1 /* 2 * debugfs ops for process ASIDs 3 * 4 * Copyright (C) 2000, 2001 Paolo Alberelli 5 * Copyright (C) 2003 - 2008 Paul Mundt 6 * Copyright (C) 2003, 2004 Richard Curnow 7 * 8 * Provides a debugfs file that lists out the ASIDs currently associated 9 * with the processes. 10 * 11 * In the SH-5 case, if the DM.PC register is examined through the debug 12 * link, this shows ASID + PC. To make use of this, the PID->ASID 13 * relationship needs to be known. This is primarily for debugging. 14 * 15 * This file is subject to the terms and conditions of the GNU General Public 16 * License. See the file "COPYING" in the main directory of this archive 17 * for more details. 18 */ 19 #include <linux/init.h> 20 #include <linux/debugfs.h> 21 #include <linux/seq_file.h> 22 #include <linux/spinlock.h> 23 #include <asm/processor.h> 24 #include <asm/mmu_context.h> 25 26 static int asids_seq_show(struct seq_file *file, void *iter) 27 { 28 struct task_struct *p; 29 30 read_lock(&tasklist_lock); 31 32 for_each_process(p) { 33 int pid = p->pid; 34 35 if (unlikely(!pid)) 36 continue; 37 38 if (p->mm) 39 seq_printf(file, "%5d : %04lx\n", pid, 40 cpu_asid(smp_processor_id(), p->mm)); 41 } 42 43 read_unlock(&tasklist_lock); 44 45 return 0; 46 } 47 48 static int asids_debugfs_open(struct inode *inode, struct file *file) 49 { 50 return single_open(file, asids_seq_show, inode->i_private); 51 } 52 53 static const struct file_operations asids_debugfs_fops = { 54 .owner = THIS_MODULE, 55 .open = asids_debugfs_open, 56 .read = seq_read, 57 .llseek = seq_lseek, 58 .release = single_release, 59 }; 60 61 static int __init asids_debugfs_init(void) 62 { 63 struct dentry *asids_dentry; 64 65 asids_dentry = debugfs_create_file("asids", S_IRUSR, arch_debugfs_dir, 66 NULL, &asids_debugfs_fops); 67 if (!asids_dentry) 68 return -ENOMEM; 69 70 return PTR_ERR_OR_ZERO(asids_dentry); 71 } 72 device_initcall(asids_debugfs_init); 73