Commit 747438e4 authored by Amit Kachhap's avatar Amit Kachhap

arm64: cpufeature: Fix meta-capability cpufeature check

Some existing/future meta cpucaps match need the presence of individual
cpucaps. Currently the individual cpucaps checks it via an array based
flag and this introduces dependency on the array entry order.
This limitation exists only for system scope cpufeature.

This patch introduces an internal helper function (__system_matches_cap)
to invoke the matching handler for system scope. This helper has to be
used during a narrow window when,
- The system wide safe registers are set with all the SMP CPUs and,
- The SYSTEM_FEATURE cpu_hwcaps may not have been set.

Normal users should use the existing cpus_have_{const_}cap() global
Suggested-by: Catalin Marinas's avatarCatalin Marinas <>
Signed-off-by: Amit Kachhap's avatarAmit Daniel Kachhap <>
parent 11a48a5a
......@@ -116,6 +116,8 @@ cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap);
static bool __system_matches_cap(unsigned int n);
* NOTE: Any changes to the visibility of features should be kept in
* sync with the documentation of the CPU feature register ABI.
......@@ -2146,6 +2148,17 @@ bool this_cpu_has_cap(unsigned int n)
return false;
static bool __system_matches_cap(unsigned int n)
if (n < ARM64_NCAPS) {
const struct arm64_cpu_capabilities *cap = cpu_hwcaps_ptrs[n];
if (cap)
return cap->matches(cap, SCOPE_SYSTEM);
return false;
void cpu_set_feature(unsigned int num)
......@@ -2218,7 +2231,7 @@ void __init setup_cpu_features(void)
static bool __maybe_unused
cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused)
return (cpus_have_const_cap(ARM64_HAS_PAN) && !cpus_have_const_cap(ARM64_HAS_UAO));
return (__system_matches_cap(ARM64_HAS_PAN) && !__system_matches_cap(ARM64_HAS_UAO));
static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap)
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