Some platforms such as hifive unmatched doesn't implement mcountinhibit
csr. However, it has hardware events that can be monitored using 2
hpmcounter it has (i.e. mhpmcounter3 & mhpmcounter4).
Currently, PMU extension disabled if mcountinhibit is absent. That's not
really necessary as long as the supervisor OS keeps track of the delta
value of the counters. Without mcountinhibit, the delta value won't be
entirely accurate because the counters are freely running. However, that
should be fine to produce an approximate counter value which can help
performance analysis. Perf sampling won't work though as sscof extension
is not present in hifive unmatched.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
The mhpm bits represent the number of bits available in mhpmcounter
while counter width describes a zero indexed value. Fix the counter width
calculation.
Fixes: 13d40f21d5 ("lib: sbi: Add PMU support")
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
The hardware solely relies on the event selector value in mhpmevent
to figure out what event to monitor using that counter. It should be
reset when counter reset happens.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
A platform may use programmable counters for cycle/instret events.
The priv spec allows that provided that cycle/instret also report those
events in addition to the programmable counters. We should allow that
functionality in OpenSBI.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
OpenSBI doesn't use any counters for its own usage. Thus, all the counters
can be made accessible for lower privilege mode always. However, the
mcountinhibit must be set so that the counter doesn't increment.
As a result, we don't have to enable/disable mcounteren at every start/stop.
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
This patch adds sscofpmf extension in pmu module which includes
following things.
1. Enable overflow irq when starting a counter.
2. Setting the correct event filters passed from supervisor.
3. Delegating the overflow interrupt to the supervisor.
4. Add RV32 support for sscofpmf.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
The sbi_pmu_exit() crashes on systems not having MCOUNTINHIBIT csr
so to fix this we check SBI_HART_HAS_MCOUNTINHIBIT feature in
sbi_pmu_exit() and do nothing if it is not available.
Fixes: 13d40f21d5 ("lib: sbi: Add PMU support")
Signed-off-by: Anup Patel <anup.patel@wdc.com>
RISC-V SBI specfication 0.3 defines a PMU extension that allows supervisor
mode to start/stop/configure pmu related events. This patch implements
all of the functionality defined in the specification.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
RISC-V SBI v0.3 specification defined a PMU extension to configure/start/stop
the hardware/firmware pmu events.
Implement PMU support in OpenSBI library. The implementation is agnostic of
event to counter mapping & mhpmevent value configuration. That means, it
expects platform hooks will be used to set up the mapping and provide
the mhpmevent value at runtime.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
