Messages in this thread Patch in this message | | | Date | Mon, 18 Mar 2019 17:26:18 +0300 | From | "Dmitry V. Levin" <> | Subject | Re: [PATCH v2 4/6] powerpc: use common ptrace_syscall_enter hook to handle _TIF_SYSCALL_EMU |
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On Mon, Mar 18, 2019 at 10:49:23AM +0000, 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@redhat.com> > Cc: Paul Mackerras <paulus@samba.org> > Cc: Michael Ellerman <mpe@ellerman.id.au> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > --- > arch/powerpc/kernel/ptrace.c | 48 ++++++++++++++++-------------------- > 1 file changed, 21 insertions(+), 27 deletions(-) > > diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c > index 2e2183b800a8..05579a5dcb12 100644 > --- a/arch/powerpc/kernel/ptrace.c > +++ b/arch/powerpc/kernel/ptrace.c > @@ -3278,35 +3278,29 @@ long do_syscall_trace_enter(struct pt_regs *regs) > > user_exit(); > > - flags = READ_ONCE(current_thread_info()->flags) & > - (_TIF_SYSCALL_EMU | _TIF_SYSCALL_TRACE); > - > - if (flags) { > - int rc = tracehook_report_syscall_entry(regs); > + if (unlikely(ptrace_syscall_enter(regs))) { > + /* > + * A nonzero return code from tracehook_report_syscall_entry() > + * tells us to prevent the syscall execution, but we are not > + * going to execute it anyway. > + * > + * Returning -1 will skip the syscall execution. We want to > + * avoid clobbering any registers, so we don't goto the skip > + * label below. > + */ > + return -1; > + }
This comment is out of sync with the changed code.
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