[PATCH v4 0/6] powerpc/watchpoint: Bug fixes plus new feature flag

[Ravi Bangoria]

Patch #1 fixes a bug about watchpoint not firing when created with
         ptrace PPC_PTRACE_SETHWDEBUG and CONFIG_HAVE_HW_BREAKPOINT=N.
         The fix uses HW_BRK_TYPE_PRIV_ALL for ptrace user which, I
         guess, should be fine because we don't leak any kernel
         addresses and PRIV_ALL will also help to cover scenarios when
         kernel accesses user memory.
Patch #2,#3 fixes infinite exception bug, again the bug happens only
         with CONFIG_HAVE_HW_BREAKPOINT=N.
Patch #4 fixes two places where we are missing to set hw_len.
Patch #5 introduce new feature bit PPC_DEBUG_FEATURE_DATA_BP_ARCH_31
         which will be set when running on ISA 3.1 compliant machine.
Patch #6 finally adds selftest to test scenarios fixed by patch#2,#3
         and also moves MODE_EXACT tests outside of BP_RANGE condition.

Christophe, let me know if this series breaks something for 8xx.

v3: https://lore.kernel.org/r/20200805062750.290289-1-ravi.bangoria@xxxxxxxxxxxxx

v3->v4:
  - Patch #1. Allow HW_BRK_TYPE_PRIV_ALL instead of HW_BRK_TYPE_USER
  - Patch #2, #3, #4 and #6 are new.
  - Rebased to powerpc/next.

Ravi Bangoria (6):
  powerpc/watchpoint/ptrace: Fix SETHWDEBUG when
    CONFIG_HAVE_HW_BREAKPOINT=N
  powerpc/watchpoint: Move DAWR detection logic outside of
    hw_breakpoint.c
  powerpc/watchpoint: Fix exception handling for
    CONFIG_HAVE_HW_BREAKPOINT=N
  powerpc/watchpoint: Add hw_len wherever missing
  powerpc/watchpoint/ptrace: Introduce PPC_DEBUG_FEATURE_DATA_BP_ARCH_31
  powerpc/watchpoint/selftests: Tests for kernel accessing user memory

 Documentation/powerpc/ptrace.rst              |   1 +
 arch/powerpc/include/asm/hw_breakpoint.h      |  11 ++
 arch/powerpc/include/uapi/asm/ptrace.h        |   1 +
 arch/powerpc/kernel/Makefile                  |   3 +-
 arch/powerpc/kernel/hw_breakpoint.c           | 149 +----------------
 .../kernel/hw_breakpoint_constraints.c        | 152 ++++++++++++++++++
 arch/powerpc/kernel/process.c                 |  48 ++++++
 arch/powerpc/kernel/ptrace/ptrace-noadv.c     |  10 +-
 arch/powerpc/xmon/xmon.c                      |   1 +
 .../selftests/powerpc/ptrace/ptrace-hwbreak.c |  48 +++++-
 10 files changed, 273 insertions(+), 151 deletions(-)
 create mode 100644 arch/powerpc/kernel/hw_breakpoint_constraints.c

-- 
2.26.2