Messages in this thread | | | Date | Tue, 26 Jan 2021 13:57:13 +0000 | From | Will Deacon <> | Subject | Re: [RFC PATCH 1/2] arm64/cpuinfo: Move init_cpu_features() ahead of setup.c::early_fixmap_init() |
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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.he@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
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