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/system.h> 22#include <asm/io.h> 23 24static DEFINE_SPINLOCK(cpcmd_lock); 25static char cpcmd_buf[241]; 26 27static 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#ifndef CONFIG_64BIT 34 " diag %1,%0,0x8\n" 35#else /* CONFIG_64BIT */ 36 " sam31\n" 37 " diag %1,%0,0x8\n" 38 " sam64\n" 39#endif /* CONFIG_64BIT */ 40 : "+d" (reg3) : "d" (reg2) : "cc"); 41 return reg3; 42} 43 44static int diag8_response(int cmdlen, char *response, int *rlen) 45{ 46 register unsigned long reg2 asm ("2") = (addr_t) cpcmd_buf; 47 register unsigned long reg3 asm ("3") = (addr_t) response; 48 register unsigned long reg4 asm ("4") = cmdlen | 0x40000000L; 49 register unsigned long reg5 asm ("5") = *rlen; 50 51 asm volatile( 52#ifndef CONFIG_64BIT 53 " diag %2,%0,0x8\n" 54 " brc 8,1f\n" 55 " ar %1,%4\n" 56#else /* CONFIG_64BIT */ 57 " sam31\n" 58 " diag %2,%0,0x8\n" 59 " sam64\n" 60 " brc 8,1f\n" 61 " agr %1,%4\n" 62#endif /* CONFIG_64BIT */ 63 "1:\n" 64 : "+d" (reg4), "+d" (reg5) 65 : "d" (reg2), "d" (reg3), "d" (*rlen) : "cc"); 66 *rlen = reg5; 67 return reg4; 68} 69 70/* 71 * __cpcmd has some restrictions over cpcmd 72 * - the response buffer must reside below 2GB (if any) 73 * - __cpcmd is unlocked and therefore not SMP-safe 74 */ 75int __cpcmd(const char *cmd, char *response, int rlen, int *response_code) 76{ 77 int cmdlen; 78 int rc; 79 int response_len; 80 81 cmdlen = strlen(cmd); 82 BUG_ON(cmdlen > 240); 83 memcpy(cpcmd_buf, cmd, cmdlen); 84 ASCEBC(cpcmd_buf, cmdlen); 85 86 if (response) { 87 memset(response, 0, rlen); 88 response_len = rlen; 89 rc = diag8_response(cmdlen, response, &rlen); 90 EBCASC(response, response_len); 91 } else { 92 rc = diag8_noresponse(cmdlen); 93 } 94 if (response_code) 95 *response_code = rc; 96 return rlen; 97} 98EXPORT_SYMBOL(__cpcmd); 99 100int cpcmd(const char *cmd, char *response, int rlen, int *response_code) 101{ 102 char *lowbuf; 103 int len; 104 unsigned long flags; 105 106 if ((virt_to_phys(response) != (unsigned long) response) || 107 (((unsigned long)response + rlen) >> 31)) { 108 lowbuf = kmalloc(rlen, GFP_KERNEL | GFP_DMA); 109 if (!lowbuf) { 110 pr_warning("The cpcmd kernel function failed to " 111 "allocate a response buffer\n"); 112 return -ENOMEM; 113 } 114 spin_lock_irqsave(&cpcmd_lock, flags); 115 len = __cpcmd(cmd, lowbuf, rlen, response_code); 116 spin_unlock_irqrestore(&cpcmd_lock, flags); 117 memcpy(response, lowbuf, rlen); 118 kfree(lowbuf); 119 } else { 120 spin_lock_irqsave(&cpcmd_lock, flags); 121 len = __cpcmd(cmd, response, rlen, response_code); 122 spin_unlock_irqrestore(&cpcmd_lock, flags); 123 } 124 return len; 125} 126EXPORT_SYMBOL(cpcmd); 127