From: Conor Dooley <mail@conchuod.ie>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Palmer Dabbelt <palmer@rivosinc.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Sudeep Holla <sudeep.holla@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>
Cc: Daire McNamara <daire.mcnamara@microchip.com>,
Conor Dooley <conor.dooley@microchip.com>,
Niklas Cassel <niklas.cassel@wdc.com>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Zong Li <zong.li@sifive.com>,
Emil Renner Berthing <kernel@esmil.dk>,
Jonas Hahnfeld <hahnjo@hahnjo.de>, Guo Ren <guoren@kernel.org>,
Anup Patel <anup@brainfault.org>,
Atish Patra <atishp@atishpatra.org>,
Heiko Stuebner <heiko@sntech.de>,
Philipp Tomsich <philipp.tomsich@vrull.eu>,
Rob Herring <robh@kernel.org>, Marc Zyngier <maz@kernel.org>,
Viresh Kumar <viresh.kumar@linaro.org>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Brice Goglin <Brice.Goglin@inria.fr>
Subject: [PATCH v4 1/2] arm64: topology: move store_cpu_topology() to shared code
Date: Fri, 15 Jul 2022 18:51:55 +0100 [thread overview]
Message-ID: <20220715175155.3567243-2-mail@conchuod.ie> (raw)
In-Reply-To: <20220715175155.3567243-1-mail@conchuod.ie>
From: Conor Dooley <conor.dooley@microchip.com>
arm64's method of defining a default cpu topology requires only minimal
changes to apply to RISC-V also. The current arm64 implementation exits
early in a uniprocessor configuration by reading MPIDR & claiming that
uniprocessor can rely on the default values.
This is appears to be a hangover from prior to '3102bc0e6ac7 ("arm64:
topology: Stop using MPIDR for topology information")', because the
current code just assigns default values for multiprocessor systems.
With the MPIDR references removed, store_cpu_topolgy() can be moved to
the common arch_topology code.
CC: stable@vger.kernel.org
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
---
arch/arm64/kernel/topology.c | 40 ------------------------------------
drivers/base/arch_topology.c | 19 +++++++++++++++++
2 files changed, 19 insertions(+), 40 deletions(-)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 869ffc4d4484..7889a00f5487 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -22,46 +22,6 @@
#include <asm/cputype.h>
#include <asm/topology.h>
-void store_cpu_topology(unsigned int cpuid)
-{
- struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
- u64 mpidr;
-
- if (cpuid_topo->package_id != -1)
- goto topology_populated;
-
- mpidr = read_cpuid_mpidr();
-
- /* Uniprocessor systems can rely on default topology values */
- if (mpidr & MPIDR_UP_BITMASK)
- return;
-
- /*
- * This would be the place to create cpu topology based on MPIDR.
- *
- * However, it cannot be trusted to depict the actual topology; some
- * pieces of the architecture enforce an artificial cap on Aff0 values
- * (e.g. GICv3's ICC_SGI1R_EL1 limits it to 15), leading to an
- * artificial cycling of Aff1, Aff2 and Aff3 values. IOW, these end up
- * having absolutely no relationship to the actual underlying system
- * topology, and cannot be reasonably used as core / package ID.
- *
- * If the MT bit is set, Aff0 *could* be used to define a thread ID, but
- * we still wouldn't be able to obtain a sane core ID. This means we
- * need to entirely ignore MPIDR for any topology deduction.
- */
- cpuid_topo->thread_id = -1;
- cpuid_topo->core_id = cpuid;
- cpuid_topo->package_id = cpu_to_node(cpuid);
-
- pr_debug("CPU%u: cluster %d core %d thread %d mpidr %#016llx\n",
- cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
- cpuid_topo->thread_id, mpidr);
-
-topology_populated:
- update_siblings_masks(cpuid);
-}
-
#ifdef CONFIG_ACPI
static bool __init acpi_cpu_is_threaded(int cpu)
{
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 0424b59b695e..0e2c6b30dd69 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -841,4 +841,23 @@ void __init init_cpu_topology(void)
return;
}
}
+
+void store_cpu_topology(unsigned int cpuid)
+{
+ struct cpu_topology *cpuid_topo = &cpu_topology[cpuid];
+
+ if (cpuid_topo->package_id != -1)
+ goto topology_populated;
+
+ cpuid_topo->thread_id = -1;
+ cpuid_topo->core_id = cpuid;
+ cpuid_topo->package_id = cpu_to_node(cpuid);
+
+ pr_debug("CPU%u: package %d core %d thread %d\n",
+ cpuid, cpuid_topo->package_id, cpuid_topo->core_id,
+ cpuid_topo->thread_id);
+
+topology_populated:
+ update_siblings_masks(cpuid);
+}
#endif
--
2.37.1
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next prev parent reply other threads:[~2022-07-15 17:54 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-15 17:51 [PATCH v4 0/2] Fix RISC-V's arch-topology reporting Conor Dooley
2022-07-15 17:51 ` Conor Dooley [this message]
2022-07-19 11:41 ` [PATCH v4 1/2] arm64: topology: move store_cpu_topology() to shared code Catalin Marinas
2022-07-19 11:51 ` Conor.Dooley
2022-07-19 12:00 ` Catalin Marinas
2022-07-26 8:10 ` Atish Patra
2022-07-15 17:51 ` [PATCH v4 2/2] riscv: topology: fix default topology reporting Conor Dooley
2022-07-26 8:24 ` Atish Patra
2022-07-16 13:35 ` [PATCH v4 0/2] Fix RISC-V's arch-topology reporting Conor.Dooley
2022-07-23 11:22 ` Conor.Dooley
2022-07-25 9:13 ` Will Deacon
2022-07-25 9:20 ` Conor.Dooley
2022-07-26 8:12 ` Atish Patra
2022-07-26 9:14 ` Conor.Dooley
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