[PATCH v4 0/2] Fix RISC-V's arch-topology reporting

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 0/2] Fix RISC-V's arch-topology reporting
Date: Fri, 15 Jul 2022 18:51:54 +0100	[thread overview]
Message-ID: <20220715175155.3567243-1-mail@conchuod.ie> (raw)

From: Conor Dooley <conor.dooley@microchip.com>

Hey all,
It's my first time messing around with arch/ code at all, let alone
more than one arch, so forgive me if I have screwed up how to do a
migration like this.

The goal here is the fix the incorrectly reported arch topology on
RISC-V which seems to have been broken since it was added.
cpu, package and thread IDs are all currently reported as -1, so tools
like lstopo think systems have multiple threads on the same core when
this is not true:
https://github.com/open-mpi/hwloc/issues/536

arm64's topology code basically applies to RISC-V too, so it has been
made generic along with the removal of MPIDR related code, which
appears to be redudant code since '3102bc0e6ac7 ("arm64: topology: Stop
using MPIDR for topology information")' replaced the code that actually
interacted with MPIDR with default values.

I only built tested for arm{,64} , so hopefully it is not broken when
used. Testing on both arm64 & !SMP RISC-V would really be appreciated!

For V2, I dropped the idea of doing a RISC-V specific implementation
followed by a move to the generic code & just went for the more straight
forward method of moving to the shared version first. I also dropped the
RFC.

V3 moves store_cpu_topology()'s definition down inside the arch check
alongside the init function so that boot on 32bit arm is not broken.

V4 has moved the RISC-V boot hart's call to store_cpu_topology() later
into the boot process it is now right before SMP is brought up (or not
in the case of !SMP). This prevents calling detect_cache_attributes()
while we cannot allocate memory.

V4 is also rebased on next-20220715 to get Sudeep's most recent
arch_topology patchset.

Thanks,
Conor

Conor Dooley (2):
  arm64: topology: move store_cpu_topology() to shared code
  riscv: topology: fix default topology reporting

 arch/arm64/kernel/topology.c | 40 ------------------------------------
 arch/riscv/Kconfig           |  2 +-
 arch/riscv/kernel/smpboot.c  |  3 ++-
 drivers/base/arch_topology.c | 19 +++++++++++++++++
 4 files changed, 22 insertions(+), 42 deletions(-)

base-commit: 6014cfa5bf32cf8c5c58b3cfd5ee0e1542c8a825
-- 
2.37.1