arch/s390/lib/probes.c

   1 /*
   2  *    Common helper functions for kprobes and uprobes
   3  *
   4  *    Copyright IBM Corp. 2014
   5  */
   6
   7 #include <linux/errno.h>
   8 #include <asm/kprobes.h>
   9 #include <asm/dis.h>
  10
  11 int probe_is_prohibited_opcode(u16 *insn)
  12 {
  13         if (!is_known_insn((unsigned char *)insn))
  14                 return -EINVAL;
  15         switch (insn[0] >> 8) {
  16         case 0x0c:      /* bassm */
  17         case 0x0b:      /* bsm   */
  18         case 0x83:      /* diag  */
  19         case 0x44:      /* ex    */
  20         case 0xac:      /* stnsm */
  21         case 0xad:      /* stosm */
  22                 return -EINVAL;
  23         case 0xc6:
  24                 switch (insn[0] & 0x0f) {
  25                 case 0x00: /* exrl   */
  26                         return -EINVAL;
  27                 }
  28         }
  29         switch (insn[0]) {
  30         case 0x0101:    /* pr    */
  31         case 0xb25a:    /* bsa   */
  32         case 0xb240:    /* bakr  */
  33         case 0xb258:    /* bsg   */
  34         case 0xb218:    /* pc    */
  35         case 0xb228:    /* pt    */
  36         case 0xb98d:    /* epsw  */
  37         case 0xe560:    /* tbegin */
  38         case 0xe561:    /* tbeginc */
  39         case 0xb2f8:    /* tend  */
  40                 return -EINVAL;
  41         }
  42         return 0;
  43 }
  44
  45 int probe_get_fixup_type(u16 *insn)
  46 {
  47         /* default fixup method */
  48         int fixup = FIXUP_PSW_NORMAL;
  49
  50         switch (insn[0] >> 8) {
  51         case 0x05:      /* balr */
  52         case 0x0d:      /* basr */
  53                 fixup = FIXUP_RETURN_REGISTER;
  54                 /* if r2 = 0, no branch will be taken */
  55                 if ((insn[0] & 0x0f) == 0)
  56                         fixup |= FIXUP_BRANCH_NOT_TAKEN;
  57                 break;
  58         case 0x06:      /* bctr */
  59         case 0x07:      /* bcr  */
  60                 fixup = FIXUP_BRANCH_NOT_TAKEN;
  61                 break;
  62         case 0x45:      /* bal  */
  63         case 0x4d:      /* bas  */
  64                 fixup = FIXUP_RETURN_REGISTER;
  65                 break;
  66         case 0x47:      /* bc   */
  67         case 0x46:      /* bct  */
  68         case 0x86:      /* bxh  */
  69         case 0x87:      /* bxle */
  70                 fixup = FIXUP_BRANCH_NOT_TAKEN;
  71                 break;
  72         case 0x82:      /* lpsw */
  73                 fixup = FIXUP_NOT_REQUIRED;
  74                 break;
  75         case 0xb2:      /* lpswe */
  76                 if ((insn[0] & 0xff) == 0xb2)
  77                         fixup = FIXUP_NOT_REQUIRED;
  78                 break;
  79         case 0xa7:      /* bras */
  80                 if ((insn[0] & 0x0f) == 0x05)
  81                         fixup |= FIXUP_RETURN_REGISTER;
  82                 break;
  83         case 0xc0:
  84                 if ((insn[0] & 0x0f) == 0x05)   /* brasl */
  85                         fixup |= FIXUP_RETURN_REGISTER;
  86                 break;
  87         case 0xeb:
  88                 switch (insn[2] & 0xff) {
  89                 case 0x44: /* bxhg  */
  90                 case 0x45: /* bxleg */
  91                         fixup = FIXUP_BRANCH_NOT_TAKEN;
  92                         break;
  93                 }
  94                 break;
  95         case 0xe3:      /* bctg */
  96                 if ((insn[2] & 0xff) == 0x46)
  97                         fixup = FIXUP_BRANCH_NOT_TAKEN;
  98                 break;
  99         case 0xec:
 100                 switch (insn[2] & 0xff) {
 101                 case 0xe5: /* clgrb */
 102                 case 0xe6: /* cgrb  */
 103                 case 0xf6: /* crb   */
 104                 case 0xf7: /* clrb  */
 105                 case 0xfc: /* cgib  */
 106                 case 0xfd: /* cglib */
 107                 case 0xfe: /* cib   */
 108                 case 0xff: /* clib  */
 109                         fixup = FIXUP_BRANCH_NOT_TAKEN;
 110                         break;
 111                 }
 112                 break;
 113         }
 114         return fixup;
 115 }
 116
 117 int probe_is_insn_relative_long(u16 *insn)
 118 {
 119         /* Check if we have a RIL-b or RIL-c format instruction which
 120          * we need to modify in order to avoid instruction emulation. */
 121         switch (insn[0] >> 8) {
 122         case 0xc0:
 123                 if ((insn[0] & 0x0f) == 0x00) /* larl */
 124                         return true;
 125                 break;
 126         case 0xc4:
 127                 switch (insn[0] & 0x0f) {
 128                 case 0x02: /* llhrl  */
 129                 case 0x04: /* lghrl  */
 130                 case 0x05: /* lhrl   */
 131                 case 0x06: /* llghrl */
 132                 case 0x07: /* sthrl  */
 133                 case 0x08: /* lgrl   */
 134                 case 0x0b: /* stgrl  */
 135                 case 0x0c: /* lgfrl  */
 136                 case 0x0d: /* lrl    */
 137                 case 0x0e: /* llgfrl */
 138                 case 0x0f: /* strl   */
 139                         return true;
 140                 }
 141                 break;
 142         case 0xc6:
 143                 switch (insn[0] & 0x0f) {
 144                 case 0x02: /* pfdrl  */
 145                 case 0x04: /* cghrl  */
 146                 case 0x05: /* chrl   */
 147                 case 0x06: /* clghrl */
 148                 case 0x07: /* clhrl  */
 149                 case 0x08: /* cgrl   */
 150                 case 0x0a: /* clgrl  */
 151                 case 0x0c: /* cgfrl  */
 152                 case 0x0d: /* crl    */
 153                 case 0x0e: /* clgfrl */
 154                 case 0x0f: /* clrl   */
 155                         return true;
 156                 }
 157                 break;
 158         }
 159         return false;
 160 }