arch/x86_64-all/exec/newstackswap.c

   1 /*
   2     Copyright © 1995-2011, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: NewStackSwap() - Call a function with swapped stack, x86-64 version
   6     Lang: english
   7 */
   8
   9 #include <aros/config.h>
  10 #include <aros/debug.h>
  11 #include <exec/tasks.h>
  12 #include <proto/exec.h>
  13
  14 #define _PUSH(sp, val) *--sp = (IPTR)val
  15
  16 AROS_LH3(IPTR, NewStackSwap,
  17         AROS_LHA(struct StackSwapStruct *,  sss, A0),
  18         AROS_LHA(LONG_FUNC, entry, A1),
  19         AROS_LHA(struct StackSwapArgs *, args, A2),
  20         struct ExecBase *, SysBase, 134, Exec)
  21 {
  22     AROS_LIBFUNC_INIT
  23
  24     volatile struct Task *t = FindTask(NULL);
  25     volatile IPTR *sp = sss->stk_Pointer;
  26     volatile APTR splower = t->tc_SPLower;
  27     volatile APTR spupper = t->tc_SPUpper;
  28     IPTR ret;
  29
  30     /* Only last two arguments are put to stack in x86-64 */
  31     _PUSH(sp, args->Args[7]);
  32     _PUSH(sp, args->Args[6]);
  33
  34     if (t->tc_Flags & TF_STACKCHK)
  35     {
  36         UBYTE* startfill = sss->stk_Lower;
  37
  38         while (startfill < (UBYTE *)sp)
  39             *startfill++ = 0xE1;
  40     }
  41
  42     /*
  43      * We need to Disable() before changing limits and SP, otherwise
  44      * stack check will fail if we get interrupted in the middle of this
  45      */
  46     D(bug("[NewStackSwap] SP 0x%p, entry point 0x%p\n", sp, entry));
  47     Disable();
  48
  49     /* Change limits. The rest is done in asm below */
  50     t->tc_SPLower = sss->stk_Lower;
  51     t->tc_SPUpper = sss->stk_Upper;
  52
  53     asm volatile(
  54     /* Save original RSP */
  55     "push %%rbp\n\t"
  56     "movq %%rsp, %%rbp\n\t"
  57     /* Actually change the stack */
  58     "movq %2, %%rsp\n\t"
  59
  60     /* Enable(). It preserves all registers by convention. */
  61     "call *-168(%%rdi)\n\t"
  62
  63     /* Call our function with its arguments */
  64     "movq 0(%3), %%rdi\n\t"
  65     "movq 8(%3), %%rsi\n\t"
  66     "movq 16(%3), %%rdx\n\t"
  67     "movq 24(%3), %%rcx\n\t"
  68     "movq 32(%3), %%r8\n\t"
  69     "movq 40(%3), %%r9\n\t"
  70     "call *%1\n\t"
  71
  72     /* Disable(). Also preserves registers. */
  73     "movabsq $SysBase, %%rdi\n\t"
  74     "movq (%%rdi), %%rdi\n\t"
  75     "call *-160(%%rdi)\n\t"
  76
  77     /* Restore original RSP. Function's return value is in RAX. */
  78     "movq %%rbp, %%rsp\n\t"
  79     "popq %%rbp\n"
  80     : "=a"(ret)
  81     : "r"(entry), "r"(sp), "r"(args), "D"(SysBase)
  82     : "rsi", "rdx", "rcx", "r8", "r9", "cc");
  83
  84     /* Change limits back and return */
  85     t->tc_SPLower = splower;
  86     t->tc_SPUpper = spupper;
  87     Enable();
  88
  89     D(bug("[NewStackSwap] Returning 0x%p\n", ret));
  90     return ret;
  91
  92     AROS_LIBFUNC_EXIT
  93 } /* NewStackSwap() */