Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933247AbbLVSDP (ORCPT ); Tue, 22 Dec 2015 13:03:15 -0500 Received: from mail.efficios.com ([78.47.125.74]:57847 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754781AbbLVSDC (ORCPT ); Tue, 22 Dec 2015 13:03:02 -0500 From: Mathieu Desnoyers To: Paul Turner , Andrew Hunter , Thomas Gleixner , Michael Kerrisk , Russell King Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Catalin Marinas , Will Deacon , Peter Zijlstra , Andy Lutomirski , Andi Kleen , Dave Watson , Chris Lameter , Ingo Molnar , Ben Maurer , Steven Rostedt , "Paul E. McKenney" , Josh Triplett , Linus Torvalds , Andrew Morton , linux-api@vger.kernel.org Subject: [RFC PATCH v2 2/3] thread_local_abi: wire up x86 32/64 system call Date: Tue, 22 Dec 2015 13:02:12 -0500 Message-Id: <1450807333-22104-2-git-send-email-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1450807333-22104-1-git-send-email-mathieu.desnoyers@efficios.com> References: <1450807333-22104-1-git-send-email-mathieu.desnoyers@efficios.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3009 Lines: 77 Wire up the thread local ABI on x86 32/64. Call the thread_local_abi_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 x86 by removing the need to perform a function call, "lsl" instruction, or 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/x86/entry/common.c | 2 ++ arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + 3 files changed, 4 insertions(+) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index a89fdbc..222cacf 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -249,6 +249,8 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags) if (cached_flags & _TIF_NOTIFY_RESUME) { clear_thread_flag(TIF_NOTIFY_RESUME); tracehook_notify_resume(regs); + if (thread_local_abi_active(current)) + thread_local_abi_handle_notify_resume(current); } if (cached_flags & _TIF_USER_RETURN_NOTIFY) diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl index f17705e..c6c385e 100644 --- a/arch/x86/entry/syscalls/syscall_32.tbl +++ b/arch/x86/entry/syscalls/syscall_32.tbl @@ -383,3 +383,4 @@ 374 i386 userfaultfd sys_userfaultfd 375 i386 membarrier sys_membarrier 376 i386 mlock2 sys_mlock2 +377 i386 thread_local_abi sys_thread_local_abi diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 314a90b..748aee3 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -332,6 +332,7 @@ 323 common userfaultfd sys_userfaultfd 324 common membarrier sys_membarrier 325 common mlock2 sys_mlock2 +326 common thread_local_abi sys_thread_local_abi # # x32-specific system call numbers start at 512 to avoid cache impact -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/