1 /* 2 * S390 version 3 * Copyright IBM Corp. 1999, 2007 4 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 5 * Christian Borntraeger (cborntra@de.ibm.com), 6 */ 7 8 #define KMSG_COMPONENT "cpcmd" 9 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 10 11 #include <linux/kernel.h> 12 #include <linux/export.h> 13 #include <linux/slab.h> 14 #include <linux/spinlock.h> 15 #include <linux/stddef.h> 16 #include <linux/string.h> 17 #include <asm/diag.h> 18 #include <asm/ebcdic.h> 19 #include <asm/cpcmd.h> 20 #include <asm/io.h> 21 22 static DEFINE_SPINLOCK(cpcmd_lock); 23 static char cpcmd_buf[241]; 24 25 static int diag8_noresponse(int cmdlen) 26 { 27 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; 28 register unsigned long reg3 asm ("3") = cmdlen; 29 30 asm volatile( 31 " sam31\n" 32 " diag %1,%0,0x8\n" 33 " sam64\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 " sam31\n" 47 " diag %2,%0,0x8\n" 48 " sam64\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 * - the response buffer must reside below 2GB (if any) 61 * - __cpcmd is unlocked and therefore not SMP-safe 62 */ 63 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 64 { 65 int cmdlen; 66 int rc; 67 int response_len; 68 69 cmdlen = strlen(cmd); 70 BUG_ON(cmdlen > 240); 71 memcpy(cpcmd_buf, cmd, cmdlen); 72 ASCEBC(cpcmd_buf, cmdlen); 73 74 diag_stat_inc(DIAG_STAT_X008); 75 if (response) { 76 memset(response, 0, rlen); 77 response_len = rlen; 78 rc = diag8_response(cmdlen, response, &rlen); 79 EBCASC(response, response_len); 80 } else { 81 rc = diag8_noresponse(cmdlen); 82 } 83 if (response_code) 84 *response_code = rc; 85 return rlen; 86 } 87 EXPORT_SYMBOL(__cpcmd); 88 89 int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 90 { 91 char *lowbuf; 92 int len; 93 unsigned long flags; 94 95 if ((virt_to_phys(response) != (unsigned long) response) || 96 (((unsigned long)response + rlen) >> 31)) { 97 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA); 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