[v2,1/4] arm64: standardise cpucap bitmap names

Commit Message

Mark Rutland June 7, 2023, 4:48 p.m. UTC

The 'cpu_hwcaps' and 'boot_capabilities' bitmaps are bitmaps have the
same enumerated bits, but are named wildly differently for no good
reason. The terms 'hwcaps' and 'capabilities' have become ambiguous over
time (e.g. due to clashes with ELF hwcaps and the structures used to
manage feature detection), and it would be nicer to use 'cpucaps',
matching the <asm/cpucaps.h> header the enumerated bit indices are
defined in.

While this isn't a functional problem, it makes the code harder than
necessary to understand, and hard to extend with related functionality
(e.g. per-cpu cpucap bitmaps).

To that end, this patch renames `boot_capabilities` to `boot_cpucaps`
and `cpu_hwcaps` to `system_cpucaps`. This more clearly indicates the
relationship between the two and aligns with terminology used elsewhere
in our feature management code.

This change was scripted with:

| find . -type f -name '*.[chS]' -print0 | \
|   xargs -0 sed -i 's/\<boot_capabilities\>/boot_cpucaps/'
| find . -type f -name '*.[chS]' -print0 | \
|   xargs -0 sed -i 's/\<cpu_hwcaps\>/system_cpucaps/'

... and the instance of "cpu_hwcap" (without a trailing "s") in
<asm/mmu_context.h> corrected manually to "system_cpucaps".

Subsequent patches will adjust the naming of related functions to better
align with the `cpucap` naming.

There should be no functional change as a result of this patch; this is
purely a renaming exercise.

Signed-off-by: Mark Rutland <[e-mail]>
Reviewed-by: Mark Brown <[e-mail]>
Reviewed-by: Suzuki K Poulose <[e-mail]>
Cc: Catalin Marinas <[e-mail]>
Cc: Marc Zyngier <[e-mail]>
Cc: Will Deacon <[e-mail]>
---
 arch/arm64/include/asm/cpufeature.h  | 12 ++++++------
 arch/arm64/include/asm/mmu_context.h |  2 +-
 arch/arm64/kernel/alternative.c      |  6 +++---
 arch/arm64/kernel/cpufeature.c       | 12 ++++++------
 4 files changed, 16 insertions(+), 16 deletions(-)

Patch

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 6bf013fb110d7..04e11cdeda14b 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -107,7 +107,7 @@  extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0;
  * CPU capabilities:
  *
  * We use arm64_cpu_capabilities to represent system features, errata work
- * arounds (both used internally by kernel and tracked in cpu_hwcaps) and
+ * arounds (both used internally by kernel and tracked in system_cpucaps) and
  * ELF HWCAPs (which are exposed to user).
  *
  * To support systems with heterogeneous CPUs, we need to make sure that we
@@ -419,12 +419,12 @@  static __always_inline bool is_hyp_code(void)
 	return is_vhe_hyp_code() || is_nvhe_hyp_code();
 }
 
-extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
+extern DECLARE_BITMAP(system_cpucaps, ARM64_NCAPS);
 
-extern DECLARE_BITMAP(boot_capabilities, ARM64_NCAPS);
+extern DECLARE_BITMAP(boot_cpucaps, ARM64_NCAPS);
 
 #define for_each_available_cap(cap)		\
-	for_each_set_bit(cap, cpu_hwcaps, ARM64_NCAPS)
+	for_each_set_bit(cap, system_cpucaps, ARM64_NCAPS)
 
 bool this_cpu_has_cap(unsigned int cap);
 void cpu_set_feature(unsigned int num);
@@ -449,7 +449,7 @@  static __always_inline bool cpus_have_cap(unsigned int num)
 {
 	if (num >= ARM64_NCAPS)
 		return false;
-	return arch_test_bit(num, cpu_hwcaps);
+	return arch_test_bit(num, system_cpucaps);
 }
 
 /*
@@ -510,7 +510,7 @@  static inline void cpus_set_cap(unsigned int num)
 		pr_warn("Attempt to set an illegal CPU capability (%d >= %d)\n",
 			num, ARM64_NCAPS);
 	} else {
-		__set_bit(num, cpu_hwcaps);
+		__set_bit(num, system_cpucaps);
 	}
 }
 
diff --git a/arch/arm64/include/asm/mmu_context.h b/arch/arm64/include/asm/mmu_context.h
index 56911691bef05..5e0402946c35b 100644
--- a/arch/arm64/include/asm/mmu_context.h
+++ b/arch/arm64/include/asm/mmu_context.h
@@ -164,7 +164,7 @@  static inline void cpu_replace_ttbr1(pgd_t *pgdp, pgd_t *idmap)
 		 * up (i.e. cpufeature framework is not up yet) and
 		 * latter only when we enable CNP via cpufeature's
 		 * enable() callback.
-		 * Also we rely on the cpu_hwcap bit being set before
+		 * Also we rely on the system_cpucaps bit being set before
 		 * calling the enable() function.
 		 */
 		ttbr1 |= TTBR_CNP_BIT;
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index d32d4ed5519bd..51a5dbd7f324e 100644
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -192,7 +192,7 @@  static void __apply_alternatives(const struct alt_region *region,
 		bitmap_or(applied_alternatives, applied_alternatives,
 			  feature_mask, ARM64_NCAPS);
 		bitmap_and(applied_alternatives, applied_alternatives,
-			   cpu_hwcaps, ARM64_NCAPS);
+			   system_cpucaps, ARM64_NCAPS);
 	}
 }
 
@@ -239,7 +239,7 @@  static int __init __apply_alternatives_multi_stop(void *unused)
 	} else {
 		DECLARE_BITMAP(remaining_capabilities, ARM64_NCAPS);
 
-		bitmap_complement(remaining_capabilities, boot_capabilities,
+		bitmap_complement(remaining_capabilities, boot_cpucaps,
 				  ARM64_NCAPS);
 
 		BUG_ON(all_alternatives_applied);
@@ -274,7 +274,7 @@  void __init apply_boot_alternatives(void)
 	pr_info("applying boot alternatives\n");
 
 	__apply_alternatives(&kernel_alternatives, false,
-			     &boot_capabilities[0]);
+			     &boot_cpucaps[0]);
 }
 
 #ifdef CONFIG_MODULES
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 7d7128c651614..68e012f4ea080 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -105,11 +105,11 @@  unsigned int compat_elf_hwcap __read_mostly = COMPAT_ELF_HWCAP_DEFAULT;
 unsigned int compat_elf_hwcap2 __read_mostly;
 #endif
 
-DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
-EXPORT_SYMBOL(cpu_hwcaps);
+DECLARE_BITMAP(system_cpucaps, ARM64_NCAPS);
+EXPORT_SYMBOL(system_cpucaps);
 static struct arm64_cpu_capabilities const __ro_after_init *cpu_hwcaps_ptrs[ARM64_NCAPS];
 
-DECLARE_BITMAP(boot_capabilities, ARM64_NCAPS);
+DECLARE_BITMAP(boot_cpucaps, ARM64_NCAPS);
 
 bool arm64_use_ng_mappings = false;
 EXPORT_SYMBOL(arm64_use_ng_mappings);
@@ -137,7 +137,7 @@  static cpumask_var_t cpu_32bit_el0_mask __cpumask_var_read_mostly;
 void dump_cpu_features(void)
 {
 	/* file-wide pr_fmt adds "CPU features: " prefix */
-	pr_emerg("0x%*pb\n", ARM64_NCAPS, &cpu_hwcaps);
+	pr_emerg("0x%*pb\n", ARM64_NCAPS, &system_cpucaps);
 }
 
 #define ARM64_CPUID_FIELDS(reg, field, min_value)			\
@@ -2906,7 +2906,7 @@  static void update_cpu_capabilities(u16 scope_mask)
 		cpus_set_cap(caps->capability);
 
 		if ((scope_mask & SCOPE_BOOT_CPU) && (caps->type & SCOPE_BOOT_CPU))
-			set_bit(caps->capability, boot_capabilities);
+			set_bit(caps->capability, boot_cpucaps);
 	}
 }
 
@@ -3207,7 +3207,7 @@  EXPORT_SYMBOL_GPL(this_cpu_has_cap);
 /*
  * This helper function is used in a narrow window when,
  * - The system wide safe registers are set with all the SMP CPUs and,
- * - The SYSTEM_FEATURE cpu_hwcaps may not have been set.
+ * - The SYSTEM_FEATURE system_cpucaps may not have been set.
  * In all other cases cpus_have_{const_}cap() should be used.
  */
 static bool __maybe_unused __system_matches_cap(unsigned int n)