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>,
"Ben Horgan" <ben.horgan@arm.com>,
"Ștefania Ion" <stefion@google.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Pankaj Patil" <pankaj.patil@oss.qualcomm.com>,
"Borislav Petkov" <bp@alien8.de>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Jinjie Ruan" <ruanjinjie@huawei.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"Tarun Sahu" <tarunsahu@google.com>,
"Fuad Tabba" <fuad.tabba@linux.dev>,
"David Woodhouse" <dwmw@amazon.co.uk>,
"Peter Zijlstra" <peterz@infradead.org>,
"Marc Zyngier" <maz@kernel.org>
Subject: [PATCH v2 09/23] arm64: smp: Tidy up smp_prepare_cpus()
Date: Fri, 9 Oct 2026 11:07:20 +0100 [thread overview]
Message-ID: <20261009100738.31288-10-will@kernel.org> (raw)
In-Reply-To: <20261009100738.31288-1-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.
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
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 eac217b9ebf1..d2aa949e33a3 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -781,16 +781,14 @@ 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
@@ -805,8 +803,7 @@ 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);
--
2.56.0.385.gd3acb90ef8-goog
next prev parent reply other threads:[~2026-10-09 10:08 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-09 10:07 [PATCH v2 00/23] arm64: Implement parallel CPU onlining with PSCI v0.2+ Will Deacon
2026-10-09 10:07 ` [PATCH v2 01/23] cpu/hotplug: Clean up cmpxchg() logic in cpuhp_can_boot_ap() Will Deacon
2026-10-09 10:07 ` [PATCH v2 02/23] cpu/hotplug: Avoid trying to bring up CPUs that are already online Will Deacon
2026-10-09 10:07 ` [PATCH v2 03/23] cpu/hotplug: Avoid busy-polling on archs where cpu_relax() is a no-op Will Deacon
2026-10-09 10:46 ` David Woodhouse
2026-10-09 11:07 ` Will Deacon
2026-10-09 10:07 ` [PATCH v2 04/23] cpu/hotplug: Propagate bring-up status to arch_cpuhp_cleanup_kick_cpu() Will Deacon
2026-10-09 10:07 ` [PATCH v2 05/23] arm64: cpufeature: Check arm64_ftr_regs[] before the first store Will Deacon
2026-10-09 10:07 ` [PATCH v2 06/23] arm64: cpufeature: Add read_cpuid_with_overrides() Will Deacon
2026-10-09 10:07 ` [PATCH v2 07/23] arm64: cpufeature: Read MPAMIDR_EL1 in __cpuinfo_store_cpu() Will Deacon
2026-10-09 15:44 ` Ben Horgan
2026-10-09 10:07 ` [PATCH v2 08/23] arm64: cpufeature: Store every ID register with its overrides applied Will Deacon
2026-10-09 15:51 ` Ben Horgan
2026-10-09 10:07 ` Will Deacon [this message]
2026-10-09 10:07 ` [PATCH v2 10/23] arm64: smp: Tidy up cpuinfo init and cpufeature updates Will Deacon
2026-10-09 10:07 ` [PATCH v2 11/23] arm64: smp: Defer update of secondary CPU capabilities Will Deacon
2026-10-09 10:07 ` [PATCH v2 12/23] arm64: smp: Don't bother printing the I-cache policy for each CPU Will Deacon
2026-10-09 10:07 ` [PATCH v2 13/23] arm64: smp: Defer RCU registration during secondary CPU bringup Will Deacon
2026-10-09 10:07 ` [PATCH v2 14/23] arm64: smp: Use generic HOTPLUG_CORE_SYNC_FULL machinery for CPU onlining Will Deacon
2026-10-09 10:07 ` [PATCH v2 15/23] arm64: smp: Use generic HOTPLUG_SPLIT_STARTUP " Will Deacon
2026-10-09 10:07 ` [PATCH v2 16/23] arm64: cpu_ops: Make 'cpu_operations' pointer global instead of per-cpu Will Deacon
2026-10-09 10:07 ` [PATCH v2 17/23] arm64: cpu_ops: Introduce get_secondary_cpu_ops() Will Deacon
2026-10-09 10:07 ` [PATCH v2 18/23] firmware/psci: Cache PSCI v0.2+ version number to avoid redundant SMCs Will Deacon
2026-10-09 10:07 ` [PATCH v2 19/23] firmware/psci: Extend ->cpu_on() callback to take an additional argument Will Deacon
2026-10-09 10:07 ` [PATCH v2 20/23] arm64: cpu_ops: Expose optional argument to target cpu in ->cpu_boot() Will Deacon
2026-10-09 10:07 ` [PATCH v2 21/23] arm64: smp: Pass secondary CPU boot parameters via firmware if possible Will Deacon
2026-10-09 10:07 ` [PATCH v2 22/23] arm64: smp: Use generic HOTPLUG_PARALLEL machinery for CPU onlining Will Deacon
2026-10-09 10:07 ` [PATCH v2 23/23] arm64: smp: Harden parallel CPU bringup against broken PSCI firmware Will Deacon
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