Messages in this thread | | | Subject | Re: [PATCH 08/16] arm64: capabilities: Group handling of features and errata | From | Suzuki K Poulose <> | Date | Fri, 26 Jan 2018 12:31:18 +0000 |
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On 26/01/18 11:47, Dave Martin wrote: > On Tue, Jan 23, 2018 at 12:28:01PM +0000, Suzuki K Poulose wrote: >> So far we have had separate routes for triggering errata and feature > > "triggering errata" ? ;) >
:-). Should have been "triggering errata and feature capability *checks*.
> Maybe "[...] for determining whether to activate errata workarounds and > whether to enable feature capabilities." >
>> capabilities. Also, we never allowed "features" based on local CPU >> and "errata" based on System wide safe registers. This patch >> groups the handling of errata and features and also allows them >> to have all the possible scopes. >> >> So, we now run through the arm64_features and arm64_errata: > > when?
with this patch.
> What about late cpus? >
We don't detect any new capabilities on them. They continue to get verified against the enabled capabilities.
>> 1) with SCOPE_LOCAL_CPU filter on each boot time enabeld CPUs, >> via update_cpu_local_capabilities(). > > "each [...] enabeld CPUs" -> "each [...] enabled CPU" > > Also, changing "boot time" -> "boot-time" helps avoid this being misread > as "on each boot", which could be taken to mean "each time a CPU comes > online". I'm guessing that's not the intended meaning here.
OK
>> /* >> - * The CPU Errata work arounds are detected and applied at boot time >> - * and the related information is freed soon after. If the new CPU requires >> - * an errata not detected at boot, fail this CPU. >> + * Check for all capablities within the scope of local CPU. >> + * This is run on all boot time activated CPUs. >> */ >> -static void verify_local_cpu_errata_workarounds(void) >> +static void update_cpu_local_capabilities(void) > > [Gaah, stupid git diff making function insertion look like function > modification. Sometimes --patience does a better job, but there seems > no foolproof solution... If you do a respin, it might be worth trying > it.]
Will try, thanks for the suggestion. I didn't know about that :-)
>> -static void __init setup_feature_capabilities(void) >> +static void __init setup_system_capabilities(void) >> { >> - update_cpu_capabilities(arm64_features, >> - ARM64_CPUCAP_TYPE_ALL, "detected feature:"); >> - enable_cpu_capabilities(arm64_features, ARM64_CPUCAP_TYPE_ALL); >> + /* >> + * We have finalised the system wide safe feature registers, >> + * finalise the capabilities that depend on it. >> + */ >> + update_system_capabilities(); >> + /* Enable all the available capabilities */ >> + enable_cpu_capabilities(ARM64_CPUCAP_TYPE_ALL); > > So setup_system_capabilities() enables _non_ system-wide capabilities/ > errata workarounds too?
> Maybe this function should just have a different name, like > "setup_boot_capabilities" or similar?
The problem with setup_boot_capabilities() is that it could conflict with "coming soon" setup_boot_cpu_capabilities(). May be,
setup_boot_time_system_capabilities().
> > } >> >> DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready); >> @@ -1422,9 +1435,7 @@ void __init setup_cpu_features(void) >> u32 cwg; >> int cls; >> >> - /* Set the CPU feature capabilies */ >> - setup_feature_capabilities(); >> - enable_errata_workarounds(); >> + setup_system_capabilities(); >> mark_const_caps_ready(); >> setup_elf_hwcaps(arm64_elf_hwcaps); > > I wonder whether we could unify the elf hwcaps handling too.
I was thinking about it today. The only catch is how do we know if we have "the capability", as it is spread across multiple bitmasks. (HWCAP, COMPAT_HWCAP, COMPAT_HWCAP2).
Suzuki
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