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

From: Mathieu Desnoyers
Date: Tue Feb 23 2016 - 20:05:50 EST


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@xxxxxxxxxxxx>
CC: Russell King <linux@xxxxxxxxxxxxxxxx>
CC: Catalin Marinas <catalin.marinas@xxxxxxx>
CC: Will Deacon <will.deacon@xxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CC: Paul Turner <pjt@xxxxxxxxxx>
CC: Andrew Hunter <ahh@xxxxxxxxxx>
CC: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CC: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
CC: Andi Kleen <andi@xxxxxxxxxxxxxx>
CC: Dave Watson <davejwatson@xxxxxx>
CC: Chris Lameter <cl@xxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Ben Maurer <bmaurer@xxxxxx>
CC: Steven Rostedt <rostedt@xxxxxxxxxxx>
CC: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
CC: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
CC: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
CC: linux-api@xxxxxxxxxxxxxxx
---
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