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4.6 KiB

commit 93a6d0820430bfe3d09695a1376c07abf6d2214f
Author: Roland McGrath <roland@hack.frob.com>
Date: Fri Jun 20 19:50:16 2014 -0700
Clean up stack-coloring macros.
Conflicts:
sysdeps/x86_64/nptl/Makefile
File change was applied to nptl/sysdeps/x86_64/Makefile instead.
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 2c126fd4ae447b25..0fba6ce3474e8b35 100644
--- 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
diff --git a/nptl/stack-aliasing.h b/nptl/stack-aliasing.h
new file mode 100644
index 0000000000000000..526b54e18f7e0a27
--- /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
diff --git a/nptl/sysdeps/x86_64/Makefile b/nptl/sysdeps/x86_64/Makefile
index d34dea709b363d2a..e2c47764e6e38c36 100644
--- a/nptl/sysdeps/x86_64/Makefile
+++ b/nptl/sysdeps/x86_64/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
diff --git a/sysdeps/i386/i686/stack-aliasing.h b/sysdeps/i386/i686/stack-aliasing.h
new file mode 100644
index 0000000000000000..1e35ceb2061d60f9
--- /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
diff --git a/sysdeps/x86_64/stack-aliasing.h b/sysdeps/x86_64/stack-aliasing.h
new file mode 100644
index 0000000000000000..2efdacb3b4c44c40
--- /dev/null
+++ b/sysdeps/x86_64/stack-aliasing.h
@@ -0,0 +1 @@
+#include <sysdeps/i386/i686/stack-aliasing.h>