1 /* 2 * IOCTL interface for SCLP 3 * 4 * Copyright IBM Corp. 2012 5 * 6 * Author: Michael Holzheu <holzheu@linux.vnet.ibm.com> 7 */ 8 9 #include <linux/compat.h> 10 #include <linux/uaccess.h> 11 #include <linux/miscdevice.h> 12 #include <linux/gfp.h> 13 #include <linux/module.h> 14 #include <linux/ioctl.h> 15 #include <linux/fs.h> 16 #include <asm/compat.h> 17 #include <asm/sclp_ctl.h> 18 #include <asm/sclp.h> 19 20 #include "sclp.h" 21 22 /* 23 * Supported command words 24 */ 25 static unsigned int sclp_ctl_sccb_wlist[] = { 26 0x00400002, 27 0x00410002, 28 }; 29 30 /* 31 * Check if command word is supported 32 */ 33 static int sclp_ctl_cmdw_supported(unsigned int cmdw) 34 { 35 int i; 36 37 for (i = 0; i < ARRAY_SIZE(sclp_ctl_sccb_wlist); i++) { 38 if (cmdw == sclp_ctl_sccb_wlist[i]) 39 return 1; 40 } 41 return 0; 42 } 43 44 static void __user *u64_to_uptr(u64 value) 45 { 46 if (is_compat_task()) 47 return compat_ptr(value); 48 else 49 return (void __user *)(unsigned long)value; 50 } 51 52 /* 53 * Start SCLP request 54 */ 55 static int sclp_ctl_ioctl_sccb(void __user *user_area) 56 { 57 struct sclp_ctl_sccb ctl_sccb; 58 struct sccb_header *sccb; 59 int rc; 60 61 if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb))) 62 return -EFAULT; 63 if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw)) 64 return -EOPNOTSUPP; 65 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 66 if (!sccb) 67 return -ENOMEM; 68 if (copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), sizeof(*sccb))) { 69 rc = -EFAULT; 70 goto out_free; 71 } 72 if (sccb->length > PAGE_SIZE || sccb->length < 8) 73 return -EINVAL; 74 if (copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), sccb->length)) { 75 rc = -EFAULT; 76 goto out_free; 77 } 78 rc = sclp_sync_request(ctl_sccb.cmdw, sccb); 79 if (rc) 80 goto out_free; 81 if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length)) 82 rc = -EFAULT; 83 out_free: 84 free_page((unsigned long) sccb); 85 return rc; 86 } 87 88 /* 89 * SCLP SCCB ioctl function 90 */ 91 static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd, 92 unsigned long arg) 93 { 94 void __user *argp; 95 96 if (is_compat_task()) 97 argp = compat_ptr(arg); 98 else 99 argp = (void __user *) arg; 100 switch (cmd) { 101 case SCLP_CTL_SCCB: 102 return sclp_ctl_ioctl_sccb(argp); 103 default: /* unknown ioctl number */ 104 return -ENOTTY; 105 } 106 } 107 108 /* 109 * File operations 110 */ 111 static const struct file_operations sclp_ctl_fops = { 112 .owner = THIS_MODULE, 113 .open = nonseekable_open, 114 .unlocked_ioctl = sclp_ctl_ioctl, 115 .compat_ioctl = sclp_ctl_ioctl, 116 .llseek = no_llseek, 117 }; 118 119 /* 120 * Misc device definition 121 */ 122 static struct miscdevice sclp_ctl_device = { 123 .minor = MISC_DYNAMIC_MINOR, 124 .name = "sclp", 125 .fops = &sclp_ctl_fops, 126 }; 127 128 /* 129 * Register sclp_ctl misc device 130 */ 131 static int __init sclp_ctl_init(void) 132 { 133 return misc_register(&sclp_ctl_device); 134 } 135 module_init(sclp_ctl_init); 136 137 /* 138 * Deregister sclp_ctl misc device 139 */ 140 static void __exit sclp_ctl_exit(void) 141 { 142 misc_deregister(&sclp_ctl_device); 143 } 144 module_exit(sclp_ctl_exit); 145