Xscale and Armv6 PMUs defined the cycle counter at 0 and event counters
starting at 1 and had 1:1 event index to counter numbering. On Armv7 and
later, this changed the cycle counter to 31 and event counters start at
0. The drivers for Armv7 and PMUv3 kept the old event index numbering
and introduced an event index to counter conversion. The conversion uses
masking to convert from event index to a counter number. This operation
relies on having at most 32 counters so that the cycle counter index 0
can be transformed to counter number 31.
Armv9.4 adds support for an additional fixed function counter
(instructions) which increases possible counters to more than 32, and
the conversion won't work anymore as a simple subtract and mask. The
primary reason for the translation (other than history) seems to be to
have a contiguous mask of counters 0-N. Keeping that would result in
more complicated index to counter conversions. Instead, store a mask of
available counters rather than just number of events. That provides more
information in addition to the number of events.
No (intended) functional changes.
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Tested-by: James Clark <james.clark@linaro.org>
Link: https://lore.kernel.org/r/20240731-arm-pmu-3-9-icntr-v3-1-280a8d7ff465@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
-EPERM or -EINVAL always get converted to -EOPNOTSUPP, so replace them.
This will allow __hw_perf_event_init() to return a different code or not
print that particular message for a different error in the next commit.
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-10-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Sidharth reports that on M2, the PMU never generates any interrupt
when using 'perf record', which is a annoying as you get no sample.
I'm temped to say "no sample, no problem", but others may have
a different opinion.
Upon investigation, it appears that the counters on M2 are
significantly different from the ones on M1, as they count on
64 bits instead of 48. Which of course, in the fine M1 tradition,
means that we can only use 63 bits, as the top bit is used to signal
the interrupt...
This results in having to introduce yet another flag to indicate yet
another odd counter width. Who knows what the next crazy implementation
will do...
With this, perf can work out the correct offset, and 'perf record'
works as intended.
Tested on M2 and M2-Pro CPUs.
Cc: Janne Grunau <j@jannau.net>
Cc: Hector Martin <marcan@marcan.st>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Fixes: 7d0bfb7c99 ("drivers/perf: apple_m1: Add Apple M2 support")
Reported-by: Sidharth Kshatriya <sid.kshatriya@gmail.com>
Tested-by: Sidharth Kshatriya <sid.kshatriya@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230528080205.288446-1-maz@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
The PMU itself is compatible with the one found on M1. We still know
next to nothing about the counters so keep using CPU uarch specific
compatibles/PMU names.
Signed-off-by: Janne Grunau <j@jannau.net>
Acked-by: Mark Rutland <mark.rutland@arm.com.
Reviewed-by: Hector Martin <marcan@marcan.st>
Link: https://lore.kernel.org/r/20230214-apple_m2_pmu-v1-2-9c9213ab9b63@jannau.net
Signed-off-by: Will Deacon <will@kernel.org>
Since commit 8b41fc4454 ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.
So remove it in the files in this commit, none of which can be built as
modules.
Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230217141059.392471-9-nick.alcock@oracle.com
Signed-off-by: Will Deacon <will@kernel.org>
Add a new, weird and wonderful driver for the equally weird Apple
PMU HW. Although the PMU itself is functional, we don't know much
about the events yet, so this can be considered as yet another
random number generator...
Nonetheless, it can reliably count at least cycles and instructions
in the usually wonky big-little way. For anything else, it of course
supports raw event numbers.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
