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| author | Michael Ellerman <mpe@ellerman.id.au> | 2016-07-26 22:29:18 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-08-01 11:14:56 +1000 |
| commit | a28e46f109c9637b2539b9995078d5df4f7f6c09 (patch) | |
| tree | 954cdde1913d243e517596aab5718dfa65fcd800 /arch/powerpc | |
| parent | 9e8066f398396d26010d9c6c3c2538ff25461ef8 (diff) | |
| download | linux-a28e46f109c9637b2539b9995078d5df4f7f6c09.tar.bz2 | |
powerpc/kernel: Check features don't change after patching
Early in boot we binary patch some sections of code based on the CPU and
MMU feature bits. But it is a one-time patching, there is no facility
for repatching the code later if the set of features change.
It is a major bug if the set of features changes after we've done the
code patching - so add a check for it.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/lib/feature-fixups.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c index defb2998b818..59c7caee05b2 100644 --- a/arch/powerpc/lib/feature-fixups.c +++ b/arch/powerpc/lib/feature-fixups.c @@ -152,10 +152,19 @@ static void do_final_fixups(void) #endif } -void apply_feature_fixups(void) +static unsigned long __initdata saved_cpu_features; +static unsigned int __initdata saved_mmu_features; +#ifdef CONFIG_PPC64 +static unsigned long __initdata saved_firmware_features; +#endif + +void __init apply_feature_fixups(void) { struct cpu_spec *spec = *PTRRELOC(&cur_cpu_spec); + *PTRRELOC(&saved_cpu_features) = spec->cpu_features; + *PTRRELOC(&saved_mmu_features) = spec->mmu_features; + /* * Apply the CPU-specific and firmware specific fixups to kernel text * (nop out sections not relevant to this CPU or this firmware). @@ -173,12 +182,28 @@ void apply_feature_fixups(void) PTRRELOC(&__stop___lwsync_fixup)); #ifdef CONFIG_PPC64 + saved_firmware_features = powerpc_firmware_features; do_feature_fixups(powerpc_firmware_features, &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup); #endif do_final_fixups(); } +static int __init check_features(void) +{ + WARN(saved_cpu_features != cur_cpu_spec->cpu_features, + "CPU features changed after feature patching!\n"); + WARN(saved_mmu_features != cur_cpu_spec->mmu_features, + "MMU features changed after feature patching!\n"); +#ifdef CONFIG_PPC64 + WARN(saved_firmware_features != powerpc_firmware_features, + "Firmware features changed after feature patching!\n"); +#endif + + return 0; +} +late_initcall(check_features); + #ifdef CONFIG_FTR_FIXUP_SELFTEST #define check(x) \ |