1 {
2 	"raw_tracepoint_writable: reject variable offset",
3 	.insns = {
4 		/* r6 is our tp buffer */
5 		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 0),
6 
7 		BPF_LD_MAP_FD(BPF_REG_1, 0),
8 		/* move the key (== 0) to r10-8 */
9 		BPF_MOV32_IMM(BPF_REG_0, 0),
10 		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
11 		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
12 		BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 0),
13 		/* lookup in the map */
14 		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
15 			     BPF_FUNC_map_lookup_elem),
16 
17 		/* exit clean if null */
18 		BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
19 		BPF_EXIT_INSN(),
20 
21 		/* shift the buffer pointer to a variable location */
22 		BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_0, 0),
23 		BPF_ALU64_REG(BPF_ADD, BPF_REG_6, BPF_REG_0),
24 		/* clobber whatever's there */
25 		BPF_MOV64_IMM(BPF_REG_7, 4242),
26 		BPF_STX_MEM(BPF_DW, BPF_REG_6, BPF_REG_7, 0),
27 
28 		BPF_MOV64_IMM(BPF_REG_0, 0),
29 		BPF_EXIT_INSN(),
30 	},
31 	.fixup_map_hash_8b = { 1, },
32 	.prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE,
33 	.errstr = "R6 invalid variable buffer offset: off=0, var_off=(0x0; 0xffffffff)",
34 },
35