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[PATCHv2] powerpc: Fix syscalls during early process initialization [BZ #22685]
- From: "Tulio Magno Quites Machado Filho" <tuliom at linux dot vnet dot ibm dot com>
- To: libc-alpha at sourceware dot org
- Cc: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>, Florian Weimer <fweimer at redhat dot com>, aurelien at aurel32 dot net
- Date: Fri, 12 Jan 2018 14:07:04 -0200
- Subject: [PATCHv2] powerpc: Fix syscalls during early process initialization [BZ #22685]
- Authentication-results: sourceware.org; auth=none
- References: <2bc5bd27-1901-495e-6026-6440f2434f01@linaro.org>
Changes since v1:
- Re-implemented the patch to re-define a powerpc-specific
__access_noerrno.
--- 8< ---
The tunables framework needs to execute syscall early in process
initialization, before the TCB is available for consumption. This
behavior conflicts with powerpc{|64|64le}'s lock elision code, that
checks the TCB before trying to abort transactions immediately before
executing a syscall.
This patch adds a powerpc-specific implementation of __access_noerrno
that does not abort transactions before the executing syscall.
Tested on powerpc{|64|64le}.
2018-01-12 Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
[BZ #22685]
* sysdeps/unix/sysv/linux/powerpc/not-errno.h: New file. Reuse
Linux code, but remove the code that aborts transactions.
Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
---
sysdeps/unix/sysv/linux/powerpc/not-errno.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
create mode 100644 sysdeps/unix/sysv/linux/powerpc/not-errno.h
diff --git a/sysdeps/unix/sysv/linux/powerpc/not-errno.h b/sysdeps/unix/sysv/linux/powerpc/not-errno.h
new file mode 100644
index 0000000..642cb8a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/powerpc/not-errno.h
@@ -0,0 +1,25 @@
+/* Syscall wrapper that do not set errno. Linux powerpc version.
+ Copyright (C) 2018 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/>. */
+
+/* __access_noerrno is used during process initialization in elf/dl-tunables.c
+ before the TCB is initialized, prohibiting the usage of
+ ABORT_TRANSACTION. */
+#undef ABORT_TRANSACTION
+#define ABORT_TRANSACTION
+
+#include "sysdeps/unix/sysv/linux/not-errno.h"
--
2.9.5