From: Gavin Shan <gshan@redhat.com>
To: Jonathan Cameron <Jonathan.Cameron@huawei.com>,
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>, Marc Zyngier <maz@kernel.org>,
Hanjun Guo <guohanjun@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
linuxarm@huawei.com, justin.he@arm.com, jianyong.wu@arm.com
Subject: Re: [PATCH v9 06/19] ACPI: processor: Move checks and availability of acpi_processor earlier
Date: Wed, 1 May 2024 20:33:27 +1000 [thread overview]
Message-ID: <0febde44-99f1-48ba-a233-78b9a32468da@redhat.com> (raw)
In-Reply-To: <20240430142434.10471-7-Jonathan.Cameron@huawei.com>
On 5/1/24 00:24, Jonathan Cameron 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>
>
> ---
> v9: Add back a blank line accidentally removed in code move.
> Fix up error returns so that the new cleanup in processor_add()
> is triggered on detection of the bios bug.
> Combined with the previous 2 patches, should solve the leak
> that Gavin identified.
> ---
> drivers/acpi/acpi_processor.c | 80 +++++++++++++++++++++--------------
> 1 file changed, 49 insertions(+), 31 deletions(-)
>
It would be nice for acpi_processor_set_per_cpu() to return errno,
explained as below. The patch looks good to me in either me.
Reviewed-by: Gavin Shan <gshan@redhat.com>
> diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
> index 16e36e55a560..4a79b42d649e 100644
> --- a/drivers/acpi/acpi_processor.c
> +++ b/drivers/acpi/acpi_processor.c
> @@ -183,8 +183,38 @@ static void __init acpi_pcc_cpufreq_init(void) {}
> #endif /* CONFIG_X86 */
>
> /* Initialization */
> +static DEFINE_PER_CPU(void *, processor_device_array);
> +
> +static bool 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);
> + return false;
> + }
> + /*
> + * 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;
> +
> + return true;
> +}
> +
I think it'd better for acpi_processor_set_per_cpu() to return errno. -EINVAL
is returned if a mismatched ACPI device is found, and 0 is returned on success.
With the improvement, the callers needn't to translate boolen to errno.
> #ifdef CONFIG_ACPI_HOTPLUG_CPU
> -static int acpi_processor_hotadd_init(struct acpi_processor *pr)
> +static int acpi_processor_hotadd_init(struct acpi_processor *pr,
> + struct acpi_device *device)
> {
> int ret;
>
> @@ -198,8 +228,16 @@ static int acpi_processor_hotadd_init(struct acpi_processor *pr)
> if (ret)
> goto out;
>
> + if (!acpi_processor_set_per_cpu(pr, device)) {
> + ret = -EINVAL;
> + acpi_unmap_cpu(pr->id);
> + goto out;
> + }
> +
If errno is returned from acpi_processor_set_per_cpu(), this chunk of code becomes:
ret = acpi_processor_set_per_cpu(pr, device);
if (ret) {
acpi_unmap_cpu(pr->id);
goto out;
}
> ret = arch_register_cpu(pr->id);
> if (ret) {
> + /* Leave the processor device array in place to detect buggy bios */
> + per_cpu(processors, pr->id) = NULL;
> acpi_unmap_cpu(pr->id);
> goto out;
> }
> @@ -217,7 +255,8 @@ 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;
> }
> @@ -316,10 +355,13 @@ 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);
> + int ret = acpi_processor_hotadd_init(pr, device);
>
> if (ret)
> return ret;
> + } else {
> + if (!acpi_processor_set_per_cpu(pr, device))
> + return -EINVAL;
> }
>
ret = acpi_processor_set_per_cpu(pr, device);
if (ret)
return ret;
> /*
> @@ -365,8 +407,6 @@ static int acpi_processor_get_info(struct acpi_device *device)
> * (cpu_data(cpu)) values, like CPU feature flags, family, model, etc.
> * Such things have to be put in and set up by the processor driver's .probe().
> */
> -static DEFINE_PER_CPU(void *, processor_device_array);
> -
> static int acpi_processor_add(struct acpi_device *device,
> const struct acpi_device_id *id)
> {
> @@ -395,28 +435,6 @@ static int acpi_processor_add(struct acpi_device *device,
> if (result) /* Processor is not physically present or unavailable */
> goto err_clear_driver_data;
>
> - 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. */
> - goto err_clear_driver_data;
> - }
> - /*
> - * 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;
> -
> dev = get_cpu_device(pr->id);
> if (!dev) {
> result = -ENODEV;
> @@ -470,10 +488,6 @@ static void acpi_processor_remove(struct acpi_device *device)
> device_release_driver(pr->dev);
> acpi_unbind_one(pr->dev);
>
> - /* Clean up. */
> - per_cpu(processor_device_array, pr->id) = NULL;
> - per_cpu(processors, pr->id) = NULL;
> -
> cpu_maps_update_begin();
> cpus_write_lock();
>
> @@ -481,6 +495,10 @@ static void acpi_processor_remove(struct acpi_device *device)
> arch_unregister_cpu(pr->id);
> acpi_unmap_cpu(pr->id);
>
> + /* Clean up. */
> + per_cpu(processor_device_array, pr->id) = NULL;
> + per_cpu(processors, pr->id) = NULL;
> +
> cpus_write_unlock();
> cpu_maps_update_done();
>
Thanks,
Gavin
next prev parent reply other threads:[~2024-05-01 10:33 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-30 14:24 [PATCH v9 00/19] ACPI/arm64: add support for virtual cpu hotplug Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 01/19] ACPI: processor: Simplify initial onlining to use same path for cold and hotplug Jonathan Cameron
2024-05-02 12:10 ` Miguel Luis
2024-04-30 14:24 ` [PATCH v9 02/19] cpu: Do not warn on arch_register_cpu() returning -EPROBE_DEFER Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 03/19] ACPI: processor: Drop duplicated check on _STA (enabled + present) Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 04/19] ACPI: processor: Return an error if acpi_processor_get_info() fails in processor_add() Jonathan Cameron
2024-05-01 10:18 ` Gavin Shan
2024-05-07 18:55 ` Rafael J. Wysocki
2024-04-30 14:24 ` [PATCH v9 05/19] ACPI: processor: Fix memory leaks in error paths of processor_add() Jonathan Cameron
2024-05-01 10:19 ` Gavin Shan
2024-05-07 18:57 ` Rafael J. Wysocki
2024-04-30 14:24 ` [PATCH v9 06/19] ACPI: processor: Move checks and availability of acpi_processor earlier Jonathan Cameron
2024-05-01 10:33 ` Gavin Shan [this message]
2024-05-07 19:04 ` Rafael J. Wysocki
2024-05-08 8:44 ` Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 07/19] ACPI: processor: Add acpi_get_processor_handle() helper Jonathan Cameron
2024-05-07 19:05 ` Rafael J. Wysocki
2024-04-30 14:24 ` [PATCH v9 08/19] ACPI: processor: Register deferred CPUs from acpi_processor_get_info() Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 09/19] ACPI: scan: switch to flags for acpi_scan_check_and_detach() Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 10/19] ACPI: Add post_eject to struct acpi_scan_handler for cpu hotplug Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 11/19] arm64: acpi: Move get_cpu_for_acpi_id() to a header Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 12/19] arm64: acpi: Harden get_cpu_for_acpi_id() against missing CPU entry Jonathan Cameron
2024-05-01 11:10 ` Gavin Shan
2024-04-30 14:24 ` [PATCH v9 13/19] irqchip/gic-v3: Don't return errors from gic_acpi_match_gicc() Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 14/19] irqchip/gic-v3: Add support for ACPI's disabled but 'online capable' CPUs Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 15/19] arm64: psci: Ignore DENIED CPUs Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 16/19] arm64: arch_register_cpu() variant to check if an ACPI handle is now available Jonathan Cameron
2024-04-30 14:24 ` [PATCH v9 17/19] arm64: Kconfig: Enable hotplug CPU on arm64 if ACPI_PROCESSOR is enabled Jonathan Cameron
2024-05-01 11:13 ` Gavin Shan
2024-04-30 14:24 ` [PATCH v9 18/19] arm64: document virtual CPU hotplug's expectations Jonathan Cameron
2024-05-01 11:32 ` Gavin Shan
2024-04-30 14:24 ` [PATCH v9 19/19] cpumask: Add enabled cpumask for present CPUs that can be brought online Jonathan Cameron
2024-05-01 11:14 ` Gavin Shan
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