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James Morse authored
kernel/smp.c has a fancy counter that keeps track of the number of CPUs it marked as not-present and left in cpu_park_loop(). If there are any CPUs spinning in here, features like kexec or hibernate may release them by overwriting this memory. This problem also occurs on machines using spin-tables to release secondary cores. After commit 44dbcc93 ("arm64: Fix behavior of maxcpus=N") we bring all known cpus into the secondary holding pen, meaning this memory can't be re-used by kexec or hibernate. Add a function cpus_are_stuck_in_kernel() to determine if either of these cases have occurred. Signed-off-by:
James Morse <james.morse@arm.com> Acked-by:
Mark Rutland <mark.rutland@arm.com> Reviewed-by:
Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by:
Will Deacon <will.deacon@arm.com> [catalin.marinas@arm.com: cherry-picked from mainline for kexec dependency] Signed-off-by:
Catalin Marinas <catalin.marinas@arm.com>
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