arm64: cpufeature: add cpus_have_final_cap()

[linux-2.6-microblaze.git] / arch / arm64 / include / asm / cpufeature.h

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 92ef953..940b2b6 100644 (file)
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -390,14 +390,16 @@ unsigned long cpu_get_elf_hwcap2(void);
 #define cpu_set_named_feature(name) cpu_set_feature(cpu_feature(name))
 #define cpu_have_named_feature(name) cpu_have_feature(cpu_feature(name))
 
-/* System capability check for constant caps */
-static __always_inline bool __cpus_have_const_cap(int num)
+static __always_inline bool system_capabilities_finalized(void)
 {
-       if (num >= ARM64_NCAPS)
-               return false;
-       return static_branch_unlikely(&cpu_hwcap_keys[num]);
+       return static_branch_likely(&arm64_const_caps_ready);
 }
 
+/*
+ * Test for a capability with a runtime check.
+ *
+ * Before the capability is detected, this returns false.
+ */
 static inline bool cpus_have_cap(unsigned int num)
 {
        if (num >= ARM64_NCAPS)
@@ -405,14 +407,53 @@ static inline bool cpus_have_cap(unsigned int num)
        return test_bit(num, cpu_hwcaps);
 }
 
+/*
+ * Test for a capability without a runtime check.
+ *
+ * Before capabilities are finalized, this returns false.
+ * After capabilities are finalized, this is patched to avoid a runtime check.
+ *
+ * @num must be a compile-time constant.
+ */
+static __always_inline bool __cpus_have_const_cap(int num)
+{
+       if (num >= ARM64_NCAPS)
+               return false;
+       return static_branch_unlikely(&cpu_hwcap_keys[num]);
+}
+
+/*
+ * Test for a capability, possibly with a runtime check.
+ *
+ * Before capabilities are finalized, this behaves as cpus_have_cap().
+ * After capabilities are finalized, this is patched to avoid a runtime check.
+ *
+ * @num must be a compile-time constant.
+ */
 static __always_inline bool cpus_have_const_cap(int num)
 {
-       if (static_branch_likely(&arm64_const_caps_ready))
+       if (system_capabilities_finalized())
                return __cpus_have_const_cap(num);
        else
                return cpus_have_cap(num);
 }
 
+/*
+ * Test for a capability without a runtime check.
+ *
+ * Before capabilities are finalized, this will BUG().
+ * After capabilities are finalized, this is patched to avoid a runtime check.
+ *
+ * @num must be a compile-time constant.
+ */
+static __always_inline bool cpus_have_final_cap(int num)
+{
+       if (system_capabilities_finalized())
+               return __cpus_have_const_cap(num);
+       else
+               BUG();
+}
+
 static inline void cpus_set_cap(unsigned int num)
 {
        if (num >= ARM64_NCAPS) {
@@ -613,11 +654,6 @@ static inline bool system_has_prio_mask_debugging(void)
               system_uses_irq_prio_masking();
 }
 
-static inline bool system_capabilities_finalized(void)
-{
-       return static_branch_likely(&arm64_const_caps_ready);
-}
-
 #define ARM64_BP_HARDEN_UNKNOWN                -1
 #define ARM64_BP_HARDEN_WA_NEEDED      0
 #define ARM64_BP_HARDEN_NOT_REQUIRED   1