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 <linux/sched/signal.h> 24 25 #include <asm/processor.h> 26 #include <asm/mmu_context.h> 27 28 static int asids_seq_show(struct seq_file *file, void *iter) 29 { 30 struct task_struct *p; 31 32 read_lock(&tasklist_lock); 33 34 for_each_process(p) { 35 int pid = p->pid; 36 37 if (unlikely(!pid)) 38 continue; 39 40 if (p->mm) 41 seq_printf(file, "%5d : %04lx\n", pid, 42 cpu_asid(smp_processor_id(), p->mm)); 43 } 44 45 read_unlock(&tasklist_lock); 46 47 return 0; 48 } 49 50 static int asids_debugfs_open(struct inode *inode, struct file *file) 51 { 52 return single_open(file, asids_seq_show, inode->i_private); 53 } 54 55 static const struct file_operations asids_debugfs_fops = { 56 .owner = THIS_MODULE, 57 .open = asids_debugfs_open, 58 .read = seq_read, 59 .llseek = seq_lseek, 60 .release = single_release, 61 }; 62 63 static int __init asids_debugfs_init(void) 64 { 65 struct dentry *asids_dentry; 66 67 asids_dentry = debugfs_create_file("asids", S_IRUSR, arch_debugfs_dir, 68 NULL, &asids_debugfs_fops); 69 if (!asids_dentry) 70 return -ENOMEM; 71 72 return PTR_ERR_OR_ZERO(asids_dentry); 73 } 74 device_initcall(asids_debugfs_init); 75