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| author | Pengjie Zhang <zhangpengjie2@huawei.com> | 2026-05-06 17:08:51 +0800 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-05-19 12:17:09 +0100 |
| commit | e7cec385d2c6726e692d057f91f20b08c2981af3 (patch) | |
| tree | 453048739754da3f7bbb3ed23bb88bd96a6d20b4 | |
| parent | 827ce94e0897a70241abf810b1d3d7d083053a39 (diff) | |
| download | linux-e7cec385d2c6726e692d057f91f20b08c2981af3.tar.gz linux-e7cec385d2c6726e692d057f91f20b08c2981af3.zip | |
arm64: smp: Do not mark secondary CPUs possible under nosmp
Under nosmp (maxcpus=0), arm64 never brings up secondary CPUs.
smp_prepare_cpus() already treats this as a UP-mandated boot and returns
before marking secondary CPUs present. However, smp_init_cpus() may still
enumerate firmware-described secondary CPUs and mark them possible before
that point.
Avoid marking secondary CPUs possible when nosmp/maxcpus=0 is in effect,
so that cpu_possible_mask reflects the nosmp boot policy for this boot.
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Pengjie Zhang <zhangpengjie2@huawei.com>
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/kernel/smp.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 1aa324104afb..1b63846f646a 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -745,16 +745,22 @@ void __init smp_init_cpus(void) else acpi_parse_and_init_cpus(); - if (cpu_count > nr_cpu_ids) - pr_warn("Number of cores (%d) exceeds configured maximum of %u - clipping\n", - cpu_count, nr_cpu_ids); - if (!bootcpu_valid) { pr_err("missing boot CPU MPIDR, not enabling secondaries\n"); return; } /* + * For the nosmp/maxcpus=0 case, do not mark the secondary CPUs + * possible. + */ + if (!setup_max_cpus) + return; + + if (cpu_count > nr_cpu_ids) + pr_warn("Number of cores (%d) exceeds configured maximum of %u - clipping\n", + cpu_count, nr_cpu_ids); + /* * We need to set the cpu_logical_map entries before enabling * the cpus so that cpu processor description entries (DT cpu nodes * and ACPI MADT entries) can be retrieved by matching the cpu hwid |