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
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