Revert "resolve merge"

This reverts commit 6b6ede3d15f04fe825cfa9f697507457e3640344.

1 files changed, 63 insertions, 21 deletions

diff --git a/libpthread/linuxthreads/sysdeps/i386/tls.h b/libpthread/linuxthreads/sysdeps/i386/tls.h
index 4469f0776..d79bf0779 100644
--- a/libpthread/linuxthreads/sysdeps/i386/tls.h
+++ b/libpthread/linuxthreads/sysdeps/i386/tls.h
@@ -30,7 +30,11 @@
 typedef union dtv
 {
   size_t counter;
-  void *pointer;
+  struct
+  {
+    void *val;
+    bool is_static;
+  } pointer;
 } dtv_t;
 
 
@@ -40,15 +44,28 @@ typedef struct
 			   thread descriptor used by libpthread.  */
   dtv_t *dtv;
   void *self;		/* Pointer to the thread descriptor.  */
+  int multiple_threads;
+  uintptr_t sysinfo;
 } tcbhead_t;
+
+#else /* __ASSEMBLER__ */
+# include <tcb-offsets.h>
 #endif
 
+/* We can support TLS only if the floating-stack support is available.
+   However, we want to compile in the support and test at runtime whether
+   the running kernel can support it or not.  To avoid bothering with the
+   TLS support code at all, use configure --without-tls.
+
+   We need USE_TLS to be consistently defined, for ldsodefs.h conditionals.
+   But some of the code below can cause problems in building libpthread
+   (e.g. useldt.h will defined FLOATING_STACKS when it shouldn't).  */
 
-/* We can support TLS only if the floating-stack support is available.  */
-#if defined FLOATING_STACKS && defined HAVE_TLS_SUPPORT
+#if defined HAVE_TLS_SUPPORT \
+    && (defined FLOATING_STACKS || !defined IS_IN_libpthread)
 
 /* Signal that TLS support is available.  */
-//# define USE_TLS	1
+# define USE_TLS	1
 
 # ifndef __ASSEMBLER__
 /* Get system call information.  */
@@ -97,7 +114,20 @@ typedef struct
 #   define TLS_LOAD_EBX
 #  endif
 
+#  if !defined IS_IN_libpthread && !defined DO_MODIFY_LDT
+#   include "useldt.h"		/* For the structure.  */
+#  endif
+#  if __ASSUME_LDT_WORKS > 0
+#   define TLS_DO_MODIFY_LDT_KERNEL_CHECK(doit) (doit) /* Nothing to check.  */
+#  else
+#   define TLS_DO_MODIFY_LDT_KERNEL_CHECK(doit)				      \
+  (__builtin_expect (GLRO(dl_osversion) < 131939, 0)			      \
+   ? "kernel too old for thread-local storage support\n"			      \
+   : (doit))
+#  endif
+
 #  define TLS_DO_MODIFY_LDT(descr, nr)					      \
+TLS_DO_MODIFY_LDT_KERNEL_CHECK(						      \
 ({									      \
   struct modify_ldt_ldt_s ldt_entry =					      \
     { nr, (unsigned long int) (descr), 0xfffff /* 4GB in pages */,	      \
@@ -113,8 +143,10 @@ typedef struct
 		   here.  */						      \
 		"m" (ldt_entry), TLS_EBX_ARG (1), "c" (&ldt_entry),	      \
 		"d" (sizeof (ldt_entry)));				      \
-  __builtin_expect (result, 0) != 0 ? -1 : nr * 8 + 7;			      \
-})
+  __builtin_expect (result, 0) == 0					      \
+  ? ({ __asm__ ("movw %w0, %%gs" : : "q" ((nr) * 8 + 7)); NULL; })		      \
+  : "cannot set up LDT for thread-local storage\n";			      \
+}))
 
 #  define TLS_DO_SET_THREAD_AREA(descr, secondcall)			      \
 ({									      \
@@ -135,50 +167,60 @@ typedef struct
 		   to let the compiler know that we are accessing LDT_ENTRY   \
 		   here.  */						      \
 		TLS_EBX_ARG (&ldt_entry), "m" (ldt_entry));		      \
-    __builtin_expect (result, 0) == 0 ? ldt_entry.entry_number * 8 + 3 : -1;  \
+  if (__builtin_expect (result, 0) == 0)				      \
+    __asm__ ("movw %w0, %%gs" : : "q" (ldt_entry.entry_number * 8 + 3));	      \
+  result;								      \
 })
 
 #  ifdef __ASSUME_SET_THREAD_AREA_SYSCALL
-#   define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
-  TLS_DO_SET_THREAD_AREA (descr, firstcall)
+#   define TLS_SETUP_GS_SEGMENT(descr, secondcall)			      \
+  (TLS_DO_SET_THREAD_AREA (descr, secondcall)				      \
+   ? "set_thread_area failed when setting up thread-local storage\n" : NULL)
 #  elif defined __NR_set_thread_area
 #   define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
-  ({ int __seg = TLS_DO_SET_THREAD_AREA (descr, secondcall); \
-     __seg == -1 ? TLS_DO_MODIFY_LDT (descr, 0) : __seg; })
+  (TLS_DO_SET_THREAD_AREA (descr, secondcall)				      \
+   ? TLS_DO_MODIFY_LDT (descr, 0) : NULL)
 #  else
 #   define TLS_SETUP_GS_SEGMENT(descr, secondcall) \
   TLS_DO_MODIFY_LDT ((descr), 0)
 #  endif
 
+#if defined NEED_DL_SYSINFO
+# define INIT_SYSINFO \
+  head->sysinfo = GLRO(dl_sysinfo)
+#else
+# define INIT_SYSINFO
+#endif
+
 /* Code to initially initialize the thread pointer.  This might need
    special attention since 'errno' is not yet available and if the
-   operation can cause a failure 'errno' must not be touched.  */
+   operation can cause a failure 'errno' must not be touched.
+
+   The value of this macro is null if successful, or an error string.  */
 #  define TLS_INIT_TP(descr, secondcall)				      \
   ({									      \
     void *_descr = (descr);						      \
     tcbhead_t *head = _descr;						      \
-    int __gs;								      \
 									      \
     head->tcb = _descr;							      \
     /* For now the thread descriptor is at the same address.  */	      \
     head->self = _descr;						      \
 									      \
-    __gs = TLS_SETUP_GS_SEGMENT (_descr, secondcall);			      \
-    if (__builtin_expect (__gs, 7) != -1)				      \
-      {									      \
-	__asm__ ("movw %w0, %%gs" : : "q" (__gs));				      \
-	__gs = 0;							      \
-      }									      \
-    __gs;								      \
+    INIT_SYSINFO;							      \
+    TLS_SETUP_GS_SEGMENT (_descr, secondcall);				      \
   })
 
+/* Indicate that dynamic linker shouldn't try to initialize TLS even
+   when no PT_TLS segments are found in the program and libraries
+   it is linked against.  */
+#  define TLS_INIT_TP_EXPENSIVE 1
 
 /* Return the address of the dtv for the current thread.  */
 #  define THREAD_DTV() \
   ({ struct _pthread_descr_struct *__descr;				      \
      THREAD_GETMEM (__descr, p_header.data.dtvp); })
 
-# endif	/* FLOATING_STACKS && HAVE_TLS_SUPPORT */
+# endif	/* HAVE_TLS_SUPPORT && (FLOATING_STACKS || !IS_IN_libpthread) */
 #endif /* __ASSEMBLER__ */
 
 #endif	/* tls.h */