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 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; 30 register unsigned long reg3 asm ("3") = cmdlen; 31 32 asm volatile( 33 " diag %1,%0,0x8\n" 34 : "+d" (reg3) : "d" (reg2) : "cc"); 35 return reg3; 36 } 37 38 static int diag8_response(int cmdlen, char *response, int *rlen) 39 { 40 unsigned long _cmdlen = cmdlen | 0x40000000L; 41 unsigned long _rlen = *rlen; 42 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; 43 register unsigned long reg3 asm ("3") = (addr_t) response; 44 register unsigned long reg4 asm ("4") = _cmdlen; 45 register unsigned long reg5 asm ("5") = _rlen; 46 47 asm volatile( 48 " diag %2,%0,0x8\n" 49 " brc 8,1f\n" 50 " agr %1,%4\n" 51 "1:\n" 52 : "+d" (reg4), "+d" (reg5) 53 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc"); 54 *rlen = reg5; 55 return reg4; 56 } 57 58 /* 59 * __cpcmd has some restrictions over cpcmd 60 * - __cpcmd is unlocked and therefore not SMP-safe 61 */ 62 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 63 { 64 int cmdlen; 65 int rc; 66 int response_len; 67 68 cmdlen = strlen(cmd); 69 BUG_ON(cmdlen > 240); 70 memcpy(cpcmd_buf, cmd, cmdlen); 71 ASCEBC(cpcmd_buf, cmdlen); 72 73 diag_stat_inc(DIAG_STAT_X008); 74 if (response) { 75 memset(response, 0, rlen); 76 response_len = rlen; 77 rc = diag8_response(cmdlen, response, &rlen); 78 EBCASC(response, response_len); 79 } else { 80 rc = diag8_noresponse(cmdlen); 81 } 82 if (response_code) 83 *response_code = rc; 84 return rlen; 85 } 86 EXPORT_SYMBOL(__cpcmd); 87 88 int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 89 { 90 unsigned long flags; 91 char *lowbuf; 92 int len; 93 94 if (is_vmalloc_or_module_addr(response)) { 95 lowbuf = kmalloc(rlen, GFP_KERNEL); 96 if (!lowbuf) { 97 pr_warn("The cpcmd kernel function failed to allocate a response buffer\n"); 98 return -ENOMEM; 99 } 100 spin_lock_irqsave(&cpcmd_lock, flags); 101 len = __cpcmd(cmd, lowbuf, rlen, response_code); 102 spin_unlock_irqrestore(&cpcmd_lock, flags); 103 memcpy(response, lowbuf, rlen); 104 kfree(lowbuf); 105 } else { 106 spin_lock_irqsave(&cpcmd_lock, flags); 107 len = __cpcmd(cmd, response, rlen, response_code); 108 spin_unlock_irqrestore(&cpcmd_lock, flags); 109 } 110 return len; 111 } 112 EXPORT_SYMBOL(cpcmd); 113