From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751855AbaHDRjM (ORCPT ); Mon, 4 Aug 2014 13:39:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:7948 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751059AbaHDRjJ (ORCPT ); Mon, 4 Aug 2014 13:39:09 -0400 Date: Mon, 4 Aug 2014 19:36:47 +0200 From: Oleg Nesterov To: Peter Zijlstra Cc: Denys Vlasenko , linux-kernel@vger.kernel.org, "H. Peter Anvin" , Andy Lutomirski , Frederic Weisbecker , X86 ML , Alexei Starovoitov , Will Drewry , Kees Cook Subject: [PATCH? v2] x86: reimplement ___preempt_schedule*() using THUNK helpers Message-ID: <20140804173646.GA18520@redhat.com> References: <1407158386-6201-1-git-send-email-dvlasenk@redhat.com> <1407158386-6201-5-git-send-email-dvlasenk@redhat.com> <20140804170519.GA17466@redhat.com> <20140804171814.GU19379@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140804171814.GU19379@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/04, Peter Zijlstra wrote: > > On Mon, Aug 04, 2014 at 07:05:19PM +0200, Oleg Nesterov wrote: > > Hmm. This part looks fine, but with or without this patch this all is > > suboptimal, we do not need SAVE_ALL unless I missed something. Can't we > > simply kill preempt.S ? > > > > Peter, what do you think? > > HPA right, not me? You too ;) > I'm never sure on these details, if hpa thinks its > fine, I'm good. OK, please see v2 below, I missed the unconditional "Place EIP in the arg1" in thunk_32.S. Seems to work at least on x86_64, but I do not know how to test, lets see what HPA thinks. _If_ this is correct, I should probably rebase it on top of Denys's changes... Or, given that this patch is simple, perhaps Denys can take this patch as 1/X. If correct ;) Oleg. ---------------------------------------------------------------------------- Subject: [PATCH] x86: reimplement ___preempt_schedule*() using THUNK helpers --- arch/x86/kernel/Makefile | 2 -- arch/x86/kernel/preempt.S | 25 ------------------------- arch/x86/lib/thunk_32.S | 20 ++++++++++++++++---- arch/x86/lib/thunk_64.S | 7 +++++++ 4 files changed, 23 insertions(+), 31 deletions(-) delete mode 100644 arch/x86/kernel/preempt.S diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 047f9ff..3f5d657 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -39,8 +39,6 @@ obj-y += tsc.o tsc_msr.o io_delay.o rtc.o obj-y += pci-iommu_table.o obj-y += resource.o -obj-$(CONFIG_PREEMPT) += preempt.o - obj-y += process.o obj-y += i387.o xsave.o obj-y += ptrace.o diff --git a/arch/x86/kernel/preempt.S b/arch/x86/kernel/preempt.S deleted file mode 100644 index ca7f0d5..0000000 --- a/arch/x86/kernel/preempt.S +++ /dev/null @@ -1,25 +0,0 @@ - -#include -#include -#include -#include - -ENTRY(___preempt_schedule) - CFI_STARTPROC - SAVE_ALL - call preempt_schedule - RESTORE_ALL - ret - CFI_ENDPROC - -#ifdef CONFIG_CONTEXT_TRACKING - -ENTRY(___preempt_schedule_context) - CFI_STARTPROC - SAVE_ALL - call preempt_schedule_context - RESTORE_ALL - ret - CFI_ENDPROC - -#endif diff --git a/arch/x86/lib/thunk_32.S b/arch/x86/lib/thunk_32.S index 28f85c9..7f1641a 100644 --- a/arch/x86/lib/thunk_32.S +++ b/arch/x86/lib/thunk_32.S @@ -7,16 +7,19 @@ #include #include -#ifdef CONFIG_TRACE_IRQFLAGS /* put return address in eax (arg1) */ - .macro thunk_ra name,func + .macro thunk_ra name, func, put_ret_addr_in_eax=0 .globl \name \name: pushl %eax pushl %ecx pushl %edx + + .if \put_ret_addr_in_eax /* Place EIP in the arg1 */ movl 3*4(%esp), %eax + .endif + call \func popl %edx popl %ecx @@ -25,6 +28,15 @@ _ASM_NOKPROBE(\name) .endm - thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller - thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller +#ifdef CONFIG_TRACE_IRQFLAGS + thunk_ra trace_hardirqs_on_thunk,trace_hardirqs_on_caller,1 + thunk_ra trace_hardirqs_off_thunk,trace_hardirqs_off_caller,1 +#endif + +#ifdef CONFIG_PREEMPT + THUNK ___preempt_schedule, preempt_schedule +#ifdef CONFIG_CONTEXT_TRACKING + THUNK ___preempt_schedule_context, preempt_schedule_context #endif +#endif + diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S index 92d9fea..b30b5eb 100644 --- a/arch/x86/lib/thunk_64.S +++ b/arch/x86/lib/thunk_64.S @@ -38,6 +38,13 @@ THUNK lockdep_sys_exit_thunk,lockdep_sys_exit #endif +#ifdef CONFIG_PREEMPT + THUNK ___preempt_schedule, preempt_schedule +#ifdef CONFIG_CONTEXT_TRACKING + THUNK ___preempt_schedule_context, preempt_schedule_context +#endif +#endif + /* SAVE_ARGS below is used only for the .cfi directives it contains. */ CFI_STARTPROC SAVE_ARGS -- 1.5.5.1