xref: /linux/tools/testing/selftests/bpf/progs/verifier_precision.c (revision 24168c5e6dfbdd5b414f048f47f75d64533296ca)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2023 SUSE LLC */
3 #include <linux/bpf.h>
4 #include <bpf/bpf_helpers.h>
5 #include "bpf_misc.h"
6 
7 SEC("?raw_tp")
8 __success __log_level(2)
9 __msg("mark_precise: frame0: regs=r2 stack= before 3: (bf) r1 = r10")
10 __msg("mark_precise: frame0: regs=r2 stack= before 2: (55) if r2 != 0xfffffff8 goto pc+2")
11 __msg("mark_precise: frame0: regs=r2 stack= before 1: (87) r2 = -r2")
12 __msg("mark_precise: frame0: regs=r2 stack= before 0: (b7) r2 = 8")
13 __naked int bpf_neg(void)
14 {
15 	asm volatile (
16 		"r2 = 8;"
17 		"r2 = -r2;"
18 		"if r2 != -8 goto 1f;"
19 		"r1 = r10;"
20 		"r1 += r2;"
21 	"1:"
22 		"r0 = 0;"
23 		"exit;"
24 		::: __clobber_all);
25 }
26 
27 SEC("?raw_tp")
28 __success __log_level(2)
29 __msg("mark_precise: frame0: regs=r2 stack= before 3: (bf) r1 = r10")
30 __msg("mark_precise: frame0: regs=r2 stack= before 2: (55) if r2 != 0x0 goto pc+2")
31 __msg("mark_precise: frame0: regs=r2 stack= before 1: (d4) r2 = le16 r2")
32 __msg("mark_precise: frame0: regs=r2 stack= before 0: (b7) r2 = 0")
33 __naked int bpf_end_to_le(void)
34 {
35 	asm volatile (
36 		"r2 = 0;"
37 		"r2 = le16 r2;"
38 		"if r2 != 0 goto 1f;"
39 		"r1 = r10;"
40 		"r1 += r2;"
41 	"1:"
42 		"r0 = 0;"
43 		"exit;"
44 		::: __clobber_all);
45 }
46 
47 
48 SEC("?raw_tp")
49 __success __log_level(2)
50 __msg("mark_precise: frame0: regs=r2 stack= before 3: (bf) r1 = r10")
51 __msg("mark_precise: frame0: regs=r2 stack= before 2: (55) if r2 != 0x0 goto pc+2")
52 __msg("mark_precise: frame0: regs=r2 stack= before 1: (dc) r2 = be16 r2")
53 __msg("mark_precise: frame0: regs=r2 stack= before 0: (b7) r2 = 0")
54 __naked int bpf_end_to_be(void)
55 {
56 	asm volatile (
57 		"r2 = 0;"
58 		"r2 = be16 r2;"
59 		"if r2 != 0 goto 1f;"
60 		"r1 = r10;"
61 		"r1 += r2;"
62 	"1:"
63 		"r0 = 0;"
64 		"exit;"
65 		::: __clobber_all);
66 }
67 
68 #if (defined(__TARGET_ARCH_arm64) || defined(__TARGET_ARCH_x86) || \
69 	(defined(__TARGET_ARCH_riscv) && __riscv_xlen == 64) || \
70 	defined(__TARGET_ARCH_arm) || defined(__TARGET_ARCH_s390)) && \
71 	__clang_major__ >= 18
72 
73 SEC("?raw_tp")
74 __success __log_level(2)
75 __msg("mark_precise: frame0: regs=r2 stack= before 3: (bf) r1 = r10")
76 __msg("mark_precise: frame0: regs=r2 stack= before 2: (55) if r2 != 0x0 goto pc+2")
77 __msg("mark_precise: frame0: regs=r2 stack= before 1: (d7) r2 = bswap16 r2")
78 __msg("mark_precise: frame0: regs=r2 stack= before 0: (b7) r2 = 0")
79 __naked int bpf_end_bswap(void)
80 {
81 	asm volatile (
82 		"r2 = 0;"
83 		"r2 = bswap16 r2;"
84 		"if r2 != 0 goto 1f;"
85 		"r1 = r10;"
86 		"r1 += r2;"
87 	"1:"
88 		"r0 = 0;"
89 		"exit;"
90 		::: __clobber_all);
91 }
92 
93 #endif /* v4 instruction */
94 
95 SEC("?raw_tp")
96 __success __log_level(2)
97 /*
98  * Without the bug fix there will be no history between "last_idx 3 first_idx 3"
99  * and "parent state regs=" lines. "R0_w=6" parts are here to help anchor
100  * expected log messages to the one specific mark_chain_precision operation.
101  *
102  * This is quite fragile: if verifier checkpointing heuristic changes, this
103  * might need adjusting.
104  */
105 __msg("2: (07) r0 += 1                       ; R0_w=6")
106 __msg("3: (35) if r0 >= 0xa goto pc+1")
107 __msg("mark_precise: frame0: last_idx 3 first_idx 3 subseq_idx -1")
108 __msg("mark_precise: frame0: regs=r0 stack= before 2: (07) r0 += 1")
109 __msg("mark_precise: frame0: regs=r0 stack= before 1: (07) r0 += 1")
110 __msg("mark_precise: frame0: regs=r0 stack= before 4: (05) goto pc-4")
111 __msg("mark_precise: frame0: regs=r0 stack= before 3: (35) if r0 >= 0xa goto pc+1")
112 __msg("mark_precise: frame0: parent state regs= stack=:  R0_rw=P4")
113 __msg("3: R0_w=6")
114 __naked int state_loop_first_last_equal(void)
115 {
116 	asm volatile (
117 		"r0 = 0;"
118 	"l0_%=:"
119 		"r0 += 1;"
120 		"r0 += 1;"
121 		/* every few iterations we'll have a checkpoint here with
122 		 * first_idx == last_idx, potentially confusing precision
123 		 * backtracking logic
124 		 */
125 		"if r0 >= 10 goto l1_%=;"	/* checkpoint + mark_precise */
126 		"goto l0_%=;"
127 	"l1_%=:"
128 		"exit;"
129 		::: __clobber_common
130 	);
131 }
132 
133 char _license[] SEC("license") = "GPL";
134