riscv: Prepare for user-space perf event mmap support

Provide all the necessary bits in the generic riscv pmu driver to be
able to mmap perf events in userspace: the heavy lifting lies in the
driver backend, namely the legacy and sbi implementations.

Note that arch_perf_update_userpage is almost a copy of arm64 code.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>

drivers: perf: Rename riscv pmu sbi driver

That's just cosmetic, no functional changes.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>

include: riscv: Fix wrong include guard in riscv_pmu.h

The current include guard prevents the inclusion of asm/perf_event.h
which uses the same include guard: fix the one in riscv_pmu.h so that it
matches the file name.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>

perf: RISC-V: Improve privilege mode filtering for perf

Currently, the host driver doesn't have any method to identify if the
requested perf event is from kvm or bare metal. As KVM runs in HS
mode, there are no separate hypervisor privilege mode to distinguish
between the attributes for guest/host.

Improve the privilege mode filtering by using the event specific
config1 field.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

perf: RISC-V: Define helper functions expose hpm counter width and count

KVM module needs to know how many hardware counters and the counter
width that the platform supports. Otherwise, it will not be able to show
optimal value of virtual counters to the guest. The virtual hardware
counters also need to have the same width as the logical hardware
counters for simplicity. However, there shouldn't be mapping between
virtual hardware counters and logical hardware counters. As we don't
support hetergeneous harts or counters with different width as of now,
the implementation relies on the counter width of the first available
programmable counter.

Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

perf: RISC-V: exclude invalid pmu counters from SBI calls

SBI firmware may not provide information for some counters in response
to SBI_EXT_PMU_COUNTER_GET_INFO call. Exclude such counters from the
subsequent SBI requests. For this purpose use global mask to keep track
of fully specified counters.

Signed-off-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20220830155306.301714-3-geomatsi@gmail.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

drivers/perf: riscv_pmu: Add riscv pmu pm notifier

Currently, when the CPU is doing suspend to ram, we don't
save pmu counter register and its content will be lost.

To ensure perf profiling is not affected by suspend to ram,
this patch is based on arm_pmu CPU_PM notifier and implements riscv
pmu pm notifier. In the pm notifier, we stop the counter and update
the counter value before suspend and start the counter after resume.

Signed-off-by: Eric Lin <eric.lin@sifive.com>
Link: https://lore.kernel.org/r/20220705091920.27432-1-eric.lin@sifive.com
Signed-off-by: Will Deacon <will@kernel.org>

RISC-V: Add sscofpmf extension support

The sscofpmf extension allows counter overflow and filtering for
programmable counters. Enable the perf driver to handle the overflow
interrupt. The overflow interrupt is a hart local interrupt.
Thus, per cpu overflow interrupts are setup as a child under the root
INTC irq domain.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

RISC-V: Add perf platform driver based on SBI PMU extension

RISC-V SBI specification added a PMU extension that allows to configure
start/stop any pmu counter. The RISC-V perf can use most of the generic
perf features except interrupt overflow and event filtering based on
privilege mode which will be added in future.

It also allows to monitor a handful of firmware counters that can provide
insights into firmware activity during a performance analysis.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

RISC-V: Add a simple platform driver for RISC-V legacy perf

The old RISC-V perf implementation allowed counting of only
cycle/instruction counters using perf. Restore that feature by implementing
a simple platform driver under a separate config to provide backward
compatibility. Any existing software stack will continue to work as it is.
However, it provides an easy way out in future where we can remove the
legacy driver.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

RISC-V: Add a perf core library for pmu drivers

Implement a perf core library that can support all the essential perf
features in future. It can also accommodate any type of PMU implementation
in future. Currently, both SBI based perf driver and legacy driver
implemented uses the library. Most of the common perf functionalities
are kept in this core library wile PMU specific driver can implement PMU
specific features. For example, the SBI specific functionality will be
implemented in the SBI specific driver.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>