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Commit c812c7d8 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

powerpc/mm: Catch usage of cpu/mmu_has_feature() before jump label init 



This allows us to catch incorrect usage of cpu_has_feature() and
mmu_has_feature() prior to jump labels being initialised.

mpe: Use printk() and dump_stack() rather than WARN_ON(), because
WARN_ON() may not work this early in boot. Rename the Kconfig.

Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent c12e6f24

arch/powerpc/Kconfig.debug

+10 −0
Original line number Diff line number Diff line
@@ -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

arch/powerpc/include/asm/cpu_has_feature.h

+8 −0
Original line number Diff line number Diff line
@@ -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;

arch/powerpc/include/asm/mmu.h

+8 −0
Original line number Diff line number Diff line
@@ -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;