From: Thomas Gleixner <tglx@linutronix.de>
To: David Daney <ddaney.cavm@gmail.com>
Cc: linux-mips@linux-mips.org, ralf@linux-mips.org,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org,
David Daney <david.daney@cavium.com>,
Jonas Gorski <jogo@openwrt.org>
Subject: Re: [PATCH] MIPS: Enable interrupts before WAIT instruction.
Date: Thu, 2 May 2013 23:04:19 +0200 (CEST) [thread overview]
Message-ID: <alpine.LFD.2.02.1305022303510.2891@ionos> (raw)
In-Reply-To: <1367527692-25809-1-git-send-email-ddaney.cavm@gmail.com>
On Thu, 2 May 2013, David Daney wrote:
> From: David Daney <david.daney@cavium.com>
>
> As noted by Thomas Gleixner:
>
> commit cdbedc61c8 (mips: Use generic idle loop) broke MIPS as I did
> not realize that MIPS wants to invoke the wait instructions with
> interrupts enabled.
>
> Instead of enabling interrupts in arch_cpu_idle() as Thomas' initial
> patch does, we follow Linus' suggestion of doing it in the assembly
> code to prevent the compiler from rearranging things.
Yeah, that looks way more sane.
> Signed-off-by: David Daney <david.daney@cavium.com>
> Reported-by: EunBong Song <eunb.song@samsung.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jonas Gorski <jogo@openwrt.org>
> ---
>
> This is only very lightly tested, we need more testing before
> declaring it the definitive fix.
>
> arch/mips/kernel/genex.S | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
> index ecb347c..57cda9a 100644
> --- a/arch/mips/kernel/genex.S
> +++ b/arch/mips/kernel/genex.S
> @@ -132,12 +132,13 @@ LEAF(r4k_wait)
> .set noreorder
> /* start of rollback region */
> LONG_L t0, TI_FLAGS($28)
> - nop
> andi t0, _TIF_NEED_RESCHED
> bnez t0, 1f
> nop
> - nop
> - nop
> + /* Enable interrupts so WAIT will complete */
> + mfc0 t0, CP0_STATUS
> + ori t0, ST0_IE
> + mtc0 t0, CP0_STATUS
> .set mips3
> wait
> /* end of rollback region (the region size must be power of two) */
> --
> 1.7.11.7
>
>
next prev parent reply other threads:[~2013-05-02 21:04 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-01 4:57 mips; boot fail after merge 3.9+ EUNBONG SONG
2013-05-02 8:32 ` Jonas Gorski
2013-05-02 10:42 ` Thomas Gleixner
2013-05-02 11:20 ` Jonas Gorski
2013-05-02 14:33 ` [PATCH] MIPS: Enable interrupts in arch_cpu_idle() Thomas Gleixner
2013-05-02 14:58 ` Ralf Baechle
2013-05-02 16:45 ` Linus Torvalds
2013-05-02 20:48 ` [PATCH] MIPS: Enable interrupts before WAIT instruction David Daney
2013-05-02 21:04 ` Thomas Gleixner [this message]
2013-05-03 9:54 ` Jonas Gorski
2013-05-06 14:26 ` Manuel Lauss
2013-05-22 22:32 ` Aaro Koskinen
2013-05-22 22:36 ` David Daney
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