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 16:10:19 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Alexandre Chartre <alexandre.chartre@...cle.com>,
        LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, "Paul E. McKenney" <paulmck@...nel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Petr Mladek <pmladek@...e.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Joel Fernandes <joel@...lfernandes.org>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Brian Gerst <brgerst@...il.com>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        Will Deacon <will@...nel.org>
Subject: Re: [patch V4 part 2 05/18] x86/entry: Move irq tracing on syscall entry to C-code

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.

Thanks,

        tglx