From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: [RFC PATCH v2 2/3] getcpu_cache: wire up ARM system call Date: Wed, 27 Jan 2016 11:54:42 -0500 Message-ID: <1453913683-28915-3-git-send-email-mathieu.desnoyers@efficios.com> References: <1453913683-28915-1-git-send-email-mathieu.desnoyers@efficios.com> Return-path: In-Reply-To: <1453913683-28915-1-git-send-email-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org To: Thomas Gleixner , Paul Turner , Andrew Hunter , Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Andy Lutomirski , Andi Kleen , Dave Watson , Chris Lameter , Ingo Molnar , Ben Maurer , Steven Rostedt , "Paul E. McKenney" , Josh Triplett , Linus Torvalds , Andrew Morton , Russell King , Catalin Marinas , Will Deacon , Michael Kerrisk , Mathieu Desnoyers List-Id: linux-api@vger.kernel.org Wire up the getcpu cache system call on 32-bit ARM. Call the getcpu_cache_handle_notify_resume() function on return to userspace if TIF_NOTIFY_RESUME thread flag is set. 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 CC: Russell King CC: Catalin Marinas CC: Will Deacon CC: Thomas Gleixner CC: Paul Turner CC: Andrew Hunter CC: Peter Zijlstra CC: Andy Lutomirski CC: Andi Kleen CC: Dave Watson CC: Chris Lameter CC: Ingo Molnar CC: Ben Maurer CC: Steven Rostedt CC: "Paul E. McKenney" CC: Josh Triplett CC: Linus Torvalds CC: Andrew Morton CC: Thomas Gleixner CC: linux-api@vger.kernel.org --- arch/arm/include/uapi/asm/unistd.h | 1 + arch/arm/kernel/calls.S | 1 + arch/arm/kernel/signal.c | 1 + 3 files changed, 3 insertions(+) diff --git a/arch/arm/include/uapi/asm/unistd.h b/arch/arm/include/uapi/asm/unistd.h index ede692f..ea0ea94 100644 --- a/arch/arm/include/uapi/asm/unistd.h +++ b/arch/arm/include/uapi/asm/unistd.h @@ -417,6 +417,7 @@ #define __NR_userfaultfd (__NR_SYSCALL_BASE+388) #define __NR_membarrier (__NR_SYSCALL_BASE+389) #define __NR_mlock2 (__NR_SYSCALL_BASE+390) +#define __NR_getcpu_cache (__NR_SYSCALL_BASE+391) /* * The following SWIs are ARM private. diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S index ac368bb..aa43e29 100644 --- a/arch/arm/kernel/calls.S +++ b/arch/arm/kernel/calls.S @@ -400,6 +400,7 @@ CALL(sys_userfaultfd) CALL(sys_membarrier) CALL(sys_mlock2) +/* 391 */ CALL(sys_getcpu_cache) #ifndef syscalls_counted .equ syscalls_padding, ((NR_syscalls + 3) & ~3) - NR_syscalls #define syscalls_counted diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 7b8f214..ff5052c 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -594,6 +594,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) } else { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + getcpu_cache_handle_notify_resume(current); } } local_irq_disable(); -- 2.1.4