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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: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Aneesh Kumar K.V 2016-07-23 14:42:43 +05:30 committed by Michael Ellerman
parent c12e6f24d4
commit c812c7d8f1
3 changed files with 26 additions and 0 deletions
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10
arch/powerpc/Kconfig.debug
View File

@ -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

8
arch/powerpc/include/asm/cpu_has_feature.h
View File

@ -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;

8
arch/powerpc/include/asm/mmu.h
View File

@ -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;