kernel/arch/x64/thread.cc

   1 // arch/x64/thread.cc -- Thread switching
   2 //
   3 // This software is copyright (c) 2006 Scott Wood <scott@buserror.net>.
   4 //
   5 // Permission is hereby granted, free of charge, to any person obtaining a copy of
   6 // this software and associated documentation files (the "Software"), to deal with
   7 // the Software without restriction, including without limitation the rights to
   8 // use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
   9 // of the Software, and to permit persons to whom the Software is furnished to do
  10 // so, subject to the following conditions:
  11 //
  12 //     * Redistributions of source code must retain the above copyright notice,
  13 //       this list of conditions and the following disclaimers.
  14 //
  15 //     * Redistributions in binary form must reproduce the above copyright notice,
  16 //       this list of conditions and the following disclaimers in the
  17 //       documentation and/or other materials provided with the distribution.
  18 //
  19 //     * The names of the Software's authors and/or contributors
  20 //       may not be used to endorse or promote products derived from
  21 //       this Software without specific prior written permission.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  24 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  25 // FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  26 // CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  27 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  28 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
  29 // SOFTWARE.
  30
  31 #include <kern/thread.h>
  32 #include <kern/mem.h>
  33 #include <kern/pagetable.h>
  34
  35 namespace Arch {
  36         void switch_thread(Threads::Thread *dest, Threads::Thread *src)
  37         {
  38                 u64 dummy1, dummy2;
  39
  40                 if (dest->addr_space) {
  41                         assert(dest->addr_space == dest->active_addr_space);
  42
  43                         if (dest->addr_space != src->active_addr_space) {
  44                                 u64 cr3 = Mem::kvirt_to_phys(dest->addr_space->
  45                                                              page_table->toplevel);
  46                                 asm volatile("movq %0, %%cr3" : : "r" (cr3) : "memory");
  47                         }
  48                 } else {
  49                         dest->active_addr_space = src->active_addr_space;
  50                 }
  51
  52                 Priv::tss.rsp[0] = reinterpret_cast<u64>(dest);
  53
  54                 asm volatile("movq %%rsp, (%0);"
  55                              "movq %%rbp, 8(%0);"
  56                              "movb $0, 16(%0);"
  57                              "movb 16(%1), %%al;"
  58                              "cmpb $0, %%al;"
  59                              "movq (%1), %%rsp;"
  60                              "movq 8(%1), %%rbp;"
  61                              "jnz x64_new_thread;" :
  62                              "=a" (dummy1), "=c" (dummy2) :
  63                              "0" (&src->arch.rsp), "1" (&dest->arch.rsp) :
  64                              "rbx", "rdx", "rsi", "rdi",
  65                              "r8", "r9", "r10", "r11", "r12",
  66                              "r13", "r14", "r15", "memory");
  67         }
  68 }