orc.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2#include <linux/objtool_types.h>
  3#include <asm/orc_types.h>
  4
  5#include <objtool/check.h>
  6#include <objtool/orc.h>
  7#include <objtool/warn.h>
  8
  9int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
 10{
 11	struct cfi_reg *fp = &cfi->regs[CFI_FP];
 12	struct cfi_reg *ra = &cfi->regs[CFI_RA];
 13
 14	memset(orc, 0, sizeof(*orc));
 15
 16	if (!cfi) {
 17		/*
 18		 * This is usually either unreachable nops/traps (which don't
 19		 * trigger unreachable instruction warnings), or
 20		 * STACK_FRAME_NON_STANDARD functions.
 21		 */
 22		orc->type = ORC_TYPE_UNDEFINED;
 23		return 0;
 24	}
 25
 26	switch (cfi->type) {
 27	case UNWIND_HINT_TYPE_UNDEFINED:
 28		orc->type = ORC_TYPE_UNDEFINED;
 29		return 0;
 30	case UNWIND_HINT_TYPE_END_OF_STACK:
 31		orc->type = ORC_TYPE_END_OF_STACK;
 32		return 0;
 33	case UNWIND_HINT_TYPE_CALL:
 34		orc->type = ORC_TYPE_CALL;
 35		break;
 36	case UNWIND_HINT_TYPE_REGS:
 37		orc->type = ORC_TYPE_REGS;
 38		break;
 39	case UNWIND_HINT_TYPE_REGS_PARTIAL:
 40		orc->type = ORC_TYPE_REGS_PARTIAL;
 41		break;
 42	default:
 43		ERROR_INSN(insn, "unknown unwind hint type %d", cfi->type);
 44		return -1;
 45	}
 46
 47	orc->signal = cfi->signal;
 48
 49	switch (cfi->cfa.base) {
 50	case CFI_SP:
 51		orc->sp_reg = ORC_REG_SP;
 52		break;
 53	case CFI_FP:
 54		orc->sp_reg = ORC_REG_FP;
 55		break;
 56	default:
 57		ERROR_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
 58		return -1;
 59	}
 60
 61	switch (fp->base) {
 62	case CFI_UNDEFINED:
 63		orc->fp_reg = ORC_REG_UNDEFINED;
 64		orc->fp_offset = 0;
 65		break;
 66	case CFI_CFA:
 67		orc->fp_reg = ORC_REG_PREV_SP;
 68		orc->fp_offset = fp->offset;
 69		break;
 70	case CFI_FP:
 71		orc->fp_reg = ORC_REG_FP;
 72		break;
 73	default:
 74		ERROR_INSN(insn, "unknown FP base reg %d", fp->base);
 75		return -1;
 76	}
 77
 78	switch (ra->base) {
 79	case CFI_UNDEFINED:
 80		orc->ra_reg = ORC_REG_UNDEFINED;
 81		orc->ra_offset = 0;
 82		break;
 83	case CFI_CFA:
 84		orc->ra_reg = ORC_REG_PREV_SP;
 85		orc->ra_offset = ra->offset;
 86		break;
 87	case CFI_FP:
 88		orc->ra_reg = ORC_REG_FP;
 89		break;
 90	default:
 91		ERROR_INSN(insn, "unknown RA base reg %d", ra->base);
 92		return -1;
 93	}
 94
 95	orc->sp_offset = cfi->cfa.offset;
 96
 97	return 0;
 98}
 99
100int write_orc_entry(struct elf *elf, struct section *orc_sec,
101		    struct section *ip_sec, unsigned int idx,
102		    struct section *insn_sec, unsigned long insn_off,
103		    struct orc_entry *o)
104{
105	struct orc_entry *orc;
106
107	/* populate ORC data */
108	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
109	memcpy(orc, o, sizeof(*orc));
110
111	/* populate reloc for ip */
112	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
113				     insn_sec, insn_off))
114		return -1;
115
116	return 0;
117}
118
119static const char *reg_name(unsigned int reg)
120{
121	switch (reg) {
122	case ORC_REG_SP:
123		return "sp";
124	case ORC_REG_FP:
125		return "fp";
126	case ORC_REG_PREV_SP:
127		return "prevsp";
128	default:
129		return "?";
130	}
131}
132
133static const char *orc_type_name(unsigned int type)
134{
135	switch (type) {
136	case UNWIND_HINT_TYPE_CALL:
137		return "call";
138	case UNWIND_HINT_TYPE_REGS:
139		return "regs";
140	case UNWIND_HINT_TYPE_REGS_PARTIAL:
141		return "regs (partial)";
142	default:
143		return "?";
144	}
145}
146
147static void print_reg(unsigned int reg, int offset)
148{
149	if (reg == ORC_REG_UNDEFINED)
150		printf(" (und) ");
151	else
152		printf("%s + %3d", reg_name(reg), offset);
153
154}
155
156void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
157{
158	printf("type:%s", orc_type_name(orc[i].type));
159
160	printf(" sp:");
161	print_reg(orc[i].sp_reg, orc[i].sp_offset);
162
163	printf(" fp:");
164	print_reg(orc[i].fp_reg, orc[i].fp_offset);
165
166	printf(" ra:");
167	print_reg(orc[i].ra_reg, orc[i].ra_offset);
168
169	printf(" signal:%d\n", orc[i].signal);
170}