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 // This software is provided 'as-is', without any express or implied warranty.
   6 // In no event will the authors or contributors be held liable for any damages
   7 // arising from the use of this software.
   8 //
   9 // Permission is hereby granted to everyone, free of charge, to use, copy,
  10 // modify, prepare derivative works of, publish, distribute, perform,
  11 // sublicense, and/or sell copies of the Software, provided that the above
  12 // copyright notice and disclaimer of warranty be included in all copies or
  13 // substantial portions of this software.
  14
  15 #include <kern/thread.h>
  16 #include <kern/mem.h>
  17 #include <kern/pagetable.h>
  18
  19 namespace Arch {
  20         void switch_thread(Threads::Thread *dest, Threads::Thread *src)
  21         {
  22                 u64 dummy1, dummy2;
  23
  24                 if (dest->addr_space) {
  25                         assert(dest->addr_space == dest->active_addr_space);
  26
  27                         if (dest->addr_space != src->active_addr_space) {
  28                                 u64 cr3 = Mem::kvirt_to_phys(dest->addr_space->
  29                                                              page_table->toplevel);
  30                                 asm volatile("movq %0, %%cr3" : : "r" (cr3) : "memory");
  31                         }
  32                 } else {
  33                         dest->active_addr_space = src->active_addr_space;
  34                 }
  35
  36                 Priv::tss.rsp[0] = reinterpret_cast<u64>(dest);
  37
  38                 asm volatile("movq %%rsp, (%0);"
  39                              "movq %%rbp, 8(%0);"
  40                              "movb $0, 16(%0);"
  41                              "movb 16(%1), %%al;"
  42                              "cmpb $0, %%al;"
  43                              "movq (%1), %%rsp;"
  44                              "movq 8(%1), %%rbp;"
  45                              "jnz x64_new_thread;" :
  46                              "=a" (dummy1), "=c" (dummy2) :
  47                              "0" (&src->arch.rsp), "1" (&dest->arch.rsp) :
  48                              "rbx", "rdx", "rsi", "rdi",
  49                              "r8", "r9", "r10", "r11", "r12",
  50                              "r13", "r14", "r15", "memory");
  51         }
  52 }