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