Messages in this thread | | | Date | Mon, 20 Oct 2014 10:55:30 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH 1/2] kprobes: introduce ARCH_HANDLES_KPROBES_ON_FTRACE |
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(2014/10/16 0:46), Heiko Carstens wrote: > Allow architectures to implement handling of kprobes on function > tracer call sites on their own, without depending on common code. > > This patch removes the kprobes check if a kprobe is being placed > on a function tracer call site and therefore gives full responsibility > of handling this correctly to the architecture. > > Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> > --- > arch/Kconfig | 8 ++++++++ > kernel/kprobes.c | 3 ++- > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 05d7a8a458d5..e1a8e0edf03f 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -85,6 +85,14 @@ config KPROBES_ON_FTRACE > passing of pt_regs to function tracing, then kprobes can > optimize on top of function tracing. > > +config ARCH_HANDLES_KPROBES_ON_FTRACE > + def_bool n > + help > + If an architecture can handle kprobes on function tracer call > + sites on own, then this option should be selected. This option > + removes the check which otherwise prevents to set kprobes on > + function tracer call sites. > + > config UPROBES > def_bool n > select PERCPU_RWSEM > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 3995f546d0f3..4cc48aa67635 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1428,7 +1428,8 @@ static int check_kprobe_address_safe(struct kprobe *p, > return -EILSEQ; > p->flags |= KPROBE_FLAG_FTRACE; > #else /* !CONFIG_KPROBES_ON_FTRACE */ > - return -EINVAL; > + if (!IS_ENABLED(CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE)) > + return -EINVAL; > #endif > }
Hmm, this looks a bit not straight. Maybe we'd better introduce a local check_ftrace_location() function which always returns 0 if CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE(with a comment! :)) as below.
int check_ftrace_location(kp) { unsigned long ftrace_address;
/* If an architecture handles kprobes on ftrace, we don't check it */ if (IS_ENABLED(CONFIG_ARCH_HANDLES_KPROBES_ON_FTRACE)) return 0;
... }
Thank you,
-- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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