Re: [PATCH v3 11/22] arm64: capabilities: Group handling of features and errata workarounds

[Dave Martin <Dave.Martin@arm.com>]

On Fri, Feb 09, 2018 at 05:54:51PM +0000, Suzuki K Poulose wrote:
> Now that the features and errata workarounds have the same
> rules and flow, group the handling of the tables.
> 
> Cc: Dave Martin <dave.martin@arm.com>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>

The naming gets a bit confusing, particularly with
setup_system_capabilities() which enables for SCOPE_ALL, but I can't
think of an obviously better name.

Otherwise the refactoring looks sensible, so FWIW,

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

> ---
>  arch/arm64/kernel/cpufeature.c | 72 ++++++++++++++++++++++++------------------
>  1 file changed, 41 insertions(+), 31 deletions(-)
> 
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 45bac0c4ae91..9b111d560b30 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -504,8 +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_capabilities(const struct arm64_cpu_capabilities *caps,
> -				    u16 scope_mask, const char *info);
> +static void update_cpu_capabilities(u16 scope_mask);
>  
>  void __init init_cpu_features(struct cpuinfo_arm64 *info)
>  {
> @@ -554,10 +553,7 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info)
>  	 * Run the errata work around and local feature checks on the
>  	 * boot CPU, once we have initialised the cpu feature infrastructure.
>  	 */
> -	update_cpu_capabilities(arm64_errata, SCOPE_LOCAL_CPU,
> -				"enabling workaround for");
> -	update_cpu_capabilities(arm64_features, SCOPE_LOCAL_CPU,
> -				"detected feature:");
> +	update_cpu_capabilities(SCOPE_LOCAL_CPU);
>  }
>  
>  static void update_cpu_ftr_reg(struct arm64_ftr_reg *reg, u64 new)
> @@ -1225,7 +1221,7 @@ 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,
> +static void __update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
>  				    u16 scope_mask, const char *info)
>  {
>  	scope_mask &= ARM64_CPUCAP_SCOPE_MASK;
> @@ -1240,6 +1236,14 @@ 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 workaround for");
> +}
> +
>  static int __enable_cpu_capability(void *arg)
>  {
>  	const struct arm64_cpu_capabilities *cap = arg;
> @@ -1253,7 +1257,7 @@ 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++) {
> @@ -1277,6 +1281,12 @@ enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps, u16 scope_mas
>  	}
>  }
>  
> +static void __init enable_cpu_capabilities(u16 scope_mask)
> +{
> +	__enable_cpu_capabilities(arm64_features, scope_mask);
> +	__enable_cpu_capabilities(arm64_errata, scope_mask);
> +}
> +
>  /*
>   * Run through the list of capabilities to check for conflicts.
>   * If the system has already detected a capability, take necessary
> @@ -1332,6 +1342,12 @@ 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_errata, scope_mask) &&
> +	       __verify_local_cpu_caps(arm64_features, scope_mask);
> +}
> +
>  /*
>   * Check for CPU features that are used in early boot
>   * based on the Boot CPU value.
> @@ -1371,7 +1387,6 @@ static void verify_sve_features(void)
>  	/* Add checks on other ZCR bits here if necessary */
>  }
>  
> -
>  /*
>   * Run through the enabled system capabilities and enable() it on this CPU.
>   * The capabilities were decided based on the available CPUs at the boot time.
> @@ -1382,15 +1397,9 @@ static void verify_sve_features(void)
>   */
>  static void verify_local_cpu_capabilities(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.
> -	 */
> -	if (!__verify_local_cpu_caps(arm64_errata, SCOPE_ALL))
> -		cpu_die_early();
> -	if (!__verify_local_cpu_caps(arm64_features, SCOPE_ALL))
> +	if (!verify_local_cpu_caps(SCOPE_ALL))
>  		cpu_die_early();
> +
>  	verify_local_elf_hwcaps(arm64_elf_hwcaps);
>  
>  	if (system_supports_32bit_el0())
> @@ -1417,14 +1426,10 @@ void check_local_cpu_capabilities(void)
>  	 * Otherwise, this CPU should verify that it has all the system
>  	 * advertised capabilities.
>  	 */
> -	if (!sys_caps_initialised) {
> -		update_cpu_capabilities(arm64_errata, SCOPE_LOCAL_CPU,
> -					"enabling workaround for");
> -		update_cpu_capabilities(arm64_features, SCOPE_LOCAL_CPU,
> -					"detected feature:");
> -	} else {
> +	if (!sys_caps_initialised)
> +		update_cpu_capabilities(SCOPE_LOCAL_CPU);
> +	else
>  		verify_local_cpu_capabilities();
> -	}
>  }
>  
>  DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
> @@ -1443,18 +1448,23 @@ bool this_cpu_has_cap(unsigned int cap)
>  		__this_cpu_has_cap(arm64_errata, cap));
>  }
>  
> +static void __init setup_system_capabilities(void)
> +{
> +	/*
> +	 * We have finalised the system-wide safe feature
> +	 * registers, finalise the capabilities that depend
> +	 * on it. Also enable all the available capabilities.
> +	 */
> +	update_cpu_capabilities(SCOPE_SYSTEM);
> +	enable_cpu_capabilities(SCOPE_ALL);
> +}
> +
>  void __init setup_cpu_features(void)
>  {
>  	u32 cwg;
>  	int cls;
>  
> -	/* Set the CPU feature capabilies */
> -	update_cpu_capabilities(arm64_features, SCOPE_SYSTEM,
> -				"detected feature:");
> -	update_cpu_capabilities(arm64_errata, SCOPE_SYSTEM,
> -				"enabling workaround for");
> -	enable_cpu_capabilities(arm64_features, SCOPE_ALL);
> -	enable_cpu_capabilities(arm64_errata, SCOPE_ALL);
> +	setup_system_capabilities();
>  	mark_const_caps_ready();
>  	setup_elf_hwcaps(arm64_elf_hwcaps);
>  
> -- 
> 2.14.3
> 
> 
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