kernel/system/do_mcontext.c

   1 /* The kernel calls that are implemented in this file:
   2  *   m_type:    SYS_SETMCONTEXT
   3  *   m_type:    SYS_GETMCONTEXT
   4  *
   5  * The parameters for these kernel calls are:
   6  *     m1_i1:   PR_ENDPT        # proc endpoint doing call
   7  *     m1_p1:   PR_MEM_PTR      # pointer to mcontext structure
   8  *
   9  */
  10
  11 #include "kernel/system.h"
  12 #include <string.h>
  13 #include <assert.h>
  14 #include <machine/mcontext.h>
  15
  16 #if USE_MCONTEXT
  17 /*===========================================================================*
  18  *                            do_getmcontext                                 *
  19  *===========================================================================*/
  20 int do_getmcontext(struct proc * caller, message * m_ptr)
  21 {
  22 /* Retrieve machine context of a process */
  23
  24   register struct proc *rp;
  25   int proc_nr, r;
  26   mcontext_t mc;
  27
  28   if (! isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return(EINVAL);
  29   if (iskerneln(proc_nr)) return(EPERM);
  30   rp = proc_addr(proc_nr);
  31
  32 #if defined(__i386__)
  33   if (!proc_used_fpu(rp))
  34         return(OK);     /* No state to copy */
  35 #endif
  36
  37   /* Get the mcontext structure into our address space.  */
  38   if ((r = data_copy(m_ptr->PR_ENDPT, (vir_bytes) m_ptr->PR_CTX_PTR, KERNEL,
  39                 (vir_bytes) &mc, (phys_bytes) sizeof(mcontext_t))) != OK)
  40         return(r);
  41
  42   mc.mc_flags = 0;
  43 #if defined(__i386__)
  44   /* Copy FPU state */
  45   if (proc_used_fpu(rp)) {
  46         /* make sure that the FPU context is saved into proc structure first */
  47         save_fpu(rp);
  48         mc.mc_flags = (rp->p_misc_flags & MF_FPU_INITIALIZED) ? _MC_FPU_SAVED : 0;
  49         assert(sizeof(mc.__fpregs.__fp_reg_set) == FPU_XFP_SIZE);
  50         memcpy(&(mc.__fpregs.__fp_reg_set), rp->p_seg.fpu_state, FPU_XFP_SIZE);
  51   }
  52 #endif
  53
  54
  55   /* Copy the mcontext structure to the user's address space. */
  56   if ((r = data_copy(KERNEL, (vir_bytes) &mc, m_ptr->PR_ENDPT,
  57         (vir_bytes) m_ptr->PR_CTX_PTR,
  58         (phys_bytes) sizeof(mcontext_t))) != OK)
  59         return(r);
  60
  61   return(OK);
  62 }
  63
  64
  65 /*===========================================================================*
  66  *                            do_setmcontext                                 *
  67  *===========================================================================*/
  68 int do_setmcontext(struct proc * caller, message * m_ptr)
  69 {
  70 /* Set machine context of a process */
  71
  72   register struct proc *rp;
  73   int proc_nr, r;
  74   mcontext_t mc;
  75
  76   if (!isokendpt(m_ptr->PR_ENDPT, &proc_nr)) return(EINVAL);
  77   rp = proc_addr(proc_nr);
  78
  79   /* Get the mcontext structure into our address space.  */
  80   if ((r = data_copy(m_ptr->PR_ENDPT, (vir_bytes) m_ptr->PR_CTX_PTR, KERNEL,
  81                 (vir_bytes) &mc, (phys_bytes) sizeof(mcontext_t))) != OK)
  82         return(r);
  83
  84 #if defined(__i386__)
  85   /* Copy FPU state */
  86   if (mc.mc_flags & _MC_FPU_SAVED) {
  87         rp->p_misc_flags |= MF_FPU_INITIALIZED;
  88         assert(sizeof(mc.__fpregs.__fp_reg_set) == FPU_XFP_SIZE);
  89         memcpy(rp->p_seg.fpu_state, &(mc.__fpregs.__fp_reg_set), FPU_XFP_SIZE);
  90   } else
  91         rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
  92   /* force reloading FPU in either case */
  93   release_fpu(rp);
  94 #endif
  95
  96   return(OK);
  97 }
  98
  99 #endif