Commit Graph
23 Commits
Author SHA1 Message Date
Atish PatraandAnup Patel 5b305e30a5 lib: sbi: Only enable TM bit in scounteren
The S-mode should disable Cycle and instruction counter for user space
to avoid side channel attacks. The Linux kernel already does this so that
any random user space code shouldn't be able to monitor cycle/instruction
without higher privilege mode involvement.

Remove the CY/IR bits in scountern in OpenSBI.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Link: https://lore.kernel.org/r/20250513-fix_scounteren-v1-1-01018e0c0b0a@rivosinc.com
Signed-off-by: Anup Patel <anup@brainfault.org>
2025-07-21 16:33:03 +05:30
Atish PatraandAnup Patel 51dbc57fc7 lib: sbi_pmu: Verify the raw events first during event info
The raw events have same event_idx. Thus, the event info sanity check
only relies on the select mask. The raw event check should be done first
so that regular hardware events can be verified using event idx range
check.

Fixes: e434584216 ("lib: sbi_pmu: Implement SBI PMU event info function")
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-12-15 14:13:12 +05:30
Atish PatraandAnup Patel 0928ca21bc lib: sbi_pmu: Fix the sanity check condition for hw event map
The hardware event map function invoked from platform code should
exclude any raw events as there is a separate function for the raw
events.

Fixes: d8a483fc7f ("lib: sbi_pmu: PMU raw event v2 support")
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-12-15 14:06:52 +05:30
Atish PatraandAnup Patel e434584216 lib: sbi_pmu: Implement SBI PMU event info function
Allow the supervisor software to query about the event using the
new function. This supports both firmware and hardware events.
The hardware event presence is verified hw_event_map which is populated
via PMU device tree node. The firmware event presence is checked through
event validation function which should take care of both standard and
platform firmware events.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-12-02 09:52:55 +05:30
Atish PatraandAnup Patel 05970d273c lib: sbi_pmu: Add SBI PMU event info function details.
The SBI v3.0 introduced a new function to query about the events
without invoking CFG_MATCH. This allows supervisor software to
identify which events are supported on the platform with single
SBI call instead of a CFG_MATCH for each event.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-12-02 09:52:52 +05:30
Atish PatraandAnup Patel cf196d80aa lib: sbi_pmu: Remove redundant check for fw events
The pmu_validate_event already has the same check for fw events.
The validate function is called prior to the current function
to find a counter for firmware. That's why, the redudant
check can be removed from the find counter function.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-12-02 09:52:50 +05:30
Atish PatraandAnup Patel d8a483fc7f lib: sbi_pmu: PMU raw event v2 support
As per the updated ISA specification and SBI PMU v3.0, lower 56
bits are available for the platform to implement mhpmeventX
encoding. Implement the PMU raw event V2 support defined in SBI
v3.0 which allows more bits for platforms to encode the raw events.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-12-02 09:52:04 +05:30
Atish PatraandAnup Patel 00093a2000 docs: Remove github PR as an option
OpenSBI development workflow is mailing list based from the
beginning. Initially, github PRs were added as an option but it turned
out that it is not feasible to support both github PR and mailing list
based workflows. Hence, all the PRs has been redirected to use the
mailing list from a long time. In fact, it is source of confusion to
have both options.

Update the documentation to reflect the reality.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-09-23 17:55:30 +05:30
Atish PatraandAnup Patel 6bb6b61c27 lib: sbi: Add support for smcsrind and smcdeleg
Smcsrind allows generic indirect CSR access mechanism while
Smcdeleg allows delegating hpmcounters in Supervisor mode.

Enable both extensions and set the appropriate bits in mstateen
and menvcfg.

Co-developed-by: Kaiwen Xue <kaiwenxue1@gmail.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2024-03-04 10:20:41 +05:30
Atish PatraandAnup Patel 11a0ba5d4b lib: sbi_pmu: Fix the counter info function
The counter info should only return valid hardware counters for the ones
set in the counter mask. Otherwise, it will report incorrect number of
hardware counters to the supervisor if the platform has discontiguous
counters.

Fixes: c744ed77b1 ("lib: sbi_pmu: Enable noncontigous hpm event and counters")
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Xiang W <wxjstz@126.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2023-12-08 22:50:23 +05:30
Atish PatraandAnup Patel ee725174ba lib: sbi_pmu: Add PMU snapshot definitions
OpenSBI doesn't support SBI PMU snapshot yet as there is not much benefit
unless the multiple counters overflow at the same time.

Just add the definition and return not supported error at this moment. The
default returned error is also not supported. Thus, no functional change
intended.

Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
2023-12-08 22:50:21 +05:30
Atish PatraandAnup Patel d5d12a91d1 docs: pmu: Update the pmu doc with removal of mcountinhbit restriction
Since commit b28f070, it is possible for platforms to run perf monitoring
even if mcountinhibit is not supported. Sampling still won't be possible
though as it requires sscofpmf extension.

Update the docs to remove the restriction.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-12-24 11:07:14 +05:30
Atish PatraandAnup Patel 11c0008862 lib: sbi: Fix fw_event_map initialization
fw_event_map represents array of firmware events. It should initialized
for maximum number of firmware events not counters.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-07-30 11:28:36 +05:30
Atish PatraandAnup Patel 860a376817 lib: sbi: Fix possible buffer overrun in counter validation
The active_events array is accessed with counter ID passed from the supervisor
software before the counter ID bound check. This may cause a buffer overrun
if a supervisor passes an invalid counter ID.

Fix this by moving the access part after the bound check.

Reported-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-07-30 11:25:48 +05:30
Atish PatraandAnup Patel 83db3af5f9 lib: sbi: Add the bound check for events during config match
Currently, there is no sanity check for firmware event code. We don't see
any issue as Linux kernel driver does a bound check on firmware events
already. However, OpenSBI can't assume sane supervisor mode software
always. Thus, an invalid event idx can cause a buffer overflow error.
For hardware events, the match will fail for invalid event code anyways.
However, a search is unecessary if event code is invalid.

Add a event ID validation function to solve the issue.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-07-30 11:22:50 +05:30
Atish PatraandAnup Patel 1545afd342 lib: sbi: Fix counter index sanity check
The current implementation computes the possible counter range
by doing a left shift of counter base. However, this may overflow depending
on the counter base value. In case of overflow, the highest counter id
may be computed incorrectly. As per the SBI specification, the respective
function should return an error if any of the counter is not valid.

Fix the counter index check by avoiding left shifting while doing the
sanity checks. Without the shift, the implementation just iterates
over the counter mask and computes the correct counter index by adding
the base to it.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-07-30 11:09:18 +05:30
Atish PatraandAnup Patel b0c9df514b lib: sbi: Fix mhpmeventh access for rv32 in absence of sscofpmf
MHPMEVENT3H-31H are defined in sscofpmf extension. Thus, they should be
accessed only if sscofpmf is present.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-05-07 09:40:59 +05:30
Atish PatraandAnup Patel d62f6da062 lib: sbi: Implement Sstc extension
Recently, Sstc extension was ratified. It defines stimecmp which allows
the supervisor mode to directly update the timecmp value without the
need of the SBI call. The hardware also can inject the S-mode timer
interrupt direclty to the supervisor without going through the M-mode.
To maintain backward compatibility with the older software, SBI call
now uses stimecmp directly if the hardware supports.

Implement the Sstc extension.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-04-28 11:45:21 +05:30
Atish PatraandAnup Patel 4035ae94be docs: pmu: Improve the PMU DT bindings
The current DT binding description is misleading and confusing. Clarify
the text and provide more examples.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-04-28 11:40:15 +05:30
Atish PatraandAnup Patel 31fecad46d lib: sbi: Detect menvcfg CSR at boot time
We add the menvcfg CSR as a HART feature and detect it at boot time
using traping mechanism.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Xiang W <wxjstz@126.com>
2022-04-05 08:50:48 +05:30
Atish PatraandAnup Patel a26dc609df lib: sbi: Disable interrupt and inhibit counting in M-mode during init
Currently, the mhpmevent CSRs are untouched during hart init during
cold/warm boot. Ideally, we should clear out all the bits except
overflow and MINH bit. That is required to disable overflow
interrupt and inhibit counting in M-mode to avoid any spurious
interrupts before perf start.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-02-04 10:10:28 +05:30
Atish PatraandAnup Patel 3b7c204dca lib: sbi: Disable interrupt during config matching
PMU overflow interrupt should be disabled durinig initial configuration of
counters. They should be enabled while starting counters.

Fixes: 730f01bb41 ("lib: sbi: Support sscofpmf extension in OpenSBI")
Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-02-04 10:08:57 +05:30
Atish PatraandAnup Patel 632f59392b lib: sbi: Map only the counters enabled in hardware
The counter mapping in DT may be incorrect if all the counters specified
in the mapping are actually not physically present in the hardware.
OpenSBI should only keep a mapping of counters enabled in hardware and
defined in DT. This assume that all the programmable hpmcounters are
consecutive as it doesn't make sense to build a system with sparse
hpmcounters.

Signed-off-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
2022-02-04 10:07:07 +05:30