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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Grygorii Strashko <grygorii.strashko@ti.com>,
	Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>
Subject: Re: [rfc patch v4.4-rt2] sched: fix up preempt lazy forward port
Date: Mon, 1 Feb 2016 14:04:48 +0100	[thread overview]
Message-ID: <56AF57F0.80300@linutronix.de> (raw)
In-Reply-To: <56A657DD.8080602@ti.com>

On 01/25/2016 06:14 PM, Grygorii Strashko wrote:

>> diff --git a/arch/arm/kernel/entry-common.S
>> b/arch/arm/kernel/entry-common.S
>> index 30a7228eaceb..c3bd6cbfce4b 100644
>> --- a/arch/arm/kernel/entry-common.S
>> +++ b/arch/arm/kernel/entry-common.S
>> @@ -36,7 +36,9 @@
>>    UNWIND(.cantunwind    )
>>       disable_irq_notrace            @ disable interrupts
>>       ldr    r1, [tsk, #TI_FLAGS]        @ re-check for syscall tracing
>> -    tst    r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
>> +    tst    r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP)
>> +    bne    fast_work_pending
>         ^^^^^^^^^^^^^^^^
> 
>> +    tst    r1, #_TIF_SECCOMP
>>       bne    fast_work_pending
>         ^^^^^^^^^^^^^^^^^
> 
> Should it be "fast_work_pending" in both cases?

Yes, I think so and it is, isn't it?
The original is

     tst    r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
     bne    fast_work_pending

and with the LAZY bits in it, the ASM opcode no longer works because
the constant is too large (or has to many bits set). So I removed the
_TIF_SECCOMP bit out of the mask and made two compare & jumps here.

Sebastian

      reply	other threads:[~2016-02-01 13:04 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-18  9:08 [rfc patch v4.4-rt2] sched: fix up preempt lazy forward port Mike Galbraith
2016-01-18 20:18 ` Sebastian Andrzej Siewior
2016-01-19  2:29   ` Mike Galbraith
2016-01-21 12:54     ` Sebastian Andrzej Siewior
2016-01-22 12:24       ` Grygorii Strashko
2016-01-22 13:19         ` Sebastian Andrzej Siewior
2016-01-22 13:34           ` Grygorii Strashko
2016-01-22 14:14             ` Sebastian Andrzej Siewior
2016-01-22 15:04               ` Grygorii Strashko
2016-01-22 18:21                 ` Grygorii Strashko
2016-02-21 15:11       ` [patch] sched,rt: __always_inline preemptible_lazy() Mike Galbraith
2016-01-19  4:41   ` [rfc patch v4.4-rt2] sched: fix up preempt lazy forward port Mike Galbraith
2016-01-19  5:14     ` Mike Galbraith
2016-01-22 11:58   ` Grygorii Strashko
2016-01-22 12:54     ` Sebastian Andrzej Siewior
2016-01-22 20:40       ` Sebastian Andrzej Siewior
2016-01-25 17:14         ` Grygorii Strashko
2016-02-01 13:04           ` Sebastian Andrzej Siewior [this message]

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