1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Hypervisor filesystem for Linux on s390 - debugfs interface 4 * 5 * Copyright IBM Corp. 2010 6 * Author(s): Michael Holzheu <holzheu@linux.vnet.ibm.com> 7 */ 8 9 #include <linux/security.h> 10 #include <linux/slab.h> 11 #include "hypfs.h" 12 13 static struct dentry *dbfs_dir; 14 15 static struct hypfs_dbfs_data *hypfs_dbfs_data_alloc(struct hypfs_dbfs_file *f) 16 { 17 struct hypfs_dbfs_data *data; 18 19 data = kmalloc(sizeof(*data), GFP_KERNEL); 20 if (!data) 21 return NULL; 22 data->dbfs_file = f; 23 return data; 24 } 25 26 static void hypfs_dbfs_data_free(struct hypfs_dbfs_data *data) 27 { 28 data->dbfs_file->data_free(data->buf_free_ptr); 29 kfree(data); 30 } 31 32 static ssize_t dbfs_read(struct file *file, char __user *buf, 33 size_t size, loff_t *ppos) 34 { 35 struct hypfs_dbfs_data *data; 36 struct hypfs_dbfs_file *df; 37 ssize_t rc; 38 39 if (*ppos != 0) 40 return 0; 41 42 df = file_inode(file)->i_private; 43 if (mutex_lock_interruptible(&df->lock)) 44 return -ERESTARTSYS; 45 46 data = hypfs_dbfs_data_alloc(df); 47 if (!data) { 48 mutex_unlock(&df->lock); 49 return -ENOMEM; 50 } 51 rc = df->data_create(&data->buf, &data->buf_free_ptr, &data->size); 52 if (rc) { 53 mutex_unlock(&df->lock); 54 kfree(data); 55 return rc; 56 } 57 mutex_unlock(&df->lock); 58 59 rc = simple_read_from_buffer(buf, size, ppos, data->buf, data->size); 60 hypfs_dbfs_data_free(data); 61 return rc; 62 } 63 64 static long dbfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 65 { 66 struct hypfs_dbfs_file *df = file_inode(file)->i_private; 67 long rc; 68 69 mutex_lock(&df->lock); 70 rc = df->unlocked_ioctl(file, cmd, arg); 71 mutex_unlock(&df->lock); 72 return rc; 73 } 74 75 static const struct file_operations dbfs_ops_ioctl = { 76 .read = dbfs_read, 77 .unlocked_ioctl = dbfs_ioctl, 78 }; 79 80 static const struct file_operations dbfs_ops = { 81 .read = dbfs_read, 82 }; 83 84 void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df) 85 { 86 const struct file_operations *fops = &dbfs_ops; 87 88 if (df->unlocked_ioctl && !security_locked_down(LOCKDOWN_DEBUGFS)) 89 fops = &dbfs_ops_ioctl; 90 df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df, fops); 91 mutex_init(&df->lock); 92 } 93 94 void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df) 95 { 96 debugfs_remove(df->dentry); 97 } 98 99 static int __init hypfs_dbfs_init(void) 100 { 101 int rc = -ENODATA; 102 103 dbfs_dir = debugfs_create_dir("s390_hypfs", NULL); 104 if (hypfs_diag_init()) 105 goto fail_dbfs_exit; 106 if (hypfs_vm_init()) 107 goto fail_hypfs_diag_exit; 108 hypfs_sprp_init(); 109 if (hypfs_diag0c_init()) 110 goto fail_hypfs_sprp_exit; 111 rc = hypfs_fs_init(); 112 if (rc) 113 goto fail_hypfs_diag0c_exit; 114 return 0; 115 116 fail_hypfs_diag0c_exit: 117 hypfs_diag0c_exit(); 118 fail_hypfs_sprp_exit: 119 hypfs_sprp_exit(); 120 hypfs_vm_exit(); 121 fail_hypfs_diag_exit: 122 hypfs_diag_exit(); 123 pr_err("Initialization of hypfs failed with rc=%i\n", rc); 124 fail_dbfs_exit: 125 debugfs_remove(dbfs_dir); 126 return rc; 127 } 128 device_initcall(hypfs_dbfs_init) 129