htl: Initialize later

Since htl does not actually need a stack switch, we can initialize it
like nptl is, avoiding all sorts of startup issues with ifunc.

More precisely, htl defines __pthread_initialize_minimal instead of the
elder _cthread_init_routine. We can then drop the stack switching dances.

htl/Versions

@@ -43,8 +43,6 @@ libpthread {
 
     __pthread_mutex_transfer_np;
 
-    _cthread_init_routine;
-
     cthread_detach;
     cthread_fork;
     cthread_keycreate;
@@ -168,6 +166,8 @@ libpthread {
   }
 
   GLIBC_PRIVATE {
+    __pthread_initialize_minimal;
+
     __shm_directory;
     __pthread_threads;
 

htl/libpthread_syms.a

@@ -1,6 +1,6 @@
 /* pthread initializer is weak in glibc.  It must be included if glibc
    is to start threading. */
-EXTERN(_cthread_init_routine)
+EXTERN(__pthread_initialize_minimal)
 
 /* Weak references in glibc that must be filled if glibc is to be
    thread safe.  */

hurd/Versions

@@ -143,9 +143,6 @@ libc {
     __cthread_fork; __cthread_detach;
     __pthread_getattr_np; __pthread_attr_getstack;
 
-    # variables used for detecting cthreads
-    _cthread_exit_routine; _cthread_init_routine;
-
     # cthreads functions with stubs in libc
     __cthread_keycreate; __cthread_getspecific; __cthread_setspecific;
   }

sysdeps/mach/hurd/htl/pt-sysdep.c

@@ -28,13 +28,6 @@
 
 __thread struct __pthread *___pthread_self;
 
-/* Forward.  */
-static void *init_routine (void);
-
-/* OK, the name of this variable isn't really appropriate, but I don't
-   want to change it yet.  */
-void *(*_cthread_init_routine) (void) = &init_routine;
-
 static void
 reset_pthread_total (void)
 {
@@ -45,7 +38,7 @@ reset_pthread_total (void)
 /* This function is called from the Hurd-specific startup code.  It
    should return a new stack pointer for the main thread.  The caller
    will switch to this new stack before doing anything serious.  */
-static void *
+static void
 _init_routine (void *stack)
 {
   struct __pthread *thread;
@@ -54,7 +47,7 @@ _init_routine (void *stack)
 
   if (__pthread_threads != NULL)
     /* Already initialized */
-    return 0;
+    return;
 
   /* Initialize the library.  */
   ___pthread_init ();
@@ -96,14 +89,12 @@ _init_routine (void *stack)
 
   /* Make MiG code thread aware.  */
   __mig_init (thread->stackaddr);
-
-  return thread->mcontext.sp;
 }
 
-static void *
+void
-init_routine (void)
+__pthread_initialize_minimal (void)
 {
-  return _init_routine (0);
+  _init_routine (__libc_stack_end);
 }
 
 #ifdef SHARED

sysdeps/mach/hurd/i386/init-first.c

@@ -46,9 +46,6 @@ extern int __libc_argc attribute_hidden;
 extern char **__libc_argv attribute_hidden;
 extern char **_dl_argv;
 
-extern void *(*_cthread_init_routine) (void) __attribute__ ((weak));
-void (*_cthread_exit_routine) (int status) __attribute__ ((__noreturn__));
-
 /* Things that want to be run before _hurd_init or much anything else.
    Importantly, these are called before anything tries to use malloc.  */
 DEFINE_HOOK (_hurd_preinit_hook, (void));
@@ -96,10 +93,6 @@ init1 (int argc, char *arg0, ...)
     ++envp;
   d = (void *) ++envp;
 
-  /* Initialize libpthread if linked in.  */
-  if (__pthread_initialize_minimal != NULL)
-    __pthread_initialize_minimal ();
-
   if ((void *) d == argv[0])
     /* No Hurd data block to process.  */
     return;
@@ -145,7 +138,6 @@ init (int *data)
   int argc = *data;
   char **argv = (void *) (data + 1);
   char **envp = &argv[argc + 1];
-  struct hurd_startup_data *d;
 
   /* Since the cthreads initialization code uses malloc, and the
      malloc initialization code needs to get at the environment, make
@@ -154,11 +146,13 @@ init (int *data)
      stored.  */
   __environ = envp;
 
+#ifndef SHARED
+  struct hurd_startup_data *d;
+
   while (*envp)
     ++envp;
   d = (void *) ++envp;
 
-#ifndef SHARED
   /* If we are the bootstrap task started by the kernel,
      then after the environment pointers there is no Hurd
      data block; the argument strings start there.  */
@@ -190,79 +184,27 @@ init (int *data)
   __libc_setup_tls ();
 #endif
 
-  /* After possibly switching stacks, call `init1' (above) with the user
+  /* Call `init1' (above) with the user code as the return address, and the
-     code as the return address, and the argument data immediately above
+     argument data immediately above that on the stack.  */
-     that on the stack.  */
 
-  if (&_cthread_init_routine && _cthread_init_routine)
+  int usercode;
-    {
-      /* Initialize cthreads, which will allocate us a new stack to run on.  */
-      int *newsp = (*_cthread_init_routine) ();
-      struct hurd_startup_data *od;
 
-      void switch_stacks (void);
+  void call_init1 (void);
 
-      __libc_stack_end = newsp;
+  /* The argument data is just above the stack frame we will unwind by
-
+     returning.  Mutate our own return address to run the code below.  */
-      /* Copy the argdata from the old stack to the new one.  */
+  /* The following expression would typically be written as
-      newsp = memcpy (newsp - ((char *) &d[1] - (char *) data), data,
+     ``__builtin_return_address (0)''.  But, for example, GCC 4.4.6 doesn't
-		      (char *) d - (char *) data);
+     recognize that this read operation may alias the following write
-
+     operation, and thus is free to reorder the two, clobbering the
-#ifdef SHARED
+     original return address.  */
-      /* And readjust the dynamic linker's idea of where the argument
+  usercode = *((int *) __builtin_frame_address (0) + 1);
-	 vector lives.  */
+  /* GCC 4.4.6 also wants us to force loading USERCODE already here.  */
-      assert (_dl_argv == argv);
+  asm volatile ("# %0" : : "X" (usercode));
-      _dl_argv = (void *) (newsp + 1);
+  *((void **) __builtin_frame_address (0) + 1) = &call_init1;
-#endif
+  /* Force USERCODE into %eax and &init1 into %ecx, which are not
-
+     restored by function return.  */
-      /* Set up the Hurd startup data block immediately following
+  asm volatile ("# a %0 c %1" : : "a" (usercode), "c" (&init1));
-	 the argument and environment pointers on the new stack.  */
-      od = ((void *) newsp + ((char *) d - (char *) data));
-      if ((void *) argv[0] == d)
-	/* We were started up by the kernel with arguments on the stack.
-	   There is no Hurd startup data, so zero the block.  */
-	memset (od, 0, sizeof *od);
-      else
-	/* Copy the Hurd startup data block to the new stack.  */
-	*od = *d;
-
-      /* Push the user code address on the top of the new stack.  It will
-	 be the return address for `init1'; we will jump there with NEWSP
-	 as the stack pointer.  */
-      /* The following expression would typically be written as
-	 ``__builtin_return_address (0)''.  But, for example, GCC 4.4.6 doesn't
-	 recognize that this read operation may alias the following write
-	 operation, and thus is free to reorder the two, clobbering the
-	 original return address.  */
-      *--newsp = *((int *) __builtin_frame_address (0) + 1);
-      /* GCC 4.4.6 also wants us to force loading *NEWSP already here.  */
-      asm volatile ("# %0" : : "X" (*newsp));
-      *((void **) __builtin_frame_address (0) + 1) = &switch_stacks;
-      /* Force NEWSP into %eax and &init1 into %ecx, which are not restored
-	 by function return.  */
-      asm volatile ("# a %0 c %1" : : "a" (newsp), "c" (&init1));
-    }
-  else
-    {
-      int usercode;
-
-      void call_init1 (void);
-
-      /* The argument data is just above the stack frame we will unwind by
-	 returning.  Mutate our own return address to run the code below.  */
-      /* The following expression would typically be written as
-	 ``__builtin_return_address (0)''.  But, for example, GCC 4.4.6 doesn't
-	 recognize that this read operation may alias the following write
-	 operation, and thus is free to reorder the two, clobbering the
-	 original return address.  */
-      usercode = *((int *) __builtin_frame_address (0) + 1);
-      /* GCC 4.4.6 also wants us to force loading USERCODE already here.  */
-      asm volatile ("# %0" : : "X" (usercode));
-      *((void **) __builtin_frame_address (0) + 1) = &call_init1;
-      /* Force USERCODE into %eax and &init1 into %ecx, which are not
-	 restored by function return.  */
-      asm volatile ("# a %0 c %1" : : "a" (usercode), "c" (&init1));
-    }
 
   DIAG_POP_NEEDS_COMMENT;	/* -Warray-bounds.  */
 }

sysdeps/mach/hurd/i386/libc.abilist

@@ -2333,4 +2333,3 @@ HURD_CTHREADS_0.3 __spin_lock_init F
 HURD_CTHREADS_0.3 __spin_lock_solid F
 HURD_CTHREADS_0.3 __spin_try_lock F
 HURD_CTHREADS_0.3 __spin_unlock F
-HURD_CTHREADS_0.3 _cthread_exit_routine D 0x4

sysdeps/mach/hurd/i386/libpthread.abilist

@@ -10,7 +10,6 @@ GLIBC_2.12 __pthread_spin_init F
 GLIBC_2.12 __pthread_spin_lock F
 GLIBC_2.12 __pthread_spin_trylock F
 GLIBC_2.12 __pthread_spin_unlock F
-GLIBC_2.12 _cthread_init_routine D 0x4
 GLIBC_2.12 _cthreads_flockfile F
 GLIBC_2.12 _cthreads_ftrylockfile F
 GLIBC_2.12 _cthreads_funlockfile F

sysdeps/mach/i386/sysdep.h

@@ -39,16 +39,6 @@
       envp = p;							      \
     } while (0)
 
-#define CALL_WITH_SP(fn, info, sp) \
-  do {									      \
-	void **ptr = (void **) sp;					      \
-	*--(__typeof (info) *) ptr = info;				      \
-	ptr[-1] = ptr;							      \
-	--ptr;								      \
-    asm volatile ("movl %0, %%esp; call %1" : : 			      \
-		  "g" (ptr), "m" (*(long int *) (fn)) : "%esp"); 	      \
-  } while (0)
-
 #define RETURN_TO(sp, pc, retval) \
   asm volatile ("movl %0, %%esp; jmp %*%1 # %2" \
 		: : "g" (sp), "r" (pc), "a" (retval))

sysdeps/mach/sysdep.h

@@ -62,14 +62,6 @@
 #error SNARF_ARGS not defined by sysdeps/mach/MACHINE/sysdep.h
 #endif
 
-/* Call the C function FN with no arguments,
-   on a stack starting at SP (as returned by *_cthread_init_routine).
-   You don't need to deal with FN returning; it shouldn't.  */
-#ifndef	CALL_WITH_SP
-#define CALL_WITH_SP(fn, sp)
-#error CALL_WITH_SP not defined by sysdeps/mach/MACHINE/sysdep.h
-#endif
-
 /* LOSE can be defined as the `halt' instruction or something
    similar which will cause the process to die in a characteristic
    way suggesting a bug.  */