In case of programmable counters configured to count inst/cycles
we often end-up with counter not incrementing at all from kernel's
perspective.
For example:
- Kernel configures hpm3 to count instructions and sets hpmcounter
to -10000 and all modes except U mode are inhibited.
- In QEMU we configure a timer to expire after ~10000 instructions.
- Problem is, it's often the case that kernel might not even schedule
Umode task and we hit the timer callback in QEMU.
- In the timer callback we inject the interrupt into kernel, kernel
runs the handler and reads hpmcounter3 value.
- Given QEMU maintains individual counters to count for each privilege
mode, and given umode never ran, the umode counter didn't increment
and QEMU returns same value as was programmed by the kernel when
starting the counter.
- Kernel checks for overflow using previous and current value of the
counter and reprograms the counter given there wasn't an overflow
as per the counter value. (Which itself is a problem. We have QEMU
telling kernel that counter3 overflowed but the counter value
returned by QEMU doesn't seem to reflect that.).
This change makes sure that timer is reprogrammed from the handler
if the counter didn't overflow based on the counter value.
Second, this change makes sure that whenever the counter is read,
it's value is updated to reflect the latest count.
Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20240711-smcntrpmf_v7-v8-11-b7c38ae7b263@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Privilege mode filtering can also be emulated for cycle/instret by
tracking host_ticks/icount during each privilege mode switch. This
patch implements that for both cycle/instret and mhpmcounters. The
first one requires Smcntrpmf while the other one requires Sscofpmf
to be enabled.
The cycle/instret are still computed using host ticks when icount
is not enabled. Otherwise, they are computed using raw icount which
is more accurate in icount mode.
Co-Developed-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
Signed-off-by: Rajnesh Kanwal <rkanwal@rivosinc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-ID: <20240711-smcntrpmf_v7-v8-7-b7c38ae7b263@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Add missing include guard in pmu.h to avoid the problem of double
inclusion.
Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-ID: <20240220110907.10479-1-frank.chang@sifive.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
During the FDT generation use the existing mask containing the enabled
counters rather then generating a new one. Using the existing mask will
support the use of discontinuous counters.
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Message-ID: <20231031154000.18134-4-rbradford@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
More closely follow the QEMU style by returning an Error and propagating
it there is an error relating to the PMU setup.
Further simplify the function by removing the num_counters parameter as
this is available from the passed in cpu pointer.
Signed-off-by: Rob Bradford <rbradford@rivosinc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Message-ID: <20231031154000.18134-2-rbradford@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
"qemu/main-loop.h" declares functions related to QEMU's
main loop mutex, which these files don't access. Remove
the unused "qemu/main-loop.h" header.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230828221314.18435-8-philmd@linaro.org>
These files don't use the CPU ld/st API, remove the unnecessary
"exec/cpu_ldst.h" header.
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230828221314.18435-7-philmd@linaro.org>
Declarations from "riscv/pmu.h" don't need anything from "qemu/log.h",
reduce it's inclusion to the source.
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230828221314.18435-3-philmd@linaro.org>
This commit was created with scripts/clean-includes.
All .c should include qemu/osdep.h first. The script performs three
related cleanups:
* Ensure .c files include qemu/osdep.h first.
* Including it in a .h is redundant, since the .c already includes
it. Drop such inclusions.
* Likewise, including headers qemu/osdep.h includes is redundant.
Drop these, too.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20230202133830.2152150-15-armbru@redhat.com>
Qemu virt machine can support few cache events and cycle/instret counters.
It also supports counter overflow for these events.
Add a DT node so that OpenSBI/Linux kernel is aware of the virt machine
capabilities. There are some dummy nodes added for testing as well.
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221701.41932-5-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
The Sscofpmf ('Ss' for Privileged arch and Supervisor-level extensions,
and 'cofpmf' for Count OverFlow and Privilege Mode Filtering)
extension allows the perf to handle overflow interrupts and filtering
support. This patch provides a framework for programmable
counters to leverage the extension. As the extension doesn't have any
provision for the overflow bit for fixed counters, the fixed events
can also be monitoring using programmable counters. The underlying
counters for cycle and instruction counters are always running. Thus,
a separate timer device is programmed to handle the overflow.
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220824221701.41932-2-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
mcycle/minstret are actually WARL registers and can be written with any
given value. With SBI PMU extension, it will be used to store a initial
value provided from supervisor OS. The Qemu also need prohibit the counter
increment if mcountinhibit is set.
Support mcycle/minstret through generic counter infrastructure.
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Message-Id: <20220620231603.2547260-8-atishp@rivosinc.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
