The tinfo probe only discovers trigger types; WARL fields tied off
inside an implemented trigger CSR (e.g. an mcontrol6 trigger without
load/store address match) are not discoverable. sbi_alloc_trigger()
also selects the first free trigger slot irrespective of the requested
trigger type or configuration. Unsupported configurations are thus
silently dropped by the hardware while SBI reports success, where SBI
v3.0 sections 19.4 / 19.5 require SBI_ERR_NOT_SUPPORTED.
Add an optional platform device, struct sbi_dbtr_device, with a
trigger_supported(idx, tdata1, tdata2, tdata3) callback reporting
whether the trigger slot selected by idx (the tselect value) supports
a given configuration. Use it, together with the probed per-slot
type_mask, to:
- allocate only trigger slots supporting the requested configuration
(new dbtr_find_free_slot() helper)
- reject unsupportable install/update requests with
SBI_ERR_NOT_SUPPORTED
- count only supporting slots in sbi_dbtr_num_trig() (SBI v3.0
section 19.1)
The install path now dry-runs the allocation of the whole batch before
programming any trigger, so a partially-installed batch is never left
behind. Without a registered device, only the type matching applies (unchanged behavior).
Fixes: 97f234f15c ("lib: sbi: Introduce the SBI debug triggers extension support")
Signed-off-by: David E. Garcia Porras <david.garcia@aheadcomputing.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260727183041.258377-2-david.garcia@aheadcomputing.com
Signed-off-by: Anup Patel <anup@brainfault.org>
RISC-V Debug specification includes Sdtrig ISA extension
which describes Trigger Module. Triggers can cause
a breakpoint exception or trace action without execution
of a special instruction. They can be used to implement
hardware breakpoints and watchpoints for native debugging.
The SBI Debut Trigger extension (Draft v6) can be found at:
https://lists.riscv.org/g/tech-debug/topic/99825362#1302
This patch is an initial implementation of SBI Debug
Trigger Extension (Draft v6) in OpenSBI.
The following features are supported:
* mcontrol, mcontrol6 triggers
* Breakpoint and trace actions
NOTE: Chained triggers are not supported
Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
David E. Garcia Porras