From: Gavin Shan <gshan@redhat.com>
To: "Russell King (Oracle)" <linux@armlinux.org.uk>
Cc: linux-pm@vger.kernel.org, loongarch@lists.linux.dev,
linux-acpi@vger.kernel.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-riscv@lists.infradead.org, kvmarm@lists.linux.dev,
x86@kernel.org, linux-csky@vger.kernel.org,
linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org,
linux-parisc@vger.kernel.org,
Salil Mehta <salil.mehta@huawei.com>,
Jean-Philippe Brucker <jean-philippe@linaro.org>,
jianyong.wu@arm.com, justin.he@arm.com,
James Morse <james.morse@arm.com>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>
Subject: Re: [PATCH RFC 05/22] ACPI: Move ACPI_HOTPLUG_CPU to be disabled on arm64 and riscv
Date: Mon, 13 Nov 2023 20:01:27 +1000 [thread overview]
Message-ID: <29090279-a682-43ff-9710-181cb91bbf91@redhat.com> (raw)
In-Reply-To: <ZVHkykFMp+CMUqyf@shell.armlinux.org.uk>
On 11/13/23 18:56, Russell King (Oracle) wrote:
> On Mon, Nov 13, 2023 at 10:29:39AM +1000, Gavin Shan wrote:
>> On 11/7/23 20:29, Russell King (Oracle) wrote:
>>> From: James Morse <james.morse@arm.com>
>>>
>>> Neither arm64 nor riscv support physical hotadd of CPUs that were not
>>> present at boot. For arm64 much of the platform description is in static
>>> tables which do not have update methods. arm64 does support HOTPLUG_CPU,
>>> which is backed by a firmware interface to turn CPUs on and off.
>>>
>>> acpi_processor_hotadd_init() and acpi_processor_remove() are for adding
>>> and removing CPUs that were not present at boot. arm64 systems that do this
>>> are not supported as there is currently insufficient information in the
>>> platform description. (e.g. did the GICR get removed too?)
>>>
>>> arm64 currently relies on the MADT enabled flag check in map_gicc_mpidr()
>>> to prevent CPUs that were not described as present at boot from being
>>> added to the system. Similarly, riscv relies on the same check in
>>> map_rintc_hartid(). Both architectures also rely on the weak 'always fails'
>>> definitions of acpi_map_cpu() and arch_register_cpu().
>>>
>>> Subsequent changes will redefine ACPI_HOTPLUG_CPU as making possible
>>> CPUs present. Neither arm64 nor riscv support this.
>>>
>>> Disable ACPI_HOTPLUG_CPU for arm64 and riscv by removing 'default y' and
>>> selecting it on the other three ACPI architectures. This allows the weak
>>> definitions of some symbols to be removed.
>>>
>>> Signed-off-by: James Morse <james.morse@arm.com>
>>> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
>>> ---
>>> Changes since RFC:
>>> * Expanded conditions to avoid ACPI_HOTPLUG_CPU being enabled when
>>> HOTPLUG_CPU isn't.
>>> Changes since RFC v3:
>>> * Dropped ia64 changes
>>> ---
>>> arch/loongarch/Kconfig | 1 +
>>> arch/x86/Kconfig | 1 +
>>> drivers/acpi/Kconfig | 1 -
>>> drivers/acpi/acpi_processor.c | 18 ------------------
>>> 4 files changed, 2 insertions(+), 19 deletions(-)
>>>
>>
>> With the following nits addressed:
>>
>> Reviewed-by: Gavin Shan <gshan@redhat.com>
>>
>>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
>>> index d889a0b97bc1..64620e90c12c 100644
>>> --- a/arch/loongarch/Kconfig
>>> +++ b/arch/loongarch/Kconfig
>>> @@ -5,6 +5,7 @@ config LOONGARCH
>>> select ACPI
>>> select ACPI_GENERIC_GSI if ACPI
>>> select ACPI_MCFG if ACPI
>>> + select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
>>> select ACPI_PPTT if ACPI
>>> select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
>>> select ARCH_BINFMT_ELF_STATE
>>> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
>>> index 3762f41bb092..dbdcfc708369 100644
>>> --- a/arch/x86/Kconfig
>>> +++ b/arch/x86/Kconfig
>>> @@ -59,6 +59,7 @@ config X86
>>> #
>>> select ACPI_LEGACY_TABLES_LOOKUP if ACPI
>>> select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
>>> + select ACPI_HOTPLUG_CPU if ACPI_PROCESSOR && HOTPLUG_CPU
>>> select ARCH_32BIT_OFF_T if X86_32
>>> select ARCH_CLOCKSOURCE_INIT
>>> select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
>>> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
>>> index f819e760ff19..a3acfc750fce 100644
>>> --- a/drivers/acpi/Kconfig
>>> +++ b/drivers/acpi/Kconfig
>>> @@ -310,7 +310,6 @@ config ACPI_HOTPLUG_CPU
>>> bool
>>> depends on ACPI_PROCESSOR && HOTPLUG_CPU
>>> select ACPI_CONTAINER
>>> - default y
>>> config ACPI_PROCESSOR_AGGREGATOR
>>> tristate "Processor Aggregator"
>>> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
>>> index 0f5218e361df..4fe2ef54088c 100644
>>> --- a/drivers/acpi/acpi_processor.c
>>> +++ b/drivers/acpi/acpi_processor.c
>>> @@ -184,24 +184,6 @@ static void __init acpi_pcc_cpufreq_init(void) {}
>>> /* Initialization */
>>> #ifdef CONFIG_ACPI_HOTPLUG_CPU
>>> -int __weak acpi_map_cpu(acpi_handle handle,
>>> - phys_cpuid_t physid, u32 acpi_id, int *pcpu)
>>> -{
>>> - return -ENODEV;
>>> -}
>>> -
>>> -int __weak acpi_unmap_cpu(int cpu)
>>> -{
>>> - return -ENODEV;
>>> -}
>>> -
>>> -int __weak arch_register_cpu(int cpu)
>>> -{
>>> - return -ENODEV;
>>> -}
>>> -
>>> -void __weak arch_unregister_cpu(int cpu) {}
>>> -
>>
>> Since we're here, EXPORT_SYMBOL() can be dropped for these functions on
>> x86 and loongarch because they're not called from a module?
>
> I'm confused, and don't understand your comment. You've r-b the
> previous two patches that remove the EXPORT_SYMBOL()s for
> arch_register_cpu() and arch_unregister_cpu() from x86 and loongarch.
> So it seems your comment is already addressed, and thus makes no
> sense.
>
> Please clarify.
>
Exactly, I must be looking into wrong code when reviewing this patch.
Please ignore my comments and my r-b still valid. Sorry for the
unnecessary confusion.
Thanks,
Gavin
next prev parent reply other threads:[~2023-11-13 10:01 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-07 10:28 [PATCH RFC 00/22] Initial cleanups for vCPU hotplug Russell King (Oracle)
2023-11-07 10:29 ` [PATCH RFC 01/22] arch_topology: Make register_cpu_capacity_sysctl() tolerant to late CPUs Russell King
2023-11-13 0:04 ` Gavin Shan
2023-11-28 14:37 ` Jonathan Cameron
2023-11-28 15:41 ` Russell King (Oracle)
2023-11-07 10:29 ` [PATCH RFC 02/22] x86: intel_epb: Don't rely on link order Russell King
2023-11-13 0:03 ` Gavin Shan
2023-11-28 14:40 ` Jonathan Cameron
2023-11-28 15:42 ` Russell King (Oracle)
2023-11-07 10:29 ` [PATCH RFC 03/22] x86/topology: remove arch_*register_cpu() exports Russell King (Oracle)
2023-11-13 0:08 ` Gavin Shan
2023-11-28 14:42 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 04/22] Loongarch: " Russell King (Oracle)
2023-11-13 0:11 ` Gavin Shan
2023-11-28 14:43 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 05/22] ACPI: Move ACPI_HOTPLUG_CPU to be disabled on arm64 and riscv Russell King
2023-11-09 9:43 ` Shaoqin Huang
2023-11-13 0:29 ` Gavin Shan
2023-11-13 8:56 ` Russell King (Oracle)
2023-11-13 10:01 ` Gavin Shan [this message]
2023-11-28 14:46 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 06/22] drivers: base: Use present CPUs in GENERIC_CPU_DEVICES Russell King
2023-11-09 10:09 ` Shaoqin Huang
2023-11-09 10:29 ` Russell King (Oracle)
2023-11-09 10:59 ` Shaoqin Huang
2023-11-13 0:37 ` Gavin Shan
2023-11-07 10:29 ` [PATCH RFC 07/22] drivers: base: Allow parts of GENERIC_CPU_DEVICES to be overridden Russell King
2023-11-09 10:13 ` Shaoqin Huang
2023-11-13 0:42 ` Gavin Shan
2023-11-28 14:49 ` Jonathan Cameron
2023-11-07 10:29 ` [PATCH RFC 08/22] drivers: base: Implement weak arch_unregister_cpu() Russell King
2023-11-09 10:51 ` Shaoqin Huang
2023-11-13 0:45 ` Gavin Shan
2023-11-21 13:33 ` Russell King (Oracle)
2023-11-28 14:51 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 09/22] drivers: base: add arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-10 3:27 ` Shaoqin Huang
2023-11-13 0:56 ` Gavin Shan
2023-11-28 14:53 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 10/22] drivers: base: Move cpu_dev_init() after node_dev_init() Russell King
2023-11-13 0:58 ` Gavin Shan
2023-11-13 8:00 ` Russell King (Oracle)
2023-11-21 13:27 ` Russell King (Oracle)
2023-11-28 13:55 ` Jonathan Cameron
2023-11-28 15:00 ` Jonathan Cameron
2023-11-30 12:17 ` Russell King (Oracle)
2023-11-07 10:30 ` [PATCH RFC 11/22] drivers: base: remove unnecessary call to register_cpu_under_node() Russell King (Oracle)
2023-11-13 4:04 ` Gavin Shan
2023-11-15 10:11 ` Russell King (Oracle)
2023-11-07 10:30 ` [PATCH RFC 12/22] drivers: base: Print a warning instead of panic() when register_cpu() fails Russell King
2023-11-10 3:35 ` Shaoqin Huang
2023-11-13 4:03 ` Gavin Shan
2023-11-28 15:05 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 13/22] arm64: setup: Switch over to GENERIC_CPU_DEVICES using arch_register_cpu() Russell King
2023-11-10 3:36 ` Shaoqin Huang
2023-11-13 4:07 ` Gavin Shan
2023-11-28 15:08 ` Jonathan Cameron
2023-11-28 15:12 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 14/22] arm64: convert to arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-10 3:37 ` Shaoqin Huang
2023-11-13 4:09 ` Gavin Shan
2023-11-28 15:11 ` Jonathan Cameron
2023-11-30 12:09 ` Russell King (Oracle)
2023-11-07 10:30 ` [PATCH RFC 15/22] x86/topology: Switch over to GENERIC_CPU_DEVICES Russell King
2023-11-13 4:13 ` Gavin Shan
2023-11-28 15:16 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 16/22] x86/topology: use weak version of arch_unregister_cpu() Russell King (Oracle)
2023-11-13 4:16 ` Gavin Shan
2023-11-28 15:17 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 17/22] x86/topology: convert to use arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-13 4:18 ` Gavin Shan
2023-11-28 15:18 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 18/22] LoongArch: Switch over to GENERIC_CPU_DEVICES Russell King
2023-11-13 4:20 ` Gavin Shan
2023-11-28 15:19 ` Jonathan Cameron
2023-11-07 10:30 ` [PATCH RFC 19/22] LoongArch: Use the __weak version of arch_unregister_cpu() Russell King
2023-11-07 10:31 ` [PATCH RFC 20/22] LoongArch: convert to use arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-13 4:22 ` Gavin Shan
2023-11-28 15:20 ` Jonathan Cameron
2023-11-07 10:31 ` [PATCH RFC 21/22] riscv: Switch over to GENERIC_CPU_DEVICES Russell King
2023-11-07 17:48 ` Palmer Dabbelt
2023-11-13 4:23 ` Gavin Shan
2023-11-07 10:31 ` [PATCH RFC 22/22] riscv: convert to use arch_cpu_is_hotpluggable() Russell King (Oracle)
2023-11-07 17:48 ` Palmer Dabbelt
2023-11-13 4:24 ` Gavin Shan
2023-11-28 15:21 ` Jonathan Cameron
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