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/compat.h> 18 #include <asm/sclp_ctl.h> 19 #include <asm/sclp.h> 20 21 #include "sclp.h" 22 23 /* 24 * Supported command words 25 */ 26 static unsigned int sclp_ctl_sccb_wlist[] = { 27 0x00400002, 28 0x00410002, 29 }; 30 31 /* 32 * Check if command word is supported 33 */ 34 static int sclp_ctl_cmdw_supported(unsigned int cmdw) 35 { 36 int i; 37 38 for (i = 0; i < ARRAY_SIZE(sclp_ctl_sccb_wlist); i++) { 39 if (cmdw == sclp_ctl_sccb_wlist[i]) 40 return 1; 41 } 42 return 0; 43 } 44 45 static void __user *u64_to_uptr(u64 value) 46 { 47 if (is_compat_task()) 48 return compat_ptr(value); 49 else 50 return (void __user *)(unsigned long)value; 51 } 52 53 /* 54 * Start SCLP request 55 */ 56 static int sclp_ctl_ioctl_sccb(void __user *user_area) 57 { 58 struct sclp_ctl_sccb ctl_sccb; 59 struct sccb_header *sccb; 60 unsigned long copied; 61 int rc; 62 63 if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb))) 64 return -EFAULT; 65 if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw)) 66 return -EOPNOTSUPP; 67 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 68 if (!sccb) 69 return -ENOMEM; 70 copied = PAGE_SIZE - 71 copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), PAGE_SIZE); 72 if (offsetof(struct sccb_header, length) + 73 sizeof(sccb->length) > copied || sccb->length > copied) { 74 rc = -EFAULT; 75 goto out_free; 76 } 77 if (sccb->length < 8) { 78 rc = -EINVAL; 79 goto out_free; 80 } 81 rc = sclp_sync_request(ctl_sccb.cmdw, sccb); 82 if (rc) 83 goto out_free; 84 if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length)) 85 rc = -EFAULT; 86 out_free: 87 free_page((unsigned long) sccb); 88 return rc; 89 } 90 91 /* 92 * SCLP SCCB ioctl function 93 */ 94 static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd, 95 unsigned long arg) 96 { 97 void __user *argp; 98 99 if (is_compat_task()) 100 argp = compat_ptr(arg); 101 else 102 argp = (void __user *) arg; 103 switch (cmd) { 104 case SCLP_CTL_SCCB: 105 return sclp_ctl_ioctl_sccb(argp); 106 default: /* unknown ioctl number */ 107 return -ENOTTY; 108 } 109 } 110 111 /* 112 * File operations 113 */ 114 static const struct file_operations sclp_ctl_fops = { 115 .owner = THIS_MODULE, 116 .open = nonseekable_open, 117 .unlocked_ioctl = sclp_ctl_ioctl, 118 .compat_ioctl = sclp_ctl_ioctl, 119 .llseek = no_llseek, 120 }; 121 122 /* 123 * Misc device definition 124 */ 125 static struct miscdevice sclp_ctl_device = { 126 .minor = MISC_DYNAMIC_MINOR, 127 .name = "sclp", 128 .fops = &sclp_ctl_fops, 129 }; 130 builtin_misc_device(sclp_ctl_device); 131