Commit 9113c2aa authored Jul 21, 2016 by Suzuki K Poulose Committed by Catalin Marinas Jul 21, 2016

arm64: Fix incorrect per-cpu usage for boot CPU



In smp_prepare_boot_cpu(), we invoke cpuinfo_store_boot_cpu to  store
the cpuinfo in a per-cpu ptr, before initialising the per-cpu offset for
the boot CPU. This patch reorders the sequence to make sure we initialise
the per-cpu offset before accessing the per-cpu area.

Commit 4b998ff1 ("arm64: Delay cpuinfo_store_boot_cpu") fixed the
issue where we modified the per-cpu area even before the kernel initialises
the per-cpu areas, but failed to wait until the boot cpu updated it's
offset.

Fixes: 4b998ff1 ("arm64: Delay cpuinfo_store_boot_cpu")
Cc: <stable@vger.kernel.org> # 4.4+
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

parent 25722141

arch/arm64/kernel/smp.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -436,9 +436,9 @@ void __init smp_cpus_done(unsigned int max_cpus)

		void __init smp_prepare_boot_cpu(void)
		{
		set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
		cpuinfo_store_boot_cpu();
		save_boot_cpu_run_el();
		set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
		}

		static u64 __init of_get_cpu_mpidr(struct device_node *dn)

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