1 files changed, 109 insertions, 182 deletions

diff --git a/tools/objtool/orc_gen.c b/tools/objtool/orc_gen.c
index 3f98dcfbc177..1045e1380ffd 100644
--- a/tools/objtool/orc_gen.c
+++ b/tools/objtool/orc_gen.c
@@ -1,223 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2017 Josh Poimboeuf <jpoimboe@redhat.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version 2
- * of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <stdlib.h>
 #include <string.h>
 
-#include "orc.h"
-#include "check.h"
-#include "warn.h"
+#include <linux/objtool_types.h>
+#include <asm/orc_types.h>
 
-int create_orc(struct objtool_file *file)
-{
-	struct instruction *insn;
-
-	for_each_insn(file, insn) {
-		struct orc_entry *orc = &insn->orc;
-		struct cfi_reg *cfa = &insn->state.cfa;
-		struct cfi_reg *bp = &insn->state.regs[CFI_BP];
-
-		orc->end = insn->state.end;
-
-		if (cfa->base == CFI_UNDEFINED) {
-			orc->sp_reg = ORC_REG_UNDEFINED;
-			continue;
-		}
-
-		switch (cfa->base) {
-		case CFI_SP:
-			orc->sp_reg = ORC_REG_SP;
-			break;
-		case CFI_SP_INDIRECT:
-			orc->sp_reg = ORC_REG_SP_INDIRECT;
-			break;
-		case CFI_BP:
-			orc->sp_reg = ORC_REG_BP;
-			break;
-		case CFI_BP_INDIRECT:
-			orc->sp_reg = ORC_REG_BP_INDIRECT;
-			break;
-		case CFI_R10:
-			orc->sp_reg = ORC_REG_R10;
-			break;
-		case CFI_R13:
-			orc->sp_reg = ORC_REG_R13;
-			break;
-		case CFI_DI:
-			orc->sp_reg = ORC_REG_DI;
-			break;
-		case CFI_DX:
-			orc->sp_reg = ORC_REG_DX;
-			break;
-		default:
-			WARN_FUNC("unknown CFA base reg %d",
-				  insn->sec, insn->offset, cfa->base);
-			return -1;
-		}
-
-		switch(bp->base) {
-		case CFI_UNDEFINED:
-			orc->bp_reg = ORC_REG_UNDEFINED;
-			break;
-		case CFI_CFA:
-			orc->bp_reg = ORC_REG_PREV_SP;
-			break;
-		case CFI_BP:
-			orc->bp_reg = ORC_REG_BP;
-			break;
-		default:
-			WARN_FUNC("unknown BP base reg %d",
-				  insn->sec, insn->offset, bp->base);
-			return -1;
-		}
+#include <objtool/check.h>
+#include <objtool/orc.h>
+#include <objtool/warn.h>
 
-		orc->sp_offset = cfa->offset;
-		orc->bp_offset = bp->offset;
-		orc->type = insn->state.type;
-	}
-
-	return 0;
-}
+struct orc_list_entry {
+	struct list_head list;
+	struct orc_entry orc;
+	struct section *insn_sec;
+	unsigned long insn_off;
+};
 
-static int create_orc_entry(struct section *u_sec, struct section *ip_relasec,
-				unsigned int idx, struct section *insn_sec,
-				unsigned long insn_off, struct orc_entry *o)
+static int orc_list_add(struct list_head *orc_list, struct orc_entry *orc,
+			struct section *sec, unsigned long offset)
 {
-	struct orc_entry *orc;
-	struct rela *rela;
+	struct orc_list_entry *entry = malloc(sizeof(*entry));
 
-	if (!insn_sec->sym) {
-		WARN("missing symbol for section %s", insn_sec->name);
+	if (!entry) {
+		WARN("malloc failed");
 		return -1;
 	}
 
-	/* populate ORC data */
-	orc = (struct orc_entry *)u_sec->data->d_buf + idx;
-	memcpy(orc, o, sizeof(*orc));
-
-	/* populate rela for ip */
-	rela = malloc(sizeof(*rela));
-	if (!rela) {
-		perror("malloc");
-		return -1;
-	}
-	memset(rela, 0, sizeof(*rela));
-
-	rela->sym = insn_sec->sym;
-	rela->addend = insn_off;
-	rela->type = R_X86_64_PC32;
-	rela->offset = idx * sizeof(int);
-
-	list_add_tail(&rela->list, &ip_relasec->rela_list);
-	hash_add(ip_relasec->rela_hash, &rela->hash, rela->offset);
+	entry->orc	= *orc;
+	entry->insn_sec = sec;
+	entry->insn_off = offset;
 
+	list_add_tail(&entry->list, orc_list);
 	return 0;
 }
 
-int create_orc_sections(struct objtool_file *file)
+static unsigned long alt_group_len(struct alt_group *alt_group)
 {
-	struct instruction *insn, *prev_insn;
-	struct section *sec, *u_sec, *ip_relasec;
-	unsigned int idx;
-
-	struct orc_entry empty = {
-		.sp_reg = ORC_REG_UNDEFINED,
-		.bp_reg  = ORC_REG_UNDEFINED,
-		.type    = ORC_TYPE_CALL,
-	};
-
-	sec = find_section_by_name(file->elf, ".orc_unwind");
-	if (sec) {
-		WARN("file already has .orc_unwind section, skipping");
-		return -1;
-	}
-
-	/* count the number of needed orcs */
-	idx = 0;
-	for_each_sec(file, sec) {
-		if (!sec->text)
-			continue;
-
-		prev_insn = NULL;
-		sec_for_each_insn(file, sec, insn) {
-			if (!prev_insn ||
-			    memcmp(&insn->orc, &prev_insn->orc,
-				   sizeof(struct orc_entry))) {
-				idx++;
-			}
-			prev_insn = insn;
-		}
-
-		/* section terminator */
-		if (prev_insn)
-			idx++;
-	}
-	if (!idx)
-		return -1;
-
+	return alt_group->last_insn->offset +
+	       alt_group->last_insn->len -
+	       alt_group->first_insn->offset;
+}
 
-	/* create .orc_unwind_ip and .rela.orc_unwind_ip sections */
-	sec = elf_create_section(file->elf, ".orc_unwind_ip", sizeof(int), idx);
-	if (!sec)
-		return -1;
+int orc_create(struct objtool_file *file)
+{
+	struct section *sec, *orc_sec;
+	unsigned int nr = 0, idx = 0;
+	struct orc_list_entry *entry;
+	struct list_head orc_list;
 
-	ip_relasec = elf_create_rela_section(file->elf, sec);
-	if (!ip_relasec)
-		return -1;
+	struct orc_entry null = { .type = ORC_TYPE_UNDEFINED };
 
-	/* create .orc_unwind section */
-	u_sec = elf_create_section(file->elf, ".orc_unwind",
-				   sizeof(struct orc_entry), idx);
+	/* Build a deduplicated list of ORC entries: */
+	INIT_LIST_HEAD(&orc_list);
+	for_each_sec(file->elf, sec) {
+		struct orc_entry orc, prev_orc = {0};
+		struct instruction *insn;
+		bool empty = true;
 
-	/* populate sections */
-	idx = 0;
-	for_each_sec(file, sec) {
 		if (!sec->text)
 			continue;
 
-		prev_insn = NULL;
 		sec_for_each_insn(file, sec, insn) {
-			if (!prev_insn || memcmp(&insn->orc, &prev_insn->orc,
-						 sizeof(struct orc_entry))) {
+			struct alt_group *alt_group = insn->alt_group;
+			int i;
 
-				if (create_orc_entry(u_sec, ip_relasec, idx,
-						     insn->sec, insn->offset,
-						     &insn->orc))
+			if (!alt_group) {
+				if (init_orc_entry(&orc, insn->cfi, insn))
+					return -1;
+				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+					continue;
+				if (orc_list_add(&orc_list, &orc, sec,
+						 insn->offset))
 					return -1;
+				nr++;
+				prev_orc = orc;
+				empty = false;
+				continue;
+			}
 
-				idx++;
+			/*
+			 * Alternatives can have different stack layout
+			 * possibilities (but they shouldn't conflict).
+			 * Instead of traversing the instructions, use the
+			 * alt_group's flattened byte-offset-addressed CFI
+			 * array.
+			 */
+			for (i = 0; i < alt_group_len(alt_group); i++) {
+				struct cfi_state *cfi = alt_group->cfi[i];
+				if (!cfi)
+					continue;
+				/* errors are reported on the original insn */
+				if (init_orc_entry(&orc, cfi, insn))
+					return -1;
+				if (!memcmp(&prev_orc, &orc, sizeof(orc)))
+					continue;
+				if (orc_list_add(&orc_list, &orc, insn->sec,
+						 insn->offset + i))
+					return -1;
+				nr++;
+				prev_orc = orc;
+				empty = false;
 			}
-			prev_insn = insn;
-		}
 
-		/* section terminator */
-		if (prev_insn) {
-			if (create_orc_entry(u_sec, ip_relasec, idx,
-					     prev_insn->sec,
-					     prev_insn->offset + prev_insn->len,
-					     &empty))
-				return -1;
+			/* Skip to the end of the alt_group */
+			insn = alt_group->last_insn;
+		}
 
-			idx++;
+		/* Add a section terminator */
+		if (!empty) {
+			orc_list_add(&orc_list, &null, sec, sec->sh.sh_size);
+			nr++;
 		}
 	}
+	if (!nr)
+		return 0;
 
-	if (elf_rebuild_rela_section(ip_relasec))
+	/* Create .orc_unwind, .orc_unwind_ip and .rela.orc_unwind_ip sections: */
+	sec = find_section_by_name(file->elf, ".orc_unwind");
+	if (sec) {
+		WARN("file already has .orc_unwind section, skipping");
 		return -1;
+	}
+	orc_sec = elf_create_section(file->elf, ".orc_unwind",
+				     nr * sizeof(struct orc_entry),
+				     sizeof(struct orc_entry),
+				     SHT_PROGBITS,
+				     1,
+				     SHF_ALLOC);
+	if (!orc_sec)
+		return -1;
+
+	sec = elf_create_section_pair(file->elf, ".orc_unwind_ip", sizeof(int), nr, nr);
+	if (!sec)
+		return -1;
+
+	/* Write ORC entries to sections: */
+	list_for_each_entry(entry, &orc_list, list) {
+		if (write_orc_entry(file->elf, orc_sec, sec, idx++,
+				    entry->insn_sec, entry->insn_off,
+				    &entry->orc))
+			return -1;
+	}
 
 	return 0;
 }