On Sat, Jul 10, 2021 at 04:55:12PM +0900, Masami Hiramatsu wrote:
> On Wed, 7 Jul 2021 23:47:48 +0200
> Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> > Adding bpf_get_func_ip helper for BPF_PROG_TYPE_KPROBE programs,
> > so it's now possible to call bpf_get_func_ip from both kprobe and
> > kretprobe programs.
> >
> > Taking the caller's address from 'struct kprobe::addr', which is
> > defined for both kprobe and kretprobe.
> >
>
> Note that the kp->addr of kretprobe will be the callee function
> address, even if the handler is called when the end of the callee.
yes, that's what we need
>
> Anyway, this looks good to me.
>
> Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
thanks,
jirka
>
> Thank you,
>
> > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > ---
> > include/uapi/linux/bpf.h | 2 +-
> > kernel/bpf/verifier.c | 2 ++
> > kernel/trace/bpf_trace.c | 17 +++++++++++++++++
> > tools/include/uapi/linux/bpf.h | 2 +-
> > 4 files changed, 21 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 83e87ffdbb6e..4894f99a1993 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -4783,7 +4783,7 @@ union bpf_attr {
> > *
> > * u64 bpf_get_func_ip(void *ctx)
> > * Description
> > - * Get address of the traced function (for tracing programs).
> > + * Get address of the traced function (for tracing and kprobe programs).
> > * Return
> > * Address of the traced function.
> > */
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index f975a3aa9368..79eb9d81a198 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -5979,6 +5979,8 @@ static int has_get_func_ip(struct bpf_verifier_env *env)
> > return -ENOTSUPP;
> > }
> > return 0;
> > + } else if (type == BPF_PROG_TYPE_KPROBE) {
> > + return 0;
> > }
> >
> > verbose(env, "func %s#%d not supported for program type %d\n",
> > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> > index 9edd3b1a00ad..55acf56b0c3a 100644
> > --- a/kernel/trace/bpf_trace.c
> > +++ b/kernel/trace/bpf_trace.c
> > @@ -17,6 +17,7 @@
> > #include <linux/error-injection.h>
> > #include <linux/btf_ids.h>
> > #include <linux/bpf_lsm.h>
> > +#include <linux/kprobes.h>
> >
> > #include <net/bpf_sk_storage.h>
> >
> > @@ -961,6 +962,20 @@ static const struct bpf_func_proto bpf_get_func_ip_proto_tracing = {
> > .arg1_type = ARG_PTR_TO_CTX,
> > };
> >
> > +BPF_CALL_1(bpf_get_func_ip_kprobe, struct pt_regs *, regs)
> > +{
> > + struct kprobe *kp = kprobe_running();
> > +
> > + return kp ? (u64) kp->addr : 0;
> > +}
> > +
> > +static const struct bpf_func_proto bpf_get_func_ip_proto_kprobe = {
> > + .func = bpf_get_func_ip_kprobe,
> > + .gpl_only = true,
> > + .ret_type = RET_INTEGER,
> > + .arg1_type = ARG_PTR_TO_CTX,
> > +};
> > +
> > const struct bpf_func_proto *
> > bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > {
> > @@ -1092,6 +1107,8 @@ kprobe_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > case BPF_FUNC_override_return:
> > return &bpf_override_return_proto;
> > #endif
> > + case BPF_FUNC_get_func_ip:
> > + return &bpf_get_func_ip_proto_kprobe;
> > default:
> > return bpf_tracing_func_proto(func_id, prog);
> > }
> > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> > index 83e87ffdbb6e..4894f99a1993 100644
> > --- a/tools/include/uapi/linux/bpf.h
> > +++ b/tools/include/uapi/linux/bpf.h
> > @@ -4783,7 +4783,7 @@ union bpf_attr {
> > *
> > * u64 bpf_get_func_ip(void *ctx)
> > * Description
> > - * Get address of the traced function (for tracing programs).
> > + * Get address of the traced function (for tracing and kprobe programs).
> > * Return
> > * Address of the traced function.
> > */
> > --
> > 2.31.1
> >
>
>
> --
> Masami Hiramatsu <mhiramat@xxxxxxxxxx>
>
