Re: [PATCH] powerpc: Fix syscalls during early process initialization [BZ #22685]

[Aurelien Jarno <aurelien@aurel32.net>]

On 2018-01-11 17:27, Tulio Magno Quites Machado Filho wrote:
> The tunables framework needs to make syscall early during process
> initialization, before the TCB is available for consumption.  This
> behavior conflicts with powerpc{|64|64le}'s lock elision code, that
> tries to abort transactions before a syscall when lock elision is
> available and enabled.
> 
> This patch adds the macro EARLY_INTERNAL_SYSCALL in order to let early
> syscalls happen without depending on the TCB initialization for
> powerpc{|64|64le}.  Other architectures are redirected to INTERNAL_SYSCALL.
> 
> Tested on powerpc{|64|64le}, s390x and x86_64.
> 
> 2018-01-11  Tulio Magno Quites Machado Filho  <tuliom@linux.vnet.ibm.com>
> 
> 	[BZ #22685]
> 	* sysdeps/unix/sysdep.h (__EARLY_INTERNAL_SYSCALL0,
> 	__EARLY_INTERNAL_SYSCALL1, __EARLY_INTERNAL_SYSCALL2,
> 	__EARLY_INTERNAL_SYSCALL3, __EARLY_INTERNAL_SYSCALL4,
> 	__EARLY_INTERNAL_SYSCALL5, __EARLY_INTERNAL_SYSCALL6,
> 	__EARLY_INTERNAL_SYSCALL7, EARLY_INTERNAL_SYSCALL_CALL): New macros
> 	(EARLY_INTERNAL_SYSCALL): New macro.  Redirect to
> 	INTERNAL_SYSCALL by default.
> 	* sysdeps/unix/sysv/linux/not-errno.h (__access_noerrno):
> 	Replace INTERNAL_SYSCALL_CALL with EARLY_INTERNAL_SYSCALL_CALL.
> 	* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
> 	(EARLY_INTERNAL_SYSCALL_NCS, EARLY_INTERNAL_SYSCALL): New macros.
> 	* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
> 	(EARLY_INTERNAL_SYSCALL_NCS, EARLY_INTERNAL_SYSCALL): Likewise.
> 
> Signed-off-by: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
> ---
>  sysdeps/unix/sysdep.h                              | 25 +++++++++++++++
>  sysdeps/unix/sysv/linux/not-errno.h                |  4 +--
>  sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h | 36 +++++++++++++++++++++-
>  sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h | 34 +++++++++++++++++++-
>  4 files changed, 95 insertions(+), 4 deletions(-)

Thanks for the patch, I have just tested it and I confirm it fixes the
issue.

Tested-by: Aurelien Jarno <aurelien@aurel32.net>

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                 http://www.aurel32.net