Re: [PATCH] [4.7] arm64: Honor nosmp kernel command line option

From	Catalin Marinas <catalin.marinas@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] [4.7] arm64: Honor nosmp kernel command line option
Date	2016-07-21 17:10 +0200
Message-ID	<rXnLQ-DS-19@gated-at.bofh.it> (permalink)
References	<rXjfb-67q-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Jul 21, 2016 at 11:15:27AM +0100, Suzuki K. Poulose wrote:
> Passing "nosmp" should boot the kernel with a single processor, without
> provision to enable secondary CPUs even if they are present. "nosmp" is
> implemented by setting maxcpus=0. At the moment we still mark the secondary
> CPUs present even with nosmp, which allows the userspace to bring them
> up. This patch corrects the smp_prepare_cpus() to honor the maxcpus == 0.
> 
> Commit 44dbcc93ab67145 ("arm64: Fix behavior of maxcpus=N") fixed the
> behavior for maxcpus >= 1, but broke maxcpus = 0.
> 
> Fixes: commit 44dbcc93ab67145 ("arm64: Fix behavior of maxcpus=N")
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: James Morse <james.morse@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

Queued for 4.8, with Mark's comment and a cc stable for 4.7

-- 
Catalin

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[PATCH] [4.7] arm64: Honor nosmp kernel command line option Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-07-21 12:20 +0200
  Re: [PATCH] [4.7] arm64: Honor nosmp kernel command line option Mark Rutland <mark.rutland@arm.com> - 2016-07-21 12:40 +0200
  Re: [PATCH] [4.7] arm64: Honor nosmp kernel command line option Catalin Marinas <catalin.marinas@arm.com> - 2016-07-21 17:10 +0200

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