1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * S390 version 4 * Copyright IBM Corp. 1999, 2007 5 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 6 * Christian Borntraeger (cborntra@de.ibm.com), 7 */ 8 9 #define KMSG_COMPONENT "cpcmd" 10 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 11 12 #include <linux/kernel.h> 13 #include <linux/export.h> 14 #include <linux/slab.h> 15 #include <linux/spinlock.h> 16 #include <linux/stddef.h> 17 #include <linux/string.h> 18 #include <linux/mm.h> 19 #include <asm/diag.h> 20 #include <asm/ebcdic.h> 21 #include <asm/cpcmd.h> 22 #include <asm/io.h> 23 24 static DEFINE_SPINLOCK(cpcmd_lock); 25 static char cpcmd_buf[241]; 26 27 static int diag8_noresponse(int cmdlen) 28 { 29 asm volatile( 30 " diag %[rx],%[ry],0x8\n" 31 : [ry] "+&d" (cmdlen) 32 : [rx] "d" (__pa(cpcmd_buf)) 33 : "cc"); 34 return cmdlen; 35 } 36 37 static int diag8_response(int cmdlen, char *response, int *rlen) 38 { 39 union register_pair rx, ry; 40 int cc; 41 42 rx.even = __pa(cpcmd_buf); 43 rx.odd = __pa(response); 44 ry.even = cmdlen | 0x40000000L; 45 ry.odd = *rlen; 46 asm volatile( 47 " diag %[rx],%[ry],0x8\n" 48 " ipm %[cc]\n" 49 " srl %[cc],28\n" 50 : [cc] "=&d" (cc), [ry] "+&d" (ry.pair) 51 : [rx] "d" (rx.pair) 52 : "cc"); 53 if (cc) 54 *rlen += ry.odd; 55 else 56 *rlen = ry.odd; 57 return ry.even; 58 } 59 60 /* 61 * __cpcmd has some restrictions over cpcmd 62 * - __cpcmd is unlocked and therefore not SMP-safe 63 */ 64 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 65 { 66 int cmdlen; 67 int rc; 68 int response_len; 69 70 cmdlen = strlen(cmd); 71 BUG_ON(cmdlen > 240); 72 memcpy(cpcmd_buf, cmd, cmdlen); 73 ASCEBC(cpcmd_buf, cmdlen); 74 75 diag_stat_inc(DIAG_STAT_X008); 76 if (response) { 77 memset(response, 0, rlen); 78 response_len = rlen; 79 rc = diag8_response(cmdlen, response, &rlen); 80 EBCASC(response, response_len); 81 } else { 82 rc = diag8_noresponse(cmdlen); 83 } 84 if (response_code) 85 *response_code = rc; 86 return rlen; 87 } 88 EXPORT_SYMBOL(__cpcmd); 89 90 int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 91 { 92 unsigned long flags; 93 char *lowbuf; 94 int len; 95 96 if (is_vmalloc_or_module_addr(response)) { 97 lowbuf = kmalloc(rlen, GFP_KERNEL); 98 if (!lowbuf) { 99 pr_warn("The cpcmd kernel function failed to allocate a response buffer\n"); 100 return -ENOMEM; 101 } 102 spin_lock_irqsave(&cpcmd_lock, flags); 103 len = __cpcmd(cmd, lowbuf, rlen, response_code); 104 spin_unlock_irqrestore(&cpcmd_lock, flags); 105 memcpy(response, lowbuf, rlen); 106 kfree(lowbuf); 107 } else { 108 spin_lock_irqsave(&cpcmd_lock, flags); 109 len = __cpcmd(cmd, response, rlen, response_code); 110 spin_unlock_irqrestore(&cpcmd_lock, flags); 111 } 112 return len; 113 } 114 EXPORT_SYMBOL(cpcmd); 115