[PATCH] docs: cputopology: move the sysfs ABI description to right place

From: Barry Song
Date: Fri Jun 11 2021 - 01:23:13 EST

From: Tian Tao <tiantao6@xxxxxxxxxxxxx>

Documentation/admin-guide/cputopology.rst is the wrong place to describe
sysfs ABI. So move the cputopology ABI things to
Documentation/ABI/stable/sysfs-devices-system-cpu and add a reference to
ABI doc in Documentation/admin-guide/cputopology.rst.

Link: https://lkml.kernel.org/r/20210319041618.14316-1-song.bao.hua@xxxxxxxxxxxxx
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Tian Tao <tiantao6@xxxxxxxxxxxxx>
Signed-off-by: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
---
*this patch is addressing the concern of Greg KH in the above link tag:

"Why are these sysfs files in this file, and not in a
Documentation/ABI/ file which can be correctly parsed
and shown to userspace?"

.../ABI/stable/sysfs-devices-system-cpu | 83 ++++++++++++++++++
Documentation/admin-guide/cputopology.rst | 85 +------------------
2 files changed, 87 insertions(+), 81 deletions(-)

diff --git a/Documentation/ABI/stable/sysfs-devices-system-cpu b/Documentation/ABI/stable/sysfs-devices-system-cpu
index 33c133e2a631..516dafea03eb 100644
--- a/Documentation/ABI/stable/sysfs-devices-system-cpu
+++ b/Documentation/ABI/stable/sysfs-devices-system-cpu
@@ -23,3 +23,86 @@ Description: Default value for the Data Stream Control Register (DSCR) on
here).
If set by a process it will be inherited by child processes.
Values: 64 bit unsigned integer (bit field)
+
+What: /sys/devices/system/cpu/cpuX/topology/physical_package_id
+Description: physical package id of cpuX. Typically corresponds to a physical
+ socket number, but the actual value is architecture and platform
+ dependent.
+Values: integer
+
+What: /sys/devices/system/cpu/cpuX/topology/die_id
+Description: the CPU die ID of cpuX. Typically it is the hardware platform's
+ identifier (rather than the kernel's). The actual value is
+ architecture and platform dependent.
+Values: integer
+
+What: /sys/devices/system/cpu/cpuX/topology/core_id
+Description: the CPU core ID of cpuX. Typically it is the hardware platform's
+ identifier (rather than the kernel's). The actual value is
+ architecture and platform dependent.
+Values: integer
+
+What: /sys/devices/system/cpu/cpuX/topology/book_id
+Description: the book ID of cpuX. Typically it is the hardware platform's
+ identifier (rather than the kernel's). The actual value is
+ architecture and platform dependent. it's only used on s390.
+Values: integer
+
+What: /sys/devices/system/cpu/cpuX/topology/drawer_id
+Description: the drawer ID of cpuX. Typically it is the hardware platform's
+ identifier (rather than the kernel's). The actual value is
+ architecture and platform dependent. it's only used on s390.
+Values: integer
+
+What: /sys/devices/system/cpu/cpuX/topology/core_cpus
+Description: internal kernel map of CPUs within the same core.
+ (deprecated name: "thread_siblings")
+Values: hexadecimal bitmask.
+
+What: /sys/devices/system/cpu/cpuX/topology/core_cpus_list
+Description: human-readable list of CPUs within the same core.
+ The format is like 0-3, 8-11, 14,17.
+ (deprecated name: "thread_siblings_list").
+Values: decimal list.
+
+What: /sys/devices/system/cpu/cpuX/topology/package_cpus
+Description: internal kernel map of the CPUs sharing the same physical_package_id.
+ (deprecated name: "core_siblings").
+Values: hexadecimal bitmask.
+
+What: /sys/devices/system/cpu/cpuX/topology/package_cpus_list
+Description: human-readable list of CPUs sharing the same physical_package_id.
+ The format is like 0-3, 8-11, 14,17.
+ (deprecated name: "core_siblings_list")
+Values: decimal list.
+
+What: /sys/devices/system/cpu/cpuX/topology/die_cpus
+Description: internal kernel map of CPUs within the same die.
+Values: hexadecimal bitmask.
+
+What: /sys/devices/system/cpu/cpuX/topology/die_cpus_list
+Description: human-readable list of CPUs within the same die.
+ The format is like 0-3, 8-11, 14,17.
+Values: decimal list.
+
+What: /sys/devices/system/cpu/cpuX/topology/book_siblings
+Description: internal kernel map of cpuX's hardware threads within the same
+ book_id. it's only used on s390.
+Values: hexadecimal bitmask.
+
+What: /sys/devices/system/cpu/cpuX/topology/book_siblings_list
+Description: human-readable list of cpuX's hardware threads within the same
+ book_id.
+ The format is like 0-3, 8-11, 14,17. it's only used on s390.
+Values: decimal list.
+
+What: /sys/devices/system/cpu/cpuX/topology/drawer_siblings
+Description: internal kernel map of cpuX's hardware threads within the same
+ drawer_id. it's only used on s390.
+Values: hexadecimal bitmask.
+
+What: /sys/devices/system/cpu/cpuX/topology/drawer_siblings_list
+Description: human-readable list of cpuX's hardware threads within the same
+ drawer_id.
+ The format is like 0-3, 8-11, 14,17. it's only used on s390.
+Values: decimal list.
diff --git a/Documentation/admin-guide/cputopology.rst b/Documentation/admin-guide/cputopology.rst
index b90dafcc8237..8632a1db36e4 100644
--- a/Documentation/admin-guide/cputopology.rst
+++ b/Documentation/admin-guide/cputopology.rst
@@ -2,87 +2,10 @@
How CPU topology info is exported via sysfs
===========================================

-Export CPU topology info via sysfs. Items (attributes) are similar
-to /proc/cpuinfo output of some architectures. They reside in
-/sys/devices/system/cpu/cpuX/topology/:
-
-physical_package_id:
-
- physical package id of cpuX. Typically corresponds to a physical
- socket number, but the actual value is architecture and platform
- dependent.
-
-die_id:
-
- the CPU die ID of cpuX. Typically it is the hardware platform's
- identifier (rather than the kernel's). The actual value is
- architecture and platform dependent.
-
-core_id:
-
- the CPU core ID of cpuX. Typically it is the hardware platform's
- identifier (rather than the kernel's). The actual value is
- architecture and platform dependent.
-
-book_id:
-
- the book ID of cpuX. Typically it is the hardware platform's
- identifier (rather than the kernel's). The actual value is
- architecture and platform dependent.
-
-drawer_id:
-
- the drawer ID of cpuX. Typically it is the hardware platform's
- identifier (rather than the kernel's). The actual value is
- architecture and platform dependent.
-
-core_cpus:
-
- internal kernel map of CPUs within the same core.
- (deprecated name: "thread_siblings")
-
-core_cpus_list:
-
- human-readable list of CPUs within the same core.
- (deprecated name: "thread_siblings_list");
-
-package_cpus:
-
- internal kernel map of the CPUs sharing the same physical_package_id.
- (deprecated name: "core_siblings")
-
-package_cpus_list:
-
- human-readable list of CPUs sharing the same physical_package_id.
- (deprecated name: "core_siblings_list")
-
-die_cpus:
-
- internal kernel map of CPUs within the same die.
-
-die_cpus_list:
-
- human-readable list of CPUs within the same die.
-
-book_siblings:
-
- internal kernel map of cpuX's hardware threads within the same
- book_id.
-
-book_siblings_list:
-
- human-readable list of cpuX's hardware threads within the same
- book_id.
-
-drawer_siblings:
-
- internal kernel map of cpuX's hardware threads within the same
- drawer_id.
-
-drawer_siblings_list:
-
- human-readable list of cpuX's hardware threads within the same
- drawer_id.
+CPU topology info is exported via sysfs. Items (attributes) are similar
+to /proc/cpuinfo output of some architectures. They reside in
+/sys/devices/system/cpu/cpuX/topology/. Please refer to the ABI file:
+Documentation/ABI/stable/sysfs-devices-system-cpu.

Architecture-neutral, drivers/base/topology.c, exports these attributes.
However, the book and drawer related sysfs files will only be created if
--
2.25.1