arm64: Honor nosmp kernel command line option
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 44dbcc93 ("arm64: Fix behavior of maxcpus=N") fixed the behavior for maxcpus >= 1, but broke maxcpus = 0. Fixes: 44dbcc93 ("arm64: Fix behavior of maxcpus=N") Cc: <stable@vger.kernel.org> # 4.7+ Cc: Will Deacon <will.deacon@arm.com> Cc: James Morse <james.morse@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.com> [catalin.marinas@arm.com: updated code comment] Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
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