Re: [PATCH v4 0/5] Powerpc/Watchpoint: Few important fixes

[Christophe Leroy]

Le 10/10/2019 Ã 06:44, Ravi Bangoria a ÃcritÂ:
> > > @Christophe, Is patch5 works for you on 8xx?
> >
> > Getting the following :
> >
> > root@vgoip:~# ./ptrace-hwbreak
> > test: ptrace-hwbreak
> > tags: git_version:v5.4-rc2-710-gf0082e173fe4-dirty
> > 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: Fail
> > failure: ptrace-hwbreak
>
> Thanks Christophe. I don't have any 8xx box. I checked qemu and it seems
> qemu emulation for 8xx is not yet supported. So I can't debug this. Can
> you please check why it's failing?

First issue: we get a mismatch between the parent and the child, because 
len 8 test generates two reads/writes while the parent installs the 
breakpoint only once.

Changing glvar from __u64 to unsigned long fixes the problem.

Then I get:

test: ptrace-hwbreak
tags: git_version:v5.4-rc2-710-gf0082e173fe4-dirty
PTRACE_SET_DEBUGREG, WO, len: 1: Ok
PTRACE_SET_DEBUGREG, WO, len: 2: Ok
PTRACE_SET_DEBUGREG, WO, len: 4: 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, RW, len: 1: Ok
PTRACE_SET_DEBUGREG, RW, len: 2: Ok
PTRACE_SET_DEBUGREG, RW, len: 4: 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: Fail
failure: ptrace-hwbreak

Which shows that PPC_PTRACE_SETHWDEBUG doesn't work in MODE_RANGE

Christophe