xref: /linux/tools/objtool/arch/powerpc/decode.c (revision 4f77c3462308c62ffe7129cc18b9ac937f44b5a5)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <objtool/check.h>
6 #include <objtool/elf.h>
7 #include <objtool/arch.h>
8 #include <objtool/warn.h>
9 #include <objtool/builtin.h>
10 #include <objtool/endianness.h>
11 
12 int arch_ftrace_match(char *name)
13 {
14 	return !strcmp(name, "_mcount");
15 }
16 
17 unsigned long arch_dest_reloc_offset(int addend)
18 {
19 	return addend;
20 }
21 
22 bool arch_callee_saved_reg(unsigned char reg)
23 {
24 	return false;
25 }
26 
27 int arch_decode_hint_reg(u8 sp_reg, int *base)
28 {
29 	exit(-1);
30 }
31 
32 const char *arch_nop_insn(int len)
33 {
34 	exit(-1);
35 }
36 
37 const char *arch_ret_insn(int len)
38 {
39 	exit(-1);
40 }
41 
42 int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
43 			    unsigned long offset, unsigned int maxlen,
44 			    struct instruction *insn)
45 {
46 	unsigned int opcode;
47 	enum insn_type typ;
48 	unsigned long imm;
49 	u32 ins;
50 
51 	ins = bswap_if_needed(file->elf, *(u32 *)(sec->data->d_buf + offset));
52 	opcode = ins >> 26;
53 	typ = INSN_OTHER;
54 	imm = 0;
55 
56 	switch (opcode) {
57 	case 18: /* b[l][a] */
58 		if ((ins & 3) == 1) /* bl */
59 			typ = INSN_CALL;
60 
61 		imm = ins & 0x3fffffc;
62 		if (imm & 0x2000000)
63 			imm -= 0x4000000;
64 		break;
65 	}
66 
67 	if (opcode == 1)
68 		insn->len = 8;
69 	else
70 		insn->len = 4;
71 
72 	insn->type = typ;
73 	insn->immediate = imm;
74 
75 	return 0;
76 }
77 
78 unsigned long arch_jump_destination(struct instruction *insn)
79 {
80 	return insn->offset + insn->immediate;
81 }
82 
83 bool arch_pc_relative_reloc(struct reloc *reloc)
84 {
85 	/*
86 	 * The powerpc build only allows certain relocation types, see
87 	 * relocs_check.sh, and none of those accepted are PC relative.
88 	 */
89 	return false;
90 }
91 
92 void arch_initial_func_cfi_state(struct cfi_init_state *state)
93 {
94 	int i;
95 
96 	for (i = 0; i < CFI_NUM_REGS; i++) {
97 		state->regs[i].base = CFI_UNDEFINED;
98 		state->regs[i].offset = 0;
99 	}
100 
101 	/* initial CFA (call frame address) */
102 	state->cfa.base = CFI_SP;
103 	state->cfa.offset = 0;
104 
105 	/* initial LR (return address) */
106 	state->regs[CFI_RA].base = CFI_CFA;
107 	state->regs[CFI_RA].offset = 0;
108 }
109