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eddyz87gregkh
eddyz87
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gregkh
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selftests/bpf: allow checking xlated programs in verifier_* tests
[ Upstream commit 9c9f733 ] Add a macro __xlated("...") for use with test_loader tests. When such annotations are present for the test case: - bpf_prog_get_info_by_fd() is used to get BPF program after all rewrites are applied by verifier. - the program is disassembled and patterns specified in __xlated are searched for in the disassembly text. __xlated matching follows the same mechanics as __msg: each subsequent pattern is matched from the point where previous pattern ended. This allows to write tests like below, where the goal is to verify the behavior of one of the of the transformations applied by verifier: SEC("raw_tp") __xlated("1: w0 = ") __xlated("2: r0 = &(void __percpu *)(r0)") __xlated("3: r0 = *(u32 *)(r0 +0)") __xlated("4: exit") __success __naked void simple(void) { asm volatile ( "call %[bpf_get_smp_processor_id];" "exit;" : : __imm(bpf_get_smp_processor_id) : __clobber_all); } Acked-by: Andrii Nakryiko <[email protected]> Signed-off-by: Eduard Zingerman <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Stable-dep-of: f00bb75 ("selftests/bpf: fix to avoid __msg tag de-duplication by clang") Signed-off-by: Sasha Levin <[email protected]>
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‎tools/testing/selftests/bpf/progs/bpf_misc.h‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -26,6 +26,9 @@
2626
*
2727
* __regex Same as __msg, but using a regular expression.
2828
* __regex_unpriv Same as __msg_unpriv but using a regular expression.
29+
* __xlated Expect a line in a disassembly log after verifier applies rewrites.
30+
* Multiple __xlated attributes could be specified.
31+
* __xlated_unpriv Same as __xlated but for unprivileged mode.
2932
*
3033
* __success Expect program load success in privileged mode.
3134
* __success_unpriv Expect program load success in unprivileged mode.
@@ -63,11 +66,13 @@
6366
*/
6467
#define __msg(msg) __attribute__((btf_decl_tag("comment:test_expect_msg=" msg)))
6568
#define __regex(regex) __attribute__((btf_decl_tag("comment:test_expect_regex=" regex)))
69+
#define __xlated(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated=" msg)))
6670
#define __failure __attribute__((btf_decl_tag("comment:test_expect_failure")))
6771
#define __success __attribute__((btf_decl_tag("comment:test_expect_success")))
6872
#define __description(desc) __attribute__((btf_decl_tag("comment:test_description=" desc)))
6973
#define __msg_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_msg_unpriv=" msg)))
7074
#define __regex_unpriv(regex) __attribute__((btf_decl_tag("comment:test_expect_regex_unpriv=" regex)))
75+
#define __xlated_unpriv(msg) __attribute__((btf_decl_tag("comment:test_expect_xlated_unpriv=" msg)))
7176
#define __failure_unpriv __attribute__((btf_decl_tag("comment:test_expect_failure_unpriv")))
7277
#define __success_unpriv __attribute__((btf_decl_tag("comment:test_expect_success_unpriv")))
7378
#define __log_level(lvl) __attribute__((btf_decl_tag("comment:test_log_level="#lvl)))

‎tools/testing/selftests/bpf/test_loader.c‎

Lines changed: 79 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -7,6 +7,7 @@
77
#include <bpf/btf.h>
88

99
#include "autoconf_helper.h"
10+
#include "disasm_helpers.h"
1011
#include "unpriv_helpers.h"
1112
#include "cap_helpers.h"
1213

@@ -19,10 +20,12 @@
1920
#define TEST_TAG_EXPECT_SUCCESS "comment:test_expect_success"
2021
#define TEST_TAG_EXPECT_MSG_PFX "comment:test_expect_msg="
2122
#define TEST_TAG_EXPECT_REGEX_PFX "comment:test_expect_regex="
23+
#define TEST_TAG_EXPECT_XLATED_PFX "comment:test_expect_xlated="
2224
#define TEST_TAG_EXPECT_FAILURE_UNPRIV "comment:test_expect_failure_unpriv"
2325
#define TEST_TAG_EXPECT_SUCCESS_UNPRIV "comment:test_expect_success_unpriv"
2426
#define TEST_TAG_EXPECT_MSG_PFX_UNPRIV "comment:test_expect_msg_unpriv="
2527
#define TEST_TAG_EXPECT_REGEX_PFX_UNPRIV "comment:test_expect_regex_unpriv="
28+
#define TEST_TAG_EXPECT_XLATED_PFX_UNPRIV "comment:test_expect_xlated_unpriv="
2629
#define TEST_TAG_LOG_LEVEL_PFX "comment:test_log_level="
2730
#define TEST_TAG_PROG_FLAGS_PFX "comment:test_prog_flags="
2831
#define TEST_TAG_DESCRIPTION_PFX "comment:test_description="
@@ -64,6 +67,7 @@ struct test_subspec {
6467
char *name;
6568
bool expect_failure;
6669
struct expected_msgs expect_msgs;
70+
struct expected_msgs expect_xlated;
6771
int retval;
6872
bool execute;
6973
};
@@ -117,6 +121,8 @@ static void free_test_spec(struct test_spec *spec)
117121
/* Deallocate expect_msgs arrays. */
118122
free_msgs(&spec->priv.expect_msgs);
119123
free_msgs(&spec->unpriv.expect_msgs);
124+
free_msgs(&spec->priv.expect_xlated);
125+
free_msgs(&spec->unpriv.expect_xlated);
120126

121127
free(spec->priv.name);
122128
free(spec->unpriv.name);
@@ -299,6 +305,18 @@ static int parse_test_spec(struct test_loader *tester,
299305
if (err)
300306
goto cleanup;
301307
spec->mode_mask |= UNPRIV;
308+
} else if (str_has_pfx(s, TEST_TAG_EXPECT_XLATED_PFX)) {
309+
msg = s + sizeof(TEST_TAG_EXPECT_XLATED_PFX) - 1;
310+
err = push_msg(msg, NULL, &spec->priv.expect_xlated);
311+
if (err)
312+
goto cleanup;
313+
spec->mode_mask |= PRIV;
314+
} else if (str_has_pfx(s, TEST_TAG_EXPECT_XLATED_PFX_UNPRIV)) {
315+
msg = s + sizeof(TEST_TAG_EXPECT_XLATED_PFX_UNPRIV) - 1;
316+
err = push_msg(msg, NULL, &spec->unpriv.expect_xlated);
317+
if (err)
318+
goto cleanup;
319+
spec->mode_mask |= UNPRIV;
302320
} else if (str_has_pfx(s, TEST_TAG_RETVAL_PFX)) {
303321
val = s + sizeof(TEST_TAG_RETVAL_PFX) - 1;
304322
err = parse_retval(val, &spec->priv.retval, "__retval");
@@ -402,6 +420,16 @@ static int parse_test_spec(struct test_loader *tester,
402420
goto cleanup;
403421
}
404422
}
423+
if (spec->unpriv.expect_xlated.cnt == 0) {
424+
for (i = 0; i < spec->priv.expect_xlated.cnt; i++) {
425+
struct expect_msg *msg = &spec->priv.expect_xlated.patterns[i];
426+
427+
err = push_msg(msg->substr, msg->regex_str,
428+
&spec->unpriv.expect_xlated);
429+
if (err)
430+
goto cleanup;
431+
}
432+
}
405433
}
406434

407435
spec->valid = true;
@@ -449,7 +477,15 @@ static void emit_verifier_log(const char *log_buf, bool force)
449477
fprintf(stdout, "VERIFIER LOG:\n=============\n%s=============\n", log_buf);
450478
}
451479

452-
static void validate_msgs(char *log_buf, struct expected_msgs *msgs)
480+
static void emit_xlated(const char *xlated, bool force)
481+
{
482+
if (!force && env.verbosity == VERBOSE_NONE)
483+
return;
484+
fprintf(stdout, "XLATED:\n=============\n%s=============\n", xlated);
485+
}
486+
487+
static void validate_msgs(char *log_buf, struct expected_msgs *msgs,
488+
void (*emit_fn)(const char *buf, bool force))
453489
{
454490
regmatch_t reg_match[1];
455491
const char *log = log_buf;
@@ -473,7 +509,7 @@ static void validate_msgs(char *log_buf, struct expected_msgs *msgs)
473509

474510
if (!ASSERT_OK_PTR(match, "expect_msg")) {
475511
if (env.verbosity == VERBOSE_NONE)
476-
emit_verifier_log(log_buf, true /*force*/);
512+
emit_fn(log_buf, true /*force*/);
477513
for (j = 0; j <= i; j++) {
478514
msg = &msgs->patterns[j];
479515
fprintf(stderr, "%s %s: '%s'\n",
@@ -610,6 +646,37 @@ static bool should_do_test_run(struct test_spec *spec, struct test_subspec *subs
610646
return true;
611647
}
612648

649+
/* Get a disassembly of BPF program after verifier applies all rewrites */
650+
static int get_xlated_program_text(int prog_fd, char *text, size_t text_sz)
651+
{
652+
struct bpf_insn *insn_start = NULL, *insn, *insn_end;
653+
__u32 insns_cnt = 0, i;
654+
char buf[64];
655+
FILE *out = NULL;
656+
int err;
657+
658+
err = get_xlated_program(prog_fd, &insn_start, &insns_cnt);
659+
if (!ASSERT_OK(err, "get_xlated_program"))
660+
goto out;
661+
out = fmemopen(text, text_sz, "w");
662+
if (!ASSERT_OK_PTR(out, "open_memstream"))
663+
goto out;
664+
insn_end = insn_start + insns_cnt;
665+
insn = insn_start;
666+
while (insn < insn_end) {
667+
i = insn - insn_start;
668+
insn = disasm_insn(insn, buf, sizeof(buf));
669+
fprintf(out, "%d: %s\n", i, buf);
670+
}
671+
fflush(out);
672+
673+
out:
674+
free(insn_start);
675+
if (out)
676+
fclose(out);
677+
return err;
678+
}
679+
613680
/* this function is forced noinline and has short generic name to look better
614681
* in test_progs output (in case of a failure)
615682
*/
@@ -695,7 +762,16 @@ void run_subtest(struct test_loader *tester,
695762
}
696763
}
697764
emit_verifier_log(tester->log_buf, false /*force*/);
698-
validate_msgs(tester->log_buf, &subspec->expect_msgs);
765+
validate_msgs(tester->log_buf, &subspec->expect_msgs, emit_verifier_log);
766+
767+
if (subspec->expect_xlated.cnt) {
768+
err = get_xlated_program_text(bpf_program__fd(tprog),
769+
tester->log_buf, tester->log_buf_sz);
770+
if (err)
771+
goto tobj_cleanup;
772+
emit_xlated(tester->log_buf, false /*force*/);
773+
validate_msgs(tester->log_buf, &subspec->expect_xlated, emit_xlated);
774+
}
699775

700776
if (should_do_test_run(spec, subspec)) {
701777
/* For some reason test_verifier executes programs

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