Re: [PATCH v5 10/13] powerpc/ptrace: split out ADV_DEBUG_REGS related functions.

[Christophe Leroy]

On 03/20/2020 02:12 AM, Michael Ellerman wrote:
> Christophe Leroy <christophe.leroy@xxxxxx> writes:
> > Move ADV_DEBUG_REGS functions out of ptrace.c, into
> > ptrace-adv.c and ptrace-noadv.c
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
> > ---
> > v4: Leave hw_breakpoint.h for ptrace.c
> > ---
> >   arch/powerpc/kernel/ptrace/Makefile       |   4 +
> >   arch/powerpc/kernel/ptrace/ptrace-adv.c   | 468 ++++++++++++++++
> >   arch/powerpc/kernel/ptrace/ptrace-decl.h  |   5 +
> >   arch/powerpc/kernel/ptrace/ptrace-noadv.c | 236 ++++++++
> >   arch/powerpc/kernel/ptrace/ptrace.c       | 650 ----------------------
> >   5 files changed, 713 insertions(+), 650 deletions(-)
> >   create mode 100644 arch/powerpc/kernel/ptrace/ptrace-adv.c
> >   create mode 100644 arch/powerpc/kernel/ptrace/ptrace-noadv.c
>
> This is somehow breaking the ptrace-hwbreak selftest on Power8:
>
>    test: ptrace-hwbreak
>    tags: git_version:v5.6-rc6-892-g7a285a6067d6
>    PTRACE_SET_DEBUGREG, WO, len: 1: Ok
>    PTRACE_SET_DEBUGREG, WO, len: 2: Ok
>    PTRACE_SET_DEBUGREG, WO, len: 4: Ok
>    PTRACE_SET_DEBUGREG, WO, len: 8: Ok
>    PTRACE_SET_DEBUGREG, RO, len: 1: Ok
>    PTRACE_SET_DEBUGREG, RO, len: 2: Ok
>    PTRACE_SET_DEBUGREG, RO, len: 4: Ok
>    PTRACE_SET_DEBUGREG, RO, len: 8: Ok
>    PTRACE_SET_DEBUGREG, RW, len: 1: Ok
>    PTRACE_SET_DEBUGREG, RW, len: 2: Ok
>    PTRACE_SET_DEBUGREG, RW, len: 4: Ok
>    PTRACE_SET_DEBUGREG, RW, len: 8: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_EXACT, WO, len: 1: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RO, len: 1: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_EXACT, RW, len: 1: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, WO, len: 6: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, RO, len: 6: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW ALIGNED, RW, len: 6: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW UNALIGNED, WO, len: 6: Ok
>    PPC_PTRACE_SETHWDEBUG, MODE_RANGE, DW UNALIGNED, RO, len: 6: Fail
>    failure: ptrace-hwbreak
>
> I haven't had time to work out why yet.

A (big) part of commit c3f68b0478e7 ("powerpc/watchpoint: Fix ptrace 
code that muck around with address/len") was lost during rebase.

I'll send a fix, up to you to squash it in or commit it as is.

Christophe