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From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>, <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>, <kvmarm@lists.linux.dev>,
	<x86@kernel.org>, Russell King <linux@armlinux.org.uk>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Miguel Luis <miguel.luis@oracle.com>,
	"James Morse" <james.morse@arm.com>,
	Salil Mehta <salil.mehta@huawei.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>, <linuxarm@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"Dave Hansen" <dave.hansen@linux.intel.com>, <justin.he@arm.com>,
	<jianyong.wu@arm.com>
Subject: Re: [PATCH v6 04/16] ACPI: processor: Move checks and availability of acpi_processor earlier
Date: Thu, 18 Apr 2024 09:16:27 +0100	[thread overview]
Message-ID: <20240417174707.00002e86@huawei.com> (raw)
In-Reply-To: <20240417131909.7925-5-Jonathan.Cameron@huawei.com>

On Wed, 17 Apr 2024 14:18:57 +0100
Jonathan Cameron <Jonathan.Cameron@huawei.com> wrote:

> Make the per_cpu(processors, cpu) entries available earlier so that
> they are available in arch_register_cpu() as ARM64 will need access
> to the acpi_handle to distinguish between acpi_processor_add()
> and earlier registration attempts (which will fail as _STA cannot
> be checked).
> 
> Reorder the remove flow to clear this per_cpu() after
> arch_unregister_cpu() has completed, allowing it to be used in
> there as well.
> 
> Note that on x86 for the CPU hotplug case, the pr->id prior to
> acpi_map_cpu() may be invalid. Thus the per_cpu() structures
> must be initialized after that call or after checking the ID
> is valid (not hotplug path).
> 
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> ---
> v6: As per discussion in v5 thread, don't use the cpu->dev and
>     make this data available earlier by moving the assignment checks
>     int acpi_processor_get_info().
> ---
>  drivers/acpi/acpi_processor.c | 79 +++++++++++++++++++++--------------
>  1 file changed, 47 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index ba0a6f0ac841..2c164451ab53 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -184,7 +184,35 @@ static void __init acpi_pcc_cpufreq_init(void) {}
>  
>  /* Initialization */
>  #ifdef CONFIG_ACPI_HOTPLUG_CPU
Note I messed up a rebase here.  This ifdef should come after the new function
(see later)

Will fix for v7.
> -static int acpi_processor_hotadd_init(struct acpi_processor *pr)
> +static DEFINE_PER_CPU(void *, processor_device_array);
> +
> +static void acpi_processor_set_per_cpu(struct acpi_processor *pr,
> +				       struct acpi_device *device)
> +{
> +	BUG_ON(pr->id >= nr_cpu_ids);
> +	/*
> +	 * Buggy BIOS check.
> +	 * ACPI id of processors can be reported wrongly by the BIOS.
> +	 * Don't trust it blindly
> +	 */
> +	if (per_cpu(processor_device_array, pr->id) != NULL &&
> +	    per_cpu(processor_device_array, pr->id) != device) {
> +		dev_warn(&device->dev,
> +			 "BIOS reported wrong ACPI id %d for the processor\n",
> +			 pr->id);
> +		/* Give up, but do not abort the namespace scan. */
> +		return;
> +	}
> +	/*
> +	 * processor_device_array is not cleared on errors to allow buggy BIOS
> +	 * checks.
> +	 */
> +	per_cpu(processor_device_array, pr->id) = device;
> +	per_cpu(processors, pr->id) = pr;
> +}
> +

The ifdef should be here as...

> +static int acpi_processor_hotadd_init(struct acpi_processor *pr,
> +				      struct acpi_device *device)
>  {
>  	int ret;
>  
> @@ -198,6 +226,8 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
>  	if (ret)
>  		goto out;
>  
> +	acpi_processor_set_per_cpu(pr, device);
> +
>  	ret = arch_register_cpu(pr->id);
>  	if (ret) {
>  		acpi_unmap_cpu(pr->id);
> @@ -217,7 +247,8 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
>  	return ret;
>  }
>  #else
> -static inline int acpi_processor_hotadd_init(struct acpi_processor *pr)
> +static inline int acpi_processor_hotadd_init(struct acpi_processor *pr,
> +					     struct acpi_device *device)
>  {
>  	return -ENODEV;
>  }
> @@ -232,6 +263,7 @@ static int acpi_processor_get_info(struct acpi_device *device)
>  	acpi_status status = AE_OK;
>  	static int cpu0_initialized;
>  	unsigned long long value;
> +	int ret;
>  
>  	acpi_processor_errata();
>  
> @@ -316,10 +348,12 @@ static int acpi_processor_get_info(struct acpi_device *device)
>  	 *  because cpuid <-> apicid mapping is persistent now.
>  	 */
>  	if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id)) {
> -		int ret = acpi_processor_hotadd_init(pr);
> +		ret = acpi_processor_hotadd_init(pr, device);
>  
>  		if (ret)
> -			return ret;
> +			goto err;
> +	} else {
> +		acpi_processor_set_per_cpu(pr, device);

This is not covered by CONFIG_ACPI_HOTPLUG_CPU

>  	}



  parent reply	other threads:[~2024-04-18  8:16 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-17 13:18 [PATCH v6 00/16] ACPI/arm64: add support for virtual cpu hotplug Jonathan Cameron
2024-04-17 13:18 ` [PATCH v6 01/16] ACPI: processor: Simplify initial onlining to use same path for cold and hotplug Jonathan Cameron
2024-04-17 13:18 ` [PATCH v6 02/16] cpu: Do not warn on arch_register_cpu() returning -EPROBE_DEFER Jonathan Cameron
2024-04-17 14:01   ` Russell King (Oracle)
2024-04-17 14:41     ` Jonathan Cameron
2024-04-17 13:18 ` [PATCH v6 03/16] ACPI: processor: Drop duplicated check on _STA (enabled + present) Jonathan Cameron
2024-04-17 13:18 ` [PATCH v6 04/16] ACPI: processor: Move checks and availability of acpi_processor earlier Jonathan Cameron
2024-04-17 15:08   ` Salil Mehta
2024-04-17 15:19     ` Jonathan Cameron
2024-04-18  8:16   ` Jonathan Cameron [this message]
2024-04-17 13:18 ` [PATCH v6 05/16] ACPI: processor: Add acpi_get_processor_handle() helper Jonathan Cameron
2024-04-17 13:18 ` [PATCH v6 06/16] ACPI: processor: Register deferred CPUs from acpi_processor_get_info() Jonathan Cameron
2024-04-17 15:03   ` Salil Mehta
2024-04-17 15:38     ` Jonathan Cameron
2024-04-17 15:59       ` Rafael J. Wysocki
2024-04-17 17:09         ` Jonathan Cameron
2024-04-17 17:59           ` Rafael J. Wysocki
2024-04-17 18:57             ` Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 07/16] ACPI: scan: switch to flags for acpi_scan_check_and_detach(); Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 08/16] ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 09/16] arm64: acpi: Move get_cpu_for_acpi_id() to a header Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 10/16] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc() Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 11/16] irqchip/gic-v3: Add support for ACPI's disabled but 'online capable' CPUs Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 12/16] arm64: psci: Ignore DENIED CPUs Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 13/16] arm64: arch_register_cpu() variant to check if an ACPI handle is now available Jonathan Cameron
2024-04-17 16:33   ` Salil Mehta
2024-04-17 16:55     ` Jonathan Cameron
2024-04-17 17:03       ` Salil Mehta
2024-04-17 13:19 ` [PATCH v6 14/16] arm64: Kconfig: Enable hotplug CPU on arm64 if ACPI_PROCESSOR is enabled Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 15/16] arm64: document virtual CPU hotplug's expectations Jonathan Cameron
2024-04-17 13:19 ` [PATCH v6 16/16] cpumask: Add enabled cpumask for present CPUs that can be brought online Jonathan Cameron
2024-04-17 17:01   ` Salil Mehta

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