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From: Thomas Gleixner <tglx@linutronix.de>
To: Alexandre Chartre <alexandre.chartre@oracle.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code
Date: Thu, 07 May 2020 19:06:45 +0200	[thread overview]
Message-ID: <87zhajekt6.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <87368bg528.fsf@nanos.tec.linutronix.de>

Thomas Gleixner <tglx@linutronix.de> writes:
> Thomas Gleixner <tglx@linutronix.de> writes:
>> Alexandre Chartre <alexandre.chartre@oracle.com> writes:
>>> On 5/5/20 3:41 PM, Thomas Gleixner wrote:
>>>> -	/*
>>>> -	 * User mode is traced as though IRQs are on, and the interrupt
>>>> -	 * gate turned them off.
>>>> -	 */
>>>> -	TRACE_IRQS_OFF
>>>> -
>>>>   	movq	%rsp, %rdi
>>>>   	call	do_int80_syscall_32
>>>>   .Lsyscall_32_done:
>>>> 
>>>
>>> enter_from_user_mode() is also called with the CALL_enter_from_user_mode macro,
>>> which is used in interrupt_entry() and identry. Don't you need to also remove
>>> the TRACE_IRQS_OFF there now?
>>
>> Hrm. right. OTOH, it's just redundant and should be no harm, but let me have a
>> look at that again.
>
> Grr, no. It'll trigger the warnon when context tracking is enabled. /me
> scratches head and goes to fix.

Scratch that. After unfrying my brain by walking the dogs for an hour,
it's really just redundant calls into lockdep and tracing and both are
happy about it.

I could do a temporary function for that or just mention it in the
changelog.

Thanks,

        tglx

  reply	other threads:[~2020-05-07 17:06 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-05 13:41 [patch V4 part 2 00/18] x86/entry: Entry/exception code rework, syscall and KVM changes Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 01/18] x86/entry/64: Move non entry code into .text section Thomas Gleixner
2020-05-06 15:51   ` Peter Zijlstra
2020-05-08  1:31   ` Steven Rostedt
2020-05-08 23:53   ` Andy Lutomirski
2020-05-10 13:39     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 02/18] x86/entry/32: " Thomas Gleixner
2020-05-07 13:15   ` Alexandre Chartre
2020-05-07 14:14     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 03/18] x86/entry: Mark enter_from_user_mode() noinstr Thomas Gleixner
2020-05-08  8:21   ` Masami Hiramatsu
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 04/18] x86/entry/common: Protect against instrumentation Thomas Gleixner
2020-05-07 13:39   ` Alexandre Chartre
2020-05-07 14:13     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code Thomas Gleixner
2020-05-07 13:55   ` Alexandre Chartre
2020-05-07 14:10     ` Thomas Gleixner
2020-05-07 15:03       ` Thomas Gleixner
2020-05-07 17:06         ` Thomas Gleixner [this message]
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 06/18] x86/entry: Move irq flags tracing to prepare_exit_to_usermode() Thomas Gleixner
2020-05-08 23:57   ` Andy Lutomirski
2020-05-09 10:16     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 07/18] context_tracking: Ensure that the critical path cannot be instrumented Thomas Gleixner
2020-05-08  8:23   ` Masami Hiramatsu
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 08/18] lib/smp_processor_id: Move it into noinstr section Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline tip-bot2 for Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] lib/smp_processor_id: Move it into noinstr section tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 09/18] x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inline Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 10/18] x86/entry/64: Check IF in __preempt_enable_notrace() thunk Thomas Gleixner
2020-05-07 14:15   ` Alexandre Chartre
2020-05-09  0:10   ` Andy Lutomirski
2020-05-09 10:25     ` Thomas Gleixner
2020-05-10 18:47       ` Thomas Gleixner
2020-05-11 18:27         ` Thomas Gleixner
2020-05-12  1:48     ` Steven Rostedt
2020-05-12  1:51   ` Steven Rostedt
2020-05-12  8:14     ` Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 11/18] x86/entry/64: Mark ___preempt_schedule_notrace() thunk noinstr Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 12/18] x86,objtool: Make entry_64_compat.S objtool clean Thomas Gleixner
2020-05-09  0:11   ` Andy Lutomirski
2020-05-09 10:06     ` Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] x86/entry: " tip-bot2 for Peter Zijlstra
2020-05-05 13:41 ` [patch V4 part 2 13/18] x86/kvm: Move context tracking where it belongs Thomas Gleixner
2020-05-06  7:42   ` Paolo Bonzini
2020-05-09  0:14   ` Andy Lutomirski
2020-05-09 10:12     ` Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 14/18] x86/kvm/vmx: Add hardirq tracing to guest enter/exit Thomas Gleixner
2020-05-06  7:55   ` Paolo Bonzini
2020-05-05 13:41 ` [patch V4 part 2 15/18] x86/kvm/svm: Handle hardirqs proper on " Thomas Gleixner
2020-05-06  8:15   ` Paolo Bonzini
2020-05-06  8:48     ` Thomas Gleixner
2020-05-06  9:21       ` Paolo Bonzini
2020-05-07 14:44         ` [patch V5 " Thomas Gleixner
2020-05-08 13:45           ` Paolo Bonzini
2020-05-08 14:01             ` Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 16/18] context_tracking: Make guest_enter/exit() .noinstr ready Thomas Gleixner
2020-05-19 19:58   ` [tip: x86/entry] " tip-bot2 for Thomas Gleixner
2020-05-05 13:41 ` [patch V4 part 2 17/18] x86/kvm/vmx: Move guest enter/exit into .noinstr.text Thomas Gleixner
2020-05-06  8:17   ` Paolo Bonzini
2020-05-05 13:41 ` [patch V4 part 2 18/18] x86/kvm/svm: " Thomas Gleixner
2020-05-06  8:17   ` Paolo Bonzini
2020-05-07 14:47   ` Alexandre Chartre

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