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/uaccess.h> 11 #include <linux/miscdevice.h> 12 #include <linux/gfp.h> 13 #include <linux/init.h> 14 #include <linux/ioctl.h> 15 #include <linux/fs.h> 16 #include <asm/sclp_ctl.h> 17 #include <asm/sclp.h> 18 19 #include "sclp.h" 20 21 /* 22 * Supported command words 23 */ 24 static unsigned int sclp_ctl_sccb_wlist[] = { 25 0x00400002, 26 0x00410002, 27 }; 28 29 /* 30 * Check if command word is supported 31 */ 32 static int sclp_ctl_cmdw_supported(unsigned int cmdw) 33 { 34 int i; 35 36 for (i = 0; i < ARRAY_SIZE(sclp_ctl_sccb_wlist); i++) { 37 if (cmdw == sclp_ctl_sccb_wlist[i]) 38 return 1; 39 } 40 return 0; 41 } 42 43 static void __user *u64_to_uptr(u64 value) 44 { 45 return (void __user *)(unsigned long)value; 46 } 47 48 /* 49 * Start SCLP request 50 */ 51 static int sclp_ctl_ioctl_sccb(void __user *user_area) 52 { 53 struct sclp_ctl_sccb ctl_sccb; 54 struct sccb_header *sccb; 55 unsigned long copied; 56 int rc; 57 58 if (copy_from_user(&ctl_sccb, user_area, sizeof(ctl_sccb))) 59 return -EFAULT; 60 if (!sclp_ctl_cmdw_supported(ctl_sccb.cmdw)) 61 return -EOPNOTSUPP; 62 sccb = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); 63 if (!sccb) 64 return -ENOMEM; 65 copied = PAGE_SIZE - 66 copy_from_user(sccb, u64_to_uptr(ctl_sccb.sccb), PAGE_SIZE); 67 if (offsetof(struct sccb_header, length) + 68 sizeof(sccb->length) > copied || sccb->length > copied) { 69 rc = -EFAULT; 70 goto out_free; 71 } 72 if (sccb->length < 8) { 73 rc = -EINVAL; 74 goto out_free; 75 } 76 rc = sclp_sync_request(ctl_sccb.cmdw, sccb); 77 if (rc) 78 goto out_free; 79 if (copy_to_user(u64_to_uptr(ctl_sccb.sccb), sccb, sccb->length)) 80 rc = -EFAULT; 81 out_free: 82 free_page((unsigned long) sccb); 83 return rc; 84 } 85 86 /* 87 * SCLP SCCB ioctl function 88 */ 89 static long sclp_ctl_ioctl(struct file *filp, unsigned int cmd, 90 unsigned long arg) 91 { 92 void __user *argp; 93 94 argp = (void __user *)arg; 95 switch (cmd) { 96 case SCLP_CTL_SCCB: 97 return sclp_ctl_ioctl_sccb(argp); 98 default: /* unknown ioctl number */ 99 return -ENOTTY; 100 } 101 } 102 103 /* 104 * File operations 105 */ 106 static const struct file_operations sclp_ctl_fops = { 107 .owner = THIS_MODULE, 108 .open = nonseekable_open, 109 .unlocked_ioctl = sclp_ctl_ioctl, 110 }; 111 112 /* 113 * Misc device definition 114 */ 115 static struct miscdevice sclp_ctl_device = { 116 .minor = MISC_DYNAMIC_MINOR, 117 .name = "sclp", 118 .fops = &sclp_ctl_fops, 119 }; 120 builtin_misc_device(sclp_ctl_device); 121