1b2441318SGreg Kroah-Hartman // SPDX-License-Identifier: GPL-2.0 26b979de3SChristian Borntraeger /* 3f73a2b03SHeiko Carstens * Copyright IBM Corp. 2004, 2010 445af3af8SChristian Borntraeger * Interface implementation for communication with the z/VM control program 56b979de3SChristian Borntraeger * 6f73a2b03SHeiko Carstens * Author(s): Christian Borntraeger <borntraeger@de.ibm.com> 76b979de3SChristian Borntraeger * 86b979de3SChristian Borntraeger * z/VMs CP offers the possibility to issue commands via the diagnose code 8 96b979de3SChristian Borntraeger * this driver implements a character device that issues these commands and 106b979de3SChristian Borntraeger * returns the answer of CP. 11f73a2b03SHeiko Carstens * 126b979de3SChristian Borntraeger * The idea of this driver is based on cpint from Neale Ferguson and #CP in CMS 136b979de3SChristian Borntraeger */ 146b979de3SChristian Borntraeger 156b979de3SChristian Borntraeger #include <linux/fs.h> 166b979de3SChristian Borntraeger #include <linux/init.h> 17048cd4e5SHeiko Carstens #include <linux/compat.h> 186b979de3SChristian Borntraeger #include <linux/kernel.h> 196b979de3SChristian Borntraeger #include <linux/miscdevice.h> 205a0e3ad6STejun Heo #include <linux/slab.h> 213f429842SHeiko Carstens #include <linux/uaccess.h> 223a4c5d59SHeiko Carstens #include <linux/export.h> 233f429842SHeiko Carstens #include <linux/mutex.h> 243f429842SHeiko Carstens #include <linux/cma.h> 253f429842SHeiko Carstens #include <linux/mm.h> 266b979de3SChristian Borntraeger #include <asm/cpcmd.h> 276b979de3SChristian Borntraeger #include <asm/debug.h> 28ef267938SHeiko Carstens #include <asm/vmcp.h> 29ef267938SHeiko Carstens 30ef267938SHeiko Carstens struct vmcp_session { 31ef267938SHeiko Carstens char *response; 32ef267938SHeiko Carstens unsigned int bufsize; 33ef267938SHeiko Carstens unsigned int cma_alloc : 1; 34ef267938SHeiko Carstens int resp_size; 35ef267938SHeiko Carstens int resp_code; 36ef267938SHeiko Carstens struct mutex mutex; 37ef267938SHeiko Carstens }; 386b979de3SChristian Borntraeger 396b979de3SChristian Borntraeger static debug_info_t *vmcp_debug; 406b979de3SChristian Borntraeger 413f429842SHeiko Carstens static unsigned long vmcp_cma_size __initdata = CONFIG_VMCP_CMA_SIZE * 1024 * 1024; 423f429842SHeiko Carstens static struct cma *vmcp_cma; 433f429842SHeiko Carstens 443f429842SHeiko Carstens static int __init early_parse_vmcp_cma(char *p) 453f429842SHeiko Carstens { 46a45425d8SVasily Gorbik if (!p) 47a45425d8SVasily Gorbik return 1; 483f429842SHeiko Carstens vmcp_cma_size = ALIGN(memparse(p, NULL), PAGE_SIZE); 493f429842SHeiko Carstens return 0; 503f429842SHeiko Carstens } 513f429842SHeiko Carstens early_param("vmcp_cma", early_parse_vmcp_cma); 523f429842SHeiko Carstens 533f429842SHeiko Carstens void __init vmcp_cma_reserve(void) 543f429842SHeiko Carstens { 553f429842SHeiko Carstens if (!MACHINE_IS_VM) 563f429842SHeiko Carstens return; 573f429842SHeiko Carstens cma_declare_contiguous(0, vmcp_cma_size, 0, 0, 0, false, "vmcp", &vmcp_cma); 583f429842SHeiko Carstens } 593f429842SHeiko Carstens 603f429842SHeiko Carstens static void vmcp_response_alloc(struct vmcp_session *session) 613f429842SHeiko Carstens { 623f429842SHeiko Carstens struct page *page = NULL; 633f429842SHeiko Carstens int nr_pages, order; 643f429842SHeiko Carstens 653f429842SHeiko Carstens order = get_order(session->bufsize); 663f429842SHeiko Carstens nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT; 673f429842SHeiko Carstens /* 683f429842SHeiko Carstens * For anything below order 3 allocations rely on the buddy 693f429842SHeiko Carstens * allocator. If such low-order allocations can't be handled 703f429842SHeiko Carstens * anymore the system won't work anyway. 713f429842SHeiko Carstens */ 723f429842SHeiko Carstens if (order > 2) 7365182029SMarek Szyprowski page = cma_alloc(vmcp_cma, nr_pages, 0, false); 743f429842SHeiko Carstens if (page) { 7597aa7468SHeiko Carstens session->response = (char *)page_to_virt(page); 763f429842SHeiko Carstens session->cma_alloc = 1; 773f429842SHeiko Carstens return; 783f429842SHeiko Carstens } 793f429842SHeiko Carstens session->response = (char *)__get_free_pages(GFP_KERNEL | __GFP_RETRY_MAYFAIL, order); 803f429842SHeiko Carstens } 813f429842SHeiko Carstens 823f429842SHeiko Carstens static void vmcp_response_free(struct vmcp_session *session) 833f429842SHeiko Carstens { 843f429842SHeiko Carstens int nr_pages, order; 853f429842SHeiko Carstens struct page *page; 863f429842SHeiko Carstens 873f429842SHeiko Carstens if (!session->response) 883f429842SHeiko Carstens return; 893f429842SHeiko Carstens order = get_order(session->bufsize); 903f429842SHeiko Carstens nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT; 913f429842SHeiko Carstens if (session->cma_alloc) { 92*2d1494fbSLinus Walleij page = virt_to_page(session->response); 933f429842SHeiko Carstens cma_release(vmcp_cma, page, nr_pages); 943f429842SHeiko Carstens session->cma_alloc = 0; 95eb304e80SHeiko Carstens } else { 963f429842SHeiko Carstens free_pages((unsigned long)session->response, order); 97eb304e80SHeiko Carstens } 983f429842SHeiko Carstens session->response = NULL; 993f429842SHeiko Carstens } 1003f429842SHeiko Carstens 1016b979de3SChristian Borntraeger static int vmcp_open(struct inode *inode, struct file *file) 1026b979de3SChristian Borntraeger { 1036b979de3SChristian Borntraeger struct vmcp_session *session; 1046b979de3SChristian Borntraeger 1056b979de3SChristian Borntraeger if (!capable(CAP_SYS_ADMIN)) 1066b979de3SChristian Borntraeger return -EPERM; 1076b979de3SChristian Borntraeger 1086b979de3SChristian Borntraeger session = kmalloc(sizeof(*session), GFP_KERNEL); 1096b979de3SChristian Borntraeger if (!session) 1106b979de3SChristian Borntraeger return -ENOMEM; 1116c111d88SArnd Bergmann 1126b979de3SChristian Borntraeger session->bufsize = PAGE_SIZE; 1136b979de3SChristian Borntraeger session->response = NULL; 1146b979de3SChristian Borntraeger session->resp_size = 0; 115d9d119f1SChristian Borntraeger mutex_init(&session->mutex); 1166b979de3SChristian Borntraeger file->private_data = session; 1176b979de3SChristian Borntraeger return nonseekable_open(inode, file); 1186b979de3SChristian Borntraeger } 1196b979de3SChristian Borntraeger 1206b979de3SChristian Borntraeger static int vmcp_release(struct inode *inode, struct file *file) 1216b979de3SChristian Borntraeger { 1226b979de3SChristian Borntraeger struct vmcp_session *session; 1236b979de3SChristian Borntraeger 12427e49945SJoe Perches session = file->private_data; 1256b979de3SChristian Borntraeger file->private_data = NULL; 1263f429842SHeiko Carstens vmcp_response_free(session); 1276b979de3SChristian Borntraeger kfree(session); 1286b979de3SChristian Borntraeger return 0; 1296b979de3SChristian Borntraeger } 1306b979de3SChristian Borntraeger 1316b979de3SChristian Borntraeger static ssize_t 1326b979de3SChristian Borntraeger vmcp_read(struct file *file, char __user *buff, size_t count, loff_t *ppos) 1336b979de3SChristian Borntraeger { 1347785857aSAkinobu Mita ssize_t ret; 1357785857aSAkinobu Mita size_t size; 1366b979de3SChristian Borntraeger struct vmcp_session *session; 1376b979de3SChristian Borntraeger 1387785857aSAkinobu Mita session = file->private_data; 139d9d119f1SChristian Borntraeger if (mutex_lock_interruptible(&session->mutex)) 1406b979de3SChristian Borntraeger return -ERESTARTSYS; 1416b979de3SChristian Borntraeger if (!session->response) { 142d9d119f1SChristian Borntraeger mutex_unlock(&session->mutex); 1436b979de3SChristian Borntraeger return 0; 1446b979de3SChristian Borntraeger } 1457785857aSAkinobu Mita size = min_t(size_t, session->resp_size, session->bufsize); 1467785857aSAkinobu Mita ret = simple_read_from_buffer(buff, count, ppos, 1477785857aSAkinobu Mita session->response, size); 1486b979de3SChristian Borntraeger 149d9d119f1SChristian Borntraeger mutex_unlock(&session->mutex); 1507785857aSAkinobu Mita 1517785857aSAkinobu Mita return ret; 1526b979de3SChristian Borntraeger } 1536b979de3SChristian Borntraeger 1546b979de3SChristian Borntraeger static ssize_t 1556b979de3SChristian Borntraeger vmcp_write(struct file *file, const char __user *buff, size_t count, 1566b979de3SChristian Borntraeger loff_t *ppos) 1576b979de3SChristian Borntraeger { 1586b979de3SChristian Borntraeger char *cmd; 1596b979de3SChristian Borntraeger struct vmcp_session *session; 1606b979de3SChristian Borntraeger 1616b979de3SChristian Borntraeger if (count > 240) 1626b979de3SChristian Borntraeger return -EINVAL; 16316e5c1fcSAl Viro cmd = memdup_user_nul(buff, count); 16416e5c1fcSAl Viro if (IS_ERR(cmd)) 16516e5c1fcSAl Viro return PTR_ERR(cmd); 16627e49945SJoe Perches session = file->private_data; 167d9d119f1SChristian Borntraeger if (mutex_lock_interruptible(&session->mutex)) { 168a5da866fSChristian Borntraeger kfree(cmd); 1696b979de3SChristian Borntraeger return -ERESTARTSYS; 170a5da866fSChristian Borntraeger } 1716b979de3SChristian Borntraeger if (!session->response) 1723f429842SHeiko Carstens vmcp_response_alloc(session); 1736b979de3SChristian Borntraeger if (!session->response) { 174d9d119f1SChristian Borntraeger mutex_unlock(&session->mutex); 1756b979de3SChristian Borntraeger kfree(cmd); 1766b979de3SChristian Borntraeger return -ENOMEM; 1776b979de3SChristian Borntraeger } 1786b979de3SChristian Borntraeger debug_text_event(vmcp_debug, 1, cmd); 179d9d119f1SChristian Borntraeger session->resp_size = cpcmd(cmd, session->response, session->bufsize, 1806b979de3SChristian Borntraeger &session->resp_code); 181d9d119f1SChristian Borntraeger mutex_unlock(&session->mutex); 1826b979de3SChristian Borntraeger kfree(cmd); 1836b979de3SChristian Borntraeger *ppos = 0; /* reset the file pointer after a command */ 1846b979de3SChristian Borntraeger return count; 1856b979de3SChristian Borntraeger } 1866b979de3SChristian Borntraeger 1876b979de3SChristian Borntraeger 1886b979de3SChristian Borntraeger /* 1896b979de3SChristian Borntraeger * These ioctls are available, as the semantics of the diagnose 8 call 1906b979de3SChristian Borntraeger * does not fit very well into a Linux call. Diagnose X'08' is described in 1916b979de3SChristian Borntraeger * CP Programming Services SC24-6084-00 1926b979de3SChristian Borntraeger * 1936b979de3SChristian Borntraeger * VMCP_GETCODE: gives the CP return code back to user space 1946b979de3SChristian Borntraeger * VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8 1956b979de3SChristian Borntraeger * expects adjacent pages in real storage and to make matters worse, we 1966b979de3SChristian Borntraeger * dont know the size of the response. Therefore we default to PAGESIZE and 1976b979de3SChristian Borntraeger * let userspace to change the response size, if userspace expects a bigger 1986b979de3SChristian Borntraeger * response 1996b979de3SChristian Borntraeger */ 2006b979de3SChristian Borntraeger static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 2016b979de3SChristian Borntraeger { 2026b979de3SChristian Borntraeger struct vmcp_session *session; 203307957b6SHeiko Carstens int ret = -ENOTTY; 2048f3eabe3SHeiko Carstens int __user *argp; 2056b979de3SChristian Borntraeger 20627e49945SJoe Perches session = file->private_data; 2078f3eabe3SHeiko Carstens if (is_compat_task()) 2088f3eabe3SHeiko Carstens argp = compat_ptr(arg); 2098f3eabe3SHeiko Carstens else 2108f3eabe3SHeiko Carstens argp = (int __user *)arg; 211d9d119f1SChristian Borntraeger if (mutex_lock_interruptible(&session->mutex)) 2126b979de3SChristian Borntraeger return -ERESTARTSYS; 2136b979de3SChristian Borntraeger switch (cmd) { 2146b979de3SChristian Borntraeger case VMCP_GETCODE: 215307957b6SHeiko Carstens ret = put_user(session->resp_code, argp); 216307957b6SHeiko Carstens break; 2176b979de3SChristian Borntraeger case VMCP_SETBUF: 2183f429842SHeiko Carstens vmcp_response_free(session); 219307957b6SHeiko Carstens ret = get_user(session->bufsize, argp); 220307957b6SHeiko Carstens if (ret) 221267239ccSHeiko Carstens session->bufsize = PAGE_SIZE; 222267239ccSHeiko Carstens if (!session->bufsize || get_order(session->bufsize) > 8) { 2236b979de3SChristian Borntraeger session->bufsize = PAGE_SIZE; 224307957b6SHeiko Carstens ret = -EINVAL; 2256b979de3SChristian Borntraeger } 226307957b6SHeiko Carstens break; 2276b979de3SChristian Borntraeger case VMCP_GETSIZE: 228307957b6SHeiko Carstens ret = put_user(session->resp_size, argp); 229307957b6SHeiko Carstens break; 2306b979de3SChristian Borntraeger default: 231307957b6SHeiko Carstens break; 2326b979de3SChristian Borntraeger } 233307957b6SHeiko Carstens mutex_unlock(&session->mutex); 234307957b6SHeiko Carstens return ret; 2356b979de3SChristian Borntraeger } 2366b979de3SChristian Borntraeger 237d54b1fdbSArjan van de Ven static const struct file_operations vmcp_fops = { 2386b979de3SChristian Borntraeger .owner = THIS_MODULE, 239d197e692SRobert P. J. Day .open = vmcp_open, 240d197e692SRobert P. J. Day .release = vmcp_release, 241d197e692SRobert P. J. Day .read = vmcp_read, 242d197e692SRobert P. J. Day .write = vmcp_write, 243d197e692SRobert P. J. Day .unlocked_ioctl = vmcp_ioctl, 244d9d119f1SChristian Borntraeger .compat_ioctl = vmcp_ioctl, 2456b979de3SChristian Borntraeger }; 2466b979de3SChristian Borntraeger 2476b979de3SChristian Borntraeger static struct miscdevice vmcp_dev = { 2486b979de3SChristian Borntraeger .name = "vmcp", 2496b979de3SChristian Borntraeger .minor = MISC_DYNAMIC_MINOR, 2506b979de3SChristian Borntraeger .fops = &vmcp_fops, 2516b979de3SChristian Borntraeger }; 2526b979de3SChristian Borntraeger 2536b979de3SChristian Borntraeger static int __init vmcp_init(void) 2546b979de3SChristian Borntraeger { 2556b979de3SChristian Borntraeger int ret; 2566b979de3SChristian Borntraeger 257f73a2b03SHeiko Carstens if (!MACHINE_IS_VM) 258f73a2b03SHeiko Carstens return 0; 259a44008f2SChristian Borntraeger 26066a464dbSMichael Holzheu vmcp_debug = debug_register("vmcp", 1, 1, 240); 261a44008f2SChristian Borntraeger if (!vmcp_debug) 262d9d119f1SChristian Borntraeger return -ENOMEM; 263a44008f2SChristian Borntraeger 264d9d119f1SChristian Borntraeger ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view); 265d9d119f1SChristian Borntraeger if (ret) { 266d9d119f1SChristian Borntraeger debug_unregister(vmcp_debug); 2676b979de3SChristian Borntraeger return ret; 2686b979de3SChristian Borntraeger } 269a44008f2SChristian Borntraeger 270d9d119f1SChristian Borntraeger ret = misc_register(&vmcp_dev); 271f73a2b03SHeiko Carstens if (ret) 272d9d119f1SChristian Borntraeger debug_unregister(vmcp_debug); 273d9d119f1SChristian Borntraeger return ret; 274d9d119f1SChristian Borntraeger } 275f73a2b03SHeiko Carstens device_initcall(vmcp_init); 276