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| author | James Morse <james.morse@arm.com> | 2019-06-18 16:17:33 +0100 |
|---|---|---|
| committer | Marc Zyngier <marc.zyngier@arm.com> | 2019-07-05 13:03:29 +0100 |
| commit | 2b68a2a963a157f024c67c0697b16f5f792c8a35 (patch) | |
| tree | fb83b9c73f83ab18a025a435eb057b0715f67bec /arch/arm64/include | |
| parent | 4b972a01a7da614b4796475f933094751a295a2f (diff) | |
| download | linux-2b68a2a963a157f024c67c0697b16f5f792c8a35.tar.bz2 | |
arm64: assembler: Switch ESB-instruction with a vanilla nop if !ARM64_HAS_RAS
The ESB-instruction is a nop on CPUs that don't implement the RAS
extensions. This lets us use it in places like the vectors without
having to use alternatives.
If someone disables CONFIG_ARM64_RAS_EXTN, this instruction still has
its RAS extensions behaviour, but we no longer read DISR_EL1 as this
register does depend on alternatives.
This could go wrong if we want to synchronize an SError from a KVM
guest. On a CPU that has the RAS extensions, but the KConfig option
was disabled, we consume the pending SError with no chance of ever
reading it.
Hide the ESB-instruction behind the CONFIG_ARM64_RAS_EXTN option,
outputting a regular nop if the feature has been disabled.
Reported-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/include')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 570d195a184d..e3a15c751b13 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -96,7 +96,11 @@ * RAS Error Synchronization barrier */ .macro esb +#ifdef CONFIG_ARM64_RAS_EXTN hint #16 +#else + nop +#endif .endm /* |