linux-kernel - Re: [PATCH 4/6] powerpc: use common ptrace_syscall_enter hook to handle _TIF_SYSCALL

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Message-ID: <20190304104206.GB1504@e107155-lin>
Date:   Mon, 4 Mar 2019 10:42:06 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     "Haibo Xu (Arm Technology China)" <Haibo.Xu@....com>
Cc:     "x86@...nel.org" <x86@...nel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        Catalin Marinas <Catalin.Marinas@....com>,
        Will Deacon <Will.Deacon@....com>,
        Oleg Nesterov <oleg@...hat.com>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Richard Weinberger <richard@....at>,
        "jdike@...toit.com" <jdike@...toit.com>,
        Steve Capper <Steve.Capper@....com>,
        "Bin Lu (Arm Technology China)" <Bin.Lu@....com>,
        Sudeep Holla <sudeep.holla@....com>
Subject: Re: [PATCH 4/6] powerpc: use common ptrace_syscall_enter hook to
 handle _TIF_SYSCALL_EMU

On Mon, Mar 04, 2019 at 09:36:27AM +0000, Haibo Xu (Arm Technology China) wrote:
> On 2019/3/1 2:32, Sudeep Holla wrote:
> > Now that we have a new hook ptrace_syscall_enter that can be called from
> > syscall entry code and it handles PTRACE_SYSEMU in generic code, we
> > can do some cleanup using the same in do_syscall_trace_enter.
> >
> > Cc: Oleg Nesterov <oleg@...hat.com>
> > Cc: Paul Mackerras <paulus@...ba.org>
> > Cc: Michael Ellerman <mpe@...erman.id.au>
> > Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> > ---
> >  arch/powerpc/kernel/ptrace.c | 50 ++++++++++++++++--------------------
> >  1 file changed, 22 insertions(+), 28 deletions(-)
> >
> > diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c
> > index cb7e1439cafb..978cd2aac29e 100644
> > --- a/arch/powerpc/kernel/ptrace.c
> > +++ b/arch/powerpc/kernel/ptrace.c
> > @@ -3264,37 +3264,31 @@ long do_syscall_trace_enter(struct pt_regs *regs)
> >  {
> >  	u32 flags;
> >
> > -	user_exit();
>
> We'd better keep the user_exit() at here in case both context tracking and
> SYSCALL_EMU are enabled.
>

Ah right, spurious change will fix it.

--
Regards,
Sudeep