From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org,
John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
"Andreas K . Huettel" <dilfridge@gentoo.org>
Subject: [PATCH v2] m68k: Enforce 4-byte alignment on internal locks (BZ #29537)
Date: Mon, 5 Sep 2022 14:10:43 -0300 [thread overview]
Message-ID: <20220905171043.1097209-1-adhemerval.zanella@linaro.org> (raw)
A new internal definition, __LIBC_LOCK_ALIGNMENT, is used to force
the 4-byte alignment only for m68k, other architecture keep the
natural alignment of the type used internally (and hppa does not
require 16-byte alignment for kernel-assisted CAS).
---
sysdeps/generic/libc-lock-arch.h | 25 +++++++++++++++++++
sysdeps/nptl/libc-lock.h | 8 +++++-
sysdeps/nptl/libc-lockP.h | 3 ++-
sysdeps/unix/sysv/linux/m68k/libc-lock-arch.h | 25 +++++++++++++++++++
4 files changed, 59 insertions(+), 2 deletions(-)
create mode 100644 sysdeps/generic/libc-lock-arch.h
create mode 100644 sysdeps/unix/sysv/linux/m68k/libc-lock-arch.h
diff --git a/sysdeps/generic/libc-lock-arch.h b/sysdeps/generic/libc-lock-arch.h
new file mode 100644
index 0000000000..4713b30a8a
--- /dev/null
+++ b/sysdeps/generic/libc-lock-arch.h
@@ -0,0 +1,25 @@
+/* Private libc-internal arch-specific definitions. Generic version.
+ Copyright (C) 2022 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; see the file COPYING.LIB. If
+ not, see <https://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC_LOCK_ARCH_H
+#define _LIBC_LOCK_ARCH_H
+
+/* The default definition uses the natural alignment from the lock type. */
+#define __LIBC_LOCK_ALIGNMENT
+
+#endif
diff --git a/sysdeps/nptl/libc-lock.h b/sysdeps/nptl/libc-lock.h
index 5af476c48b..63b3f3d75c 100644
--- a/sysdeps/nptl/libc-lock.h
+++ b/sysdeps/nptl/libc-lock.h
@@ -22,6 +22,7 @@
#include <pthread.h>
#define __need_NULL
#include <stddef.h>
+#include <libc-lock-arch.h>
/* Mutex type. */
@@ -29,7 +30,12 @@
# if (!IS_IN (libc) && !IS_IN (libpthread)) || !defined _LIBC
typedef struct { pthread_mutex_t mutex; } __libc_lock_recursive_t;
# else
-typedef struct { int lock; int cnt; void *owner; } __libc_lock_recursive_t;
+typedef struct
+{
+ int lock __LIBC_LOCK_ALIGNMENT;
+ int cnt;
+ void *owner;
+} __libc_lock_recursive_t;
# endif
#else
typedef struct __libc_lock_recursive_opaque__ __libc_lock_recursive_t;
diff --git a/sysdeps/nptl/libc-lockP.h b/sysdeps/nptl/libc-lockP.h
index d3a6837fd2..425f514c5c 100644
--- a/sysdeps/nptl/libc-lockP.h
+++ b/sysdeps/nptl/libc-lockP.h
@@ -32,9 +32,10 @@
ld.so might be used on old kernels with a different libc.so. */
#include <lowlevellock.h>
#include <tls.h>
+#include <libc-lock-arch.h>
/* Mutex type. */
-typedef int __libc_lock_t;
+typedef int __libc_lock_t __LIBC_LOCK_ALIGNMENT;
typedef struct { pthread_mutex_t mutex; } __rtld_lock_recursive_t;
typedef pthread_rwlock_t __libc_rwlock_t;
diff --git a/sysdeps/unix/sysv/linux/m68k/libc-lock-arch.h b/sysdeps/unix/sysv/linux/m68k/libc-lock-arch.h
new file mode 100644
index 0000000000..1844bbaf6f
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/m68k/libc-lock-arch.h
@@ -0,0 +1,25 @@
+/* Private libc-internal arch-specific definitions. m68k version.
+ Copyright (C) 2022 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; see the file COPYING.LIB. If
+ not, see <https://www.gnu.org/licenses/>. */
+
+#ifndef _LIBC_LOCK_ARCH_H
+#define _LIBC_LOCK_ARCH_H
+
+/* Linux enforces 4-bytes alignment on futex inputs. */
+#define __LIBC_LOCK_ALIGNMENT __attribute__ ((__aligned__ (4)))
+
+#endif
--
2.34.1
next reply other threads:[~2022-09-05 17:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-05 17:10 Adhemerval Zanella [this message]
2022-09-14 18:56 ` Andreas K. Huettel
2022-09-20 12:49 ` Florian Weimer
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