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LLVM ignores everything inside the if statement and doesn't generate
errors, but GCC doesn't ignore it, resulting in the following error:
drivers/perf/arm_pmuv3.c: In function ‘armv8pmu_write_evtype’:
include/linux/bits.h:34:29: error: left shift count >= width of type [-Werror=shift-count-overflow]
34 | (((~UL(0)) - (UL(1) << (l)) + 1) & \
Fix it by using GENMASK_ULL which doesn't overflow on arm32 (even though
the value is never used there).
Fixes: 3115ee021bfb ("arm64: perf: Include threshold control fields in PMEVTYPER mask")
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Closes: https://lore.kernel.org/linux-arm-kernel/20231215120817.h2f3akgv72zhrtqo@pengutronix.de/
Signed-off-by: James Clark <james.clark@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20231215175648.3397170-2-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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FEAT_PMUv3_TH (Armv8.8) permits a PMU counter to increment only on
events whose count meets a specified threshold condition. For example if
PMEVTYPERn.TC (Threshold Control) is set to 0b101 (Greater than or
equal, count), and the threshold is set to 2, then the PMU counter will
now only increment by 1 when an event would have previously incremented
the PMU counter by 2 or more on a single processor cycle.
Three new Perf event config fields, 'threshold', 'threshold_compare' and
'threshold_count' have been added to control the feature.
threshold_compare maps to the upper two bits of PMEVTYPERn.TC and
threshold_count maps to the first bit of TC. These separate attributes
have been picked rather than enumerating all the possible combinations
of the TC field as in the Arm ARM. The attributes would be used on a
Perf command line like this:
$ perf stat -e stall_slot/threshold=2,threshold_compare=2/
A new capability for reading out the maximum supported threshold value
has also been added:
$ cat /sys/bus/event_source/devices/armv8_pmuv3/caps/threshold_max
0x000000ff
If a threshold higher than threshold_max is provided, then an error is
generated. If FEAT_PMUv3_TH isn't implemented or a 32 bit kernel is
running, then threshold_max reads zero, and attempting to set a
threshold value will also result in an error.
The threshold is per PMU counter, and there are potentially different
threshold_max values per PMU type on heterogeneous systems.
Bits higher than 32 now need to be written into PMEVTYPER, so
armv8pmu_write_evtype() has to be updated to take an unsigned long value
rather than u32 which gives the correct behavior on both aarch32 and 64.
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-11-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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FEAT_PMUv3_TH (Armv8.8) adds two new fields to PMEVTYPER, so include
them in the mask. These aren't writable on 32 bit kernels as they are in
the high part of the register, so only include them for arm64.
It would be difficult to do this statically in the asm header files for
each platform without resulting in circular includes or #ifdefs inline
in the code. For that reason the ARMV8_PMU_EVTYPE_MASK definition has
been removed and the mask is constructed programmatically.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-6-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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Convert the remaining fields to use either GENMASK or be built from
other fields. These all already started at bit 0 so don't need a code
change for the lack of _SHIFT.
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-5-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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This is so that FIELD_GET and FIELD_PREP can be used and that the fields
are in a consistent format to arm64/tools/sysreg
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-4-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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This is so that FIELD_GET and FIELD_PREP can be used and that the fields
are in a consistent format to arm64/tools/sysreg
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20231211161331.1277825-3-james.clark@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
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Suzuki noticed that KVM's PMU emulation is oblivious to the NSU and NSK
event filter bits. On systems that have EL3 these bits modify the
filter behavior in non-secure EL0 and EL1, respectively. Even though the
kernel doesn't use these bits, it is entirely possible some other guest
OS does. Additionally, it would appear that these and the M bit are
required by the architecture if EL3 is implemented.
Allow the EL3 event filter bits to be set if EL3 is advertised in the
guest's ID register. Implement the behavior of NSU and NSK according to
the pseudocode, and entirely ignore the M bit for perf event creation.
Reported-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231019185618.3442949-3-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
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As we want to enable 32bit support, we need to distanciate the
PMUv3 driver from the AArch64 system register names.
This patch moves all system register accesses to an architecture
specific include file, allowing the 32bit counterpart to be
slotted in at a later time.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Co-developed-by: Zaid Al-Bassam <zalbassam@google.com>
Signed-off-by: Zaid Al-Bassam <zalbassam@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230317195027.3746949-3-zalbassam@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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Having the ARM PMUv3 driver sitting in arch/arm64/kernel is getting
in the way of being able to use perf on ARMv8 cores running a 32bit
kernel, such as 32bit KVM guests.
This patch moves it into drivers/perf/arm_pmuv3.c, with an include
file in include/linux/perf/arm_pmuv3.h. The only thing left in
arch/arm64 is some mundane perf stuff.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Zaid Al-Bassam <zalbassam@google.com>
Tested-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230317195027.3746949-2-zalbassam@google.com
Signed-off-by: Will Deacon <will@kernel.org>
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