1 /* 2 * arch/s390/kernel/cpcmd.c 3 * 4 * S390 version 5 * Copyright IBM Corp. 1999,2007 6 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 7 * Christian Borntraeger (cborntra@de.ibm.com), 8 */ 9 10 #define KMSG_COMPONENT "cpcmd" 11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt 12 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/stddef.h> 18 #include <linux/string.h> 19 #include <asm/ebcdic.h> 20 #include <asm/cpcmd.h> 21 #include <asm/io.h> 22 23 static DEFINE_SPINLOCK(cpcmd_lock); 24 static char cpcmd_buf[241]; 25 26 static int diag8_noresponse(int cmdlen) 27 { 28 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; 29 register unsigned long reg3 asm ("3") = cmdlen; 30 31 asm volatile( 32 #ifndef CONFIG_64BIT 33 " diag %1,%0,0x8\n" 34 #else /* CONFIG_64BIT */ 35 " sam31\n" 36 " diag %1,%0,0x8\n" 37 " sam64\n" 38 #endif /* CONFIG_64BIT */ 39 : "+d" (reg3) : "d" (reg2) : "cc"); 40 return reg3; 41 } 42 43 static int diag8_response(int cmdlen, char *response, int *rlen) 44 { 45 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; 46 register unsigned long reg3 asm ("3") = (addr_t) response; 47 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L; 48 register unsigned long reg5 asm ("5") = *rlen; 49 50 asm volatile( 51 #ifndef CONFIG_64BIT 52 " diag %2,%0,0x8\n" 53 " brc 8,1f\n" 54 " ar %1,%4\n" 55 #else /* CONFIG_64BIT */ 56 " sam31\n" 57 " diag %2,%0,0x8\n" 58 " sam64\n" 59 " brc 8,1f\n" 60 " agr %1,%4\n" 61 #endif /* CONFIG_64BIT */ 62 "1:\n" 63 : "+d" (reg4), "+d" (reg5) 64 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc"); 65 *rlen = reg5; 66 return reg4; 67 } 68 69 /* 70 * __cpcmd has some restrictions over cpcmd 71 * - the response buffer must reside below 2GB (if any) 72 * - __cpcmd is unlocked and therefore not SMP-safe 73 */ 74 int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 75 { 76 int cmdlen; 77 int rc; 78 int response_len; 79 80 cmdlen = strlen(cmd); 81 BUG_ON(cmdlen > 240); 82 memcpy(cpcmd_buf, cmd, cmdlen); 83 ASCEBC(cpcmd_buf, cmdlen); 84 85 if (response) { 86 memset(response, 0, rlen); 87 response_len = rlen; 88 rc = diag8_response(cmdlen, response, &rlen); 89 EBCASC(response, response_len); 90 } else { 91 rc = diag8_noresponse(cmdlen); 92 } 93 if (response_code) 94 *response_code = rc; 95 return rlen; 96 } 97 EXPORT_SYMBOL(__cpcmd); 98 99 int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 100 { 101 char *lowbuf; 102 int len; 103 unsigned long flags; 104 105 if ((virt_to_phys(response) != (unsigned long) response) || 106 (((unsigned long)response + rlen) >> 31)) { 107 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA); 108 if (!lowbuf) { 109 pr_warning("The cpcmd kernel function failed to " 110 "allocate a response buffer\n"); 111 return -ENOMEM; 112 } 113 spin_lock_irqsave(&cpcmd_lock, flags); 114 len = __cpcmd(cmd, lowbuf, rlen, response_code); 115 spin_unlock_irqrestore(&cpcmd_lock, flags); 116 memcpy(response, lowbuf, rlen); 117 kfree(lowbuf); 118 } else { 119 spin_lock_irqsave(&cpcmd_lock, flags); 120 len = __cpcmd(cmd, response, rlen, response_code); 121 spin_unlock_irqrestore(&cpcmd_lock, flags); 122 } 123 return len; 124 } 125 EXPORT_SYMBOL(cpcmd); 126