arm64: capabilities: Unify the verification

Now that each capability describes how to treat the conflicts
of CPU cap state vs System wide cap state, we can unify the
verification logic to a single place.

Reviewed-by: Dave Martin <dave.martin@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 0b8e6b9..1fda957 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1305,6 +1305,58 @@ enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
        }
 }
 
+/*
+ * Run through the list of capabilities to check for conflicts.
+ * If the system has already detected a capability, take necessary
+ * action on this CPU.
+ *
+ * Returns "false" on conflicts.
+ */
+static bool
+__verify_local_cpu_caps(const struct arm64_cpu_capabilities *caps_list)
+{
+       bool cpu_has_cap, system_has_cap;
+       const struct arm64_cpu_capabilities *caps;
+
+       for (caps = caps_list; caps->matches; caps++) {
+               cpu_has_cap = __this_cpu_has_cap(caps_list, caps->capability);
+               system_has_cap = cpus_have_cap(caps->capability);
+
+               if (system_has_cap) {
+                       /*
+                        * Check if the new CPU misses an advertised feature,
+                        * which is not safe to miss.
+                        */
+                       if (!cpu_has_cap && !cpucap_late_cpu_optional(caps))
+                               break;
+                       /*
+                        * We have to issue cpu_enable() irrespective of
+                        * whether the CPU has it or not, as it is enabeld
+                        * system wide. It is upto the call back to take
+                        * appropriate action on this CPU.
+                        */
+                       if (caps->cpu_enable)
+                               caps->cpu_enable(caps);
+               } else {
+                       /*
+                        * Check if the CPU has this capability if it isn't
+                        * safe to have when the system doesn't.
+                        */
+                       if (cpu_has_cap && !cpucap_late_cpu_permitted(caps))
+                               break;
+               }
+       }
+
+       if (caps->matches) {
+               pr_crit("CPU%d: Detected conflict for capability %d (%s), System: %d, CPU: %d\n",
+                       smp_processor_id(), caps->capability,
+                       caps->desc, system_has_cap, cpu_has_cap);
+               return false;
+       }
+
+       return true;
+}
+
 /*
  * Check for CPU features that are used in early boot
  * based on the Boot CPU value.
@@ -1327,25 +1379,10 @@ verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps)
                }
 }
 
-static void
-verify_local_cpu_features(const struct arm64_cpu_capabilities *caps_list)
+static void verify_local_cpu_features(void)
 {
-       const struct arm64_cpu_capabilities *caps = caps_list;
-       for (; caps->matches; caps++) {
-               if (!cpus_have_cap(caps->capability))
-                       continue;
-               /*
-                * If the new CPU misses an advertised feature, we cannot proceed
-                * further, park the cpu.
-                */
-               if (!__this_cpu_has_cap(caps_list, caps->capability)) {
-                       pr_crit("CPU%d: missing feature: %s\n",
-                                       smp_processor_id(), caps->desc);
-                       cpu_die_early();
-               }
-               if (caps->cpu_enable)
-                       caps->cpu_enable(caps);
-       }
+       if (!__verify_local_cpu_caps(arm64_features))
+               cpu_die_early();
 }
 
 static void verify_sve_features(void)
@@ -1372,20 +1409,8 @@ static void verify_sve_features(void)
  */
 static void verify_local_cpu_errata_workarounds(void)
 {
-       const struct arm64_cpu_capabilities *caps = arm64_errata;
-
-       for (; caps->matches; caps++) {
-               if (cpus_have_cap(caps->capability)) {
-                       if (caps->cpu_enable)
-                               caps->cpu_enable(caps);
-               } else if (caps->matches(caps, SCOPE_LOCAL_CPU)) {
-                       pr_crit("CPU%d: Requires work around for %s, not detected"
-                                       " at boot time\n",
-                               smp_processor_id(),
-                               caps->desc ? : "an erratum");
-                       cpu_die_early();
-               }
-       }
+       if (!__verify_local_cpu_caps(arm64_errata))
+               cpu_die_early();
 }
 
 static void update_cpu_errata_workarounds(void)
@@ -1409,7 +1434,7 @@ static void __init enable_errata_workarounds(void)
 static void verify_local_cpu_capabilities(void)
 {
        verify_local_cpu_errata_workarounds();
-       verify_local_cpu_features(arm64_features);
+       verify_local_cpu_features();
        verify_local_elf_hwcaps(arm64_elf_hwcaps);
 
        if (system_supports_32bit_el0())