kernel/arch/s390/kernel/sclp.c

   1 /*
   2  *    Copyright IBM Corp. 2015
   3  *    Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   4  */
   5 #include <linux/kernel.h>
   6 #include <asm/ebcdic.h>
   7 #include <asm/irq.h>
   8 #include <asm/lowcore.h>
   9 #include <asm/processor.h>
  10 #include <asm/sclp.h>
  11
  12 static char _sclp_work_area[4096] __aligned(PAGE_SIZE);
  13
  14 static void _sclp_wait_int(void)
  15 {
  16         unsigned long cr0, cr0_new, psw_mask, addr;
  17         psw_t psw_ext_save, psw_wait;
  18
  19         __ctl_store(cr0, 0, 0);
  20         cr0_new = cr0 | 0x200;
  21         __ctl_load(cr0_new, 0, 0);
  22
  23         psw_ext_save = S390_lowcore.external_new_psw;
  24         psw_mask = __extract_psw();
  25         S390_lowcore.external_new_psw.mask = psw_mask;
  26         psw_wait.mask = psw_mask | PSW_MASK_EXT | PSW_MASK_WAIT;
  27         S390_lowcore.ext_int_code = 0;
  28
  29         do {
  30                 asm volatile(
  31                         "       larl    %[addr],0f\n"
  32                         "       stg     %[addr],%[psw_wait_addr]\n"
  33                         "       stg     %[addr],%[psw_ext_addr]\n"
  34                         "       lpswe   %[psw_wait]\n"
  35                         "0:\n"
  36                         : [addr] "=&d" (addr),
  37                           [psw_wait_addr] "=Q" (psw_wait.addr),
  38                           [psw_ext_addr] "=Q" (S390_lowcore.external_new_psw.addr)
  39                         : [psw_wait] "Q" (psw_wait)
  40                         : "cc", "memory");
  41         } while (S390_lowcore.ext_int_code != EXT_IRQ_SERVICE_SIG);
  42
  43         __ctl_load(cr0, 0, 0);
  44         S390_lowcore.external_new_psw = psw_ext_save;
  45 }
  46
  47 static int _sclp_servc(unsigned int cmd, char *sccb)
  48 {
  49         unsigned int cc;
  50
  51         do {
  52                 asm volatile(
  53                         "       .insn   rre,0xb2200000,%1,%2\n"
  54                         "       ipm     %0\n"
  55                         : "=d" (cc) : "d" (cmd), "a" (sccb)
  56                         : "cc", "memory");
  57                 cc >>= 28;
  58                 if (cc == 3)
  59                         return -EINVAL;
  60                 _sclp_wait_int();
  61         } while (cc != 0);
  62         return (*(unsigned short *)(sccb + 6) == 0x20) ? 0 : -EIO;
  63 }
  64
  65 static int _sclp_setup(int disable)
  66 {
  67         static unsigned char init_sccb[] = {
  68                 0x00, 0x1c,
  69                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  70                 0x00, 0x04,
  71                 0x80, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,
  72                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
  73         };
  74         unsigned int *masks;
  75         int rc;
  76
  77         memcpy(_sclp_work_area, init_sccb, 28);
  78         masks = (unsigned int *)(_sclp_work_area + 12);
  79         if (disable)
  80                 memset(masks, 0, 16);
  81         /* SCLP write mask */
  82         rc = _sclp_servc(0x00780005, _sclp_work_area);
  83         if (rc)
  84                 return rc;
  85         if ((masks[0] & masks[3]) != masks[0] ||
  86             (masks[1] & masks[2]) != masks[1])
  87                 return -EIO;
  88         return 0;
  89 }
  90
  91 static int _sclp_print(const char *str)
  92 {
  93         static unsigned char write_head[] = {
  94                 /* sccb header */
  95                 0x00, 0x52,                                     /* 0 */
  96                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,             /* 2 */
  97                 /* evbuf */
  98                 0x00, 0x4a,                                     /* 8 */
  99                 0x02, 0x00, 0x00, 0x00,                         /* 10 */
 100                 /* mdb */
 101                 0x00, 0x44,                                     /* 14 */
 102                 0x00, 0x01,                                     /* 16 */
 103                 0xd4, 0xc4, 0xc2, 0x40,                         /* 18 */
 104                 0x00, 0x00, 0x00, 0x01,                         /* 22 */
 105                 /* go */
 106                 0x00, 0x38,                                     /* 26 */
 107                 0x00, 0x01,                                     /* 28 */
 108                 0x00, 0x00, 0x00, 0x00,                         /* 30 */
 109                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 34 */
 110                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 42 */
 111                 0x00, 0x00, 0x00, 0x00,                         /* 50 */
 112                 0x00, 0x00,                                     /* 54 */
 113                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 56 */
 114                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 64 */
 115                 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 72 */
 116                 0x00, 0x00,                                     /* 80 */
 117         };
 118         static unsigned char write_mto[] = {
 119                 /* mto  */
 120                 0x00, 0x0a,                                     /* 0 */
 121                 0x00, 0x04,                                     /* 2 */
 122                 0x10, 0x00,                                     /* 4 */
 123                 0x00, 0x00, 0x00, 0x00                          /* 6 */
 124         };
 125         unsigned char *ptr, ch;
 126         unsigned int count;
 127
 128         memcpy(_sclp_work_area, write_head, sizeof(write_head));
 129         ptr = _sclp_work_area + sizeof(write_head);
 130         do {
 131                 memcpy(ptr, write_mto, sizeof(write_mto));
 132                 for (count = sizeof(write_mto); (ch = *str++) != 0; count++) {
 133                         if (ch == 0x0a)
 134                                 break;
 135                         ptr[count] = _ascebc[ch];
 136                 }
 137                 /* Update length fields in mto, mdb, evbuf and sccb */
 138                 *(unsigned short *) ptr = count;
 139                 *(unsigned short *)(_sclp_work_area + 14) += count;
 140                 *(unsigned short *)(_sclp_work_area + 8) += count;
 141                 *(unsigned short *)(_sclp_work_area + 0) += count;
 142                 ptr += count;
 143         } while (ch != 0);
 144
 145         /* SCLP write data */
 146         return _sclp_servc(0x00760005, _sclp_work_area);
 147 }
 148
 149 int _sclp_print_early(const char *str)
 150 {
 151         int rc;
 152
 153         rc = _sclp_setup(0);
 154         if (rc)
 155                 return rc;
 156         rc = _sclp_print(str);
 157         if (rc)
 158                 return rc;
 159         return _sclp_setup(1);
 160 }