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authorLinus Torvalds <torvalds@linux-foundation.org>2025-05-26 14:38:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2025-05-26 14:38:57 -0700
commit3349ada3cffdbe4579872a004360daa31938f683 (patch)
treee1bb25ee685df1ced55c85343ac620b8a3af3cd2 /Documentation
parentMerge tag 's390-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux (diff)
parentMAINTAINERS: powerpc: Remove myself as a reviewer (diff)
downloadwireguard-linux-3349ada3cffdbe4579872a004360daa31938f683.tar.xz
wireguard-linux-3349ada3cffdbe4579872a004360daa31938f683.zip
Merge tag 'powerpc-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Madhavan Srinivasan: - Support for dynamic preemption - Migrate powerpc boards GPIO driver to new setter API - Added new PMU for KVM host-wide measurement - Enhancement to htmdump driver to support more functions - Added character device for couple RTAS supported APIs - Minor fixes and cleanup Thanks to Amit Machhiwal, Athira Rajeev, Bagas Sanjaya, Bartosz Golaszewski, Christophe Leroy, Eddie James, Gaurav Batra, Gautam Menghani, Geert Uytterhoeven, Haren Myneni, Hari Bathini, Jiri Slaby (SUSE), Linus Walleij, Michal Suchanek, Naveen N Rao (AMD), Nilay Shroff, Ricardo B. Marlière, Ritesh Harjani (IBM), Sathvika Vasireddy, Shrikanth Hegde, Stephen Rothwell, Sourabh Jain, Thorsten Blum, Vaibhav Jain, Venkat Rao Bagalkote, and Viktor Malik. * tag 'powerpc-6.16-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (52 commits) MAINTAINERS: powerpc: Remove myself as a reviewer powerpc/iommu: Use str_disabled_enabled() helper powerpc/powermac: Use str_enabled_disabled() and str_on_off() helpers powerpc/mm/fault: Use str_write_read() helper function powerpc: Replace strcpy() with strscpy() in proc_ppc64_init() powerpc/pseries/iommu: Fix kmemleak in TCE table userspace view powerpc/kernel: Fix ppc_save_regs inclusion in build powerpc: Transliterate author name and remove FIXME powerpc/pseries/htmdump: Include header file to get is_kvm_guest() definition KVM: PPC: Book3S HV: Fix IRQ map warnings with XICS on pSeries KVM Guest powerpc/8xx: Reduce alignment constraint for kernel memory powerpc/boot: Fix build with gcc 15 powerpc/pseries/htmdump: Add documentation for H_HTM debugfs interface powerpc/pseries/htmdump: Add htm capabilities support to htmdump module powerpc/pseries/htmdump: Add htm flags support to htmdump module powerpc/pseries/htmdump: Add htm setup support to htmdump module powerpc/pseries/htmdump: Add htm info support to htmdump module powerpc/pseries/htmdump: Add htm status support to htmdump module powerpc/pseries/htmdump: Add htm start support to htmdump module powerpc/pseries/htmdump: Add htm configure support to htmdump module ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/arch/powerpc/htm.rst104
-rw-r--r--Documentation/arch/powerpc/kvm-nested.rst40
-rw-r--r--Documentation/userspace-api/ioctl/ioctl-number.rst6
3 files changed, 140 insertions, 10 deletions
diff --git a/Documentation/arch/powerpc/htm.rst b/Documentation/arch/powerpc/htm.rst
new file mode 100644
index 000000000000..fcb4eb6306b1
--- /dev/null
+++ b/Documentation/arch/powerpc/htm.rst
@@ -0,0 +1,104 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. _htm:
+
+===================================
+HTM (Hardware Trace Macro)
+===================================
+
+Athira Rajeev, 2 Mar 2025
+
+.. contents::
+ :depth: 3
+
+
+Basic overview
+==============
+
+H_HTM is used as an interface for executing Hardware Trace Macro (HTM)
+functions, including setup, configuration, control and dumping of the HTM data.
+For using HTM, it is required to setup HTM buffers and HTM operations can
+be controlled using the H_HTM hcall. The hcall can be invoked for any core/chip
+of the system from within a partition itself. To use this feature, a debugfs
+folder called "htmdump" is present under /sys/kernel/debug/powerpc.
+
+
+HTM debugfs example usage
+=========================
+
+.. code-block:: sh
+
+ # ls /sys/kernel/debug/powerpc/htmdump/
+ coreindexonchip htmcaps htmconfigure htmflags htminfo htmsetup
+ htmstart htmstatus htmtype nodalchipindex nodeindex trace
+
+Details on each file:
+
+* nodeindex, nodalchipindex, coreindexonchip specifies which partition to configure the HTM for.
+* htmtype: specifies the type of HTM. Supported target is hardwareTarget.
+* trace: is to read the HTM data.
+* htmconfigure: Configure/Deconfigure the HTM. Writing 1 to the file will configure the trace, writing 0 to the file will do deconfigure.
+* htmstart: start/Stop the HTM. Writing 1 to the file will start the tracing, writing 0 to the file will stop the tracing.
+* htmstatus: get the status of HTM. This is needed to understand the HTM state after each operation.
+* htmsetup: set the HTM buffer size. Size of HTM buffer is in power of 2
+* htminfo: provides the system processor configuration details. This is needed to understand the appropriate values for nodeindex, nodalchipindex, coreindexonchip.
+* htmcaps : provides the HTM capabilities like minimum/maximum buffer size, what kind of tracing the HTM supports etc.
+* htmflags : allows to pass flags to hcall. Currently supports controlling the wrapping of HTM buffer.
+
+To see the system processor configuration details:
+
+.. code-block:: sh
+
+ # cat /sys/kernel/debug/powerpc/htmdump/htminfo > htminfo_file
+
+The result can be interpreted using hexdump.
+
+To collect HTM traces for a partition represented by nodeindex as
+zero, nodalchipindex as 1 and coreindexonchip as 12
+
+.. code-block:: sh
+
+ # cd /sys/kernel/debug/powerpc/htmdump/
+ # echo 2 > htmtype
+ # echo 33 > htmsetup ( sets 8GB memory for HTM buffer, number is size in power of 2 )
+
+This requires a CEC reboot to get the HTM buffers allocated.
+
+.. code-block:: sh
+
+ # cd /sys/kernel/debug/powerpc/htmdump/
+ # echo 2 > htmtype
+ # echo 0 > nodeindex
+ # echo 1 > nodalchipindex
+ # echo 12 > coreindexonchip
+ # echo 1 > htmflags # to set noWrap for HTM buffers
+ # echo 1 > htmconfigure # Configure the HTM
+ # echo 1 > htmstart # Start the HTM
+ # echo 0 > htmstart # Stop the HTM
+ # echo 0 > htmconfigure # Deconfigure the HTM
+ # cat htmstatus # Dump the status of HTM entries as data
+
+Above will set the htmtype and core details, followed by executing respective HTM operation.
+
+Read the HTM trace data
+========================
+
+After starting the trace collection, run the workload
+of interest. Stop the trace collection after required period
+of time, and read the trace file.
+
+.. code-block:: sh
+
+ # cat /sys/kernel/debug/powerpc/htmdump/trace > trace_file
+
+This trace file will contain the relevant instruction traces
+collected during the workload execution. And can be used as
+input file for trace decoders to understand data.
+
+Benefits of using HTM debugfs interface
+=======================================
+
+It is now possible to collect traces for a particular core/chip
+from within any partition of the system and decode it. Through
+this enablement, a small partition can be dedicated to collect the
+trace data and analyze to provide important information for Performance
+analysis, Software tuning, or Hardware debug.
diff --git a/Documentation/arch/powerpc/kvm-nested.rst b/Documentation/arch/powerpc/kvm-nested.rst
index 5defd13cc6c1..574592505604 100644
--- a/Documentation/arch/powerpc/kvm-nested.rst
+++ b/Documentation/arch/powerpc/kvm-nested.rst
@@ -208,13 +208,9 @@ associated values for each ID in the GSB::
flags:
Bit 0: getGuestWideState: Request state of the Guest instead
of an individual VCPU.
- Bit 1: takeOwnershipOfVcpuState Indicate the L1 is taking
- over ownership of the VCPU state and that the L0 can free
- the storage holding the state. The VCPU state will need to
- be returned to the Hypervisor via H_GUEST_SET_STATE prior
- to H_GUEST_RUN_VCPU being called for this VCPU. The data
- returned in the dataBuffer is in a Hypervisor internal
- format.
+ Bit 1: getHostWideState: Request stats of the Host. This causes
+ the guestId and vcpuId parameters to be ignored and attempting
+ to get the VCPU/Guest state will cause an error.
Bits 2-63: Reserved
guestId: ID obtained from H_GUEST_CREATE
vcpuId: ID of the vCPU pass to H_GUEST_CREATE_VCPU
@@ -406,9 +402,10 @@ the partition like the timebase offset and partition scoped page
table information.
+--------+-------+----+--------+----------------------------------+
-| ID | Size | RW | Thread | Details |
-| | Bytes | | Guest | |
-| | | | Scope | |
+| ID | Size | RW |(H)ost | Details |
+| | Bytes | |(G)uest | |
+| | | |(T)hread| |
+| | | |Scope | |
+========+=======+====+========+==================================+
| 0x0000 | | RW | TG | NOP element |
+--------+-------+----+--------+----------------------------------+
@@ -434,6 +431,29 @@ table information.
| | | | |- 0x8 Table size. |
+--------+-------+----+--------+----------------------------------+
| 0x0007-| | | | Reserved |
+| 0x07FF | | | | |
++--------+-------+----+--------+----------------------------------+
+| 0x0800 | 0x08 | R | H | Current usage in bytes of the |
+| | | | | L0's Guest Management Space |
+| | | | | for an L1-Lpar. |
++--------+-------+----+--------+----------------------------------+
+| 0x0801 | 0x08 | R | H | Max bytes available in the |
+| | | | | L0's Guest Management Space for |
+| | | | | an L1-Lpar |
++--------+-------+----+--------+----------------------------------+
+| 0x0802 | 0x08 | R | H | Current usage in bytes of the |
+| | | | | L0's Guest Page Table Management |
+| | | | | Space for an L1-Lpar |
++--------+-------+----+--------+----------------------------------+
+| 0x0803 | 0x08 | R | H | Max bytes available in the L0's |
+| | | | | Guest Page Table Management |
+| | | | | Space for an L1-Lpar |
++--------+-------+----+--------+----------------------------------+
+| 0x0804 | 0x08 | R | H | Cumulative Reclaimed bytes from |
+| | | | | L0 Guest's Page Table Management |
+| | | | | Space due to overcommit |
++--------+-------+----+--------+----------------------------------+
+| 0x0805-| | | | Reserved |
| 0x0BFF | | | | |
+--------+-------+----+--------+----------------------------------+
| 0x0C00 | 0x10 | RW | T |Run vCPU Input Buffer: |
diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst b/Documentation/userspace-api/ioctl/ioctl-number.rst
index 7a1409ecc238..fee5c4731501 100644
--- a/Documentation/userspace-api/ioctl/ioctl-number.rst
+++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
@@ -366,6 +366,12 @@ Code Seq# Include File Comments
<mailto:linuxppc-dev>
0xB2 01-02 arch/powerpc/include/uapi/asm/papr-sysparm.h powerpc/pseries system parameter API
<mailto:linuxppc-dev>
+0xB2 03-05 arch/powerpc/include/uapi/asm/papr-indices.h powerpc/pseries indices API
+ <mailto:linuxppc-dev>
+0xB2 06-07 arch/powerpc/include/uapi/asm/papr-platform-dump.h powerpc/pseries Platform Dump API
+ <mailto:linuxppc-dev>
+0xB2 08 powerpc/include/uapi/asm/papr-physical-attestation.h powerpc/pseries Physical Attestation API
+ <mailto:linuxppc-dev>
0xB3 00 linux/mmc/ioctl.h
0xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
0xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>