s390/bug: Indicate modified PSW in disassembly

With [1] the PSW address is set to the return address of the calling
__WARN_trap() function in order to provide a more useful disassembly of
the caller rather than the helper itself.

However, since regs->psw.addr is modified, regs->int_code has nothing to
do with the exception. In order to make that more obvious change the
disassembler output.

Introduce a new PIF_WARN_TRAP_SKIPPED pt_regs flag and set it whenever
__WARN_trap() is skipped. In the disassembler output print a "WARN RET"
prefix to make it obvious that the PSW points to the return address of
the warning trap function.

Also do not print the interruption code and instruction length code for
this case, since they have nothing to do with the modified PSW.

Example output:

Krnl Code:
           000003ffe185bc1c: e3f0ff98ff71 lay     %r15,-104(%r15)
           000003ffe185bc22: e3e0f0980024 stg     %r14,152(%r15)
           000003ffe185bc28: c0e5ff45ed94 brasl   %r14,000003ffe0119750
 WARN RET >000003ffe185bc2e: c0e5ffa052b9 brasl   %r14,000003ffe0c661a0
           000003ffe185bc34: c020fffe86d6 larl    %r2,000003ffe182c9e0
           000003ffe185bc3a: e548f0a80006 mvghi   168(%r15),6
           000003ffe185bc40: e548f0a00005 mvghi   160(%r15),5
           000003ffe185bc46: a7690004     lghi    %r6,4

[1] 79996065cfa2 ("s390/bug: Skip __WARN_trap() in call traces")

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

0 files changed, 0 insertions, 0 deletions