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 condition:
  11 //
  12 // The above copyright notice and this permission notice shall be
  13 // included in all copies or substantial portions of the Software.
  14 //
  15 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  17 // FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
  18 // CONTRIBUTORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
  21 // SOFTWARE.
  22
  23 #include <kern/thread.h>
  24 #include <kern/mem.h>
  25 #include <kern/pagetable.h>
  26
  27 namespace Arch {
  28         void switch_thread(Threads::Thread *dest, Threads::Thread *src)
  29         {
  30                 u64 dummy1, dummy2;
  31
  32                 if (dest->addr_space) {
  33                         assert(dest->addr_space == dest->active_addr_space);
  34
  35                         if (dest->addr_space != src->active_addr_space) {
  36                                 u64 cr3 = Mem::kvirt_to_phys(dest->addr_space->
  37                                                              page_table->toplevel);
  38                                 asm volatile("movq %0, %%cr3" : : "r" (cr3) : "memory");
  39                         }
  40                 } else {
  41                         dest->active_addr_space = src->active_addr_space;
  42                 }
  43
  44                 Priv::tss.rsp[0] = reinterpret_cast<u64>(dest);
  45
  46                 asm volatile("movq %%rsp, (%0);"
  47                              "movq %%rbp, 8(%0);"
  48                              "movb $0, 16(%0);"
  49                              "movb 16(%1), %%al;"
  50                              "cmpb $0, %%al;"
  51                              "movq (%1), %%rsp;"
  52                              "movq 8(%1), %%rbp;"
  53                              "jnz x64_new_thread;" :
  54                              "=a" (dummy1), "=c" (dummy2) :
  55                              "0" (&src->arch.rsp), "1" (&dest->arch.rsp) :
  56                              "rbx", "rdx", "rsi", "rdi",
  57                              "r8", "r9", "r10", "r11", "r12",
  58                              "r13", "r14", "r15", "memory");
  59         }
  60 }