From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: Jeremy Linton <jeremy.linton@arm.com>,
<linux-arm-kernel@lists.infradead.org>
Cc: <mark.rutland@arm.com>, <lorenzo.pieralisi@arm.com>,
<will.deacon@arm.com>, <sudeep.holla@arm.com>,
<rjw@rjwysocki.net>, <linuxarm@huawei.com>,
<linux-acpi@vger.kernel.org>, <catalin.marinas@arm.com>,
<lenb@kernel.org>
Subject: Re: [PATCH v3 2/5] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
Date: Sun, 5 May 2019 15:09:01 +0800 [thread overview]
Message-ID: <b52d15ab-de9c-8aa4-d2a4-dacdcb9d137e@huawei.com> (raw)
Message-ID: <20190505070901.AqqwQ0SFxag6BDuokrQP_6gSQvESTtNsTWTn6DWVHzs@z> (raw)
In-Reply-To: <20190503232407.37195-3-jeremy.linton@arm.com>
On 2019/5/4 7:24, Jeremy Linton wrote:
> ACPI 6.3 adds a flag to indicate that child nodes are all
> identical cores. This is useful to authoritatively determine
> if a set of (possibly offline) cores are identical or not.
>
> Since the flag doesn't give us a unique id we can generate
> one and use it to create bitmaps of sibling nodes, or simply
> in a loop to determine if a subset of cores are identical.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
> ---
> drivers/acpi/pptt.c | 26 ++++++++++++++++++++++++++
> include/linux/acpi.h | 5 +++++
> 2 files changed, 31 insertions(+)
>
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index 83a026765faa..1865515297ca 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -660,3 +660,29 @@ int find_acpi_cpu_topology_package(unsigned int cpu)
> return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
> ACPI_PPTT_PHYSICAL_PACKAGE);
> }
> +
> +/**
> + * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag
> + * @cpu: Kernel logical CPU number
> + *
> + * Determine a unique heterogeneous tag for the given CPU. CPUs with the same
> + * implementation should have matching tags.
> + *
> + * The returned tag can be used to group peers with identical implementation.
> + *
> + * The search terminates when a level is found with the identical implementation
> + * flag set or we reach a root node.
> + *
> + * Due to limitations in the PPTT data structure, there may be rare situations
> + * where two cores in a heterogeneous machine may be identical, but won't have
> + * the same tag.
> + *
> + * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
> + * Otherwise returns a value which represents a group of identical cores
> + * similar to this CPU.
> + */
> +int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
> +{
> + return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
> + ACPI_PPTT_ACPI_IDENTICAL);
> +}
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index d5dcebd7aad3..1444fb042898 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -1309,6 +1309,7 @@ static inline int lpit_read_residency_count_address(u64 *address)
> #ifdef CONFIG_ACPI_PPTT
> int find_acpi_cpu_topology(unsigned int cpu, int level);
> int find_acpi_cpu_topology_package(unsigned int cpu);
> +int find_acpi_cpu_topology_hetero_id(unsigned int cpu);
> int find_acpi_cpu_cache_topology(unsigned int cpu, int level);
> #else
> static inline int find_acpi_cpu_topology(unsigned int cpu, int level)
> @@ -1319,6 +1320,10 @@ static inline int find_acpi_cpu_topology_package(unsigned int cpu)
> {
> return -EINVAL;
> }
static inline int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
> +static int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
> +{
> + return -EINVAL;
> +}
> static inline int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
> {
> return -EINVAL;
next prev parent reply other threads:[~2019-05-05 7:10 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-03 23:24 [PATCH v3 0/5] arm64: SPE ACPI enablement Jeremy Linton
2019-05-03 23:24 ` Jeremy Linton
2019-05-03 23:24 ` [PATCH v3 1/5] ACPI/PPTT: Trivial, change the capitalization of CPU Jeremy Linton
2019-05-03 23:24 ` Jeremy Linton
2019-05-07 18:12 ` Jeremy Linton
2019-05-07 18:12 ` Jeremy Linton
2019-05-03 23:24 ` [PATCH v3 2/5] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens Jeremy Linton
2019-05-03 23:24 ` Jeremy Linton
2019-05-05 7:09 ` Kefeng Wang [this message]
2019-05-05 7:09 ` Kefeng Wang
2019-05-07 18:26 ` Jeremy Linton
2019-05-07 18:26 ` Jeremy Linton
2019-06-07 9:49 ` Sudeep Holla
2019-05-03 23:24 ` [PATCH v3 3/5] ACPI/PPTT: Modify node flag detection to find last IDENTICAL Jeremy Linton
2019-05-03 23:24 ` Jeremy Linton
2019-06-07 9:53 ` Sudeep Holla
2019-06-07 13:15 ` Jeremy Linton
2019-06-07 13:47 ` Sudeep Holla
2019-05-03 23:24 ` [PATCH v3 4/5] arm_pmu: acpi: spe: Add initial MADT/SPE probing Jeremy Linton
2019-05-03 23:24 ` Jeremy Linton
2019-05-08 11:18 ` John Garry
2019-05-08 20:04 ` Jeremy Linton
2019-06-07 9:57 ` Sudeep Holla
2019-06-07 13:28 ` Jeremy Linton
2019-06-07 13:37 ` Sudeep Holla
2019-05-03 23:24 ` [PATCH v3 5/5] perf: arm_spe: Enable ACPI/Platform automatic module loading Jeremy Linton
2019-05-03 23:24 ` Jeremy Linton
2019-05-04 11:06 ` [PATCH v3 0/5] arm64: SPE ACPI enablement Hanjun Guo
2019-05-04 11:06 ` Hanjun Guo
2019-05-07 17:58 ` Jeremy Linton
2019-05-07 17:58 ` Jeremy Linton
2019-05-08 9:35 ` Hanjun Guo
2019-05-08 16:51 ` Sudeep Holla
2019-05-09 9:28 ` Will Deacon
2019-05-09 10:35 ` Sudeep Holla
2019-05-09 14:13 ` Sudeep Holla
2019-05-13 10:56 ` Will Deacon
2019-05-13 11:31 ` Sudeep Holla
2019-05-13 11:10 ` Hanjun Guo
2019-05-08 16:45 ` Sudeep Holla
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