s390/dis: Improve show_code() output

Replace the '>' and '*' instruction markers with explicit 'PSW >' and
'PGM >' markers which identify both the PSW address and the faulting
instruction.

Previously, '>' marked the PSW address, while '*' marked the preceding
instruction as a guess for the faulting instruction for suppressing
exceptions:

 Krnl Code:
            000003ff8dc7bff8: e310f0080004 lg      %r1,8(%r15)
           *000003ff8dc7bffe: e3a0e0000004 lg      %r10,0(%r14)
           >000003ff8dc7c004: a7280000     lhi     %r2,0
            000003ff8dc7c008: eb9ff0900024 stmg    %r9,%r15,144(%r15)

Now 'PGM >' explicitly marks the faulting instruction without guessing
and 'PSW >' marks the PSW address:

 Krnl Code:
            000003ff8dc7bff8: e310f0080004 lg      %r1,8(%r15)
       PGM >000003ff8dc7bffe: e3a0e0000004 lg      %r10,0(%r14)
       PSW >000003ff8dc7c004: a7280000     lhi     %r2,0
            000003ff8dc7c008: eb9ff0900024 stmg    %r9,%r15,144(%r15)

For nullifying exceptions where both addresses are the same,
'PGM+PSW >' is printed instead:

 Krnl Code:
            000003ff8dc7bff8: e310f0080004 lg      %r1,8(%r15)
   PGM+PSW >000003ff8dc7bffe: e3a0e0000004 lg      %r10,0(%r14)
            000003ff8dc7c004: a7280000     lhi     %r2,0
            000003ff8dc7c008: eb9ff0900024 stmg    %r9,%r15,144(%r15)

show_code() may also be called in other contexts where pt_regs does not
originate from a program check (e.g. system calls). Introduce and set
PIF_PGM_CHECK to indicate when in program check context, and print the
PGM marker only in such a context.

Note that corner cases are not taken into account. Like before kprobes is
not considered, which means that the disassembly may contain unexpected
instructions, or that disassembly and/or instruction length count as well
as interruption do not match.

Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

0 files changed, 0 insertions, 0 deletions