Commit e3661b12 authored by Marc Zyngier's avatar Marc Zyngier Committed by Will Deacon

arm64: Allow a capability to be checked on a single CPU

Now that the capabilities are only available once all the CPUs
have booted, we're unable to check for a particular feature
in any subsystem that gets initialized before then.

In order to support this, introduce a local_cpu_has_cap() function
that tests for the presence of a given capability independently
of the whole framework.
Reviewed-by: default avatarCatalin Marinas <>
Signed-off-by: default avatarMarc Zyngier <>
[ Added preemptible() check ]
Signed-off-by: default avatarSuzuki K Poulose <>
[will: remove duplicate initialisation of caps in this_cpu_has_cap]
Signed-off-by: default avatarWill Deacon <>
parent 92406f0c
......@@ -109,6 +109,8 @@ struct arm64_cpu_capabilities {
extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS);
bool this_cpu_has_cap(unsigned int cap);
static inline bool cpu_have_feature(unsigned int num)
return elf_hwcap & (1UL << num);
......@@ -1010,6 +1010,24 @@ static void __init setup_feature_capabilities(void)
* Check if the current CPU has a given feature capability.
* Should be called from non-preemptible context.
bool this_cpu_has_cap(unsigned int cap)
const struct arm64_cpu_capabilities *caps;
if (WARN_ON(preemptible()))
return false;
for (caps = arm64_features; caps->desc; caps++)
if (caps->capability == cap && caps->matches)
return caps->matches(caps, SCOPE_LOCAL_CPU);
return false;
void __init setup_cpu_features(void)
u32 cwg;
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