[v2,0/3] riscv: Support trap-based WARN() and fix bug in do_trap_break

Message

Vincent Chen March 5, 2019, 3:23 a.m. UTC

Changes in v2:
  - Remove unnecessary non-functional diff
  - Rearrange the order of the patches
  - Edit the commit description

The trap-based WARN() will help developers to analyze the cause of WARN()
because if the debugger is connected, the control flow will be transferred
to debugging environment.

BUG() is currently not working properly. When the C extension is supported,
the assembler translates the "ebreak" to "c.ebreak" opcode. Hence the trap
is possibly triggered by "c.ebreak" instead of expected the "ebreak". This
will cause the check mechanism in is_valid_bugaddr(bugaddr) to think that
the trap triggered by "c.ebreak" occurs in an invalidate bug address. This
patch set will add "c.ebreak" into the check mechanism. In addition, BUG()
is also unable to work in the kernel module due to an inappropriate
condition in is_valid_bugaddr().

Vincent Chen (3):
  riscv: support trap-based WARN()
  riscv: Add the support for c.ebreak check in is_valid_bugaddr()
  riscv: Support BUG() in kernel module

 arch/riscv/include/asm/bug.h |   34 ++++++++++++++++++++++++----------
 arch/riscv/kernel/traps.c    |   22 ++++++++++++++++++----
 2 files changed, 42 insertions(+), 14 deletions(-)