include/asm/cpufeature.h

1 /* SPDX-License-Identifier: GPL-2.0-only */
9 #include <asm/alternative-macros.h>
34  * between the values, the features are classified into 3 types - LOWER_SAFE,
80  * A @mask field set to full-1 indicates that the corresponding field
83  * A @mask field set to full-0 with the corresponding @val field set
84  * to full-0 denotes that this field has no override
86  * A @mask field set to full-0 with the corresponding @val field set
87  * to full-1 denotes that this field has an invalid override.
95  * @arm64_ftr_reg - Feature register
144  *     c) SCOPE_BOOT_CPU: Check only on the primary boot CPU to detect the
154  *    actions if any. Usually, this is done, after all the boot-time
155  *    enabled CPUs are brought up by the kernel, so that it can make
158  *    boot by the primary boot CPU. (e.g, running the kernel at EL2 with
164  *    CPUs are treated "late CPUs" for capabilities determined by the boot
168  *      a) Boot CPU scope capabilities - Finalised by primary boot CPU via
170  *      b) Everything except (a) - Run via setup_system_capabilities().
177  *	secondary_start_kernel()-> check_local_cpu_capabilities()
185  *	except for the primary boot CPU.
188  *	user after the kernel boot are verified against the capability.
210  *	  check_local_cpu_capabilities() -> verify_local_cpu_capabilities()
215  *		x-----------------------------x
217  *		|-----------------------------|
219  *		|-----------------------------|
221  *		x-----------------------------x
225  *		ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU - Case(a) is allowed
226  *		ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU - Case(b) is allowed
229  *     all CPUs to have in order for the capability to be enabled. This is
232  *     Case (b) is not permitted for a capability that must be enabled
233  *     during boot if any CPU in the system requires it in order to run
235  *     enabled after the corresponding capability is finalised.
237  *     In some non-typical cases either both (a) and (b), or neither,
249  * On any local CPU vs System wide vs the primary boot CPU
254  * The capabilitiy is detected on the Boot CPU and is used by kernel
255  * during early boot. i.e, the capability should be "detected" and
256  * "enabled" as early as possibly on all booting CPUs.
271  * hasn't already enabled it ?
280  * CPU errata workarounds that need to be enabled at boot time if one or
282  * has been enabled, it is safe to allow any CPU to boot that doesn't
284  * requires a workaround and the system hasn't enabled it already.
289  * CPU feature detected at boot time based on system-wide value of a
291  * the system hasn't enabled it, although the feature will not be used
292  * by Linux in this case. If the system has enabled this feature already,
298  * CPU feature detected at boot time based on feature of one or more CPUs.
309  * CPU feature detected at boot time, on one or more CPUs. A late CPU
318  * CPU feature used early in the boot based on the boot CPU. All secondary
319  * CPUs must match the state of the capability as detected by the boot CPU. In
326  * CPU feature used early in the boot based on the boot CPU. It is safe for a
327  * late CPU to have this feature even though the boot CPU hasn't enabled it,
328  * although the feature will not be used by Linux in this case. If the boot CPU
329  * has enabled this feature already, then every late CPU must have it.
391 	return cap->type & ARM64_CPUCAP_SCOPE_MASK;  in cpucap_default_scope()
405 	for (caps = entry->match_list; caps->matches; caps++)  in cpucap_multi_entry_cap_matches()
406 		if (caps->matches(caps, scope))  in cpucap_multi_entry_cap_matches()
472  * Before boot capabilities are finalized, this will BUG().
473  * After boot capabilities are finalized, this is patched to avoid a runtime
476  * @num must be a compile-time constant.
493  * @num must be a compile-time constant.
506 	return (s64)(features << (64 - width - field)) >> (64 - width);  in cpuid_feature_extract_signed_field_width()
518 	return (u64)(features << (64 - width - field)) >> (64 - width);  in cpuid_feature_extract_unsigned_field_width()
529  * not follow the standard ID scheme. See ARM DDI 0487E.a page D13-2825,
552 	return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);  in arm64_ftr_mask()
557 	return (reg->user_val | (reg->sys_val & reg->user_mask));  in arm64_ftr_reg_user_value()
578 	return (s64)cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->width, ftrp->sign);  in arm64_ftr_value()
937 	u64 oval = override->val;  in arm64_apply_feature_override()
942 	 * override code will set the mask to 0x0 and the value to non-zero for  in arm64_apply_feature_override()
947 	oval &= GENMASK_ULL(feat + width - 1, feat);  in arm64_apply_feature_override()
953 	if (oval == (oval & override->mask)) {  in arm64_apply_feature_override()
954 		val &= ~override->mask;  in arm64_apply_feature_override()