[COMMITTED] Clean up stack-coloring macros.
diff mbox

Message ID 20140621025400.0EAFA2C39AE@topped-with-meat.com
State New
Headers show

Commit Message

Roland McGrath June 21, 2014, 2:53 a.m. UTC
Adding -D switches in sysdeps/.../Makefile is (almost?) always the wrong
thing to do.  It creates an implicit dependency not tracked by Make, and it
is usually not typo-proof and/or -Wundef-friendly.  This change gets rid of
-Wundef warnings for these two macros.

Verified on x86_64-linux-gnu and i686-linux-gnu that no code changes
(except some assert line numbers).

	* nptl/allocatestack.c: Include <stack-aliasing.h>.
	* nptl/stack-aliasing.h: New file.
	* sysdeps/i386/i686/stack-aliasing.h: New file.
	* sysdeps/i386/i686/nptl/Makefile: File removed.
	* sysdeps/x86_64/stack-aliasing.h: New file.
	* sysdeps/x86_64/nptl/Makefile
	(CFLAGS-pthread_create.c): Variable removed.

Patch
diff mbox

--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -30,6 +30,7 @@ 
 #include <list.h>
 #include <lowlevellock.h>
 #include <kernel-features.h>
+#include <stack-aliasing.h>
 
 
 #ifndef NEED_SEPARATE_REGISTER_STACK
--- /dev/null
+++ b/nptl/stack-aliasing.h
@@ -0,0 +1,29 @@ 
+/* Define macros for stack address aliasing issues for NPTL.  Stub version.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This is a number of bytes (less than a page) by which to "color" the
+   starting stack address of new threads.  This number is multiplied by the
+   number of threads created so far and then truncated modulo page size,
+   to get a roughly even distribution of values for different threads.  */
+#define COLORING_INCREMENT      0
+
+/* This is a number of bytes that is an alignment that should be avoided
+   when choosing the exact size of a new thread's stack.  If the size
+   chosen is aligned to this, an extra page will be added to render the
+   size off-aligned.  */
+#define MULTI_PAGE_ALIASING     0
--- a/sysdeps/i386/i686/nptl/Makefile
+++ /dev/null
@@ -1,31 +0,0 @@ 
-# Copyright (C) 2003-2014 Free Software Foundation, Inc.
-# This file is part of the GNU C Library.
-# Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
-
-# The GNU C Library is free software; you can redistribute it and/or
-# modify it under the terms of the GNU Lesser General Public
-# License as published by the Free Software Foundation; either
-# version 2.1 of the License, or (at your option) any later version.
-
-# The GNU C Library is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# Lesser General Public License for more details.
-
-# You should have received a copy of the GNU Lesser General Public
-# License along with the GNU C Library; if not, see
-# <http://www.gnu.org/licenses/>.
-
-ifeq ($(subdir),nptl)
-# It turns out that stack coloring is in general not good on P4s.  Some
-# applications will benefit.  We will probably have a configuration option
-# at some point.  Enabling coloring can be done with
-#
-#   -DCOLORING_INCREMENT=128
-#
-# What is useful is to avoid the 64k aliasing problem which reliably
-# happens if all stacks use sizes which are a multiple of 64k.  Tell
-# the stack allocator to disturb this by allocation one more page if
-# necessary.
-CFLAGS-pthread_create.c += -DMULTI_PAGE_ALIASING=65536
-endif
--- /dev/null
+++ b/sysdeps/i386/i686/stack-aliasing.h
@@ -0,0 +1,28 @@ 
+/* Define macros for stack address aliasing issues for NPTL.  i686 version.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* It turns out that stack coloring is in general not good on P4s.  Some
+   applications will benefit.  We will probably have a configuration option
+   at some point.  To enable coloring, set this to 128.  */
+#define COLORING_INCREMENT      0
+
+/* What is useful is to avoid the 64k aliasing problem which reliably
+   happens if all stacks use sizes which are a multiple of 64k.  Tell
+   the stack allocator to disturb this by allocation one more page if
+   necessary.  */
+#define MULTI_PAGE_ALIASING     65536
--- a/sysdeps/x86_64/nptl/Makefile
+++ b/sysdeps/x86_64/nptl/Makefile
@@ -18,10 +18,3 @@ 
 ifeq ($(subdir),csu)
 gen-as-const-headers += tcb-offsets.sym
 endif
-
-ifeq ($(subdir),nptl)
-# P4s have problems with 4M aliasing.  We disturb the allocation of stacks
-# just enough so the subsequent allocations do not use stack address
-# (mod 4M) == 0.
-CFLAGS-pthread_create.c += -DMULTI_PAGE_ALIASING=65536
-endif
--- /dev/null
+++ b/sysdeps/x86_64/stack-aliasing.h
@@ -0,0 +1 @@ 
+#include <sysdeps/i386/i686/stack-aliasing.h>