On Wed, Jan 31, 2018 at 06:27:55PM +0000, Suzuki K Poulose wrote: > So far we have had separate routes for triggering errata and feature > capability detection. 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 both > arm64_features and arm64_errata, in two phases for detection. > > 1) with SCOPE_LOCAL_CPU filter on each boot time enabled CPUs, > via update_cpu_local_capabilities(). > > 2) with SCOPE_SYSTEM filter only once after all boot time enabled > CPUs are active, triggered from setup_cpu_features(). > > A late CPU goes through both the tables for verification against > established capabilities, as before. > > We could ideally merge the two tables into one. But leave it as > it is for easy access to the list of particular type. > > Cc: Dave Martin <[email protected]> > Cc: Will Deacon <[email protected]> > Signed-off-by: Suzuki K Poulose <[email protected]>
I don't know if there's a way of splitting or refactoring this patch to make it easier to understand the changes, but I think I get what's going on here now. So, Reviewed-by: Dave Martin <[email protected]> (But if you can see a good way to split it, I'll be happy to take another look.) > --- > arch/arm64/kernel/cpufeature.c | 77 > ++++++++++++++++++++++++------------------ > 1 file changed, 44 insertions(+), 33 deletions(-) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 5163dc51b975..c710ef28524e 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -504,7 +504,7 @@ static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) > } > > extern const struct arm64_cpu_capabilities arm64_errata[]; > -static void update_cpu_errata_workarounds(void); > +static void update_cpu_local_capabilities(void); > > void __init init_cpu_features(struct cpuinfo_arm64 *info) > { > @@ -553,7 +553,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info) > * Run the errata work around checks on the boot CPU, once we have > * initialised the cpu feature infrastructure. > */ > - update_cpu_errata_workarounds(); > + update_cpu_local_capabilities(); > } > > static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new) > @@ -1184,8 +1184,8 @@ static bool __this_cpu_has_cap(const struct > arm64_cpu_capabilities *cap_array, > return false; > } > > -static void update_cpu_capabilities(const struct arm64_cpu_capabilities > *caps, > - u16 scope_mask, const char *info) > +static void __update_cpu_capabilities(const struct arm64_cpu_capabilities > *caps, > + u16 scope_mask, const char *info) > { > scope_mask &= ARM64_CPUCAP_SCOPE_MASK; > for (; caps->matches; caps++) { > @@ -1199,6 +1199,13 @@ static void update_cpu_capabilities(const struct > arm64_cpu_capabilities *caps, > } > } > > +static void update_cpu_capabilities(u16 scope_mask) > +{ > + __update_cpu_capabilities(arm64_features, scope_mask, > + "detected feature:"); > + __update_cpu_capabilities(arm64_errata, scope_mask, > + "enabling work around for"); > +} > > static int __enable_cpu_capability(void *arg) > { > @@ -1213,7 +1220,7 @@ static int __enable_cpu_capability(void *arg) > * CPUs > */ > static void __init > -enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 > scope_mask) > +__enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 > scope_mask) > { > scope_mask &= ARM64_CPUCAP_SCOPE_MASK; > for (; caps->matches; caps++) { > @@ -1293,6 +1300,12 @@ static bool __verify_local_cpu_caps(const struct > arm64_cpu_capabilities *caps_li > return true; > } > > +static bool verify_local_cpu_caps(u16 scope_mask) > +{ > + return __verify_local_cpu_caps(arm64_features, scope_mask) && > + __verify_local_cpu_caps(arm64_errata, scope_mask); > +} > + > /* > * Check for CPU features that are used in early boot > * based on the Boot CPU value. > @@ -1315,12 +1328,6 @@ verify_local_elf_hwcaps(const struct > arm64_cpu_capabilities *caps) > } > } > > -static void verify_local_cpu_features(void) > -{ > - if (!__verify_local_cpu_caps(arm64_features, ARM64_CPUCAP_SCOPE_ALL)) > - cpu_die_early(); > -} > - > static void verify_sve_features(void) > { > u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1); > @@ -1339,26 +1346,28 @@ static void verify_sve_features(void) > } > > /* > - * 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) > { > - if (!__verify_local_cpu_caps(arm64_errata, ARM64_CPUCAP_SCOPE_ALL)) > - cpu_die_early(); > + update_cpu_capabilities(ARM64_CPUCAP_SCOPE_LOCAL_CPU); > } > > -static void update_cpu_errata_workarounds(void) > +/* > + * Check for all capablities with a system wide scope. > + * This is run only once after all the boot CPUs are > + * brought online. > + */ > +static void update_system_capabilities(void) > { > - update_cpu_capabilities(arm64_errata, > - ARM64_CPUCAP_SCOPE_ALL, > - "enabling workaround for"); > + update_cpu_capabilities(ARM64_CPUCAP_SCOPE_SYSTEM); > } > > -static void __init enable_errata_workarounds(void) > +static void enable_cpu_capabilities(u16 scope_mask) > { > - enable_cpu_capabilities(arm64_errata, ARM64_CPUCAP_SCOPE_ALL); > + __enable_cpu_capabilities(arm64_errata, scope_mask); > + __enable_cpu_capabilities(arm64_features, scope_mask); > } > > /* > @@ -1371,8 +1380,8 @@ static void __init enable_errata_workarounds(void) > */ > static void verify_local_cpu_capabilities(void) > { > - verify_local_cpu_errata_workarounds(); > - verify_local_cpu_features(); > + if (!verify_local_cpu_caps(ARM64_CPUCAP_SCOPE_ALL)) > + cpu_die_early(); > verify_local_elf_hwcaps(arm64_elf_hwcaps); > > if (system_supports_32bit_el0()) > @@ -1400,16 +1409,20 @@ void check_local_cpu_capabilities(void) > * advertised capabilities. > */ > if (!sys_caps_initialised) > - update_cpu_errata_workarounds(); > + update_cpu_local_capabilities(); > else > verify_local_cpu_capabilities(); > } > > -static void __init setup_feature_capabilities(void) > +static void __init setup_system_capabilities(void) > { > - update_cpu_capabilities(arm64_features, > - ARM64_CPUCAP_SCOPE_ALL, "detected feature:"); > - enable_cpu_capabilities(arm64_features, ARM64_CPUCAP_SCOPE_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_SCOPE_ALL); > } > > DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready); > @@ -1433,9 +1446,7 @@ 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); > > -- > 2.14.3 > > > _______________________________________________ > linux-arm-kernel mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
