On Wed, Jan 13, 2021 at 09:40:46AM +0800, Jia He wrote:
> Move init_cpu_features() ahead of setup_arch()->early_fixmap_init(), which
> is the preparation work for checking the condition to assign
> arm64_use_ng_mappings as cpus_have_const_cap(ARM64_UNMAP_KERNEL_AT_EL0).
>
> Besides, jump_label_init() is also moved ahead because
> cpus_have_const_cap() depends on static key enable api.
>
> Percpu helpers should be avoided in cpuinfo_store_boot_cpu() before percpu
> init at main.c::setup_per_cpu_areas()
>
> Signed-off-by: Jia He <justin...@arm.com>
> ---
> arch/arm64/include/asm/cpu.h | 1 +
> arch/arm64/kernel/cpuinfo.c | 13 ++++++++++---
> arch/arm64/kernel/setup.c | 14 +++++++++-----
> arch/arm64/kernel/smp.c | 3 +--
> 4 files changed, 21 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/include/asm/cpu.h b/arch/arm64/include/asm/cpu.h
> index 7faae6ff3ab4..59f36f5e3c04 100644
> --- a/arch/arm64/include/asm/cpu.h
> +++ b/arch/arm64/include/asm/cpu.h
> @@ -63,6 +63,7 @@ DECLARE_PER_CPU(struct cpuinfo_arm64, cpu_data);
>
> void cpuinfo_store_cpu(void);
> void __init cpuinfo_store_boot_cpu(void);
> +void __init save_boot_cpuinfo_data(void);
>
> void __init init_cpu_features(struct cpuinfo_arm64 *info);
> void update_cpu_features(int cpu, struct cpuinfo_arm64 *info,
> diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c
> index 77605aec25fe..f8de5b8bae20 100644
> --- a/arch/arm64/kernel/cpuinfo.c
> +++ b/arch/arm64/kernel/cpuinfo.c
> @@ -413,9 +413,16 @@ void cpuinfo_store_cpu(void)
>
> void __init cpuinfo_store_boot_cpu(void)
> {
> - struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
> - __cpuinfo_store_cpu(info);
> + __cpuinfo_store_cpu(&boot_cpu_data);
>
> - boot_cpu_data = *info;
> init_cpu_features(&boot_cpu_data);
> }
> +
> +void __init save_boot_cpuinfo_data(void)
> +{
> + struct cpuinfo_arm64 *info;
> +
> + set_my_cpu_offset(per_cpu_offset(smp_processor_id()));
> + info = &per_cpu(cpu_data, 0);
> + *info = boot_cpu_data;
> +}
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index 1a57a76e1cc2..e078ab068f3b 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -297,16 +297,20 @@ void __init __no_sanitize_address setup_arch(char
> **cmdline_p)
> */
> arm64_use_ng_mappings = kaslr_requires_kpti();
>
> - early_fixmap_init();
> - early_ioremap_init();
> -
> - setup_machine_fdt(__fdt_pointer);
> -
> /*
> * Initialise the static keys early as they may be enabled by the
> * cpufeature code and early parameters.
> */
> jump_label_init();
I don't think your patch changes this, but afaict jump_label_init() uses
per-cpu variables via cpus_read_lock(), yet we don't initialise our offset
until later on. Any idea how that works?
Will
