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authorH.J. Lu <hjl.tools@gmail.com>2021-03-19 12:53:40 -0700
committerH.J. Lu <hjl.tools@gmail.com>2021-03-19 15:04:17 -0700
commit3e2f285c5f12045e425060b6cbdf7a7cab540594 (patch)
treed85f4e33fd6caa432c8e877555d0a573c1523db4 /nptl
parent9cbe4ed14ec66415be34ad142abf4fa83aed3f58 (diff)
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nptl: Remove MULTI_PAGE_ALIASING [BZ #23554]
MULTI_PAGE_ALIASING was introduced to mitigate an aliasing issue on Pentium 4. It is no longer needed for processors after Pentium 4.
Diffstat (limited to 'nptl')
-rw-r--r--nptl/allocatestack.c10
-rw-r--r--nptl/stack-aliasing.h23
2 files changed, 0 insertions, 33 deletions
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 149b999..00fddbd 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -31,7 +31,6 @@
#include <lowlevellock.h>
#include <futex-internal.h>
#include <kernel-features.h>
-#include <stack-aliasing.h>
#ifndef NEED_SEPARATE_REGISTER_STACK
@@ -547,15 +546,6 @@ allocate_stack (const struct pthread_attr *attr, struct pthread **pdp,
pd = get_cached_stack (&size, &mem);
if (pd == NULL)
{
- /* To avoid aliasing effects on a larger scale than pages we
- adjust the allocated stack size if necessary. This way
- allocations directly following each other will not have
- aliasing problems. */
-#if MULTI_PAGE_ALIASING != 0
- if ((size % MULTI_PAGE_ALIASING) == 0)
- size += pagesize_m1 + 1;
-#endif
-
/* If a guard page is required, avoid committing memory by first
allocate with PROT_NONE and then reserve with required permission
excluding the guard page. */
diff --git a/nptl/stack-aliasing.h b/nptl/stack-aliasing.h
deleted file mode 100644
index bfdde53..0000000
--- a/nptl/stack-aliasing.h
+++ /dev/null
@@ -1,23 +0,0 @@
-/* Define macros for stack address aliasing issues for NPTL. Stub version.
- Copyright (C) 2014-2021 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
- <https://www.gnu.org/licenses/>. */
-
-/* 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