Everyone has a TLS register.

Change-Id: Id7cdf67087aa7d5074c9c59b7e595bc391d9f146

libc/Android.mk

@@ -270,6 +270,7 @@ libc_bionic_src_files := \
     bionic/brk.cpp \
     bionic/debug_format.cpp \
     bionic/dirent.cpp \
+    bionic/__errno.c \
     bionic/eventfd.cpp \
     bionic/__fgets_chk.cpp \
     bionic/getauxval.cpp \
@@ -299,6 +300,7 @@ libc_bionic_src_files := \
     bionic/__strncpy_chk.cpp \
     bionic/strsignal.cpp \
     bionic/stubs.cpp \
+    bionic/sysconf.cpp \
     bionic/tdestroy.cpp \
     bionic/tmpfile.cpp \
     bionic/__umask_chk.cpp \
@@ -349,23 +351,6 @@ libc_upstream_netbsd_src_files := \
     upstream-netbsd/libc/string/strxfrm.c \
     upstream-netbsd/libc/unistd/killpg.c \
 
-# The following files are common, but must be compiled
-# with different C flags when building a static C library.
-#
-# The reason for this is the implementation of __get_tls()
-# that will differ between the shared and static versions
-# of the library.
-#
-# See comments in private/bionic_tls.h for more details.
-#
-# NOTE: bionic/pthread.c is added later to this list
-#       because it needs special handling on ARM, see
-#       below.
-#
-libc_static_common_src_files := \
-        bionic/__errno.c \
-        bionic/sysconf.cpp \
-
 # Architecture specific source files go here
 # =========================================================
 ifeq ($(TARGET_ARCH),arm)
@@ -545,18 +530,8 @@ ifeq ($(TARGET_ARCH),arm)
   libc_common_cflags += -fstrict-aliasing
   libc_crt_target_cflags := -mthumb-interwork
   #
-  # Define HAVE_ARM_TLS_REGISTER macro to indicate to the C library
+  # Define HAVE_32_BYTE_CACHE_LINES to indicate to the C library
-  # that it should access the hardware TLS register directly in
+  # that it should use the 32-byte version of memcpy, not
-  # private/bionic_tls.h
-  #
-  # The value must match your kernel configuration
-  #
-  ifeq ($(ARCH_ARM_HAVE_TLS_REGISTER),true)
-    libc_common_cflags += -DHAVE_ARM_TLS_REGISTER
-  endif
-  #
-  # Define HAVE_32_BYTE_CACHE_LINES to indicate to C
-  # library it should use to 32-byte version of memcpy, and not
   # the 64-byte version.
   #
   ifeq ($(ARCH_ARM_HAVE_32_BYTE_CACHE_LINES),true)
@@ -822,10 +797,10 @@ include $(BUILD_STATIC_LIBRARY)
 # ========================================================
 #
 # This is a version of the static C library that does not
-# include malloc. It's useful in situations when calling
+# include malloc. It's useful in situations when the user wants
-# the user wants to provide their own malloc implementation,
+# to provide their own malloc implementation, or wants to
-# or wants to explicitly disallow the use of the use of malloc,
+# explicitly disallow the use of the use of malloc,
-# like the dynamic loader.
+# such as in the dynamic loader.
 
 include $(CLEAR_VARS)
 

libc/private/bionic_tls.h

@@ -79,54 +79,19 @@ enum {
 #define BIONIC_TLS_SLOTS 64
 
 /* set the Thread Local Storage, must contain at least BIONIC_TLS_SLOTS pointers */
-extern void __init_tls(void**  tls, void*  thread_info);
+extern void __init_tls(void** tls, void* thread_info);
 
 /* syscall only, do not call directly */
-extern int __set_tls(void *ptr);
+extern int __set_tls(void* ptr);
 
 /* get the TLS */
-#ifdef __arm__
+#if defined(__arm__)
-/* The standard way to get the TLS is to call a kernel helper
+# define __get_tls() \
- * function (i.e. a function provided at a fixed address in a
- * "magic page" mapped in all user-space address spaces ), which
- * contains the most appropriate code path for the target device.
- *
- * However, for performance reasons, we're going to use our own
- * machine code for the system's C shared library.
- *
- * We cannot use this optimization in the static version of the
- * C library, because we don't know where the corresponding code
- * is going to run.
- */
-#  ifdef LIBC_STATIC
-
-/* Use the kernel helper in static C library. */
-  typedef volatile void* (__kernel_get_tls_t)(void);
-#    define __get_tls() (*(__kernel_get_tls_t *)0xffff0fe0)()
-
-#  else /* !LIBC_STATIC */
-/* Use optimized code path.
- * Note that HAVE_ARM_TLS_REGISTER is build-specific
- * (it must match your kernel configuration)
- */
-#    ifdef HAVE_ARM_TLS_REGISTER
- /* We can read the address directly from a coprocessor
-  * register, which avoids touching the data cache
-  * completely.
-  */
-#      define __get_tls() \
     ({ register unsigned int __val asm("r0"); \
        asm ("mrc p15, 0, r0, c13, c0, 3" : "=r"(__val) ); \
        (volatile void*)__val; })
-#    else /* !HAVE_ARM_TLS_REGISTER */
- /* The kernel provides the address of the TLS at a fixed
-  * address of the magic page too.
-  */
-#      define __get_tls() ( *((volatile void **) 0xffff0ff0) )
-#    endif
-#  endif /* !LIBC_STATIC */
 #elif defined(__mips__)
-#    define __get_tls() \
+# define __get_tls() \
     ({ register unsigned int __val asm("v1");   \
         asm (                                   \
             "   .set    push\n"                 \
@@ -136,12 +101,17 @@ extern int __set_tls(void *ptr);
             : "=r"(__val)                       \
             );                                  \
         (volatile void*)__val; })
+#elif defined(__i386__)
+# define __get_tls() \
+    ({ register void* __val; \
+       asm ("movl %%gs:0, %0" : "=r"(__val)); \
+       (volatile void*) __val; })
 #else
-extern void*  __get_tls( void );
+#error unsupported architecture
 #endif
 
 /* return the stack base and size, used by our malloc debugger */
-extern void*  __get_stack_base(int  *p_stack_size);
+extern void* __get_stack_base(int* p_stack_size);
 
 __END_DECLS
 

linker/Android.mk

@@ -23,15 +23,9 @@ LOCAL_CFLAGS += -fno-stack-protector \
         -fvisibility=hidden \
         -Wall -Wextra -Werror
 
-# We need to access Bionic private headers in the linker...
+# We need to access Bionic private headers in the linker.
 LOCAL_CFLAGS += -I$(LOCAL_PATH)/../libc/
 
-# ...one of which is <private/bionic_tls.h>, for which we
-# need HAVE_ARM_TLS_REGISTER.
-ifeq ($(TARGET_ARCH)-$(ARCH_ARM_HAVE_TLS_REGISTER),arm-true)
-    LOCAL_CFLAGS += -DHAVE_ARM_TLS_REGISTER
-endif
-
 ifeq ($(TARGET_ARCH),arm)
     LOCAL_CFLAGS += -DANDROID_ARM_LINKER
 endif