[PATCHv3] powerpc: Fix syscalls during early process initialization [BZ #22685]
Commit Message
Changes since v2:
- Limited the scope of the changes to ABORT_TRANSACTION.
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/powerpc/powerpc32/sysdep.h (ABORT_TRANSACTION_IMPL): Renamed
from ABORT_TRANSACTION.
(ABORT_TRANSACTION): Redirect to ABORT_TRANSACTION_IMPL.
* sysdeps/powerpc/powerpc64/sysdep.h (ABORT_TRANSACTION,
ABORT_TRANSACTION_IMPL): Likewise.
* 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/powerpc/powerpc32/sysdep.h | 5 +++--
sysdeps/powerpc/powerpc64/sysdep.h | 5 +++--
sysdeps/unix/sysv/linux/powerpc/not-errno.h | 30 +++++++++++++++++++++++++++++
3 files changed, 36 insertions(+), 4 deletions(-)
create mode 100644 sysdeps/unix/sysv/linux/powerpc/not-errno.h
Comments
On 2018-01-12 18:52, Tulio Magno Quites Machado Filho wrote:
> Changes since v2:
> - Limited the scope of the changes to ABORT_TRANSACTION.
>
> 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/powerpc/powerpc32/sysdep.h (ABORT_TRANSACTION_IMPL): Renamed
> from ABORT_TRANSACTION.
> (ABORT_TRANSACTION): Redirect to ABORT_TRANSACTION_IMPL.
> * sysdeps/powerpc/powerpc64/sysdep.h (ABORT_TRANSACTION,
> ABORT_TRANSACTION_IMPL): Likewise.
> * sysdeps/unix/sysv/linux/powerpc/not-errno.h: New file. Reuse
> Linux code, but remove the code that aborts transactions.
Thanks for this new version. It is indeed much simpler than the initial
version. I confirm it fixes the issue and does not introduce regressions
in the testsuite.
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
@@ -91,7 +91,7 @@ GOT_LABEL: ; \
ASM_SIZE_DIRECTIVE(name)
#if ! IS_IN(rtld)
-# define ABORT_TRANSACTION \
+# define ABORT_TRANSACTION_IMPL \
cmpwi 2,0; \
beq 1f; \
lwz 0,TM_CAPABLE(2); \
@@ -102,8 +102,9 @@ GOT_LABEL: ; \
.align 4; \
1:
#else
-# define ABORT_TRANSACTION
+# define ABORT_TRANSACTION_IMPL
#endif
+#define ABORT_TRANSACTION ABORT_TRANSACTION_IMPL
#define DO_CALL(syscall) \
ABORT_TRANSACTION \
@@ -264,7 +264,7 @@ LT_LABELSUFFIX(name,_name_end): ; \
END_2(name)
#if !IS_IN(rtld)
-# define ABORT_TRANSACTION \
+# define ABORT_TRANSACTION_IMPL \
cmpdi 13,0; \
beq 1f; \
lwz 0,TM_CAPABLE(13); \
@@ -275,8 +275,9 @@ LT_LABELSUFFIX(name,_name_end): ; \
.p2align 4; \
1:
#else
-# define ABORT_TRANSACTION
+# define ABORT_TRANSACTION_IMPL
#endif
+#define ABORT_TRANSACTION ABORT_TRANSACTION_IMPL
#define DO_CALL(syscall) \
ABORT_TRANSACTION \
new file mode 100644
@@ -0,0 +1,30 @@
+/* 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"
+
+/* Recover ABORT_TRANSACTION's previous value, in order to not affect
+ other syscalls. */
+#undef ABORT_TRANSACTION
+#define ABORT_TRANSACTION ABORT_TRANSACTION_IMPL