From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Julien Grall <julien.grall@linaro.org>
Cc: Keir Fraser <keir@xen.org>,
ian.campbell@citrix.com, tim@xen.org,
Ian Jackson <ian.jackson@eu.citrix.com>,
stefano.stabellini@citrix.com, Jan Beulich <jbeulich@suse.com>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH v5 1/6] xen: Add convenient macro boot_cpu
Date: Fri, 2 May 2014 16:57:51 +0100 [thread overview]
Message-ID: <5363C07F.8040603@citrix.com> (raw)
In-Reply-To: <1399045930-17364-2-git-send-email-julien.grall@linaro.org>
On 02/05/14 16:52, Julien Grall wrote:
> The macro boot_cpu will be used to get CPU variable from the boot CPU.
>
> Signed-off-by: Julien Grall <julien.grall@linaro.org>
> Suggested-by: Ian Campbell <ian.campbell@citrix.com>
> Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> Cc: Jan Beulich <jbeulich@suse.com>
> Cc: Keir Fraser <keir@xen.org>
> ---
> xen/include/xen/percpu.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/xen/include/xen/percpu.h b/xen/include/xen/percpu.h
> index abe0b11..0e848bf 100644
> --- a/xen/include/xen/percpu.h
> +++ b/xen/include/xen/percpu.h
> @@ -16,6 +16,9 @@
> /* Preferred on Xen. Also see arch-defined per_cpu(). */
> #define this_cpu(var) __get_cpu_var(var)
>
> +/* Access variable on boot CPU */
> +#define boot_cpu(var) per_cpu(var, 0)
> +
What is this actually used for?
In x86 with arbitrary cpu hotplug, we are trying to move away from the
false assumption than cpu0 is the boot cpu. Actual boot data is stored
sideways as boot_$FOO variables, and not accessed with the per-cpu
mechanism.
~Andrew
next prev parent reply other threads:[~2014-05-02 15:57 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-02 15:52 [PATCH v5 0/6] xen/arm: Interrupt management reworking Julien Grall
2014-05-02 15:52 ` [PATCH v5 1/6] xen: Add convenient macro boot_cpu Julien Grall
2014-05-02 15:57 ` Andrew Cooper [this message]
2014-05-06 15:54 ` Julien Grall
2014-05-08 9:57 ` Ian Campbell
2014-05-12 12:36 ` Julien Grall
2014-05-08 9:55 ` Ian Campbell
2014-05-08 10:00 ` Jan Beulich
2014-05-08 10:19 ` Ian Campbell
2014-05-05 7:59 ` Jan Beulich
2014-05-06 15:58 ` Julien Grall
2014-05-06 16:04 ` Jan Beulich
2014-05-06 16:09 ` Andrew Cooper
2014-05-02 15:52 ` [PATCH v5 2/6] xen/arm: IRQ: Store IRQ type in arch_irq_desc Julien Grall
2014-05-08 10:03 ` Ian Campbell
2014-05-12 12:34 ` Julien Grall
2014-05-02 15:52 ` [PATCH v5 3/6] xen/arm: IRQ: Replace {request, setup}_dt_irq by {request, setup}_irq Julien Grall
2014-05-02 15:52 ` [PATCH v5 4/6] xen: IRQ: Add dev_id parameter to release_irq Julien Grall
2014-05-02 15:52 ` [PATCH v5 5/6] xen/arm: IRQ: extend {request, setup}_irq to take an irqflags in parameter Julien Grall
2014-05-02 15:52 ` [PATCH v5 6/6] xen/arm: IRQ: Handle multiple action per IRQ Julien Grall
2014-05-08 10:04 ` Ian Campbell
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