src/thread/arm/__set_thread_area.c

   1 #include <stdint.h>
   2 #include <elf.h>
   3 #include "pthread_impl.h"
   4 #include "libc.h"
   5
   6 #define HWCAP_TLS (1 << 15)
   7
   8 extern const unsigned char __attribute__((__visibility__("hidden")))
   9         __a_barrier_oldkuser[], __a_barrier_v6[], __a_barrier_v7[],
  10         __a_cas_v6[], __a_cas_v7[],
  11         __a_gettp_cp15[];
  12
  13 #define __a_barrier_kuser 0xffff0fa0
  14 #define __a_barrier_oldkuser (uintptr_t)__a_barrier_oldkuser
  15 #define __a_barrier_v6 (uintptr_t)__a_barrier_v6
  16 #define __a_barrier_v7 (uintptr_t)__a_barrier_v7
  17
  18 #define __a_cas_kuser 0xffff0fc0
  19 #define __a_cas_v6 (uintptr_t)__a_cas_v6
  20 #define __a_cas_v7 (uintptr_t)__a_cas_v7
  21
  22 #define __a_gettp_kuser 0xffff0fe0
  23 #define __a_gettp_cp15 (uintptr_t)__a_gettp_cp15
  24
  25 extern uintptr_t __attribute__((__visibility__("hidden")))
  26         __a_barrier_ptr, __a_cas_ptr, __a_gettp_ptr;
  27
  28 int __set_thread_area(void *p)
  29 {
  30 #if !__ARM_ARCH_7A__ && !__ARM_ARCH_7R__ && __ARM_ARCH < 7
  31         if (__hwcap & HWCAP_TLS) {
  32                 size_t *aux;
  33                 __a_cas_ptr = __a_cas_v7;
  34                 __a_barrier_ptr = __a_barrier_v7;
  35                 for (aux=libc.auxv; *aux; aux+=2) {
  36                         if (*aux != AT_PLATFORM) continue;
  37                         const char *s = (void *)aux[1];
  38                         if (s[0]!='v' || s[1]!='6' || s[2]-'0'<10u) break;
  39                         __a_cas_ptr = __a_cas_v6;
  40                         __a_barrier_ptr = __a_barrier_v6;
  41                         break;
  42                 }
  43         } else {
  44                 int ver = *(int *)0xffff0ffc;
  45                 __a_gettp_ptr = __a_gettp_kuser;
  46                 __a_cas_ptr = __a_cas_kuser;
  47                 __a_barrier_ptr = __a_barrier_kuser;
  48                 if (ver < 2) a_crash();
  49                 if (ver < 3) __a_barrier_ptr = __a_barrier_oldkuser;
  50         }
  51 #endif
  52         return __syscall(0xf0005, p);
  53 }