[PATCH v4 (updated)] getcpu_cache: wire up ARM system call

Wire up the getcpu cache system call on 32-bit ARM.

This provides an ABI improving the speed of a getcpu operation
on ARM by skipping the getcpu system call on the fast path.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
CC: Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>
CC: Catalin Marinas <redacted>
CC: Will Deacon <redacted>
CC: Thomas Gleixner <redacted>
CC: Paul Turner <redacted>
CC: Andrew Hunter <redacted>
CC: Peter Zijlstra <redacted>
CC: Andy Lutomirski <redacted>
CC: Andi Kleen <andi-Vw/NltI1exuRpAAqCnN02g@public.gmane.org>
CC: Dave Watson <redacted>
CC: Chris Lameter <redacted>
CC: Ingo Molnar <redacted>
CC: Ben Maurer <redacted>
CC: Steven Rostedt <redacted>
CC: "Paul E. McKenney" <redacted>
CC: Josh Triplett <redacted>
CC: Linus Torvalds <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
CC: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
CC: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
 arch/arm/include/asm/unistd.h      | 2 +-
 arch/arm/include/uapi/asm/unistd.h | 1 +
 arch/arm/kernel/calls.S            | 3 ++-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 7b84657..194b699 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h

@@ -19,7 +19,7 @@
  * This may need to be greater than __NR_last_syscall+1 in order to
  * account for the padding in the syscall table
  */
-#define __NR_syscalls  (392)
+#define __NR_syscalls  (396)
 
 #define __ARCH_WANT_STAT64
 #define __ARCH_WANT_SYS_GETHOSTNAME

diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h
index 5dd2528..1ad1351 100644
--- a/arch/arm/include/uapi/asm/unistd.h
+++ b/arch/arm/include/uapi/asm/unistd.h

@@ -418,6 +418,7 @@
 #define __NR_membarrier			(__NR_SYSCALL_BASE+389)
 #define __NR_mlock2			(__NR_SYSCALL_BASE+390)
 #define __NR_copy_file_range		(__NR_SYSCALL_BASE+391)
+#define __NR_getcpu_cache		(__NR_SYSCALL_BASE+392)
 
 /*
  * The following SWIs are ARM private.

diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
index dfc7cd6..7e794e9 100644
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S

@@ -399,8 +399,9 @@
 		CALL(sys_execveat)
 		CALL(sys_userfaultfd)
 		CALL(sys_membarrier)
-		CALL(sys_mlock2)
+/* 390 */	CALL(sys_mlock2)
 		CALL(sys_copy_file_range)
+		CALL(sys_getcpu_cache)
 #ifndef syscalls_counted
 .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls
 #define syscalls_counted

-- 
2.1.4