Commit 59bff30a authored by Randy Dunlap's avatar Randy Dunlap Committed by Catalin Marinas

Documentation: arm64: fix amu.rst doc warnings

Fix bullet list formatting to eliminate doc warnings:

Documentation/arm64/amu.rst:26: WARNING: Unexpected indentation.
Documentation/arm64/amu.rst:60: WARNING: Unexpected indentation.
Documentation/arm64/amu.rst:81: WARNING: Unexpected indentation.
Documentation/arm64/amu.rst:108: WARNING: Unexpected indentation.
Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Cc: Ionela Voinescu <ionela.voinescu@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 3fabb438
...@@ -23,12 +23,13 @@ optional external memory-mapped interface. ...@@ -23,12 +23,13 @@ optional external memory-mapped interface.
Version 1 of the Activity Monitors architecture implements a counter group Version 1 of the Activity Monitors architecture implements a counter group
of four fixed and architecturally defined 64-bit event counters. of four fixed and architecturally defined 64-bit event counters.
- CPU cycle counter: increments at the frequency of the CPU.
- Constant counter: increments at the fixed frequency of the system - CPU cycle counter: increments at the frequency of the CPU.
- Constant counter: increments at the fixed frequency of the system
clock. clock.
- Instructions retired: increments with every architecturally executed - Instructions retired: increments with every architecturally executed
instruction. instruction.
- Memory stall cycles: counts instruction dispatch stall cycles caused by - Memory stall cycles: counts instruction dispatch stall cycles caused by
misses in the last level cache within the clock domain. misses in the last level cache within the clock domain.
When in WFI or WFE these counters do not increment. When in WFI or WFE these counters do not increment.
...@@ -57,10 +58,11 @@ counters, only the presence of the extension. ...@@ -57,10 +58,11 @@ counters, only the presence of the extension.
Firmware (code running at higher exception levels, e.g. arm-tf) support is Firmware (code running at higher exception levels, e.g. arm-tf) support is
needed to: needed to:
- Enable access for lower exception levels (EL2 and EL1) to the AMU
- Enable access for lower exception levels (EL2 and EL1) to the AMU
registers. registers.
- Enable the counters. If not enabled these will read as 0. - Enable the counters. If not enabled these will read as 0.
- Save/restore the counters before/after the CPU is being put/brought up - Save/restore the counters before/after the CPU is being put/brought up
from the 'off' power state. from the 'off' power state.
When using kernels that have this feature enabled but boot with broken When using kernels that have this feature enabled but boot with broken
...@@ -78,10 +80,11 @@ are not trapped in EL2/EL3. ...@@ -78,10 +80,11 @@ are not trapped in EL2/EL3.
The fixed counters of AMUv1 are accessible though the following system The fixed counters of AMUv1 are accessible though the following system
register definitions: register definitions:
- SYS_AMEVCNTR0_CORE_EL0
- SYS_AMEVCNTR0_CONST_EL0 - SYS_AMEVCNTR0_CORE_EL0
- SYS_AMEVCNTR0_INST_RET_EL0 - SYS_AMEVCNTR0_CONST_EL0
- SYS_AMEVCNTR0_MEM_STALL_EL0 - SYS_AMEVCNTR0_INST_RET_EL0
- SYS_AMEVCNTR0_MEM_STALL_EL0
Auxiliary platform specific counters can be accessed using Auxiliary platform specific counters can be accessed using
SYS_AMEVCNTR1_EL0(n), where n is a value between 0 and 15. SYS_AMEVCNTR1_EL0(n), where n is a value between 0 and 15.
...@@ -93,9 +96,10 @@ Userspace access ...@@ -93,9 +96,10 @@ Userspace access
---------------- ----------------
Currently, access from userspace to the AMU registers is disabled due to: Currently, access from userspace to the AMU registers is disabled due to:
- Security reasons: they might expose information about code executed in
- Security reasons: they might expose information about code executed in
secure mode. secure mode.
- Purpose: AMU counters are intended for system management use. - Purpose: AMU counters are intended for system management use.
Also, the presence of the feature is not visible to userspace. Also, the presence of the feature is not visible to userspace.
...@@ -105,7 +109,8 @@ Virtualization ...@@ -105,7 +109,8 @@ Virtualization
Currently, access from userspace (EL0) and kernelspace (EL1) on the KVM Currently, access from userspace (EL0) and kernelspace (EL1) on the KVM
guest side is disabled due to: guest side is disabled due to:
- Security reasons: they might expose information about code executed
- Security reasons: they might expose information about code executed
by other guests or the host. by other guests or the host.
Any attempt to access the AMU registers will result in an UNDEFINED Any attempt to access the AMU registers will result in an UNDEFINED
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment