From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Borislav Petkov <bp@alien8.de>,
Lorenzo Pieralisi <lpieralisi@kernel.org>,
Jinjie Ruan <ruanjinjie@huawei.com>,
Mark Rutland <mark.rutland@arm.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Peter Zijlstra <peterz@infradead.org>,
Marc Zyngier <maz@kernel.org>
Subject: [PATCH 05/19] arm64: smp: Tidy up smp_prepare_cpus()
Date: Mon, 7 Sep 2026 17:40:08 +0100 [thread overview]
Message-ID: <20260907164024.17164-6-will@kernel.org> (raw)
In-Reply-To: <20260907164024.17164-1-will@kernel.org>
smp_prepare_cpus() is always run on the boot CPU (i.e. CPU 0) but goes
to great lengths to support running on a CPU where smp_processor_id()
is non-zero.
Clean up the code a little by hardcoding zero for the boot CPU ID.
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/kernel/smp.c | 13 +++++--------
1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index a61dc3016a11..ff045080ca1b 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -779,16 +779,14 @@ void __init smp_init_cpus(void)
void __init smp_prepare_cpus(unsigned int max_cpus)
{
const struct cpu_operations *ops;
- int err;
unsigned int cpu;
- unsigned int this_cpu;
+ int err;
init_cpu_topology();
- this_cpu = smp_processor_id();
- store_cpu_topology(this_cpu);
- numa_store_cpu_info(this_cpu);
- numa_add_cpu(this_cpu);
+ store_cpu_topology(0);
+ numa_store_cpu_info(0);
+ numa_add_cpu(0);
/*
* If UP is mandated by "nosmp" (which implies "maxcpus=0"), don't set
@@ -803,8 +801,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
* secondaries from the bootloader.
*/
for_each_possible_cpu(cpu) {
-
- if (cpu == smp_processor_id())
+ if (cpu == 0)
continue;
ops = get_cpu_ops(cpu);
--
2.55.0.979.g7e5102b832-goog
next prev parent reply other threads:[~2026-09-07 16:41 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-07 16:40 [PATCH 00/19] arm64: Implement parallel CPU onlining with PSCI v0.2+ Will Deacon
2026-09-07 16:40 ` [PATCH 01/19] cpu/hotplug: Clean up cmpxchg() logic in cpuhp_can_boot_ap() Will Deacon
2026-09-08 2:55 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 02/19] cpu/hotplug: Avoid trying to bring up CPUs that are already online Will Deacon
2026-09-08 3:13 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 03/19] cpu/hotplug: Avoid busy-polling on archs where cpu_relax() is a no-op Will Deacon
2026-09-08 4:00 ` Jinjie Ruan
2026-09-11 7:16 ` Jinjie Ruan
2026-09-11 12:57 ` Will Deacon
2026-09-07 16:40 ` [PATCH 04/19] cpu/hotplug: Propagate bring-up status to arch_cpuhp_cleanup_kick_cpu() Will Deacon
2026-09-08 4:05 ` Jinjie Ruan
2026-09-07 16:40 ` Will Deacon [this message]
2026-09-08 7:35 ` [PATCH 05/19] arm64: smp: Tidy up smp_prepare_cpus() Jinjie Ruan
2026-09-07 16:40 ` [PATCH 06/19] arm64: smp: Tidy up cpuinfo init and cpufeature updates Will Deacon
2026-09-08 7:53 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 07/19] arm64: smp: Defer update of secondary CPU capabilities Will Deacon
2026-09-08 8:20 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 08/19] arm64: smp: Don't bother printing the I-cache policy for each CPU Will Deacon
2026-09-08 8:33 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 09/19] arm64: smp: Defer RCU registration during secondary CPU bringup Will Deacon
2026-09-08 8:55 ` Jinjie Ruan
2026-09-08 10:19 ` Will Deacon
2026-09-08 11:25 ` Jinjie Ruan
2026-09-09 12:36 ` Will Deacon
2026-09-10 2:47 ` Jinjie Ruan
2026-09-11 12:52 ` Will Deacon
2026-09-07 16:40 ` [PATCH 10/19] arm64: smp: Use generic HOTPLUG_CORE_SYNC_FULL machinery for CPU onlining Will Deacon
2026-09-08 9:01 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 11/19] arm64: smp: Use generic HOTPLUG_SPLIT_STARTUP " Will Deacon
2026-09-08 9:10 ` Jinjie Ruan
2026-09-08 11:35 ` Jinjie Ruan
2026-09-11 12:55 ` Will Deacon
2026-09-07 16:40 ` [PATCH 12/19] arm64: cpu_ops: Make 'cpu_operations' pointer global instead of per-cpu Will Deacon
2026-09-08 11:32 ` Jinjie Ruan
2026-09-11 12:55 ` Will Deacon
2026-09-07 16:40 ` [PATCH 13/19] arm64: cpu_ops: Introduce get_secondary_cpu_ops() Will Deacon
2026-09-08 11:56 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 14/19] firmware/psci: Cache PSCI v0.2+ version number to avoid redundant SMCs Will Deacon
2026-09-08 11:57 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 15/19] firmware/psci: Extend ->cpu_on() callback to take an additional argument Will Deacon
2026-09-08 12:05 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 16/19] arm64: cpu_ops: Expose optional argument to target cpu in ->cpu_boot() Will Deacon
2026-09-08 12:12 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 17/19] arm64: smp: Pass secondary CPU boot parameters via firmware if possible Will Deacon
2026-09-08 12:16 ` Jinjie Ruan
2026-09-07 16:40 ` [PATCH 18/19] arm64: smp: Use generic HOTPLUG_PARALLEL machinery for CPU onlining Will Deacon
2026-09-08 13:05 ` Jinjie Ruan
2026-09-11 12:56 ` Will Deacon
2026-09-07 16:40 ` [PATCH 19/19] arm64: smp: Harden parallel CPU bringup against broken PSCI firmware Will Deacon
2026-09-08 13:36 ` Will Deacon
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