[RFC PATCH 1/9] powerpc: allocate sys_membarrier system call number

Allow it to be used from SPU, since it should not have unwanted
side-effects.

[ Untested on this architecture. To try it out: fetch linux-next/akpm,
  apply this patch, build/run a membarrier-enabled kernel, and do make
  kselftest. ]

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-api@vger.kernel.org
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/include/asm/systbl.h      | 1 +
 arch/powerpc/include/asm/unistd.h      | 2 +-
 arch/powerpc/include/uapi/asm/unistd.h | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h
index 4d65499..126d0c4 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h

@@ -369,3 +369,4 @@ SYSCALL_SPU(bpf)
 COMPAT_SYS(execveat)
 PPC64ONLY(switch_endian)
 SYSCALL_SPU(userfaultfd)
+SYSCALL_SPU(membarrier)

diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index 4a055b6..13411be 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h

@@ -12,7 +12,7 @@
 #include <uapi/asm/unistd.h>
 
 
-#define __NR_syscalls		365
+#define __NR_syscalls		366
 
 #define __NR__exit __NR_exit
 #define NR_syscalls	__NR_syscalls

diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h
index 6ad58d4..6337738 100644
--- a/arch/powerpc/include/uapi/asm/unistd.h
+++ b/arch/powerpc/include/uapi/asm/unistd.h

@@ -387,5 +387,6 @@
 #define __NR_execveat		362
 #define __NR_switch_endian	363
 #define __NR_userfaultfd	364
+#define __NR_membarrier		365
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */

-- 
1.9.1

On Thu, 2015-08-27 at 13:56 -0400, Mathieu Desnoyers wrote:

Allow it to be used from SPU, since it should not have unwanted
side-effects.

[ Untested on this architecture. To try it out: fetch linux-next/akpm,
  apply this patch, build/run a membarrier-enabled kernel, and do make
  kselftest. ]

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-api@vger.kernel.org
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org

Thanks.

I get:

$ ./membarrier_test
membarrier MEMBARRIER_CMD_QUERY syscall available.
membarrier: MEMBARRIER_CMD_SHARED success.
membarrier: tests done!

Which looks good.

Assuming the membarrier support hits 4.3, I'll take this via my tree for 4.3
also.

cheers

----- On Aug 31, 2015, at 2:54 AM, Michael Ellerman mpe@ellerman.id.au wrote:

On Thu, 2015-08-27 at 13:56 -0400, Mathieu Desnoyers wrote:

quoted

Allow it to be used from SPU, since it should not have unwanted
side-effects.

[ Untested on this architecture. To try it out: fetch linux-next/akpm,
  apply this patch, build/run a membarrier-enabled kernel, and do make
  kselftest. ]

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-api@vger.kernel.org
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org

Thanks.

I get:

$ ./membarrier_test
membarrier MEMBARRIER_CMD_QUERY syscall available.
membarrier: MEMBARRIER_CMD_SHARED success.
membarrier: tests done!

Which looks good.

Assuming the membarrier support hits 4.3, I'll take this via my tree for 4.3
also.

Great! I'll take care of your comments about self-tests,

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

On Mon, 2015-08-31 at 15:32 +0000, Mathieu Desnoyers wrote:

----- On Aug 31, 2015, at 2:54 AM, Michael Ellerman mpe@ellerman.id.au wrote:

quoted

On Thu, 2015-08-27 at 13:56 -0400, Mathieu Desnoyers wrote:

quoted

Allow it to be used from SPU, since it should not have unwanted
side-effects.

quoted

$ ./membarrier_test
membarrier MEMBARRIER_CMD_QUERY syscall available.
membarrier: MEMBARRIER_CMD_SHARED success.
membarrier: tests done!

Which looks good.

Assuming the membarrier support hits 4.3, I'll take this via my tree for 4.3
also.

Great! I'll take care of your comments about self-tests,

Thanks. None of them are critical so we can always fix them later.

cheers