Commit 32365e64 authored by Committed by Catalin Marinas
arm64: fix bug for reloading FPSIMD state after CPU hotplug.
Now FPSIMD don't handle HOTPLUG_CPU. This introduces bug after cpu down/up process. After cpu down/up process, the FPSMID hardware register is default value, not any process's fpsimd context. when CPU_DEAD set cpu's fpsimd_state to NULL, it will force to load the fpsimd context for the thread, to avoid the chance to skip to load the context. If process A is the last user process on CPU N before cpu down, and the first user process on the same CPU N after cpu up, A's fpsimd_state.cpu is the current cpu id, and per_cpu(fpsimd_last_state) points A's fpsimd_state, so kernel will not reload the context during it return to user space. Signed-off-by: Janet Liu <email@example.com> Signed-off-by: Xiongshan An <firstname.lastname@example.org> Signed-off-by: Chunyan Zhang <email@example.com> [firstname.lastname@example.org: some mostly cosmetic clean-ups] Signed-off-by: Catalin Marinas <email@example.com>
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