From: Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: 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>,
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>,
"Gavin Shan" <gshan@redhat.com>, 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, 8 May 2024 09:44:11 +0100 [thread overview]
Message-ID: <20240508094411.00001b92@Huawei.com> (raw)
In-Reply-To: <CAJZ5v0g-Aenoj5H+pNPtoqTgV5U7K5RGNjdOnqobqxkyL5NMVQ@mail.gmail.com>
On Tue, 7 May 2024 21:04:26 +0200
"Rafael J. Wysocki" <rafael@kernel.org> wrote:
> On Tue, Apr 30, 2024 at 4:27 PM 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>
>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> One nit below.
Thanks. Given timing, this is looking like 6.11 material.
I'll tidy this up and post a v10 in a couple of weeks (so around
rc1 time). Maybe we'll pick up some more tags for the ARM
specific bits in the meantime.
Thanks for all your help!
Jonathan
>
> > ---
> > 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(-)
> >
> > 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;
> > +}
> > +
> > #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;
> > + }
> > +
> > 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;
> > }
>
> This looks a bit odd.
>
> I would make acpi_processor_set_per_cpu() return 0 on success and
> -EINVAL on failure and the above would become
>
> if (invalid_logical_cpuid(pr->id) || !cpu_present(pr->id))
> ret = acpi_processor_hotadd_init(pr, device);
> else
> ret = acpi_processor_set_per_cpu(pr, device);
>
> if (ret)
> return ret;
>
> (and of course ret needs to be defined at the beginning of the function).
>
> >
> > /*
> > @@ -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();
> >
> > --
> > 2.39.2
> >
next prev parent reply other threads:[~2024-05-08 8:44 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
2024-05-07 19:04 ` Rafael J. Wysocki
2024-05-08 8:44 ` Jonathan Cameron [this message]
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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