minix/kernel/arch/i386/breakpoints.c

   1 #include "kernel/kernel.h"
   2 #include "arch_proto.h"
   3
   4 #include "debugreg.h"
   5
   6 int breakpoint_set(phys_bytes linaddr, int bp, const int flags)
   7 {
   8         unsigned long dr7, dr7flags;
   9
  10         if (bp >= BREAKPOINT_COUNT)
  11                 return EINVAL;
  12
  13         /* convert flags */
  14         dr7flags = 0;
  15         switch (flags & BREAKPOINT_FLAG_RW_MASK) {
  16                 case BREAKPOINT_FLAG_RW_EXEC:  dr7flags |= DR7_RW_EXEC(bp);  break;
  17                 case BREAKPOINT_FLAG_RW_WRITE: dr7flags |= DR7_RW_WRITE(bp); break;
  18                 case BREAKPOINT_FLAG_RW_RW:    dr7flags |= DR7_RW_RW(bp);    break;
  19                 default: return EINVAL;
  20         }
  21         switch (flags & BREAKPOINT_FLAG_LEN_MASK) {
  22                 case BREAKPOINT_FLAG_LEN_1: dr7flags |= DR7_LN_1(bp); break;
  23                 case BREAKPOINT_FLAG_LEN_2: dr7flags |= DR7_LN_2(bp); break;
  24                 case BREAKPOINT_FLAG_LEN_4: dr7flags |= DR7_LN_4(bp); break;
  25                 default: return EINVAL;
  26         }
  27         switch (flags & BREAKPOINT_FLAG_MODE_MASK) {
  28                 case BREAKPOINT_FLAG_MODE_OFF: break;
  29                 case BREAKPOINT_FLAG_MODE_LOCAL: dr7flags |= DR7_L(bp); break;
  30                 case BREAKPOINT_FLAG_MODE_GLOBAL: dr7flags |= DR7_G(bp); break;
  31                 default: return EINVAL;
  32         }
  33
  34         /* disable breakpoint before setting address */
  35         dr7 = st_dr7();
  36         dr7 &= ~(DR7_L(bp) | DR7_G(bp) | DR7_RW_MASK(bp) | DR7_LN_MASK(bp));
  37         ld_dr7(dr7);
  38
  39         /* need to set new breakpoint? */
  40         if ((flags & BREAKPOINT_FLAG_MODE_MASK) == BREAKPOINT_FLAG_MODE_OFF)
  41                 return 0;
  42
  43         /* set breakpoint address */
  44         switch (bp) {
  45                 case 0: ld_dr0(linaddr); break;
  46                 case 1: ld_dr1(linaddr); break;
  47                 case 2: ld_dr2(linaddr); break;
  48                 case 3: ld_dr3(linaddr); break;
  49                 default: panic("%s:%d: invalid breakpoint index", __FILE__,  __LINE__);
  50         }
  51
  52         /* set new flags */
  53         dr7 |= dr7flags;
  54         ld_dr7(dr7);
  55         return 0;
  56 }
  57