[RFC PATCH for 4.15 08/14] Restartable sequences: Wire up powerpc system call

From: Boqun Feng <redacted>

Wire up the rseq system call on powerpc.

This provides an ABI improving the speed of a user-space getcpu
operation on powerpc by skipping the getcpu system call on the fast
path, as well as improving the speed of user-space operations on per-cpu
data compared to using load-reservation/store-conditional atomics.

Signed-off-by: Boqun Feng <redacted>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <redacted>
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 1c9470881c4a..a805a4d10d1c 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h

@@ -388,3 +388,4 @@ COMPAT_SYS_SPU(preadv2)
 COMPAT_SYS_SPU(pwritev2)
 SYSCALL(kexec_file_load)
 SYSCALL(statx)
+SYSCALL(rseq)

diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index 9ba11dbcaca9..e76bd5601ea4 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		384
+#define NR_syscalls		385
 
 #define __NR__exit __NR_exit
 

diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h
index b85f14228857..854a8db4144e 100644
--- a/arch/powerpc/include/uapi/asm/unistd.h
+++ b/arch/powerpc/include/uapi/asm/unistd.h

@@ -394,5 +394,6 @@
 #define __NR_pwritev2		381
 #define __NR_kexec_file_load	382
 #define __NR_statx		383
+#define __NR_rseq		384
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */

-- 
2.11.0