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-rw-r--r--arch/powerpc/Kconfig.debug10
-rw-r--r--arch/powerpc/include/asm/cpu_has_feature.h8
-rw-r--r--arch/powerpc/include/asm/mmu.h8
3 files changed, 26 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 36d7e345f599..63292f64b25a 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -69,6 +69,16 @@ config JUMP_LABEL_FEATURE_CHECKS
feature checks. This should generate more optimal code for those
checks.
+config JUMP_LABEL_FEATURE_CHECK_DEBUG
+ bool "Do extra check on feature fixup calls"
+ depends on DEBUG_KERNEL && JUMP_LABEL_FEATURE_CHECKS
+ default n
+ help
+ This tries to catch incorrect usage of cpu_has_feature() and
+ mmu_has_feature() in the code.
+
+ If you don't know what this means, say N.
+
config FTR_FIXUP_SELFTEST
bool "Run self-tests of the feature-fixup code"
depends on DEBUG_KERNEL
diff --git a/arch/powerpc/include/asm/cpu_has_feature.h b/arch/powerpc/include/asm/cpu_has_feature.h
index 039c011b4252..2ef55f8968a2 100644
--- a/arch/powerpc/include/asm/cpu_has_feature.h
+++ b/arch/powerpc/include/asm/cpu_has_feature.h
@@ -25,6 +25,14 @@ static __always_inline bool cpu_has_feature(unsigned long feature)
BUILD_BUG_ON(!__builtin_constant_p(feature));
+#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
+ if (!static_key_initialized) {
+ printk("Warning! cpu_has_feature() used prior to jump label init!\n");
+ dump_stack();
+ return early_cpu_has_feature(feature);
+ }
+#endif
+
if (CPU_FTRS_ALWAYS & feature)
return true;
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 1bf919aafd50..e2fb408f8398 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -156,6 +156,14 @@ static __always_inline bool mmu_has_feature(unsigned long feature)
BUILD_BUG_ON(!__builtin_constant_p(feature));
+#ifdef CONFIG_JUMP_LABEL_FEATURE_CHECK_DEBUG
+ if (!static_key_initialized) {
+ printk("Warning! mmu_has_feature() used prior to jump label init!\n");
+ dump_stack();
+ return early_mmu_has_feature(feature);
+ }
+#endif
+
if (!(MMU_FTRS_POSSIBLE & feature))
return false;