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d87d9a23a1
[ Upstream commit ca6f537e459e2da4b331fe8928d1a0b0f9301f42 ]
The SW_INCR event is somewhat unusual, and depends on the specific HW
counter that it is programmed into. When programmed into PMEVCNTR<n>,
SW_INCR will count any writes to PMSWINC_EL0 with bit n set, ignoring
writes to SW_INCR with bit n clear.
Event rotation means that there's no fixed relationship between
perf_events and HW counters, so this isn't all that useful.
Further, we program PMUSERENR.{SW,EN}=={0,0}, which causes EL0 writes to
PMSWINC_EL0 to be trapped and handled as UNDEFINED, resulting in a
SIGILL to userspace.
Given that, it's not a good idea to expose SW_INCR in sysfs. Hide it as
we did for CHAIN back in commit:
4ba2578fa7 ("arm64: perf: don't expose CHAIN event in sysfs")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20231204115847.2993026-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.