);
-		return 1;
-	}
-	memset(short_name, 0, short_name_size+1);
-	memset(new_efivar, 0, sizeof(efivar_entry_t));
-
-	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));
-
-	/* Create the entry in proc */
-	new_efivar->entry = create_proc_entry(short_name, 0600, efi_vars_dir);
-	kfree(short_name); short_name = NULL;
-	if (!new_efivar->entry) return 1;
-
-	new_efivar->entry->owner = THIS_MODULE;
-	new_efivar->entry->data = new_efivar;
-	new_efivar->entry->read_proc = efivar_read;
-	new_efivar->entry->write_proc = efivar_write;
-
-	spin_lock(&efivars_lock);
-	list_add(&new_efivar->list, &efivar_list);
-	spin_unlock(&efivars_lock);
-
-	return 0;
-}
-
-
-
-/***********************************************************
- * efivar_read()
- * Requires:
- * Modifies: page
- * Returns: number of bytes written, or -EINVAL on failure
- ***********************************************************/
-
-static int
-efivar_read(char *page, char **start, off_t off, int count, int *eof, void *data)
-{
-	int len = sizeof(efi_variable_t);
-	efivar_entry_t *efi_var = data;
-	efi_variable_t *var_data = (efi_variable_t *)page;
-
-	if (!page || !data) return -EINVAL;
-
-	spin_lock(&efivars_lock);
-
-	memcpy(var_data, &efi_var->var, len);
-
-	var_data->DataSize = 1024;
-	var_data->Status = efi.get_variable(var_data->VariableName,
-					    &var_data->VendorGuid,
-					    &var_data->Attributes,
-					    &var_data->DataSize,
-					    var_data->Data);
-
-	spin_unlock(&efivars_lock);
-
-	return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
-/***********************************************************
- * efivar_write()
- * Requires: data is an efi_setvariable_t data type,
- *           properly filled in, possibly by a call
- *           first to efivar_read().
- *           Caller must have CAP_SYS_ADMIN
- * Modifies: NVRAM
- * Returns: var_data->DataSize on success, errno on failure
- *
- ***********************************************************/
-static int
-efivar_write(struct file *file, const char *buffer,
-	     unsigned long count, void *data)
-{
-	unsigned long strsize1, strsize2;
-	int found=0;
-	struct list_head *pos, *n;
-	unsigned long size = sizeof(efi_variable_t);
-	efi_status_t status;
-	efivar_entry_t *efivar = data, *search_efivar = NULL;
-	efi_variable_t *var_data;
-	if (!data || count != size) {
-		printk(KERN_WARNING "efivars: improper struct of size 0x%lx passed.\n", count);
-		return -EINVAL;
-	}
-	if (!capable(CAP_SYS_ADMIN))
-		return -EACCES;
-
-	var_data = kmalloc(size, GFP_KERNEL);
-	if (!var_data)
-		return -ENOMEM;
-	if (copy_from_user(var_data, buffer, size)) {
-		kfree(var_data);
-		return -EFAULT;
-	}
-
-	spin_lock(&efivars_lock);
-
-	/* Since the data ptr we've currently got is probably for
-	   a different variable find the right variable.
-	   This allows any properly formatted data structure to
-	   be written to any of the files in /proc/efi/vars and it will work.
-	*/
-	list_for_each_safe(pos, n, &efivar_list) {
-		search_efivar = efivar_entry(pos);
-		strsize1 = utf8_strsize(search_efivar->var.VariableName, 1024);
-		strsize2 = utf8_strsize(var_data->VariableName, 1024);
-		if ( strsize1 == strsize2 &&
-		     !memcmp(&(search_efivar->var.VariableName),
-			     var_data->VariableName, strsize1) &&
-		     !efi_guidcmp(search_efivar->var.VendorGuid,
-				  var_data->VendorGuid)) {
-			found = 1;
-			break;
-		}
-	}
-	if (found) efivar = search_efivar;
-
-	status = efi.set_variable(var_data->VariableName,
-				  &var_data->VendorGuid,
-				  var_data->Attributes,
-				  var_data->DataSize,
-				  var_data->Data);
-
-	if (status != EFI_SUCCESS) {
-		printk(KERN_WARNING "set_variable() failed: status=%lx\n", status);
-		kfree(var_data);
-		spin_unlock(&efivars_lock);
-		return -EIO;
-	}
-
-
-	if (!var_data->DataSize || !var_data->Attributes) {
-		/* We just deleted the NVRAM variable */
-		remove_proc_entry(efivar->entry->name, efi_vars_dir);
-		list_del(&efivar->list);
-		kfree(efivar);
-	}
-
-	spin_unlock(&efivars_lock);
-
-	/* If this is a new variable, set up the proc entry for it. */
-	if (!found) {
-		efivar_create_proc_entry(utf8_strsize(var_data->VariableName,
-						      1024),
-					 var_data->VariableName,
-					 &var_data->VendorGuid);
-	}
-
-	kfree(var_data);
-	return size;
-}
-
-/*
- * The EFI system table contains pointers to the SAL system table,
- * HCDP, ACPI, SMBIOS, etc, that may be useful to applications.
- */
-static ssize_t
-efi_systab_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
-{
-	void *data;
-	u8 *proc_buffer;
-	ssize_t size, length;
-	int ret;
-	const int max_nr_entries = 7; 	/* num ptrs to tables we could expose */
-	const int max_line_len = 80;
-
-	if (!efi.systab)
-		return 0;
-
-	proc_buffer = kmalloc(max_nr_entries * max_line_len, GFP_KERNEL);
-	if (!proc_buffer)
-		return -ENOMEM;
-
-	length = 0;
-	if (efi.mps)
-		length += sprintf(proc_buffer + length, "MPS=0x%lx\n", __pa(efi.mps));
-	if (efi.acpi20)
-		length += sprintf(proc_buffer + length, "ACPI20=0x%lx\n", __pa(efi.acpi20));
-	if (efi.acpi)
-		length += sprintf(proc_buffer + length, "ACPI=0x%lx\n", __pa(efi.acpi));
-	if (efi.smbios)
-		length += sprintf(proc_buffer + length, "SMBIOS=0x%lx\n", __pa(efi.smbios));
-	if (efi.sal_systab)
-		length += sprintf(proc_buffer + length, "SAL=0x%lx\n", __pa(efi.sal_systab));
-	if (efi.hcdp)
-		length += sprintf(proc_buffer + length, "HCDP=0x%lx\n", __pa(efi.hcdp));
-	if (efi.boot_info)
-		length += sprintf(proc_buffer + length, "BOOTINFO=0x%lx\n", __pa(efi.boot_info));
-
-	if (*ppos >= length) {
-		ret = 0;
-		goto out;
-	}
-
-	data = proc_buffer + file->f_pos;
-	size = length - file->f_pos;
-	if (size > count)
-		size = count;
-	if (copy_to_user(buffer, data, size)) {
-		ret = -EFAULT;
-		goto out;
-	}
-
-	*ppos += size;
-	ret = size;
-
-out:
-	kfree(proc_buffer);
-	return ret;
-}
-
-static struct proc_dir_entry *efi_systab_entry;
-static struct file_operations efi_systab_fops = {
-	.read = efi_systab_read,
-};
-
-static int __init
-efivars_init(void)
-{
-	efi_status_t status;
-	efi_guid_t vendor_guid;
-	efi_char16_t *variable_name = kmalloc(1024, GFP_KERNEL);
-	unsigned long variable_name_size = 1024;
-
-	printk(KERN_INFO "EFI Variables Facility v%s\n", EFIVARS_VERSION);
-
-	/* Since efi.c happens before procfs is available,
-	   we create the directory here if it doesn't
-	   already exist.  There's probably a better way
-	   to do this.
-	*/
-	if (!efi_dir)
-		efi_dir = proc_mkdir("efi", NULL);
-
-	efi_systab_entry = create_proc_entry("systab", S_IRUSR | S_IRGRP, efi_dir);
-	if (efi_systab_entry)
-		efi_systab_entry->proc_fops = &efi_systab_fops;
-
-	efi_vars_dir = proc_mkdir("vars", efi_dir);
-
-	/* Per EFI spec, the maximum storage allocated for both
-	   the variable name and variable data is 1024 bytes.
-	*/
-
-	memset(variable_name, 0, 1024);
-
-	do {
-		variable_name_size=1024;
-
-		status = efi.get_next_variable(&variable_name_size,
-					       variable_name,
-					       &vendor_guid);
-
-
-		switch (status) {
-		case EFI_SUCCESS:
-			efivar_create_proc_entry(variable_name_size,
-						 variable_name,
-						 &vendor_guid);
-			break;
-		case EFI_NOT_FOUND:
-			break;
-		default:
-			printk(KERN_WARNING "get_next_variable: status=%lx\n", status);
-			status = EFI_NOT_FOUND;
-			break;
-		}
-
-	} while (status != EFI_NOT_FOUND);
-
-	kfree(variable_name);
-	return 0;
-}
-
-static void __exit
-efivars_exit(void)
-{
-	struct list_head *pos, *n;
-	efivar_entry_t *efivar;
-
-	spin_lock(&efivars_lock);
-	if (efi_systab_entry)
-		remove_proc_entry(efi_systab_entry->name, efi_dir);
-	list_for_each_safe(pos, n, &efivar_list) {
-		efivar = efivar_entry(pos);
-		remove_proc_entry(efivar->entry->name, efi_vars_dir);
-		list_del(&efivar->list);
-		kfree(efivar);
-	}
-	spin_unlock(&efivars_lock);
-
-	remove_proc_entry(efi_vars_dir->name, efi_dir);
-}
-
-module_init(efivars_init);
-module_exit(efivars_exit);
-
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-indent-level: 4
- * c-brace-imaginary-offset: 0
- * c-brace-offset: -4
- * c-argdecl-indent: 4
- * c-label-offset: -4
- * c-continued-statement-offset: 4
- * c-continued-brace-offset: 0
- * indent-tabs-mode: nil
- * tab-width: 8
- * End:
- */
diff -urN linux-2.6.0-test4/arch/ia64/kernel/Makefile linux-2.6.0-test4-all/arch/ia64/kernel/Makefile
--- linux-2.6.0-test4/arch/ia64/kernel/Makefile	2003-08-22 17:02:32.000000000 -0700
+++ linux-2.6.0-test4-all/arch/ia64/kernel/Makefile	2003-08-29 11:45:12.000000000 -0700
@@ -8,7 +8,6 @@
 	 irq_lsapic.o ivt.o machvec.o pal.o patch.o process.o perfmon.o ptrace.o sal.o		\
 	 semaphore.o setup.o signal.o sys_ia64.o time.o traps.o unaligned.o unwind.o
 
-obj-$(CONFIG_EFI_VARS)		+= efivars.o
 obj-$(CONFIG_IA64_BRL_EMU)	+= brl_emu.o
 obj-$(CONFIG_IA64_GENERIC)	+= acpi-ext.o
 obj-$(CONFIG_IA64_HP_ZX1)	+= acpi-ext.o
diff -urN linux-2.6.0-test4/drivers/efi/efivars.c linux-2.6.0-test4-all/drivers/efi/efivars.c
--- linux-2.6.0-test4/drivers/efi/efivars.c	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.0-test4-all/drivers/efi/efivars.c	2003-08-29 12:35:59.000000000 -0700
@@ -0,0 +1,692 @@
+/*
+ * EFI Variables - efivars.c
+ *
+ * Copyright (C) 2001 Dell Computer Corporation <Matt_Domsch@dell.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:
+ *
+ *  29 Aug 2003 - Matt Tolentino <matthew.e.tolentino@intel.com)
+ *   converted driver to export variable information via sysfs 
+ *   move to drivers/efi 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/config.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/sched.h>		/* for capable() */
+#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>
+
+MODULE_AUTHOR("Matt Domsch <Matt_Domsch@Dell.com>");
+MODULE_DESCRIPTION("sysfs interface to EFI Variables");
+MODULE_LICENSE("GPL");
+
+#define EFIVARS_VERSION "0.07 2003-Aug-29"
+
+/*
+ * 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 spinlock_t efivars_lock = SPIN_LOCK_UNLOCKED;
+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;
+};
+
+#define get_efivar_entry(n) list_entry(n, struct efivar_entry, list)
+
+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 VAR_SUBSYS_ATTR(_name, _mode, _show, _store) \
+struct subsys_attribute var_subsys_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);
+}
+
+/*
+ * Convenience function to call GetVariable/SetVariable
+ */
+static int
+get_var_data(struct efi_variable *var)
+{
+	efi_status_t status = EFI_NOT_FOUND;
+	
+	spin_lock(&efivars_lock);
+	status = efi.get_variable(var->VariableName,
+			 	  &var->VendorGuid,
+			 	  &var->Attributes,
+			 	  &var->DataSize,
+			 	  var->Data);
+	spin_unlock(&efivars_lock);
+	
+	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 || !var || !buf) 
+		return 0;
+
+	efi_guid_unparse(&var->VendorGuid, str);
+	str += strlen(str);
+	str += sprintf(str, "\n");
+
+	return str - buf;	
+}
+
+static int 
+efivar_attr_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	char *str = buf;
+	efi_status_t status = EFI_NOT_FOUND;
+	
+	if (!entry || !var || !buf)
+		return 0;
+
+	if (!var->Attributes) {
+		status = get_var_data(var);
+		if (status != EFI_SUCCESS) {
+			printk(KERN_WARNING "GetVariable() failed 0x%lx!\n",
+					     status);
+			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 int
+efivar_size_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	char *str = buf;
+	efi_status_t status = EFI_NOT_FOUND;
+	
+	if (!entry || !var || !buf)
+		return 0;
+	
+	if (!var->DataSize) {
+		status = get_var_data(var);
+		if (status != EFI_SUCCESS) {
+			printk(KERN_WARNING "GetVariable() failed 0x%lx!\n",
+					     status);
+			return -EIO;
+		}
+	}
+	str += sprintf(str, "0x%lx\n", var->DataSize);
+	
+	return str - buf;
+}
+
+static int 
+efivar_data_read(struct efivar_entry *entry, char *buf)
+{
+	struct efi_variable *var = &entry->var;
+	efi_status_t status;
+	
+	if (!entry || !buf)
+		return 0;
+
+	if (!var->Data) {
+		status = get_var_data(var);
+		if (status != EFI_SUCCESS) {
+			printk(KERN_WARNING "GetVariable() failed 0x%lx!\n",
+					     status);
+			return -EIO;
+		}
+	}
+	memcpy(buf, var->Data, var->DataSize);
+	return 0;
+}
+/* 
+ * We allow each variable to be edited via rewriting the 
+ * entire efi variable structure.
+ */
+static ssize_t 
+efivar_edit(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 -1;
+
+	new_var = (struct efi_variable *)buf;
+	/* 
+	 * If only updating the variable data, then the name 
+	 * and guid should remain the same 
+	 */
+	if (new_var->VariableName != var->VariableName) {
+		return -EINVAL;
+	}
+
+	if ((new_var->DataSize <= 0) || (new_var->Attributes == 0)){
+		printk(KERN_ERR "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);
+
+	if (status != EFI_SUCCESS) {
+		printk(KERN_WARNING "set_variable() failed: status=%lx\n", 
+				status);
+		return -EIO;
+	}
+	spin_unlock(&efivars_lock);
+
+	memcpy(&entry->var, new_var, sizeof(struct efi_variable));
+
+	return status;
+}
+
+/* 
+ * 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 = 0;
+	
+	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 = 0;
+	
+	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);
+	list_del(&var->list);
+	kfree(var);
+}
+
+static EFIVAR_ATTR(guid, 0644, efivar_guid_read, NULL);
+static EFIVAR_ATTR(attributes, 0644, efivar_attr_read, NULL);
+static EFIVAR_ATTR(size, 0644, efivar_size_read, NULL);
+static EFIVAR_ATTR(data, 0644, efivar_data_read, NULL); 
+static EFIVAR_ATTR(edit_var, 0200, NULL, efivar_edit);
+
+static struct attribute *def_attrs[] = {
+	&efivar_attr_guid.attr,
+	&efivar_attr_size.attr,
+	&efivar_attr_attributes.attr,
+	&efivar_attr_data.attr,
+	&efivar_attr_edit_var.attr,
+	NULL,
+};
+
+static struct kobj_type ktype_efivar = {
+	.release = efivar_release,
+	.sysfs_ops = &efivar_attr_ops,
+	.default_attrs = def_attrs,
+};
+
+/* Why do I need this? */
+static ssize_t 
+dummy(struct subsystem *sub, char *buf)
+{
+	return 0;
+}
+
+static inline void 
+efivar_unregister(struct efivar_entry *var)
+{
+	kobject_unregister(&var->kobj);
+}
+
+
+static ssize_t 
+efivar_create(struct subsystem *sub, const char *buf, size_t count)
+{
+	struct efi_variable *new_var = (struct efi_variable *)buf;
+	struct efivar_entry *search_efivar = NULL;
+	unsigned long strsize1, strsize2;
+	struct list_head *pos, *n;
+	efi_status_t status = EFI_NOT_FOUND;
+	int found = 0;
+
+	spin_lock(&efivars_lock);
+
+	/* 
+	 * Does this variable already exist?
+	 */
+	list_for_each_safe(pos, n, &efivar_list) {
+		search_efivar = get_efivar_entry(pos);
+		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) {
+		printk("EFI variable already exists!\n");
+        	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 "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);
+	return status;
+}
+
+static ssize_t
+efivar_delete(struct subsystem *sub, const char *buf, size_t count)
+{
+	struct efi_variable *del_var = (struct efi_variable *)buf;
+	struct efivar_entry *search_efivar = NULL;
+	unsigned long strsize1, strsize2;
+	struct list_head *pos, *n;
+	efi_status_t status = EFI_NOT_FOUND;
+	int found = 0;
+
+	spin_lock(&efivars_lock);
+
+	/* 
+	 * Does this variable already exist?
+	 */
+	list_for_each_safe(pos, n, &efivar_list) {
+		search_efivar = get_efivar_entry(pos);
+		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;
+	} 
+	
+	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 "set_variable() failed: status=%lx\n", 
+			status);
+		spin_unlock(&efivars_lock);
+		return -EIO;
+	}
+	/* complete the eradication... */
+	efivar_unregister(search_efivar);
+
+	/* It's dead Jim.... */
+        spin_unlock(&efivars_lock);
+
+	return status;
+}
+
+static VAR_SUBSYS_ATTR(new_var, 0200, dummy, efivar_create);
+static VAR_SUBSYS_ATTR(del_var, 0200, dummy, efivar_delete);
+
+static struct subsys_attribute *var_subsys_attrs[] = {
+	&var_subsys_attr_new_var,
+	&var_subsys_attr_del_var,
+	NULL,
+};
+
+static decl_subsys(vars, &ktype_efivar, NULL);
+static decl_subsys(efi, NULL, NULL);
+
+
+/*
+ * 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 = kmalloc(short_name_size + 1, GFP_KERNEL);
+        new_efivar = kmalloc(sizeof(struct efivar_entry), GFP_KERNEL);
+
+	if (!short_name || !new_efivar)  {
+		if (short_name)        kfree(short_name);
+		if (new_efivar)        kfree(new_efivar);
+		return 1;
+	}
+	memset(short_name, 0, short_name_size+1);
+	memset(new_efivar, 0, sizeof(struct efivar_entry));
+
+	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));
+
+	kobject_set_name(&new_efivar->kobj, short_name);
+
+	kobj_set_kset_s(new_efivar, vars_subsys);
+	kobject_register(&new_efivar->kobj);
+
+	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
+ * will probably 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 = kmalloc(1024, GFP_KERNEL);
+	struct subsys_attribute *attr;
+	unsigned long variable_name_size = 1024;
+	int i, rc = 0, error = 0;
+
+	printk(KERN_INFO "EFI Variables Facility v%s\n", EFIVARS_VERSION);
+
+	/* 
+	 * For now we'll register the efi subsys within this driver
+	 */
+	
+	rc = firmware_register(&efi_subsys);
+	
+	if (rc)
+		return rc;
+
+	kset_set_kset_s(&vars_subsys, efi_subsys);
+	subsystem_register(&vars_subsys);
+
+	/* 
+	 * Per EFI spec, the maximum storage allocated for both
+	 * the variable name and variable data is 1024 bytes.
+	 */
+
+	memset(variable_name, 0, 1024);
+
+	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 "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...
+	 */
+
+	for (i = 0; (attr = var_subsys_attrs[i]) && !error; i++) {
+		if (attr->show && attr->store)
+			error = subsys_create_file(&vars_subsys, attr);
+	}
+
+	kfree(variable_name);
+	return 0;
+}
+
+static void __exit
+efivars_exit(void)
+{
+	struct list_head *pos, *n;
+
+        spin_lock(&efivars_lock);
+
+	list_for_each_safe(pos, n, &efivar_list)
+		efivar_unregister(get_efivar_entry(pos));
+
+	spin_unlock(&efivars_lock);
+
+	subsystem_unregister(&vars_subsys);
+	firmware_unregister(&efi_subsys);
+}
+
+module_init(efivars_init);
+module_exit(efivars_exit);
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-indent-level: 4
+ * c-brace-imaginary-offset: 0
+ * c-brace-offset: -4
+ * c-argdecl-indent: 4
+ * c-label-offset: -4
+ * c-continued-statement-offset: 4
+ * c-continued-brace-offset: 0
+ * indent-tabs-mode: nil
+ * tab-width: 8
+ * End:
+ */
diff -urN linux-2.6.0-test4/drivers/efi/Kconfig linux-2.6.0-test4-all/drivers/efi/Kconfig
--- linux-2.6.0-test4/drivers/efi/Kconfig	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.0-test4-all/drivers/efi/Kconfig	2003-08-29 11:45:12.000000000 -0700
@@ -0,0 +1,23 @@
+#
+# EFI Configuration
+#
+
+menu "EFI Support"
+
+config EFI
+	bool "EFI Driver Support"
+	---help---
+	  EFI (Extensible Firmware Interface) support for Linux enables 
+	  the use of drivers that provide architecturally independent 
+	  functionality.  This support is applicable to architectures 
+	  that support EFI.  
+
+config EFI_VARS
+	tristate "EFI Variable Support via sysfs"
+	---help---
+	  If you say Y here, you are able to get EFI (Extensible Firmware
+	  Interface) variable information via sysfs.  You may read,
+	  write, create, and destroy EFI variables through this interface.
+
+
+endmenu
diff -urN linux-2.6.0-test4/drivers/efi/Makefile linux-2.6.0-test4-all/drivers/efi/Makefile
--- linux-2.6.0-test4/drivers/efi/Makefile	1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.0-test4-all/drivers/efi/Makefile	2003-08-29 11:45:12.000000000 -0700
@@ -0,0 +1,4 @@
+# EFI Variable Access
+
+obj-$(CONFIG_EFI_VARS)		+= efivars.o
+
diff -urN linux-2.6.0-test4/drivers/Makefile linux-2.6.0-test4-all/drivers/Makefile
--- linux-2.6.0-test4/drivers/Makefile	2003-08-22 16:58:44.000000000 -0700
+++ linux-2.6.0-test4-all/drivers/Makefile	2003-08-29 11:45:12.000000000 -0700
@@ -49,3 +49,4 @@
 obj-$(CONFIG_MCA)		+= mca/
 obj-$(CONFIG_EISA)		+= eisa/
 obj-$(CONFIG_CPU_FREQ)		+= cpufreq/
+obj-$(CONFIG_EFI)		+= efi/
diff -urN linux-2.6.0-test4/include/linux/efi.h linux-2.6.0-test4-all/include/linux/efi.h
--- linux-2.6.0-test4/include/linux/efi.h	2003-08-29 12:21:01.000000000 -0700
+++ linux-2.6.0-test4-all/include/linux/efi.h	2003-08-29 11:45:12.000000000 -0700
@@ -16,6 +16,7 @@
 #include <linux/time.h>
 #include <linux/types.h>
 #include <linux/proc_fs.h>
+#include <linux/kobject.h>
 #include <linux/rtc.h>
 #include <linux/ioport.h>
 

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Received on Fri Aug 29 17:45:27 2003

This archive was generated by hypermail 2.1.8 : 2005-08-02 09:20:17 EST