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authorLinus Torvalds <torvalds@linux-foundation.org>2019-09-16 14:31:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-16 14:31:40 -0700
commite77fafe9afb53b7f4d8176c5cd5c10c43a905bc8 (patch)
tree828ad771a2951f7ac06111c3a9a30e0f368a9b5e /Documentation/devicetree
parent52a5525214d0d612160154d902956eca0558b7c0 (diff)
parente376897f424a1c807779a2635f62eb02d7e382f9 (diff)
Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon: "Although there isn't tonnes of code in terms of line count, there are a fair few headline features which I've noted both in the tag and also in the merge commits when I pulled everything together. The part I'm most pleased with is that we had 35 contributors this time around, which feels like a big jump from the usual small group of core arm64 arch developers. Hopefully they all enjoyed it so much that they'll continue to contribute, but we'll see. It's probably worth highlighting that we've pulled in a branch from the risc-v folks which moves our CPU topology code out to where it can be shared with others. Summary: - 52-bit virtual addressing in the kernel - New ABI to allow tagged user pointers to be dereferenced by syscalls - Early RNG seeding by the bootloader - Improve robustness of SMP boot - Fix TLB invalidation in light of recent architectural clarifications - Support for i.MX8 DDR PMU - Remove direct LSE instruction patching in favour of static keys - Function error injection using kprobes - Support for the PPTT "thread" flag introduced by ACPI 6.3 - Move PSCI idle code into proper cpuidle driver - Relaxation of implicit I/O memory barriers - Build with RELR relocations when toolchain supports them - Numerous cleanups and non-critical fixes" * tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (114 commits) arm64: remove __iounmap arm64: atomics: Use K constraint when toolchain appears to support it arm64: atomics: Undefine internal macros after use arm64: lse: Make ARM64_LSE_ATOMICS depend on JUMP_LABEL arm64: asm: Kill 'asm/atomic_arch.h' arm64: lse: Remove unused 'alt_lse' assembly macro arm64: atomics: Remove atomic_ll_sc compilation unit arm64: avoid using hard-coded registers for LSE atomics arm64: atomics: avoid out-of-line ll/sc atomics arm64: Use correct ll/sc atomic constraints jump_label: Don't warn on __exit jump entries docs/perf: Add documentation for the i.MX8 DDR PMU perf/imx_ddr: Add support for AXI ID filtering arm64: kpti: ensure patched kernel text is fetched from PoU arm64: fix fixmap copy for 16K pages and 48-bit VA perf/smmuv3: Validate groups for global filtering perf/smmuv3: Validate group size arm64: Relax Documentation/arm64/tagged-pointers.rst arm64: kvm: Replace hardcoded '1' with SYS_PAR_EL1_F arm64: mm: Ignore spurious translation faults taken from the kernel ...
Diffstat (limited to 'Documentation/devicetree')
-rw-r--r--Documentation/devicetree/bindings/cpu/cpu-topology.txt (renamed from Documentation/devicetree/bindings/arm/topology.txt)256
1 files changed, 167 insertions, 89 deletions
diff --git a/Documentation/devicetree/bindings/arm/topology.txt b/Documentation/devicetree/bindings/cpu/cpu-topology.txt
index b0d80c0fb265..99918189403c 100644
--- a/Documentation/devicetree/bindings/arm/topology.txt
+++ b/Documentation/devicetree/bindings/cpu/cpu-topology.txt
@@ -1,21 +1,19 @@
===========================================
-ARM topology binding description
+CPU topology binding description
===========================================
===========================================
1 - Introduction
===========================================
-In an ARM system, the hierarchy of CPUs is defined through three entities that
+In a SMP system, the hierarchy of CPUs is defined through three entities that
are used to describe the layout of physical CPUs in the system:
+- socket
- cluster
- core
- thread
-The cpu nodes (bindings defined in [1]) represent the devices that
-correspond to physical CPUs and are to be mapped to the hierarchy levels.
-
The bottom hierarchy level sits at core or thread level depending on whether
symmetric multi-threading (SMT) is supported or not.
@@ -24,33 +22,31 @@ threads existing in the system and map to the hierarchy level "thread" above.
In systems where SMT is not supported "cpu" nodes represent all cores present
in the system and map to the hierarchy level "core" above.
-ARM topology bindings allow one to associate cpu nodes with hierarchical groups
+CPU topology bindings allow one to associate cpu nodes with hierarchical groups
corresponding to the system hierarchy; syntactically they are defined as device
tree nodes.
-The remainder of this document provides the topology bindings for ARM, based
-on the Devicetree Specification, available from:
+Currently, only ARM/RISC-V intend to use this cpu topology binding but it may be
+used for any other architecture as well.
-https://www.devicetree.org/specifications/
+The cpu nodes, as per bindings defined in [4], represent the devices that
+correspond to physical CPUs and are to be mapped to the hierarchy levels.
-If not stated otherwise, whenever a reference to a cpu node phandle is made its
-value must point to a cpu node compliant with the cpu node bindings as
-documented in [1].
A topology description containing phandles to cpu nodes that are not compliant
-with bindings standardized in [1] is therefore considered invalid.
+with bindings standardized in [4] is therefore considered invalid.
===========================================
2 - cpu-map node
===========================================
-The ARM CPU topology is defined within the cpu-map node, which is a direct
+The ARM/RISC-V CPU topology is defined within the cpu-map node, which is a direct
child of the cpus node and provides a container where the actual topology
nodes are listed.
- cpu-map node
- Usage: Optional - On ARM SMP systems provide CPUs topology to the OS.
- ARM uniprocessor systems do not require a topology
+ Usage: Optional - On SMP systems provide CPUs topology to the OS.
+ Uniprocessor systems do not require a topology
description and therefore should not define a
cpu-map node.
@@ -63,21 +59,23 @@ nodes are listed.
The cpu-map node's child nodes can be:
- - one or more cluster nodes
+ - one or more cluster nodes or
+ - one or more socket nodes in a multi-socket system
Any other configuration is considered invalid.
-The cpu-map node can only contain three types of child nodes:
+The cpu-map node can only contain 4 types of child nodes:
+- socket node
- cluster node
- core node
- thread node
whose bindings are described in paragraph 3.
-The nodes describing the CPU topology (cluster/core/thread) can only
-be defined within the cpu-map node and every core/thread in the system
-must be defined within the topology. Any other configuration is
+The nodes describing the CPU topology (socket/cluster/core/thread) can
+only be defined within the cpu-map node and every core/thread in the
+system must be defined within the topology. Any other configuration is
invalid and therefore must be ignored.
===========================================
@@ -85,26 +83,44 @@ invalid and therefore must be ignored.
===========================================
cpu-map child nodes must follow a naming convention where the node name
-must be "clusterN", "coreN", "threadN" depending on the node type (ie
-cluster/core/thread) (where N = {0, 1, ...} is the node number; nodes which
-are siblings within a single common parent node must be given a unique and
+must be "socketN", "clusterN", "coreN", "threadN" depending on the node type
+(ie socket/cluster/core/thread) (where N = {0, 1, ...} is the node number; nodes
+which are siblings within a single common parent node must be given a unique and
sequential N value, starting from 0).
cpu-map child nodes which do not share a common parent node can have the same
name (ie same number N as other cpu-map child nodes at different device tree
levels) since name uniqueness will be guaranteed by the device tree hierarchy.
===========================================
-3 - cluster/core/thread node bindings
+3 - socket/cluster/core/thread node bindings
===========================================
-Bindings for cluster/cpu/thread nodes are defined as follows:
+Bindings for socket/cluster/cpu/thread nodes are defined as follows:
+
+- socket node
+
+ Description: must be declared within a cpu-map node, one node
+ per physical socket in the system. A system can
+ contain single or multiple physical socket.
+ The association of sockets and NUMA nodes is beyond
+ the scope of this bindings, please refer [2] for
+ NUMA bindings.
+
+ This node is optional for a single socket system.
+
+ The socket node name must be "socketN" as described in 2.1 above.
+ A socket node can not be a leaf node.
+
+ A socket node's child nodes must be one or more cluster nodes.
+
+ Any other configuration is considered invalid.
- cluster node
Description: must be declared within a cpu-map node, one node
per cluster. A system can contain several layers of
- clustering and cluster nodes can be contained in parent
- cluster nodes.
+ clustering within a single physical socket and cluster
+ nodes can be contained in parent cluster nodes.
The cluster node name must be "clusterN" as described in 2.1 above.
A cluster node can not be a leaf node.
@@ -164,90 +180,93 @@ Bindings for cluster/cpu/thread nodes are defined as follows:
4 - Example dts
===========================================
-Example 1 (ARM 64-bit, 16-cpu system, two clusters of clusters):
+Example 1 (ARM 64-bit, 16-cpu system, two clusters of clusters in a single
+physical socket):
cpus {
#size-cells = <0>;
#address-cells = <2>;
cpu-map {
- cluster0 {
+ socket0 {
cluster0 {
- core0 {
- thread0 {
- cpu = <&CPU0>;
+ cluster0 {
+ core0 {
+ thread0 {
+ cpu = <&CPU0>;
+ };
+ thread1 {
+ cpu = <&CPU1>;
+ };
};
- thread1 {
- cpu = <&CPU1>;
- };
- };
- core1 {
- thread0 {
- cpu = <&CPU2>;
- };
- thread1 {
- cpu = <&CPU3>;
+ core1 {
+ thread0 {
+ cpu = <&CPU2>;
+ };
+ thread1 {
+ cpu = <&CPU3>;
+ };
};
};
- };
- cluster1 {
- core0 {
- thread0 {
- cpu = <&CPU4>;
- };
- thread1 {
- cpu = <&CPU5>;
+ cluster1 {
+ core0 {
+ thread0 {
+ cpu = <&CPU4>;
+ };
+ thread1 {
+ cpu = <&CPU5>;
+ };
};
- };
- core1 {
- thread0 {
- cpu = <&CPU6>;
- };
- thread1 {
- cpu = <&CPU7>;
- };
- };
- };
- };
-
- cluster1 {
- cluster0 {
- core0 {
- thread0 {
- cpu = <&CPU8>;
- };
- thread1 {
- cpu = <&CPU9>;
- };
- };
- core1 {
- thread0 {
- cpu = <&CPU10>;
- };
- thread1 {
- cpu = <&CPU11>;
+ core1 {
+ thread0 {
+ cpu = <&CPU6>;
+ };
+ thread1 {
+ cpu = <&CPU7>;
+ };
};
};
};
cluster1 {
- core0 {
- thread0 {
- cpu = <&CPU12>;
+ cluster0 {
+ core0 {
+ thread0 {
+ cpu = <&CPU8>;
+ };
+ thread1 {
+ cpu = <&CPU9>;
+ };
};
- thread1 {
- cpu = <&CPU13>;
+ core1 {
+ thread0 {
+ cpu = <&CPU10>;
+ };
+ thread1 {
+ cpu = <&CPU11>;
+ };
};
};
- core1 {
- thread0 {
- cpu = <&CPU14>;
+
+ cluster1 {
+ core0 {
+ thread0 {
+ cpu = <&CPU12>;
+ };
+ thread1 {
+ cpu = <&CPU13>;
+ };
};
- thread1 {
- cpu = <&CPU15>;
+ core1 {
+ thread0 {
+ cpu = <&CPU14>;
+ };
+ thread1 {
+ cpu = <&CPU15>;
+ };
};
};
};
@@ -470,6 +489,65 @@ cpus {
};
};
+Example 3: HiFive Unleashed (RISC-V 64 bit, 4 core system)
+
+{
+ #address-cells = <2>;
+ #size-cells = <2>;
+ compatible = "sifive,fu540g", "sifive,fu500";
+ model = "sifive,hifive-unleashed-a00";
+
+ ...
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ cpu-map {
+ socket0 {
+ cluster0 {
+ core0 {
+ cpu = <&CPU1>;
+ };
+ core1 {
+ cpu = <&CPU2>;
+ };
+ core2 {
+ cpu0 = <&CPU2>;
+ };
+ core3 {
+ cpu0 = <&CPU3>;
+ };
+ };
+ };
+ };
+
+ CPU1: cpu@1 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x1>;
+ }
+
+ CPU2: cpu@2 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x2>;
+ }
+ CPU3: cpu@3 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x3>;
+ }
+ CPU4: cpu@4 {
+ device_type = "cpu";
+ compatible = "sifive,rocket0", "riscv";
+ reg = <0x4>;
+ }
+ }
+};
===============================================================================
[1] ARM Linux kernel documentation
Documentation/devicetree/bindings/arm/cpus.yaml
+[2] Devicetree NUMA binding description
+ Documentation/devicetree/bindings/numa.txt
+[3] RISC-V Linux kernel documentation
+ Documentation/devicetree/bindings/riscv/cpus.txt
+[4] https://www.devicetree.org/specifications/