From: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
To: bpf@vger.kernel.org
Cc: Siddharth Chintamaneni <sidchintamaneni@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Martin KaFai Lau <martin.lau@linux.dev>,
Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
Jiri Olsa <jolsa@kernel.org>,
Emil Tsalapatis <emil@etsalapatis.com>,
Ihor Solodrai <ihor.solodrai@linux.dev>,
Anton Protopopov <a.s.protopopov@gmail.com>,
Puranjay Mohan <puranjay@kernel.org>,
rlmenge@gmail.com, hargar@microsoft.com, apais@microsoft.com
Subject: [PATCH bpf-next v2 2/2] selftests/bpf: Test terminal gotox instructions
Date: Mon, 31 Aug 2026 22:33:14 +0000 [thread overview]
Message-ID: <20260831223314.89787-2-sidchintamaneni@gmail.com> (raw)
In-Reply-To: <20260831223314.89787-1-sidchintamaneni@gmail.com>
Add tests that place gotox at the end of the main program and a
subprogram, with each jump-table target preceding the gotox instruction.
This tests gotox as a valid non-fallthrough terminal instruction.
Signed-off-by: Siddharth Chintamaneni <sidchintamaneni@gmail.com>
---
.../selftests/bpf/progs/verifier_gotox.c | 61 +++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/verifier_gotox.c b/tools/testing/selftests/bpf/progs/verifier_gotox.c
index 5b18c9a27717..89067ab7baaa 100644
--- a/tools/testing/selftests/bpf/progs/verifier_gotox.c
+++ b/tools/testing/selftests/bpf/progs/verifier_gotox.c
@@ -47,6 +47,67 @@ DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_src_reg, BPF_REG_1, 0, 0, __fa
DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_non_zero_off, BPF_REG_0, 1, 0, __failure __msg("BPF_JA|BPF_X uses reserved fields"))
DEFINE_SIMPLE_JUMP_TABLE_PROG(reserved_field_non_zero_imm, BPF_REG_0, 0, 1, __failure __msg("BPF_JA|BPF_X uses reserved fields"))
+SEC("socket")
+__success __retval(0)
+__naked void jump_table_terminal_gotox(void)
+{
+ asm volatile (" \
+ .pushsection .jumptables,\"\",@progbits; \
+jt0_%=: \
+ .quad ret0_%= - socket; \
+ .size jt0_%=, 8; \
+ .global jt0_%=; \
+ .popsection; \
+ \
+ r0 = jt0_%= ll; \
+ r0 = *(u64 *)(r0 + 0); \
+ goto end_%=; \
+ret0_%=: \
+ r0 = 0; \
+ exit; \
+end_%=: \
+ .8byte %[gotox_r0]; \
+" :
+ : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X,
+ BPF_REG_0, 0, 0, 0))
+ : __clobber_all);
+}
+
+static __naked __noinline __used
+void terminal_gotox_subprog(void)
+{
+ asm volatile (" \
+ .pushsection .jumptables,\"\",@progbits; \
+jt0_%=: \
+ .quad ret0_%= - .text; \
+ .size jt0_%=, 8; \
+ .global jt0_%=; \
+ .popsection; \
+ \
+ r0 = jt0_%= ll; \
+ r0 = *(u64 *)(r0 + 0); \
+ goto end_%=; \
+ret0_%=: \
+ r0 = 0; \
+ exit; \
+end_%=: \
+ .8byte %[gotox_r0]; \
+" :
+ : __imm_insn(gotox_r0, BPF_RAW_INSN(BPF_JMP | BPF_JA | BPF_X,
+ BPF_REG_0, 0, 0, 0))
+ : __clobber_all);
+}
+
+SEC("socket")
+__success __retval(0)
+__naked void jump_table_terminal_gotox_subprog(void)
+{
+ asm volatile (" \
+ call terminal_gotox_subprog; \
+ exit; \
+" ::: __clobber_all);
+}
+
/*
* Gotox is forbidden when there is no jump table loaded
* which points to the sub-function where the gotox is used
--
2.43.0
next prev parent reply other threads:[~2026-08-31 22:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-31 22:33 [PATCH bpf-next v2 1/2] bpf: allow terminal gotox instructions Siddharth Chintamaneni
2026-08-31 22:33 ` Siddharth Chintamaneni [this message]
2026-08-31 23:26 ` [PATCH bpf-next v2 2/2] selftests/bpf: Test " bot+bpf-ci
2026-09-01 13:58 ` Anton Protopopov
2026-09-01 16:21 ` Siddharth Chintamaneni
2026-08-31 23:26 ` [PATCH bpf-next v2 1/2] bpf: allow " bot+bpf-ci
2026-09-01 13:51 ` Anton Protopopov
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=20260831223314.89787-2-sidchintamaneni@gmail.com \
--to=sidchintamaneni@gmail.com \
--cc=a.s.protopopov@gmail.com \
--cc=andrii@kernel.org \
--cc=apais@microsoft.com \
--cc=ast@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=daniel@iogearbox.net \
--cc=eddyz87@gmail.com \
--cc=emil@etsalapatis.com \
--cc=hargar@microsoft.com \
--cc=ihor.solodrai@linux.dev \
--cc=john.fastabend@gmail.com \
--cc=jolsa@kernel.org \
--cc=martin.lau@linux.dev \
--cc=memxor@gmail.com \
--cc=puranjay@kernel.org \
--cc=rlmenge@gmail.com \
--cc=song@kernel.org \
--cc=yonghong.song@linux.dev \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.