src/system/libroot/os/arch/x86_64/tls.cpp

   1 /*
   2  * Copyright 2014, Paweł Dziepak, pdziepak@quarnos.org.
   3  * Copyright 2012, Alex Smith, alex@alex-smith.me.uk.
   4  * Distributed under the terms of the MIT License.
   5  */
   6
   7
   8 #ifndef _NO_INLINE_ASM
   9 #       define _NO_INLINE_ASM 1
  10 #endif
  11
  12 #include <atomic>
  13
  14 #include <runtime_loader/runtime_loader.h>
  15
  16 #include <support/TLS.h>
  17 #include <tls.h>
  18
  19 #include <assert.h>
  20
  21
  22 struct tls_index {
  23         unsigned long int       module;
  24         unsigned long int       offset;
  25 };
  26
  27
  28 static std::atomic<int> gNextSlot(TLS_FIRST_FREE_SLOT);
  29
  30
  31 static inline void**
  32 get_tls()
  33 {
  34         void** tls;
  35         __asm__ __volatile__ ("movq     %%fs:0, %0" : "=r" (tls));
  36         return tls;
  37 }
  38
  39
  40 int32
  41 tls_allocate()
  42 {
  43         if (gNextSlot < TLS_MAX_KEYS) {
  44                 auto next = gNextSlot++;
  45                 if (next < TLS_MAX_KEYS)
  46                         return next;
  47         }
  48
  49         return B_NO_MEMORY;
  50 }
  51
  52
  53 void*
  54 tls_get(int32 index)
  55 {
  56         return get_tls()[index];
  57 }
  58
  59
  60 void**
  61 tls_address(int32 index)
  62 {
  63         return get_tls() + index;
  64 }
  65
  66
  67 void
  68 tls_set(int32 index, void* value)
  69 {
  70         get_tls()[index] = value;
  71 }
  72
  73
  74 extern "C" void*
  75 __tls_get_addr(tls_index* ti)
  76 {
  77         return __gRuntimeLoader->get_tls_address(ti->module, ti->offset);
  78 }
  79