1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * IOCTL interface for SCLP 4 * 5 * Copyright IBM Corp. 2012 6 * 7 * Author: Michael Holzheu <holzheu@linux.vnet.ibm.com> 8 */ 9 10 #include <linux/compat.h> 11 #include <linux/uaccess.h> 12 #include <linux/miscdevice.h> 13 #include <linux/gfp.h> 14 #include <linux/init.h> 15 #include <linux/ioctl.h> 16 #include <linux/fs.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 unsigned long copied; 60 int rc; 61 62 if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb))) 63 return -EFAULT; 64 if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw)) 65 return -EOPNOTSUPP; 66 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 67 if (!sccb) 68 return -ENOMEM; 69 copied = PAGE_SIZE - 70 copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), PAGE_SIZE); 71 if (offsetof(struct sccb_header, length) + 72 sizeof(sccb->length) > copied || sccb->length > copied) { 73 rc = -EFAULT; 74 goto out_free; 75 } 76 if (sccb->length < 8) { 77 rc = -EINVAL; 78 goto out_free; 79 } 80 rc = sclp_sync_request(ctl_sccb.cmdw, sccb); 81 if (rc) 82 goto out_free; 83 if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length)) 84 rc = -EFAULT; 85 out_free: 86 free_page((unsigned long) sccb); 87 return rc; 88 } 89 90 /* 91 * SCLP SCCB ioctl function 92 */ 93 static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd, 94 unsigned long arg) 95 { 96 void __user *argp; 97 98 if (is_compat_task()) 99 argp = compat_ptr(arg); 100 else 101 argp = (void __user *) arg; 102 switch (cmd) { 103 case SCLP_CTL_SCCB: 104 return sclp_ctl_ioctl_sccb(argp); 105 default: /* unknown ioctl number */ 106 return -ENOTTY; 107 } 108 } 109 110 /* 111 * File operations 112 */ 113 static const struct file_operations sclp_ctl_fops = { 114 .owner = THIS_MODULE, 115 .open = nonseekable_open, 116 .unlocked_ioctl = sclp_ctl_ioctl, 117 .compat_ioctl = sclp_ctl_ioctl, 118 .llseek = no_llseek, 119 }; 120 121 /* 122 * Misc device definition 123 */ 124 static struct miscdevice sclp_ctl_device = { 125 .minor = MISC_DYNAMIC_MINOR, 126 .name = "sclp", 127 .fops = &sclp_ctl_fops, 128 }; 129 builtin_misc_device(sclp_ctl_device); 130