[RFC bpf-next 5/5] selftests/bpf: convert jeq_infer_not_null tests to inline assembly

[Eduard Zingerman <eddyz87@gmail.com>]

Use updated test_loader interface to convert progs/jeq_infer_not_null
verifier test to inline assembly. Some redundant comments are removed
in the process.

Existing test progs/jeq_infer_not_null_fail.c is updated to use
"Use test_loader marker" to remove trivial
progs_tests/jeq_infer_not_null.c boilerplate code.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 .../bpf/prog_tests/jeq_infer_not_null.c       |   9 -
 .../selftests/bpf/progs/jeq_infer_not_null.c  | 186 ++++++++++++++++++
 .../bpf/progs/jeq_infer_not_null_fail.c       |   1 +
 .../bpf/verifier/jeq_infer_not_null.c         | 174 ----------------
 4 files changed, 187 insertions(+), 183 deletions(-)
 delete mode 100644 tools/testing/selftests/bpf/prog_tests/jeq_infer_not_null.c
 create mode 100644 tools/testing/selftests/bpf/progs/jeq_infer_not_null.c
 delete mode 100644 tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c

diff --git a/tools/testing/selftests/bpf/prog_tests/jeq_infer_not_null.c b/tools/testing/selftests/bpf/prog_tests/jeq_infer_not_null.c
deleted file mode 100644
index 3add34df5767..000000000000
--- a/tools/testing/selftests/bpf/prog_tests/jeq_infer_not_null.c
+++ /dev/null
@@ -1,9 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <test_progs.h>
-#include "jeq_infer_not_null_fail.skel.h"
-
-void test_jeq_infer_not_null(void)
-{
-	RUN_TESTS(jeq_infer_not_null_fail);
-}
diff --git a/tools/testing/selftests/bpf/progs/jeq_infer_not_null.c b/tools/testing/selftests/bpf/progs/jeq_infer_not_null.c
new file mode 100644
index 000000000000..7c506eccacaf
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/jeq_infer_not_null.c
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Converted from tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c */
+/* Use test_loader marker */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+struct {
+	__uint(type, BPF_MAP_TYPE_XSKMAP);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, int);
+} map_xskmap SEC(".maps");
+
+/* This is equivalent to the following program:
+ *
+ *   r6 = skb->sk;
+ *   r7 = sk_fullsock(r6);
+ *   r0 = sk_fullsock(r6);
+ *   if (r0 == 0) return 0;    (a)
+ *   if (r0 != r7) return 0;   (b)
+ *   *r7->type;                (c)
+ *   return 0;
+ *
+ * It is safe to dereference r7 at point (c), because of (a) and (b).
+ * The test verifies that relation r0 == r7 is propagated from (b) to (c).
+ */
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JNE false branch")
+__success __failure_unpriv __msg_unpriv("R7 pointer comparison")
+SEC("cgroup/skb")
+__naked void sock_or_null_jne_false_branch(void)
+{
+	asm volatile (
+"	r6 = *(u64*)(r1 + %[__sk_buff_sk_offset]);	\n\
+	if r6 == 0 goto exit_%=;			\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	r7 = r0;					\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	if r0 == 0 goto exit_%=;			\n\
+	if r0 != r7 goto exit_%=;			\n\
+	r0 = *(u32*)(r7 + %[bpf_sock_type_offset]);	\n\
+exit_%=:						\n\
+	r0 = 0;						\n\
+	exit;						\n\
+"	:
+	: [__sk_buff_sk_offset]"i"(offsetof(struct __sk_buff, sk)),
+	  [bpf_sock_type_offset]"i"(offsetof(struct bpf_sock, type)),
+	  __imm(bpf_sk_fullsock)
+	: __clobber_all);
+}
+
+/* Same as above, but verify that another branch of JNE still
+ * prohibits access to PTR_MAYBE_NULL.
+ */
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JNE true branch")
+__failure __msg("R7 invalid mem access 'sock_or_null'")
+__failure_unpriv __msg_unpriv("R7 pointer comparison")
+SEC("cgroup/skb")
+__naked void sock_or_null_jne_true_branch(void)
+{
+	asm volatile (
+"	r6 = *(u64*)(r1 + %[__sk_buff_sk_offset]);	\n\
+	if r6 == 0 goto exit_%=;			\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	r7 = r0;					\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	if r0 != 0 goto exit_%=;			\n\
+	if r0 != r7 goto l1_%=;				\n\
+	goto exit_%=;					\n\
+l1_%=:							\n\
+	r0 = *(u32*)(r7 + %[bpf_sock_type_offset]);	\n\
+exit_%=:						\n\
+	r0 = 0;						\n\
+	exit;						\n\
+"	:
+	: [__sk_buff_sk_offset]"i"(offsetof(struct __sk_buff, sk)),
+	  [bpf_sock_type_offset]"i"(offsetof(struct bpf_sock, type)),
+	  __imm(bpf_sk_fullsock)
+	: __clobber_all);
+}
+
+/* Same as a first test, but not null should be inferred for JEQ branch */
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JEQ true branch")
+__success __failure_unpriv __msg_unpriv("R7 pointer comparison")
+SEC("cgroup/skb")
+__naked void sock_or_null_jeq_true_branch(void)
+{
+	asm volatile (
+"	r6 = *(u64*)(r1 + %[__sk_buff_sk_offset]);	\n\
+	if r6 == 0 goto exit_%=;			\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	r7 = r0;					\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	if r0 == 0 goto exit_%=;			\n\
+	if r0 == r7 goto l1_%=;				\n\
+	goto exit_%=;					\n\
+l1_%=:							\n\
+	r0 = *(u32*)(r7 + %[bpf_sock_type_offset]);	\n\
+exit_%=:						\n\
+	r0 = 0;						\n\
+	exit;						\n\
+"	:
+	: [__sk_buff_sk_offset]"i"(offsetof(struct __sk_buff, sk)),
+	  [bpf_sock_type_offset]"i"(offsetof(struct bpf_sock, type)),
+	  __imm(bpf_sk_fullsock)
+	: __clobber_all);
+}
+
+/* Same as above, but verify that another branch of JNE still
+ * prohibits access to PTR_MAYBE_NULL.
+ */
+__description("jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JEQ false branch")
+__failure __msg("R7 invalid mem access 'sock_or_null'")
+__failure_unpriv __msg_unpriv("R7 pointer comparison")
+SEC("cgroup/skb")
+__naked void sock_or_null_jeq_false_branch(void)
+{
+	asm volatile (
+"	r6 = *(u64*)(r1 + %[__sk_buff_sk_offset]);	\n\
+	if r6 == 0 goto exit_%=;			\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	r7 = r0;					\n\
+	r1 = r6;					\n\
+	call %[bpf_sk_fullsock];			\n\
+	if r0 == 0 goto exit_%=;			\n\
+	if r0 == r7 goto exit_%=;			\n\
+	r0 = *(u32*)(r7 + %[bpf_sock_type_offset]);	\n\
+exit_%=:						\n\
+	r0 = 0;						\n\
+	exit;						\n\
+"	:
+	: [__sk_buff_sk_offset]"i"(offsetof(struct __sk_buff, sk)),
+	  [bpf_sock_type_offset]"i"(offsetof(struct bpf_sock, type)),
+	  __imm(bpf_sk_fullsock)
+	: __clobber_all);
+}
+
+/* Maps are treated in a different branch of `mark_ptr_not_null_reg`,
+ * so separate test for maps case.
+ */
+__description("jne/jeq infer not null, PTR_TO_MAP_VALUE_OR_NULL -> PTR_TO_MAP_VALUE")
+__success
+SEC("xdp")
+__naked void ptr_to_map(void)
+{
+	asm volatile (
+"	r1 = 0;						\n\
+	*(u32*)(r10 - 8) = r1;				\n\
+	r9 = r10;					\n\
+	r9 += -8;					\n\
+	/* r8 = process local map */			\n\
+	r8 = %[map_xskmap] ll;				\n\
+	/* r6 = map_lookup_elem(r8, r9); */		\n\
+	r1 = r8;					\n\
+	r2 = r9;					\n\
+	call %[bpf_map_lookup_elem];			\n\
+	r6 = r0;					\n\
+	/* r7 = map_lookup_elem(r8, r9); */		\n\
+	r1 = r8;					\n\
+	r2 = r9;					\n\
+	call %[bpf_map_lookup_elem];			\n\
+	r7 = r0;					\n\
+	if r6 == 0 goto exit_%=;			\n\
+	if r6 != r7 goto exit_%=;			\n\
+	/* read *r7; */					\n\
+	r0 = *(u32*)(r7 + %[bpf_xdp_sock_queue_id_offset]);\n\
+exit_%=:						\n\
+	r0 = 0;						\n\
+	exit;						\n\
+"	:
+	: [bpf_xdp_sock_queue_id_offset]"i"(offsetof(struct bpf_xdp_sock, queue_id)),
+	  __imm(bpf_map_lookup_elem),
+	  __imm_addr(map_xskmap)
+	: __clobber_all);
+}
+
+char _license[] SEC("license") = "GPL";
+
diff --git a/tools/testing/selftests/bpf/progs/jeq_infer_not_null_fail.c b/tools/testing/selftests/bpf/progs/jeq_infer_not_null_fail.c
index f46965053acb..8048d76f60ca 100644
--- a/tools/testing/selftests/bpf/progs/jeq_infer_not_null_fail.c
+++ b/tools/testing/selftests/bpf/progs/jeq_infer_not_null_fail.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+/* Use test_loader marker */
 
 #include "vmlinux.h"
 #include <bpf/bpf_helpers.h>
diff --git a/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c b/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c
deleted file mode 100644
index 67a1c07ead34..000000000000
--- a/tools/testing/selftests/bpf/verifier/jeq_infer_not_null.c
+++ /dev/null
@@ -1,174 +0,0 @@
-{
-	/* This is equivalent to the following program:
-	 *
-	 *   r6 = skb->sk;
-	 *   r7 = sk_fullsock(r6);
-	 *   r0 = sk_fullsock(r6);
-	 *   if (r0 == 0) return 0;    (a)
-	 *   if (r0 != r7) return 0;   (b)
-	 *   *r7->type;                (c)
-	 *   return 0;
-	 *
-	 * It is safe to dereference r7 at point (c), because of (a) and (b).
-	 * The test verifies that relation r0 == r7 is propagated from (b) to (c).
-	 */
-	"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JNE false branch",
-	.insns = {
-	/* r6 = skb->sk; */
-	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-	/* if (r6 == 0) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8),
-	/* r7 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-	/* r0 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	/* if (r0 == null) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
-	/* if (r0 == r7) r0 = *(r7->type); */
-	BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-	/* return 0 */
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-	.result = ACCEPT,
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R7 pointer comparison",
-},
-{
-	/* Same as above, but verify that another branch of JNE still
-	 * prohibits access to PTR_MAYBE_NULL.
-	 */
-	"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JNE true branch",
-	.insns = {
-	/* r6 = skb->sk */
-	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-	/* if (r6 == 0) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9),
-	/* r7 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-	/* r0 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	/* if (r0 == null) return 0; */
-	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
-	/* if (r0 == r7) return 0; */
-	BPF_JMP_REG(BPF_JNE, BPF_REG_0, BPF_REG_7, 1), /* Use ! JNE ! */
-	BPF_JMP_IMM(BPF_JA, 0, 0, 1),
-	/* r0 = *(r7->type); */
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-	/* return 0 */
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-	.result = REJECT,
-	.errstr = "R7 invalid mem access 'sock_or_null'",
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R7 pointer comparison",
-},
-{
-	/* Same as a first test, but not null should be inferred for JEQ branch */
-	"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL -> PTR_TO_SOCKET for JEQ true branch",
-	.insns = {
-	/* r6 = skb->sk; */
-	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-	/* if (r6 == null) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 9),
-	/* r7 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-	/* r0 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	/* if (r0 == null) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
-	/* if (r0 != r7) return 0; */
-	BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */
-	BPF_JMP_IMM(BPF_JA, 0, 0, 1),
-	/* r0 = *(r7->type); */
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-	/* return 0; */
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-	.result = ACCEPT,
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R7 pointer comparison",
-},
-{
-	/* Same as above, but verify that another branch of JNE still
-	 * prohibits access to PTR_MAYBE_NULL.
-	 */
-	"jne/jeq infer not null, PTR_TO_SOCKET_OR_NULL unchanged for JEQ false branch",
-	.insns = {
-	/* r6 = skb->sk; */
-	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, offsetof(struct __sk_buff, sk)),
-	/* if (r6 == null) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 8),
-	/* r7 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-	/* r0 = sk_fullsock(skb); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
-	BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
-	/* if (r0 == null) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
-	/* if (r0 != r7) r0 = *(r7->type); */
-	BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_7, 1), /* Use ! JEQ ! */
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
-	/* return 0; */
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
-	.result = REJECT,
-	.errstr = "R7 invalid mem access 'sock_or_null'",
-	.result_unpriv = REJECT,
-	.errstr_unpriv = "R7 pointer comparison",
-},
-{
-	/* Maps are treated in a different branch of `mark_ptr_not_null_reg`,
-	 * so separate test for maps case.
-	 */
-	"jne/jeq infer not null, PTR_TO_MAP_VALUE_OR_NULL -> PTR_TO_MAP_VALUE",
-	.insns = {
-	/* r9 = &some stack to use as key */
-	BPF_ST_MEM(BPF_W, BPF_REG_10, -8, 0),
-	BPF_MOV64_REG(BPF_REG_9, BPF_REG_10),
-	BPF_ALU64_IMM(BPF_ADD, BPF_REG_9, -8),
-	/* r8 = process local map */
-	BPF_LD_MAP_FD(BPF_REG_8, 0),
-	/* r6 = map_lookup_elem(r8, r9); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
-	BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
-	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-	BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
-	/* r7 = map_lookup_elem(r8, r9); */
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_8),
-	BPF_MOV64_REG(BPF_REG_2, BPF_REG_9),
-	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
-	BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
-	/* if (r6 == 0) return 0; */
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2),
-	/* if (r6 != r7) return 0; */
-	BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_7, 1),
-	/* read *r7; */
-	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_xdp_sock, queue_id)),
-	/* return 0; */
-	BPF_MOV64_IMM(BPF_REG_0, 0),
-	BPF_EXIT_INSN(),
-	},
-	.fixup_map_xskmap = { 3 },
-	.prog_type = BPF_PROG_TYPE_XDP,
-	.result = ACCEPT,
-},
-- 
2.39.0