arm64: Simplify early check for broken TX1 when KASLR is enabled

Now that the decision to use non-global mappings is stored in a variable,
the check to avoid enabling them for the terminally broken ThunderX1
platform can be simplified so that it is only keyed off the MIDR value.

Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 4a03111..d5242b4 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -980,9 +980,7 @@ has_useable_cnp(const struct arm64_cpu_capabilities *entry, int scope)
  */
 bool kaslr_requires_kpti(void)
 {
-       bool tx1_bug;
        u64 ftr;
-
        if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE))
                return false;
 
@@ -1000,18 +998,13 @@ bool kaslr_requires_kpti(void)
         * Systems affected by Cavium erratum 24756 are incompatible
         * with KPTI.
         */
-       if (!IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
-               tx1_bug = false;
-       } else if (!static_branch_likely(&arm64_const_caps_ready)) {
+       if (IS_ENABLED(CONFIG_CAVIUM_ERRATUM_27456)) {
                extern const struct midr_range cavium_erratum_27456_cpus[];
 
-               tx1_bug = is_midr_in_range_list(read_cpuid_id(),
-                                               cavium_erratum_27456_cpus);
-       } else {
-               tx1_bug = __cpus_have_const_cap(ARM64_WORKAROUND_CAVIUM_27456);
+               if (is_midr_in_range_list(read_cpuid_id(),
+                                         cavium_erratum_27456_cpus))
+                       return false;
        }
-       if (tx1_bug)
-               return false;
 
        return kaslr_offset() > 0;
 }