arch/s390/lib/probes.c

   1 /*
   2  *    Common helper functions for kprobes and uprobes
   3  *
   4  *    Copyright IBM Corp. 2014
   5  */
   6
   7 #include <asm/kprobes.h>
   8 #include <asm/dis.h>
   9
  10 int probe_is_prohibited_opcode(u16 *insn)
  11 {
  12         if (!is_known_insn((unsigned char *)insn))
  13                 return -EINVAL;
  14         switch (insn[0] >> 8) {
  15         case 0x0c:      /* bassm */
  16         case 0x0b:      /* bsm   */
  17         case 0x83:      /* diag  */
  18         case 0x44:      /* ex    */
  19         case 0xac:      /* stnsm */
  20         case 0xad:      /* stosm */
  21                 return -EINVAL;
  22         case 0xc6:
  23                 switch (insn[0] & 0x0f) {
  24                 case 0x00: /* exrl   */
  25                         return -EINVAL;
  26                 }
  27         }
  28         switch (insn[0]) {
  29         case 0x0101:    /* pr    */
  30         case 0xb25a:    /* bsa   */
  31         case 0xb240:    /* bakr  */
  32         case 0xb258:    /* bsg   */
  33         case 0xb218:    /* pc    */
  34         case 0xb228:    /* pt    */
  35         case 0xb98d:    /* epsw  */
  36         case 0xe560:    /* tbegin */
  37         case 0xe561:    /* tbeginc */
  38         case 0xb2f8:    /* tend  */
  39                 return -EINVAL;
  40         }
  41         return 0;
  42 }
  43
  44 int probe_get_fixup_type(u16 *insn)
  45 {
  46         /* default fixup method */
  47         int fixup = FIXUP_PSW_NORMAL;
  48
  49         switch (insn[0] >> 8) {
  50         case 0x05:      /* balr */
  51         case 0x0d:      /* basr */
  52                 fixup = FIXUP_RETURN_REGISTER;
  53                 /* if r2 = 0, no branch will be taken */
  54                 if ((insn[0] & 0x0f) == 0)
  55                         fixup |= FIXUP_BRANCH_NOT_TAKEN;
  56                 break;
  57         case 0x06:      /* bctr */
  58         case 0x07:      /* bcr  */
  59                 fixup = FIXUP_BRANCH_NOT_TAKEN;
  60                 break;
  61         case 0x45:      /* bal  */
  62         case 0x4d:      /* bas  */
  63                 fixup = FIXUP_RETURN_REGISTER;
  64                 break;
  65         case 0x47:      /* bc   */
  66         case 0x46:      /* bct  */
  67         case 0x86:      /* bxh  */
  68         case 0x87:      /* bxle */
  69                 fixup = FIXUP_BRANCH_NOT_TAKEN;
  70                 break;
  71         case 0x82:      /* lpsw */
  72                 fixup = FIXUP_NOT_REQUIRED;
  73                 break;
  74         case 0xb2:      /* lpswe */
  75                 if ((insn[0] & 0xff) == 0xb2)
  76                         fixup = FIXUP_NOT_REQUIRED;
  77                 break;
  78         case 0xa7:      /* bras */
  79                 if ((insn[0] & 0x0f) == 0x05)
  80                         fixup |= FIXUP_RETURN_REGISTER;
  81                 break;
  82         case 0xc0:
  83                 if ((insn[0] & 0x0f) == 0x05)   /* brasl */
  84                         fixup |= FIXUP_RETURN_REGISTER;
  85                 break;
  86         case 0xeb:
  87                 switch (insn[2] & 0xff) {
  88                 case 0x44: /* bxhg  */
  89                 case 0x45: /* bxleg */
  90                         fixup = FIXUP_BRANCH_NOT_TAKEN;
  91                         break;
  92                 }
  93                 break;
  94         case 0xe3:      /* bctg */
  95                 if ((insn[2] & 0xff) == 0x46)
  96                         fixup = FIXUP_BRANCH_NOT_TAKEN;
  97                 break;
  98         case 0xec:
  99                 switch (insn[2] & 0xff) {
 100                 case 0xe5: /* clgrb */
 101                 case 0xe6: /* cgrb  */
 102                 case 0xf6: /* crb   */
 103                 case 0xf7: /* clrb  */
 104                 case 0xfc: /* cgib  */
 105                 case 0xfd: /* cglib */
 106                 case 0xfe: /* cib   */
 107                 case 0xff: /* clib  */
 108                         fixup = FIXUP_BRANCH_NOT_TAKEN;
 109                         break;
 110                 }
 111                 break;
 112         }
 113         return fixup;
 114 }
 115
 116 int probe_is_insn_relative_long(u16 *insn)
 117 {
 118         /* Check if we have a RIL-b or RIL-c format instruction which
 119          * we need to modify in order to avoid instruction emulation. */
 120         switch (insn[0] >> 8) {
 121         case 0xc0:
 122                 if ((insn[0] & 0x0f) == 0x00) /* larl */
 123                         return true;
 124                 break;
 125         case 0xc4:
 126                 switch (insn[0] & 0x0f) {
 127                 case 0x02: /* llhrl  */
 128                 case 0x04: /* lghrl  */
 129                 case 0x05: /* lhrl   */
 130                 case 0x06: /* llghrl */
 131                 case 0x07: /* sthrl  */
 132                 case 0x08: /* lgrl   */
 133                 case 0x0b: /* stgrl  */
 134                 case 0x0c: /* lgfrl  */
 135                 case 0x0d: /* lrl    */
 136                 case 0x0e: /* llgfrl */
 137                 case 0x0f: /* strl   */
 138                         return true;
 139                 }
 140                 break;
 141         case 0xc6:
 142                 switch (insn[0] & 0x0f) {
 143                 case 0x02: /* pfdrl  */
 144                 case 0x04: /* cghrl  */
 145                 case 0x05: /* chrl   */
 146                 case 0x06: /* clghrl */
 147                 case 0x07: /* clhrl  */
 148                 case 0x08: /* cgrl   */
 149                 case 0x0a: /* clgrl  */
 150                 case 0x0c: /* cgfrl  */
 151                 case 0x0d: /* crl    */
 152                 case 0x0e: /* clgfrl */
 153                 case 0x0f: /* clrl   */
 154                         return true;
 155                 }
 156                 break;
 157         }
 158         return false;
 159 }