From: Jiri Olsa <jolsa@redhat.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>
Subject: Re: [PATCH bpf-next 07/29] bpf, x64: Allow to use caller address from stack
Date: Fri, 19 Nov 2021 22:46:51 +0100 [thread overview]
Message-ID: <YZgbS0GUpEzAeGNu@krava> (raw)
In-Reply-To: <20211119041409.rb7b4i7nukowfcwb@ast-mbp.dhcp.thefacebook.com>
On Thu, Nov 18, 2021 at 08:14:09PM -0800, Alexei Starovoitov wrote:
> On Thu, Nov 18, 2021 at 12:24:33PM +0100, Jiri Olsa wrote:
> > Currently we call the original function by using the absolute address
> > given at the JIT generation. That's not usable when having trampoline
> > attached to multiple functions. In this case we need to take the
> > return address from the stack.
> >
> > Adding support to retrieve the original function address from the stack
> > by adding new BPF_TRAMP_F_ORIG_STACK flag for arch_prepare_bpf_trampoline
> > function.
> >
> > Basically we take the return address of the 'fentry' call:
> >
> > function + 0: call fentry # stores 'function + 5' address on stack
> > function + 5: ...
> >
> > The 'function + 5' address will be used as the address for the
> > original function to call.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > arch/x86/net/bpf_jit_comp.c | 13 +++++++++----
> > include/linux/bpf.h | 5 +++++
> > 2 files changed, 14 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
> > index 67e8ac9aaf0d..d87001073033 100644
> > --- a/arch/x86/net/bpf_jit_comp.c
> > +++ b/arch/x86/net/bpf_jit_comp.c
> > @@ -2035,10 +2035,15 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
> > if (flags & BPF_TRAMP_F_CALL_ORIG) {
> > restore_regs(m, &prog, nr_args, stack_size);
> >
> > - /* call original function */
> > - if (emit_call(&prog, orig_call, prog)) {
> > - ret = -EINVAL;
> > - goto cleanup;
> > + if (flags & BPF_TRAMP_F_ORIG_STACK) {
> > + emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, 8);
> > + EMIT2(0xff, 0xd0); /* call *rax */
>
> Either return an eror if repoline is on
> or use emit_indirect_jump().
>
ok, will check
thanks,
jirka
next prev parent reply other threads:[~2021-11-19 21:47 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 11:24 [RFC bpf-next v5 00/29] bpf: Add batch support for attaching trampolines Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 01/29] ftrace: Use direct_ops hash in unregister_ftrace_direct Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 02/29] ftrace: Add cleanup to unregister_ftrace_direct_multi Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 03/29] ftrace: Add ftrace_set_filter_ips function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 04/29] bpf: Factor bpf_check_attach_target function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 05/29] bpf: Add bpf_check_attach_model function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 06/29] bpf: Add bpf_arg/bpf_ret_value helpers for tracing programs Jiri Olsa
2021-11-24 21:43 ` Andrii Nakryiko
2021-11-25 16:14 ` Alexei Starovoitov
2021-11-28 18:07 ` Jiri Olsa
2021-11-28 18:06 ` Jiri Olsa
2021-12-01 7:13 ` Andrii Nakryiko
2021-12-01 17:37 ` Alexei Starovoitov
2021-12-01 17:59 ` Andrii Nakryiko
2021-12-01 20:36 ` Alexei Starovoitov
2021-12-01 21:16 ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 07/29] bpf, x64: Allow to use caller address from stack Jiri Olsa
2021-11-19 4:14 ` Alexei Starovoitov
2021-11-19 21:46 ` Jiri Olsa [this message]
2021-11-18 11:24 ` [PATCH bpf-next 08/29] bpf: Keep active attached trampoline in bpf_prog Jiri Olsa
2021-11-24 21:48 ` Andrii Nakryiko
2021-11-28 17:24 ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 09/29] bpf: Add support to load multi func tracing program Jiri Olsa
2021-11-19 4:11 ` Alexei Starovoitov
2021-11-22 20:15 ` Jiri Olsa
2021-11-24 21:51 ` Andrii Nakryiko
2021-11-28 17:41 ` Jiri Olsa
2021-12-01 7:17 ` Andrii Nakryiko
2021-12-01 21:20 ` Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 10/29] bpf: Add bpf_trampoline_id object Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 11/29] bpf: Add addr to " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 12/29] bpf: Add struct bpf_tramp_node layer Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 13/29] bpf: Add bpf_tramp_attach layer for trampoline attachment Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 14/29] bpf: Add support to store multiple ids in bpf_tramp_id object Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 15/29] bpf: Add support to store multiple addrs " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 16/29] bpf: Add bpf_tramp_id_single function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 17/29] bpf: Resolve id in bpf_tramp_id_single Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 18/29] bpf: Add refcount_t to struct bpf_tramp_id Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 19/29] bpf: Add support to attach trampolines with multiple IDs Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 20/29] bpf: Add support for tracing multi link Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 21/29] libbpf: Add btf__find_by_glob_kind function Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 22/29] libbpf: Add support to link multi func tracing program Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 23/29] selftests/bpf: Add bpf_arg/bpf_ret_value test Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 24/29] selftests/bpf: Add fentry multi func test Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 25/29] selftests/bpf: Add fexit " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 26/29] selftests/bpf: Add fentry/fexit " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 27/29] selftests/bpf: Add mixed " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 28/29] selftests/bpf: Add ret_mod " Jiri Olsa
2021-11-18 11:24 ` [PATCH bpf-next 29/29] selftests/bpf: Add attach " Jiri Olsa
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YZgbS0GUpEzAeGNu@krava \
--to=jolsa@redhat.com \
--cc=alexei.starovoitov@gmail.com \
--cc=andrii@kernel.org \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=john.fastabend@gmail.com \
--cc=kafai@fb.com \
--cc=kpsingh@chromium.org \
--cc=netdev@vger.kernel.org \
--cc=songliubraving@fb.com \
--cc=yhs@fb.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).