[v3,0/5] riscv: Add KGDB and KDB support

Message

Vincent Chen April 12, 2020, 1:41 a.m. UTC

This patch set implements required ports to enable RISC-V kernel to support
KGDB and KDB features. Because there is no immediate value in the RISC-V
trap instruction, the kernel cannot identify the purpose of each trap
exception through the opcode. This makes the existing identification
schemes in other architecture unsuitable for the RISC-V kernel. In order
to solve this problem, this patch adds the kgdb_has_hit_break() to kgdb.c
to help the RISC-V kernel identify the KGDB trap exception. In addition,
the XML target description was introduced in this patch set to enable KGDB
to report the contents of the status, cause and steal registers.
 
This patchset has passed the kgdbts test suite provided by Linux kernel on
HiFive unleashed board and QEMU.

Changes since v2:
1. Fix typos
2. Rename CONFIG_ARCH_SUPPORTS_GDB_XML to CONFIG_HAVE_ARCH_KGDB_QXFER_PKT
3. Add the prefix kgdb_ to the handler functions and arrays that handle 
   "qxfer" packets

Changes since v1:
1. Replace the magic number with macro when filling the gdb_regs[].
2. Only support GDB XML packet instead of all query packets.
3. Move the macros used to parse instructions to parse_asm.h

Vincent Chen (5):
  kgdb: Add kgdb_has_hit_break function
  riscv: Add KGDB support
  kgdb: enable arch to support XML packet support.
  riscv: Use the XML target descriptions to report 3 system registers
  riscv: Add SW single-step support for KDB

 arch/riscv/Kconfig                 |   2 +
 arch/riscv/include/asm/gdb_xml.h   | 117 +++++++++++
 arch/riscv/include/asm/kdebug.h    |  12 ++
 arch/riscv/include/asm/kgdb.h      | 113 +++++++++++
 arch/riscv/include/asm/parse_asm.h | 219 +++++++++++++++++++++
 arch/riscv/kernel/Makefile         |   1 +
 arch/riscv/kernel/kgdb.c           | 390 +++++++++++++++++++++++++++++++++++++
 arch/riscv/kernel/traps.c          |   5 +
 include/linux/kgdb.h               |  11 ++
 kernel/debug/debug_core.c          |  12 ++
 kernel/debug/gdbstub.c             |  13 ++
 lib/Kconfig.kgdb                   |   5 +
 12 files changed, 900 insertions(+)
 create mode 100644 arch/riscv/include/asm/gdb_xml.h
 create mode 100644 arch/riscv/include/asm/kdebug.h
 create mode 100644 arch/riscv/include/asm/kgdb.h
 create mode 100644 arch/riscv/include/asm/parse_asm.h
 create mode 100644 arch/riscv/kernel/kgdb.c