From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH v3 4/8] arm64: Handle early CPU boot failures
Date: Wed, 16 Dec 2015 11:29:15 +0000 [thread overview]
Message-ID: <20151216112914.GF4308@arm.com> (raw)
In-Reply-To: <56713F76.8080907@arm.com>
On Wed, Dec 16, 2015 at 10:39:50AM +0000, Suzuki K. Poulose wrote:
> On 15/12/15 11:55, Will Deacon wrote:
> >On Wed, Dec 09, 2015 at 09:57:15AM +0000, Suzuki K. Poulose wrote:
>
> >> /*
> >> * Initial data for bringing up a secondary CPU.
> >>+ * @stack - sp for the secondary CPU
> >>+ * @status - Result passed back from the secondary CPU to
> >>+ * indicate failure.
> >> */
> >> struct secondary_data {
> >> void *stack;
> >>-};
> >>+ unsigned long status;
> >>+} ____cacheline_aligned;
> >
> >Why is this necessary?
>
> That was based on a suggestion from Mark Rutland here:
>
> https://lkml.org/lkml/2015/12/1/580
That thread is talking about the CWG, which is not the same thing as
____cacheline_aligned. Given that the architectural maximum for the CWG
is 2K, we can probably get away with allocating the status field amongst
the head.S text instead (which we know will be clean).
Since SMP boot is serialised, that should be sufficient, right?
Will
next prev parent reply other threads:[~2015-12-16 11:29 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-09 9:57 [RFC PATCH v3 0/8] arm64: Verify early CPU features Suzuki K. Poulose
2015-12-09 9:57 ` [RFC PATCH v3 1/8] arm64: Introduce cpu_die_early Suzuki K. Poulose
2015-12-09 9:57 ` [RFC PATCH v3 2/8] arm64: Move cpu_die_early to smp.c Suzuki K. Poulose
2015-12-15 11:23 ` Will Deacon
2015-12-15 11:26 ` Mark Rutland
2015-12-09 9:57 ` [RFC PATCH v3 3/8] arm64: head.S : Change register usage Suzuki K. Poulose
2015-12-09 9:57 ` [RFC PATCH v3 4/8] arm64: Handle early CPU boot failures Suzuki K. Poulose
2015-12-15 11:37 ` Suzuki K. Poulose
2015-12-15 11:55 ` Will Deacon
2015-12-16 10:39 ` Suzuki K. Poulose
2015-12-16 11:29 ` Will Deacon [this message]
2015-12-16 11:36 ` Mark Rutland
2015-12-09 9:57 ` [RFC PATCH v3 5/8] arm64: Enable CPU capability verification unconditionally Suzuki K. Poulose
2015-12-09 9:57 ` [RFC PATCH v3 6/8] arm64: Add hook for checking early CPU features Suzuki K. Poulose
2015-12-09 9:57 ` [RFC PATCH v3 7/8] arm64: Add helper for extracting ASIDBits Suzuki K. Poulose
2015-12-09 9:57 ` [RFC PATCH v3 8/8] arm64: Ensure the secondary CPUs have safe ASIDBits size Suzuki K. Poulose
2015-12-15 12:02 ` Will Deacon
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