arch/x86_64-all/kernel/createcontext.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: Create an empty usable CPU context, x86_64 version.
   6     Lang: english
   7 */
   8
   9 #include <aros/kernel.h>
  10 #include <aros/libcall.h>
  11
  12 #include <kernel_base.h>
  13 #include <kernel_objects.h>
  14
  15 AROS_LH0(void *, KrnCreateContext,
  16           struct KernelBase *, KernelBase, 18, Kernel)
  17
  18 {
  19     AROS_LIBFUNC_INIT
  20
  21     struct ExceptionContext *ctx;
  22
  23     /*
  24      * Allocate common data block and FPU data block in one chunk.
  25      * On native ports AROSCPUContext can be simply #define'd to ExceptionContext,
  26      * so we refer to struct AROSCPUContext only for size calculation.
  27      * Below we rely on the fact that returned address is 16-byte-aligned.
  28      * MemChunk is two IPTRs, so this is true.
  29      */
  30     ctx = krnAllocCPUContext();
  31     if (ctx)
  32     {
  33         UBYTE current_xmm[512+15];
  34         UBYTE *curr = (UBYTE *)AROS_ROUNDUP2((IPTR)current_xmm, 16);
  35         IPTR fpdata = (IPTR)ctx + AROS_ROUNDUP2(sizeof(struct AROSCPUContext), 16);
  36
  37         ctx->Flags  = ECF_FPX;
  38         ctx->FXData = (struct FPXContext *)fpdata;
  39
  40         /* Set up default values for some registers */
  41         ctx->rflags = 0x3202;
  42
  43 /* These definitions may come from machine-specific kernel_cpu.h */
  44 #ifdef USER_CS
  45         ctx->Flags |= ECF_SEGMENTS;
  46         ctx->cs     = USER_CS;
  47         ctx->ds     = USER_DS;
  48         ctx->es     = USER_DS;
  49         ctx->fs     = USER_DS;
  50         ctx->gs     = USER_GS;
  51         ctx->ss     = USER_DS;
  52 #endif
  53
  54         /* Init SSE context */
  55         asm volatile(
  56             "   fxsave (%0)\n"
  57             "   fninit\n"
  58             "   fwait\n"
  59             "   fxsave (%1)\n"
  60             "   fxrstor (%0)\n"
  61             ::"r"(curr), "r"(ctx->FXData):"cc");
  62     }
  63
  64     return ctx;
  65
  66     AROS_LIBFUNC_EXIT
  67 }