[PATCH v3 0/8] Introduce support for SBI Debug Trigger Extension

[Himanshu Chauhan]

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 Debug Trigger extension 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(v6) in OpenSBI. It is based on similar patchset
from Sergey Matyukevich.
(http://lists.infradead.org/pipermail/opensbi/2022-October/003531.html)

The following features are supported:
* mcontrol, mcontrol6 triggers
* Breakpoint and trace actions

Linux Kernel Branch (Breakpoint driver support):
https://github.com/hschauhan/riscv-linux/tree/sdtrig-v6

NOTE: Chained triggers are not supported

Changes from v2:
  - Detection of sdtrig support (via trap and ISA string)
  - Removed redundant functions (sdtrig supports and get total triggers)
  - Removed check for S-mode
  - Skip the debug trigger probing if already probed for CPU (warm boot)

Changes from v1:
  - Rebased to latest OpenSBI master
  - Other cosmetic changes as per the comments

Himanshu Chauhan (8):
  include: sbi: Introduce common endianess conversion macro
  include: sbi: Add TINFO debug trigger CSR
  include: sbi: Introduce debug trigger register encodings
  lib: sbi: Detect support of debug triggers
  lib: sbi: Introduce the SBI debug triggers extension support
  include: sbi: Add SBI debug trigger extension related defines
  lib: sbi: Implement SBI debug trigger extension
  lib: sbi: Print number of debug triggers found

 include/sbi/riscv_dbtr.h          | 249 ++++++++++
 include/sbi/riscv_encoding.h      |   1 +
 include/sbi/sbi_byteorder.h       |  10 +
 include/sbi/sbi_dbtr.h            | 128 ++++++
 include/sbi/sbi_ecall_interface.h |  11 +
 include/sbi/sbi_hart.h            |   2 +
 lib/sbi/Kconfig                   |   4 +
 lib/sbi/objects.mk                |   4 +
 lib/sbi/sbi_dbtr.c                | 739 ++++++++++++++++++++++++++++++
 lib/sbi/sbi_ecall_dbtr.c          |  73 +++
 lib/sbi/sbi_hart.c                |   4 +
 lib/sbi/sbi_init.c                |  11 +
 12 files changed, 1236 insertions(+)
 create mode 100644 include/sbi/riscv_dbtr.h
 create mode 100644 include/sbi/sbi_dbtr.h
 create mode 100644 lib/sbi/sbi_dbtr.c
 create mode 100644 lib/sbi/sbi_ecall_dbtr.c

-- 
2.34.1