From: Julien Grall <julien.grall@arm.com>
To: Wei Chen <wei.chen@linaro.org>, xen-devel@lists.xen.org
Cc: sstabellini@kernel.org, steve.capper@arm.com
Subject: Re: [PATCH 4/4] xen/arm: arm64: Remove MPIDR multiprocessing extensions check
Date: Wed, 25 May 2016 15:11:47 +0100 [thread overview]
Message-ID: <5745B2A3.8000907@arm.com> (raw)
In-Reply-To: <1464142211-343-1-git-send-email-Wei.Chen@linaro.org>
Hi Wei,
On 25/05/16 03:10, Wei Chen wrote:
> In ARM64, the MPIDR multiprocessing extensions bit is reserved to 1.
Well, technically the bit is unamed for ARM64. So I would make clear
that the name is from AArch32. Something along:
"The bit 31 (former bit Multiprocessing extensions bit in AArch32) is
always RES1 for AArch64."
> So, the value check for this bit is no longer necessary on ARM64.
>
> Signed-off-by: Wei Chen <Wei.Chen@linaro.org>
> ---
> xen/arch/arm/arm64/head.S | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
> index 3090beb..91e2817 100644
> --- a/xen/arch/arm/arm64/head.S
> +++ b/xen/arch/arm/arm64/head.S
> @@ -267,7 +267,6 @@ common_start:
> * find that multiprocessor extensions are
> * present and the system is SMP */
> mrs x0, mpidr_el1
> - tbz x0, _MPIDR_SMP, 1f /* Multiprocessor extension not supported? */
> tbnz x0, _MPIDR_UP, 1f /* Uniprocessor system? */
>
> ldr x13, =(~MPIDR_HWID_MASK)
>
Regards,
--
Julien Grall
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prev parent reply other threads:[~2016-05-25 14:11 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 2:10 [PATCH 4/4] xen/arm: arm64: Remove MPIDR multiprocessing extensions check Wei Chen
2016-05-25 12:37 ` Peng Fan
2016-05-25 13:31 ` Julien Grall
2016-05-25 14:11 ` Julien Grall [this message]
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