Hi Linus,
This patch improves /proc/driver/microcode to allow to clear and free the
memory used by the saved copy of the microcode by doing something like:
# > /proc/driver/microcode
(or generally by opening it with O_WRONLY). This saves a page per CPU
pair and makes some security-conscious humans happy...
Also some minor cleanups in BFS and a typo in mtrr.c
Regards,
Tigran.
diff -urN -X dontdiff linux/arch/i386/kernel/microcode.c linux-mc/arch/i386/kernel/microcode.c
--- linux/arch/i386/kernel/microcode.c Mon Feb 21 20:55:51 2000
+++ linux-mc/arch/i386/kernel/microcode.c Mon Feb 21 22:27:28 2000
@@ -20,6 +20,9 @@
* Initial release.
* 1.01 18 February 2000, Tigran Aivazian <tigran@sco.com>
* Added read() support + cleanups.
+ * 1.02 21 February 2000, Tigran Aivazian <tigran@sco.com>
+ * Added 'device trimming' support. open(O_WRONLY) zeroes
+ * and frees the saved copy of applied microcode.
*/
#include <linux/init.h>
@@ -33,7 +36,7 @@
#include <asm/uaccess.h>
#include <asm/processor.h>
-#define MICROCODE_VERSION "1.01"
+#define MICROCODE_VERSION "1.02"
MODULE_DESCRIPTION("CPU (P6) microcode update driver");
MODULE_AUTHOR("Tigran Aivazian <tigran@ocston.org>");
@@ -53,7 +56,7 @@
/*
* Bits in microcode_status. (31 bits of room for future expansion)
*/
-#define MICROCODE_IS_OPEN 0 /* set if /dev/microcode is in use */
+#define MICROCODE_IS_OPEN 0 /* set if device is in use */
static unsigned long microcode_status = 0;
/* the actual array of microcode blocks, each 2048 bytes */
@@ -76,23 +79,12 @@
static int __init microcode_init(void)
{
- int size;
-
proc_microcode = create_proc_entry("microcode", S_IWUSR|S_IRUSR, proc_root_driver);
if (!proc_microcode) {
printk(KERN_ERR "microcode: can't create /proc/driver/microcode\n");
return -ENOMEM;
}
proc_microcode->ops = µcode_inops;
- size = smp_num_cpus * sizeof(struct microcode);
- mc_applied = kmalloc(size, GFP_KERNEL);
- if (!mc_applied) {
- remove_proc_entry("microcode", proc_root_driver);
- printk(KERN_ERR "microcode: can't allocate memory for saved microcode\n");
- return -ENOMEM;
- }
- memset(mc_applied, 0, size); /* so that reading from offsets corresponding to failed
- update makes this obvious */
printk(KERN_INFO "P6 Microcode Update Driver v%s registered\n", MICROCODE_VERSION);
return 0;
}
@@ -100,7 +92,8 @@
static void __exit microcode_exit(void)
{
remove_proc_entry("microcode", proc_root_driver);
- kfree(mc_applied);
+ if (mc_applied)
+ kfree(mc_applied);
printk(KERN_INFO "P6 Microcode Update Driver v%s unregistered\n", MICROCODE_VERSION);
}
@@ -119,6 +112,15 @@
if (test_and_set_bit(MICROCODE_IS_OPEN, µcode_status))
return -EBUSY;
+ if ((file->f_flags & O_ACCMODE) == O_WRONLY) {
+ proc_microcode->size = 0;
+ if (mc_applied) {
+ memset(mc_applied, 0, smp_num_cpus * sizeof(struct microcode));
+ kfree(mc_applied);
+ mc_applied = NULL;
+ }
+ }
+
MOD_INC_USE_COUNT;
return 0;
@@ -243,6 +245,16 @@
sizeof(struct microcode));
return -EINVAL;
}
+ if (!mc_applied) {
+ int size = smp_num_cpus * sizeof(struct microcode);
+ mc_applied = kmalloc(size, GFP_KERNEL);
+ if (!mc_applied) {
+ printk(KERN_ERR "microcode: can't allocate memory for saved microcode\n");
+ return -ENOMEM;
+ }
+ memset(mc_applied, 0, size);
+ }
+
lock_kernel();
microcode_num = len/sizeof(struct microcode);
microcode = vmalloc(len);
diff -urN -X dontdiff linux/arch/i386/kernel/mtrr.c linux-mc/arch/i386/kernel/mtrr.c
--- linux/arch/i386/kernel/mtrr.c Mon Feb 21 20:55:51 2000
+++ linux-mc/arch/i386/kernel/mtrr.c Mon Feb 21 21:54:40 2000
@@ -1838,7 +1838,7 @@
proc_root_mtrr = create_proc_entry ("mtrr", S_IWUSR | S_IRUGO, &proc_root);
proc_root_mtrr->ops = &proc_mtrr_inode_operations;
#endif
-#ifdev CONFIG_DEVFS_FS
+#ifdef CONFIG_DEVFS_FS
devfs_handle = devfs_register (NULL, "cpu/mtrr", 0, DEVFS_FL_DEFAULT, 0, 0,
S_IFREG | S_IRUGO | S_IWUSR, 0, 0,
&mtrr_fops, NULL);
diff -urN -X dontdiff linux/fs/bfs/dir.c linux-mc/fs/bfs/dir.c
--- linux/fs/bfs/dir.c Fri Feb 11 20:07:59 2000
+++ linux-mc/fs/bfs/dir.c Mon Feb 21 21:31:29 2000
@@ -76,9 +76,9 @@
}
static struct file_operations bfs_dir_operations = {
- read: bfs_dir_read,
- readdir: bfs_readdir,
- fsync: file_fsync,
+ read: bfs_dir_read,
+ readdir: bfs_readdir,
+ fsync: file_fsync,
};
extern void dump_imap(const char *, struct super_block *);
@@ -261,10 +261,6 @@
lookup: bfs_lookup,
link: bfs_link,
unlink: bfs_unlink,
- symlink: NULL,
- mkdir: NULL,
- rmdir: NULL,
- mknod: NULL,
rename: bfs_rename,
};
diff -urN -X dontdiff linux/fs/bfs/inode.c linux-mc/fs/bfs/inode.c
--- linux/fs/bfs/inode.c Fri Feb 11 20:07:59 2000
+++ linux-mc/fs/bfs/inode.c Mon Feb 21 21:32:06 2000
@@ -209,15 +209,10 @@
static struct super_operations bfs_sops = {
read_inode: bfs_read_inode,
write_inode: bfs_write_inode,
- put_inode: NULL,
delete_inode: bfs_delete_inode,
- notify_change: NULL,
put_super: bfs_put_super,
write_super: bfs_write_super,
statfs: bfs_statfs,
- remount_fs: NULL,
- clear_inode: NULL,
- umount_begin: NULL
};
void dump_imap(const char *prefix, struct super_block * s)
@@ -337,7 +332,6 @@
name: "bfs",
fs_flags: FS_REQUIRES_DEV,
read_super: bfs_read_super,
- next: NULL
};
#ifdef MODULE
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Wed Feb 23 2000 - 21:00:28 EST