From: Jeremy Linton <jeremy.linton@arm.com>
To: 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,
linux-kernel@vger.kernel.org,
Jeremy Linton <jeremy.linton@arm.com>,
linuxarm@huawei.com, linux-acpi@vger.kernel.org,
james.morse@arm.com, catalin.marinas@arm.com, lenb@kernel.org
Subject: [PATCH 1/4] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens
Date: Tue, 26 Mar 2019 17:39:35 -0500 [thread overview]
Message-ID: <20190326223938.5365-2-jeremy.linton@arm.com> (raw)
In-Reply-To: <20190326223938.5365-1-jeremy.linton@arm.com>
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 065c4fc245d1..472c95ec816b 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() - Determine a unique implementation
+ * @cpu: Kernel logical cpu number
+ *
+ * Determine a unique heterogeneous ID for the given CPU. CPUs with the same
+ * implementation should have matching IDs. Since this is a tree we can only
+ * detect implementations where the heterogeneous flag is the parent to all
+ * matching cores. AKA if a two socket machine has two different core types
+ * in each socket this will end up being represented as four unique core types
+ * rather than two.
+ *
+ * The returned ID 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.
+ *
+ * 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 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;
--
2.20.1
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next prev parent reply other threads:[~2019-03-26 22:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-26 22:39 [PATCH 0/4] arm64: SPE ACPI enablement Jeremy Linton
2019-03-26 22:39 ` Jeremy Linton [this message]
2019-03-28 10:04 ` [PATCH 1/4] ACPI/PPTT: Add function to return ACPI 6.3 Identical tokens Rafael J. Wysocki
2019-03-28 15:20 ` Jeremy Linton
2019-03-26 22:39 ` [PATCH 2/4] ACPI/PPTT: Modify node flag detection to find last IDENTICAL Jeremy Linton
2019-03-26 22:39 ` [PATCH 3/4] arm_pmu: acpi: spe: Add initial MADT/SPE probing Jeremy Linton
2019-03-28 12:40 ` John Garry
2019-04-02 19:14 ` Jeremy Linton
2019-04-05 9:23 ` John Garry
2019-03-26 22:39 ` [PATCH 4/4] perf: arm_spe: Enable ACPI/Platform automatic module loading Jeremy Linton
2019-04-04 17:04 ` Will Deacon
2019-04-04 17:24 ` Jeremy Linton
2019-04-16 13:50 ` Will Deacon
2019-04-26 0:58 ` Jeremy Linton
2019-04-26 8:04 ` Will Deacon
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