linux-kernel - Re: [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code

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Date:   Thu, 07 May 2020 17:03:59 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Alexandre Chartre <alexandre.chartre@...cle.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code

Thomas Gleixner <tglx@...utronix.de> writes:
> Alexandre Chartre <alexandre.chartre@...cle.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.