nptl: Eliminate the __static_tls_size, __static_tls_align_m1 variables

Use the  __nptl_tls_static_size_for_stack inline function instead,
and the GLRO (dl_tls_static_align) value directly.

The computation of GLRO (dl_tls_static_align)  in
_dl_determine_tlsoffset ensures that the alignment is at least
TLS_TCB_ALIGN, which at least STACK_ALIGN (see allocate_stack).
Therefore, the additional rounding-up step is removed.

ALso move the initialization of the default stack size from
__pthread_initialize_minimal_internal to __pthread_early_init.
This introduces an extra system call during single-threaded startup,
but this simplifies the initialization sequence.  No locking is
needed around the writes to __default_pthread_attr because the
process is single-threaded at this point.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

1 files changed, 28 insertions, 0 deletions

diff --git a/sysdeps/nptl/pthread_early_init.h b/sysdeps/nptl/pthread_early_init.h
index 2d15303dd9..5b49ce39c2 100644
--- a/sysdeps/nptl/pthread_early_init.h
+++ b/sysdeps/nptl/pthread_early_init.h
@@ -19,12 +19,40 @@
 #ifndef _PTHREAD_EARLY_INIT_H
 #define _PTHREAD_EARLY_INIT_H 1
 
+#include <nptl/nptl-stack.h>
 #include <nptl/pthreadP.h>
 #include <pthread_mutex_conf.h>
+#include <sys/resource.h>
 
 static inline void
 __pthread_early_init (void)
 {
+  /* Determine the default allowed stack size.  This is the size used
+     in case the user does not specify one.  */
+  struct rlimit limit;
+  if (__getrlimit (RLIMIT_STACK, &limit) != 0
+      || limit.rlim_cur == RLIM_INFINITY)
+    /* The system limit is not usable.  Use an architecture-specific
+       default.  */
+    limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
+  else if (limit.rlim_cur < PTHREAD_STACK_MIN)
+    /* The system limit is unusably small.
+       Use the minimal size acceptable.  */
+    limit.rlim_cur = PTHREAD_STACK_MIN;
+
+  /* Make sure it meets the minimum size that allocate_stack
+     (allocatestack.c) will demand, which depends on the page size.  */
+  const uintptr_t pagesz = GLRO(dl_pagesize);
+  const size_t minstack = (pagesz + __nptl_tls_static_size_for_stack ()
+                           + MINIMAL_REST_STACK);
+  if (limit.rlim_cur < minstack)
+    limit.rlim_cur = minstack;
+
+  /* Round the resource limit up to page size.  */
+  limit.rlim_cur = ALIGN_UP (limit.rlim_cur, pagesz);
+  __default_pthread_attr.internal.stacksize = limit.rlim_cur;
+  __default_pthread_attr.internal.guardsize = GLRO (dl_pagesize);
+
 #if HAVE_TUNABLES
   __pthread_tunables_init ();
 #endif