Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 4818 insertions, 0 deletions

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
new file mode 100644
index 0000000000..e308d1ba66
--- /dev/null
+++ b/tools/objtool/check.c
@@ -0,0 +1,4818 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2015-2017 Josh Poimboeuf <jpoimboe@redhat.com>
+ */
+
+#include <string.h>
+#include <stdlib.h>
+#include <inttypes.h>
+#include <sys/mman.h>
+
+#include <objtool/builtin.h>
+#include <objtool/cfi.h>
+#include <objtool/arch.h>
+#include <objtool/check.h>
+#include <objtool/special.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+#include <linux/objtool_types.h>
+#include <linux/hashtable.h>
+#include <linux/kernel.h>
+#include <linux/static_call_types.h>
+
+struct alternative {
+	struct alternative *next;
+	struct instruction *insn;
+	bool skip_orig;
+};
+
+static unsigned long nr_cfi, nr_cfi_reused, nr_cfi_cache;
+
+static struct cfi_init_state initial_func_cfi;
+static struct cfi_state init_cfi;
+static struct cfi_state func_cfi;
+static struct cfi_state force_undefined_cfi;
+
+struct instruction *find_insn(struct objtool_file *file,
+			      struct section *sec, unsigned long offset)
+{
+	struct instruction *insn;
+
+	hash_for_each_possible(file->insn_hash, insn, hash, sec_offset_hash(sec, offset)) {
+		if (insn->sec == sec && insn->offset == offset)
+			return insn;
+	}
+
+	return NULL;
+}
+
+struct instruction *next_insn_same_sec(struct objtool_file *file,
+				       struct instruction *insn)
+{
+	if (insn->idx == INSN_CHUNK_MAX)
+		return find_insn(file, insn->sec, insn->offset + insn->len);
+
+	insn++;
+	if (!insn->len)
+		return NULL;
+
+	return insn;
+}
+
+static struct instruction *next_insn_same_func(struct objtool_file *file,
+					       struct instruction *insn)
+{
+	struct instruction *next = next_insn_same_sec(file, insn);
+	struct symbol *func = insn_func(insn);
+
+	if (!func)
+		return NULL;
+
+	if (next && insn_func(next) == func)
+		return next;
+
+	/* Check if we're already in the subfunction: */
+	if (func == func->cfunc)
+		return NULL;
+
+	/* Move to the subfunction: */
+	return find_insn(file, func->cfunc->sec, func->cfunc->offset);
+}
+
+static struct instruction *prev_insn_same_sec(struct objtool_file *file,
+					      struct instruction *insn)
+{
+	if (insn->idx == 0) {
+		if (insn->prev_len)
+			return find_insn(file, insn->sec, insn->offset - insn->prev_len);
+		return NULL;
+	}
+
+	return insn - 1;
+}
+
+static struct instruction *prev_insn_same_sym(struct objtool_file *file,
+					      struct instruction *insn)
+{
+	struct instruction *prev = prev_insn_same_sec(file, insn);
+
+	if (prev && insn_func(prev) == insn_func(insn))
+		return prev;
+
+	return NULL;
+}
+
+#define for_each_insn(file, insn)					\
+	for (struct section *__sec, *__fake = (struct section *)1;	\
+	     __fake; __fake = NULL)					\
+		for_each_sec(file, __sec)				\
+			sec_for_each_insn(file, __sec, insn)
+
+#define func_for_each_insn(file, func, insn)				\
+	for (insn = find_insn(file, func->sec, func->offset);		\
+	     insn;							\
+	     insn = next_insn_same_func(file, insn))
+
+#define sym_for_each_insn(file, sym, insn)				\
+	for (insn = find_insn(file, sym->sec, sym->offset);		\
+	     insn && insn->offset < sym->offset + sym->len;		\
+	     insn = next_insn_same_sec(file, insn))
+
+#define sym_for_each_insn_continue_reverse(file, sym, insn)		\
+	for (insn = prev_insn_same_sec(file, insn);			\
+	     insn && insn->offset >= sym->offset;			\
+	     insn = prev_insn_same_sec(file, insn))
+
+#define sec_for_each_insn_from(file, insn)				\
+	for (; insn; insn = next_insn_same_sec(file, insn))
+
+#define sec_for_each_insn_continue(file, insn)				\
+	for (insn = next_insn_same_sec(file, insn); insn;		\
+	     insn = next_insn_same_sec(file, insn))
+
+static inline struct symbol *insn_call_dest(struct instruction *insn)
+{
+	if (insn->type == INSN_JUMP_DYNAMIC ||
+	    insn->type == INSN_CALL_DYNAMIC)
+		return NULL;
+
+	return insn->_call_dest;
+}
+
+static inline struct reloc *insn_jump_table(struct instruction *insn)
+{
+	if (insn->type == INSN_JUMP_DYNAMIC ||
+	    insn->type == INSN_CALL_DYNAMIC)
+		return insn->_jump_table;
+
+	return NULL;
+}
+
+static bool is_jump_table_jump(struct instruction *insn)
+{
+	struct alt_group *alt_group = insn->alt_group;
+
+	if (insn_jump_table(insn))
+		return true;
+
+	/* Retpoline alternative for a jump table? */
+	return alt_group && alt_group->orig_group &&
+	       insn_jump_table(alt_group->orig_group->first_insn);
+}
+
+static bool is_sibling_call(struct instruction *insn)
+{
+	/*
+	 * Assume only STT_FUNC calls have jump-tables.
+	 */
+	if (insn_func(insn)) {
+		/* An indirect jump is either a sibling call or a jump to a table. */
+		if (insn->type == INSN_JUMP_DYNAMIC)
+			return !is_jump_table_jump(insn);
+	}
+
+	/* add_jump_destinations() sets insn_call_dest(insn) for sibling calls. */
+	return (is_static_jump(insn) && insn_call_dest(insn));
+}
+
+/*
+ * This checks to see if the given function is a "noreturn" function.
+ *
+ * For global functions which are outside the scope of this object file, we
+ * have to keep a manual list of them.
+ *
+ * For local functions, we have to detect them manually by simply looking for
+ * the lack of a return instruction.
+ */
+static bool __dead_end_function(struct objtool_file *file, struct symbol *func,
+				int recursion)
+{
+	int i;
+	struct instruction *insn;
+	bool empty = true;
+
+#define NORETURN(func) __stringify(func),
+	static const char * const global_noreturns[] = {
+#include "noreturns.h"
+	};
+#undef NORETURN
+
+	if (!func)
+		return false;
+
+	if (func->bind == STB_GLOBAL || func->bind == STB_WEAK)
+		for (i = 0; i < ARRAY_SIZE(global_noreturns); i++)
+			if (!strcmp(func->name, global_noreturns[i]))
+				return true;
+
+	if (func->bind == STB_WEAK)
+		return false;
+
+	if (!func->len)
+		return false;
+
+	insn = find_insn(file, func->sec, func->offset);
+	if (!insn || !insn_func(insn))
+		return false;
+
+	func_for_each_insn(file, func, insn) {
+		empty = false;
+
+		if (insn->type == INSN_RETURN)
+			return false;
+	}
+
+	if (empty)
+		return false;
+
+	/*
+	 * A function can have a sibling call instead of a return.  In that
+	 * case, the function's dead-end status depends on whether the target
+	 * of the sibling call returns.
+	 */
+	func_for_each_insn(file, func, insn) {
+		if (is_sibling_call(insn)) {
+			struct instruction *dest = insn->jump_dest;
+
+			if (!dest)
+				/* sibling call to another file */
+				return false;
+
+			/* local sibling call */
+			if (recursion == 5) {
+				/*
+				 * Infinite recursion: two functions have
+				 * sibling calls to each other.  This is a very
+				 * rare case.  It means they aren't dead ends.
+				 */
+				return false;
+			}
+
+			return __dead_end_function(file, insn_func(dest), recursion+1);
+		}
+	}
+
+	return true;
+}
+
+static bool dead_end_function(struct objtool_file *file, struct symbol *func)
+{
+	return __dead_end_function(file, func, 0);
+}
+
+static void init_cfi_state(struct cfi_state *cfi)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		cfi->regs[i].base = CFI_UNDEFINED;
+		cfi->vals[i].base = CFI_UNDEFINED;
+	}
+	cfi->cfa.base = CFI_UNDEFINED;
+	cfi->drap_reg = CFI_UNDEFINED;
+	cfi->drap_offset = -1;
+}
+
+static void init_insn_state(struct objtool_file *file, struct insn_state *state,
+			    struct section *sec)
+{
+	memset(state, 0, sizeof(*state));
+	init_cfi_state(&state->cfi);
+
+	/*
+	 * We need the full vmlinux for noinstr validation, otherwise we can
+	 * not correctly determine insn_call_dest(insn)->sec (external symbols
+	 * do not have a section).
+	 */
+	if (opts.link && opts.noinstr && sec)
+		state->noinstr = sec->noinstr;
+}
+
+static struct cfi_state *cfi_alloc(void)
+{
+	struct cfi_state *cfi = calloc(sizeof(struct cfi_state), 1);
+	if (!cfi) {
+		WARN("calloc failed");
+		exit(1);
+	}
+	nr_cfi++;
+	return cfi;
+}
+
+static int cfi_bits;
+static struct hlist_head *cfi_hash;
+
+static inline bool cficmp(struct cfi_state *cfi1, struct cfi_state *cfi2)
+{
+	return memcmp((void *)cfi1 + sizeof(cfi1->hash),
+		      (void *)cfi2 + sizeof(cfi2->hash),
+		      sizeof(struct cfi_state) - sizeof(struct hlist_node));
+}
+
+static inline u32 cfi_key(struct cfi_state *cfi)
+{
+	return jhash((void *)cfi + sizeof(cfi->hash),
+		     sizeof(*cfi) - sizeof(cfi->hash), 0);
+}
+
+static struct cfi_state *cfi_hash_find_or_add(struct cfi_state *cfi)
+{
+	struct hlist_head *head = &cfi_hash[hash_min(cfi_key(cfi), cfi_bits)];
+	struct cfi_state *obj;
+
+	hlist_for_each_entry(obj, head, hash) {
+		if (!cficmp(cfi, obj)) {
+			nr_cfi_cache++;
+			return obj;
+		}
+	}
+
+	obj = cfi_alloc();
+	*obj = *cfi;
+	hlist_add_head(&obj->hash, head);
+
+	return obj;
+}
+
+static void cfi_hash_add(struct cfi_state *cfi)
+{
+	struct hlist_head *head = &cfi_hash[hash_min(cfi_key(cfi), cfi_bits)];
+
+	hlist_add_head(&cfi->hash, head);
+}
+
+static void *cfi_hash_alloc(unsigned long size)
+{
+	cfi_bits = max(10, ilog2(size));
+	cfi_hash = mmap(NULL, sizeof(struct hlist_head) << cfi_bits,
+			PROT_READ|PROT_WRITE,
+			MAP_PRIVATE|MAP_ANON, -1, 0);
+	if (cfi_hash == (void *)-1L) {
+		WARN("mmap fail cfi_hash");
+		cfi_hash = NULL;
+	}  else if (opts.stats) {
+		printf("cfi_bits: %d\n", cfi_bits);
+	}
+
+	return cfi_hash;
+}
+
+static unsigned long nr_insns;
+static unsigned long nr_insns_visited;
+
+/*
+ * Call the arch-specific instruction decoder for all the instructions and add
+ * them to the global instruction list.
+ */
+static int decode_instructions(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *func;
+	unsigned long offset;
+	struct instruction *insn;
+	int ret;
+
+	for_each_sec(file, sec) {
+		struct instruction *insns = NULL;
+		u8 prev_len = 0;
+		u8 idx = 0;
+
+		if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+			continue;
+
+		if (strcmp(sec->name, ".altinstr_replacement") &&
+		    strcmp(sec->name, ".altinstr_aux") &&
+		    strncmp(sec->name, ".discard.", 9))
+			sec->text = true;
+
+		if (!strcmp(sec->name, ".noinstr.text") ||
+		    !strcmp(sec->name, ".entry.text") ||
+		    !strcmp(sec->name, ".cpuidle.text") ||
+		    !strncmp(sec->name, ".text..__x86.", 13))
+			sec->noinstr = true;
+
+		/*
+		 * .init.text code is ran before userspace and thus doesn't
+		 * strictly need retpolines, except for modules which are
+		 * loaded late, they very much do need retpoline in their
+		 * .init.text
+		 */
+		if (!strcmp(sec->name, ".init.text") && !opts.module)
+			sec->init = true;
+
+		for (offset = 0; offset < sec->sh.sh_size; offset += insn->len) {
+			if (!insns || idx == INSN_CHUNK_MAX) {
+				insns = calloc(sizeof(*insn), INSN_CHUNK_SIZE);
+				if (!insns) {
+					WARN("malloc failed");
+					return -1;
+				}
+				idx = 0;
+			} else {
+				idx++;
+			}
+			insn = &insns[idx];
+			insn->idx = idx;
+
+			INIT_LIST_HEAD(&insn->call_node);
+			insn->sec = sec;
+			insn->offset = offset;
+			insn->prev_len = prev_len;
+
+			ret = arch_decode_instruction(file, sec, offset,
+						      sec->sh.sh_size - offset,
+						      insn);
+			if (ret)
+				return ret;
+
+			prev_len = insn->len;
+
+			/*
+			 * By default, "ud2" is a dead end unless otherwise
+			 * annotated, because GCC 7 inserts it for certain
+			 * divide-by-zero cases.
+			 */
+			if (insn->type == INSN_BUG)
+				insn->dead_end = true;
+
+			hash_add(file->insn_hash, &insn->hash, sec_offset_hash(sec, insn->offset));
+			nr_insns++;
+		}
+
+//		printf("%s: last chunk used: %d\n", sec->name, (int)idx);
+
+		sec_for_each_sym(sec, func) {
+			if (func->type != STT_NOTYPE && func->type != STT_FUNC)
+				continue;
+
+			if (func->offset == sec->sh.sh_size) {
+				/* Heuristic: likely an "end" symbol */
+				if (func->type == STT_NOTYPE)
+					continue;
+				WARN("%s(): STT_FUNC at end of section",
+				     func->name);
+				return -1;
+			}
+
+			if (func->embedded_insn || func->alias != func)
+				continue;
+
+			if (!find_insn(file, sec, func->offset)) {
+				WARN("%s(): can't find starting instruction",
+				     func->name);
+				return -1;
+			}
+
+			sym_for_each_insn(file, func, insn) {
+				insn->sym = func;
+				if (func->type == STT_FUNC &&
+				    insn->type == INSN_ENDBR &&
+				    list_empty(&insn->call_node)) {
+					if (insn->offset == func->offset) {
+						list_add_tail(&insn->call_node, &file->endbr_list);
+						file->nr_endbr++;
+					} else {
+						file->nr_endbr_int++;
+					}
+				}
+			}
+		}
+	}
+
+	if (opts.stats)
+		printf("nr_insns: %lu\n", nr_insns);
+
+	return 0;
+}
+
+/*
+ * Read the pv_ops[] .data table to find the static initialized values.
+ */
+static int add_pv_ops(struct objtool_file *file, const char *symname)
+{
+	struct symbol *sym, *func;
+	unsigned long off, end;
+	struct reloc *reloc;
+	int idx;
+
+	sym = find_symbol_by_name(file->elf, symname);
+	if (!sym)
+		return 0;
+
+	off = sym->offset;
+	end = off + sym->len;
+	for (;;) {
+		reloc = find_reloc_by_dest_range(file->elf, sym->sec, off, end - off);
+		if (!reloc)
+			break;
+
+		func = reloc->sym;
+		if (func->type == STT_SECTION)
+			func = find_symbol_by_offset(reloc->sym->sec,
+						     reloc_addend(reloc));
+
+		idx = (reloc_offset(reloc) - sym->offset) / sizeof(unsigned long);
+
+		objtool_pv_add(file, idx, func);
+
+		off = reloc_offset(reloc) + 1;
+		if (off > end)
+			break;
+	}
+
+	return 0;
+}
+
+/*
+ * Allocate and initialize file->pv_ops[].
+ */
+static int init_pv_ops(struct objtool_file *file)
+{
+	static const char *pv_ops_tables[] = {
+		"pv_ops",
+		"xen_cpu_ops",
+		"xen_irq_ops",
+		"xen_mmu_ops",
+		NULL,
+	};
+	const char *pv_ops;
+	struct symbol *sym;
+	int idx, nr;
+
+	if (!opts.noinstr)
+		return 0;
+
+	file->pv_ops = NULL;
+
+	sym = find_symbol_by_name(file->elf, "pv_ops");
+	if (!sym)
+		return 0;
+
+	nr = sym->len / sizeof(unsigned long);
+	file->pv_ops = calloc(sizeof(struct pv_state), nr);
+	if (!file->pv_ops)
+		return -1;
+
+	for (idx = 0; idx < nr; idx++)
+		INIT_LIST_HEAD(&file->pv_ops[idx].targets);
+
+	for (idx = 0; (pv_ops = pv_ops_tables[idx]); idx++)
+		add_pv_ops(file, pv_ops);
+
+	return 0;
+}
+
+static struct instruction *find_last_insn(struct objtool_file *file,
+					  struct section *sec)
+{
+	struct instruction *insn = NULL;
+	unsigned int offset;
+	unsigned int end = (sec->sh.sh_size > 10) ? sec->sh.sh_size - 10 : 0;
+
+	for (offset = sec->sh.sh_size - 1; offset >= end && !insn; offset--)
+		insn = find_insn(file, sec, offset);
+
+	return insn;
+}
+
+/*
+ * Mark "ud2" instructions and manually annotated dead ends.
+ */
+static int add_dead_ends(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+	struct instruction *insn;
+	s64 addend;
+
+	/*
+	 * Check for manually annotated dead ends.
+	 */
+	rsec = find_section_by_name(file->elf, ".rela.discard.unreachable");
+	if (!rsec)
+		goto reachable;
+
+	for_each_reloc(rsec, reloc) {
+
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		addend = reloc_addend(reloc);
+
+		insn = find_insn(file, reloc->sym->sec, addend);
+		if (insn)
+			insn = prev_insn_same_sec(file, insn);
+		else if (addend == reloc->sym->sec->sh.sh_size) {
+			insn = find_last_insn(file, reloc->sym->sec);
+			if (!insn) {
+				WARN("can't find unreachable insn at %s+0x%" PRIx64,
+				     reloc->sym->sec->name, addend);
+				return -1;
+			}
+		} else {
+			WARN("can't find unreachable insn at %s+0x%" PRIx64,
+			     reloc->sym->sec->name, addend);
+			return -1;
+		}
+
+		insn->dead_end = true;
+	}
+
+reachable:
+	/*
+	 * These manually annotated reachable checks are needed for GCC 4.4,
+	 * where the Linux unreachable() macro isn't supported.  In that case
+	 * GCC doesn't know the "ud2" is fatal, so it generates code as if it's
+	 * not a dead end.
+	 */
+	rsec = find_section_by_name(file->elf, ".rela.discard.reachable");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		addend = reloc_addend(reloc);
+
+		insn = find_insn(file, reloc->sym->sec, addend);
+		if (insn)
+			insn = prev_insn_same_sec(file, insn);
+		else if (addend == reloc->sym->sec->sh.sh_size) {
+			insn = find_last_insn(file, reloc->sym->sec);
+			if (!insn) {
+				WARN("can't find reachable insn at %s+0x%" PRIx64,
+				     reloc->sym->sec->name, addend);
+				return -1;
+			}
+		} else {
+			WARN("can't find reachable insn at %s+0x%" PRIx64,
+			     reloc->sym->sec->name, addend);
+			return -1;
+		}
+
+		insn->dead_end = false;
+	}
+
+	return 0;
+}
+
+static int create_static_call_sections(struct objtool_file *file)
+{
+	struct static_call_site *site;
+	struct section *sec;
+	struct instruction *insn;
+	struct symbol *key_sym;
+	char *key_name, *tmp;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".static_call_sites");
+	if (sec) {
+		INIT_LIST_HEAD(&file->static_call_list);
+		WARN("file already has .static_call_sites section, skipping");
+		return 0;
+	}
+
+	if (list_empty(&file->static_call_list))
+		return 0;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->static_call_list, call_node)
+		idx++;
+
+	sec = elf_create_section_pair(file->elf, ".static_call_sites",
+				      sizeof(*site), idx, idx * 2);
+	if (!sec)
+		return -1;
+
+	/* Allow modules to modify the low bits of static_call_site::key */
+	sec->sh.sh_flags |= SHF_WRITE;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->static_call_list, call_node) {
+
+		/* populate reloc for 'addr' */
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(*site), idx * 2,
+					     insn->sec, insn->offset))
+			return -1;
+
+		/* find key symbol */
+		key_name = strdup(insn_call_dest(insn)->name);
+		if (!key_name) {
+			perror("strdup");
+			return -1;
+		}
+		if (strncmp(key_name, STATIC_CALL_TRAMP_PREFIX_STR,
+			    STATIC_CALL_TRAMP_PREFIX_LEN)) {
+			WARN("static_call: trampoline name malformed: %s", key_name);
+			free(key_name);
+			return -1;
+		}
+		tmp = key_name + STATIC_CALL_TRAMP_PREFIX_LEN - STATIC_CALL_KEY_PREFIX_LEN;
+		memcpy(tmp, STATIC_CALL_KEY_PREFIX_STR, STATIC_CALL_KEY_PREFIX_LEN);
+
+		key_sym = find_symbol_by_name(file->elf, tmp);
+		if (!key_sym) {
+			if (!opts.module) {
+				WARN("static_call: can't find static_call_key symbol: %s", tmp);
+				free(key_name);
+				return -1;
+			}
+
+			/*
+			 * For modules(), the key might not be exported, which
+			 * means the module can make static calls but isn't
+			 * allowed to change them.
+			 *
+			 * In that case we temporarily set the key to be the
+			 * trampoline address.  This is fixed up in
+			 * static_call_add_module().
+			 */
+			key_sym = insn_call_dest(insn);
+		}
+		free(key_name);
+
+		/* populate reloc for 'key' */
+		if (!elf_init_reloc_data_sym(file->elf, sec,
+					     idx * sizeof(*site) + 4,
+					     (idx * 2) + 1, key_sym,
+					     is_sibling_call(insn) * STATIC_CALL_SITE_TAIL))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_retpoline_sites_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".retpoline_sites");
+	if (sec) {
+		WARN("file already has .retpoline_sites, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	list_for_each_entry(insn, &file->retpoline_call_list, call_node)
+		idx++;
+
+	if (!idx)
+		return 0;
+
+	sec = elf_create_section_pair(file->elf, ".retpoline_sites",
+				      sizeof(int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->retpoline_call_list, call_node) {
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_return_sites_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".return_sites");
+	if (sec) {
+		WARN("file already has .return_sites, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	list_for_each_entry(insn, &file->return_thunk_list, call_node)
+		idx++;
+
+	if (!idx)
+		return 0;
+
+	sec = elf_create_section_pair(file->elf, ".return_sites",
+				      sizeof(int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->return_thunk_list, call_node) {
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_ibt_endbr_seal_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".ibt_endbr_seal");
+	if (sec) {
+		WARN("file already has .ibt_endbr_seal, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	list_for_each_entry(insn, &file->endbr_list, call_node)
+		idx++;
+
+	if (opts.stats) {
+		printf("ibt: ENDBR at function start: %d\n", file->nr_endbr);
+		printf("ibt: ENDBR inside functions:  %d\n", file->nr_endbr_int);
+		printf("ibt: superfluous ENDBR:       %d\n", idx);
+	}
+
+	if (!idx)
+		return 0;
+
+	sec = elf_create_section_pair(file->elf, ".ibt_endbr_seal",
+				      sizeof(int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->endbr_list, call_node) {
+
+		int *site = (int *)sec->data->d_buf + idx;
+		struct symbol *sym = insn->sym;
+		*site = 0;
+
+		if (opts.module && sym && sym->type == STT_FUNC &&
+		    insn->offset == sym->offset &&
+		    (!strcmp(sym->name, "init_module") ||
+		     !strcmp(sym->name, "cleanup_module")))
+			WARN("%s(): not an indirect call target", sym->name);
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_cfi_sections(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *sym;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".cfi_sites");
+	if (sec) {
+		INIT_LIST_HEAD(&file->call_list);
+		WARN("file already has .cfi_sites section, skipping");
+		return 0;
+	}
+
+	idx = 0;
+	for_each_sym(file, sym) {
+		if (sym->type != STT_FUNC)
+			continue;
+
+		if (strncmp(sym->name, "__cfi_", 6))
+			continue;
+
+		idx++;
+	}
+
+	sec = elf_create_section_pair(file->elf, ".cfi_sites",
+				      sizeof(unsigned int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	for_each_sym(file, sym) {
+		if (sym->type != STT_FUNC)
+			continue;
+
+		if (strncmp(sym->name, "__cfi_", 6))
+			continue;
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(unsigned int), idx,
+					     sym->sec, sym->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_mcount_loc_sections(struct objtool_file *file)
+{
+	size_t addr_size = elf_addr_size(file->elf);
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, "__mcount_loc");
+	if (sec) {
+		INIT_LIST_HEAD(&file->mcount_loc_list);
+		WARN("file already has __mcount_loc section, skipping");
+		return 0;
+	}
+
+	if (list_empty(&file->mcount_loc_list))
+		return 0;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->mcount_loc_list, call_node)
+		idx++;
+
+	sec = elf_create_section_pair(file->elf, "__mcount_loc", addr_size,
+				      idx, idx);
+	if (!sec)
+		return -1;
+
+	sec->sh.sh_addralign = addr_size;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->mcount_loc_list, call_node) {
+
+		struct reloc *reloc;
+
+		reloc = elf_init_reloc_text_sym(file->elf, sec, idx * addr_size, idx,
+					       insn->sec, insn->offset);
+		if (!reloc)
+			return -1;
+
+		set_reloc_type(file->elf, reloc, addr_size == 8 ? R_ABS64 : R_ABS32);
+
+		idx++;
+	}
+
+	return 0;
+}
+
+static int create_direct_call_sections(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *sec;
+	int idx;
+
+	sec = find_section_by_name(file->elf, ".call_sites");
+	if (sec) {
+		INIT_LIST_HEAD(&file->call_list);
+		WARN("file already has .call_sites section, skipping");
+		return 0;
+	}
+
+	if (list_empty(&file->call_list))
+		return 0;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->call_list, call_node)
+		idx++;
+
+	sec = elf_create_section_pair(file->elf, ".call_sites",
+				      sizeof(unsigned int), idx, idx);
+	if (!sec)
+		return -1;
+
+	idx = 0;
+	list_for_each_entry(insn, &file->call_list, call_node) {
+
+		if (!elf_init_reloc_text_sym(file->elf, sec,
+					     idx * sizeof(unsigned int), idx,
+					     insn->sec, insn->offset))
+			return -1;
+
+		idx++;
+	}
+
+	return 0;
+}
+
+/*
+ * Warnings shouldn't be reported for ignored functions.
+ */
+static void add_ignores(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *rsec;
+	struct symbol *func;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.func_stack_frame_non_standard");
+	if (!rsec)
+		return;
+
+	for_each_reloc(rsec, reloc) {
+		switch (reloc->sym->type) {
+		case STT_FUNC:
+			func = reloc->sym;
+			break;
+
+		case STT_SECTION:
+			func = find_func_by_offset(reloc->sym->sec, reloc_addend(reloc));
+			if (!func)
+				continue;
+			break;
+
+		default:
+			WARN("unexpected relocation symbol type in %s: %d",
+			     rsec->name, reloc->sym->type);
+			continue;
+		}
+
+		func_for_each_insn(file, func, insn)
+			insn->ignore = true;
+	}
+}
+
+/*
+ * This is a whitelist of functions that is allowed to be called with AC set.
+ * The list is meant to be minimal and only contains compiler instrumentation
+ * ABI and a few functions used to implement *_{to,from}_user() functions.
+ *
+ * These functions must not directly change AC, but may PUSHF/POPF.
+ */
+static const char *uaccess_safe_builtin[] = {
+	/* KASAN */
+	"kasan_report",
+	"kasan_check_range",
+	/* KASAN out-of-line */
+	"__asan_loadN_noabort",
+	"__asan_load1_noabort",
+	"__asan_load2_noabort",
+	"__asan_load4_noabort",
+	"__asan_load8_noabort",
+	"__asan_load16_noabort",
+	"__asan_storeN_noabort",
+	"__asan_store1_noabort",
+	"__asan_store2_noabort",
+	"__asan_store4_noabort",
+	"__asan_store8_noabort",
+	"__asan_store16_noabort",
+	"__kasan_check_read",
+	"__kasan_check_write",
+	/* KASAN in-line */
+	"__asan_report_load_n_noabort",
+	"__asan_report_load1_noabort",
+	"__asan_report_load2_noabort",
+	"__asan_report_load4_noabort",
+	"__asan_report_load8_noabort",
+	"__asan_report_load16_noabort",
+	"__asan_report_store_n_noabort",
+	"__asan_report_store1_noabort",
+	"__asan_report_store2_noabort",
+	"__asan_report_store4_noabort",
+	"__asan_report_store8_noabort",
+	"__asan_report_store16_noabort",
+	/* KCSAN */
+	"__kcsan_check_access",
+	"__kcsan_mb",
+	"__kcsan_wmb",
+	"__kcsan_rmb",
+	"__kcsan_release",
+	"kcsan_found_watchpoint",
+	"kcsan_setup_watchpoint",
+	"kcsan_check_scoped_accesses",
+	"kcsan_disable_current",
+	"kcsan_enable_current_nowarn",
+	/* KCSAN/TSAN */
+	"__tsan_func_entry",
+	"__tsan_func_exit",
+	"__tsan_read_range",
+	"__tsan_write_range",
+	"__tsan_read1",
+	"__tsan_read2",
+	"__tsan_read4",
+	"__tsan_read8",
+	"__tsan_read16",
+	"__tsan_write1",
+	"__tsan_write2",
+	"__tsan_write4",
+	"__tsan_write8",
+	"__tsan_write16",
+	"__tsan_read_write1",
+	"__tsan_read_write2",
+	"__tsan_read_write4",
+	"__tsan_read_write8",
+	"__tsan_read_write16",
+	"__tsan_volatile_read1",
+	"__tsan_volatile_read2",
+	"__tsan_volatile_read4",
+	"__tsan_volatile_read8",
+	"__tsan_volatile_read16",
+	"__tsan_volatile_write1",
+	"__tsan_volatile_write2",
+	"__tsan_volatile_write4",
+	"__tsan_volatile_write8",
+	"__tsan_volatile_write16",
+	"__tsan_atomic8_load",
+	"__tsan_atomic16_load",
+	"__tsan_atomic32_load",
+	"__tsan_atomic64_load",
+	"__tsan_atomic8_store",
+	"__tsan_atomic16_store",
+	"__tsan_atomic32_store",
+	"__tsan_atomic64_store",
+	"__tsan_atomic8_exchange",
+	"__tsan_atomic16_exchange",
+	"__tsan_atomic32_exchange",
+	"__tsan_atomic64_exchange",
+	"__tsan_atomic8_fetch_add",
+	"__tsan_atomic16_fetch_add",
+	"__tsan_atomic32_fetch_add",
+	"__tsan_atomic64_fetch_add",
+	"__tsan_atomic8_fetch_sub",
+	"__tsan_atomic16_fetch_sub",
+	"__tsan_atomic32_fetch_sub",
+	"__tsan_atomic64_fetch_sub",
+	"__tsan_atomic8_fetch_and",
+	"__tsan_atomic16_fetch_and",
+	"__tsan_atomic32_fetch_and",
+	"__tsan_atomic64_fetch_and",
+	"__tsan_atomic8_fetch_or",
+	"__tsan_atomic16_fetch_or",
+	"__tsan_atomic32_fetch_or",
+	"__tsan_atomic64_fetch_or",
+	"__tsan_atomic8_fetch_xor",
+	"__tsan_atomic16_fetch_xor",
+	"__tsan_atomic32_fetch_xor",
+	"__tsan_atomic64_fetch_xor",
+	"__tsan_atomic8_fetch_nand",
+	"__tsan_atomic16_fetch_nand",
+	"__tsan_atomic32_fetch_nand",
+	"__tsan_atomic64_fetch_nand",
+	"__tsan_atomic8_compare_exchange_strong",
+	"__tsan_atomic16_compare_exchange_strong",
+	"__tsan_atomic32_compare_exchange_strong",
+	"__tsan_atomic64_compare_exchange_strong",
+	"__tsan_atomic8_compare_exchange_weak",
+	"__tsan_atomic16_compare_exchange_weak",
+	"__tsan_atomic32_compare_exchange_weak",
+	"__tsan_atomic64_compare_exchange_weak",
+	"__tsan_atomic8_compare_exchange_val",
+	"__tsan_atomic16_compare_exchange_val",
+	"__tsan_atomic32_compare_exchange_val",
+	"__tsan_atomic64_compare_exchange_val",
+	"__tsan_atomic_thread_fence",
+	"__tsan_atomic_signal_fence",
+	"__tsan_unaligned_read16",
+	"__tsan_unaligned_write16",
+	/* KCOV */
+	"write_comp_data",
+	"check_kcov_mode",
+	"__sanitizer_cov_trace_pc",
+	"__sanitizer_cov_trace_const_cmp1",
+	"__sanitizer_cov_trace_const_cmp2",
+	"__sanitizer_cov_trace_const_cmp4",
+	"__sanitizer_cov_trace_const_cmp8",
+	"__sanitizer_cov_trace_cmp1",
+	"__sanitizer_cov_trace_cmp2",
+	"__sanitizer_cov_trace_cmp4",
+	"__sanitizer_cov_trace_cmp8",
+	"__sanitizer_cov_trace_switch",
+	/* KMSAN */
+	"kmsan_copy_to_user",
+	"kmsan_report",
+	"kmsan_unpoison_entry_regs",
+	"kmsan_unpoison_memory",
+	"__msan_chain_origin",
+	"__msan_get_context_state",
+	"__msan_instrument_asm_store",
+	"__msan_metadata_ptr_for_load_1",
+	"__msan_metadata_ptr_for_load_2",
+	"__msan_metadata_ptr_for_load_4",
+	"__msan_metadata_ptr_for_load_8",
+	"__msan_metadata_ptr_for_load_n",
+	"__msan_metadata_ptr_for_store_1",
+	"__msan_metadata_ptr_for_store_2",
+	"__msan_metadata_ptr_for_store_4",
+	"__msan_metadata_ptr_for_store_8",
+	"__msan_metadata_ptr_for_store_n",
+	"__msan_poison_alloca",
+	"__msan_warning",
+	/* UBSAN */
+	"ubsan_type_mismatch_common",
+	"__ubsan_handle_type_mismatch",
+	"__ubsan_handle_type_mismatch_v1",
+	"__ubsan_handle_shift_out_of_bounds",
+	"__ubsan_handle_load_invalid_value",
+	/* STACKLEAK */
+	"stackleak_track_stack",
+	/* misc */
+	"csum_partial_copy_generic",
+	"copy_mc_fragile",
+	"copy_mc_fragile_handle_tail",
+	"copy_mc_enhanced_fast_string",
+	"ftrace_likely_update", /* CONFIG_TRACE_BRANCH_PROFILING */
+	"rep_stos_alternative",
+	"rep_movs_alternative",
+	"__copy_user_nocache",
+	NULL
+};
+
+static void add_uaccess_safe(struct objtool_file *file)
+{
+	struct symbol *func;
+	const char **name;
+
+	if (!opts.uaccess)
+		return;
+
+	for (name = uaccess_safe_builtin; *name; name++) {
+		func = find_symbol_by_name(file->elf, *name);
+		if (!func)
+			continue;
+
+		func->uaccess_safe = true;
+	}
+}
+
+/*
+ * FIXME: For now, just ignore any alternatives which add retpolines.  This is
+ * a temporary hack, as it doesn't allow ORC to unwind from inside a retpoline.
+ * But it at least allows objtool to understand the control flow *around* the
+ * retpoline.
+ */
+static int add_ignore_alternatives(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct reloc *reloc;
+	struct instruction *insn;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.ignore_alts");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.ignore_alts entry");
+			return -1;
+		}
+
+		insn->ignore_alts = true;
+	}
+
+	return 0;
+}
+
+/*
+ * Symbols that replace INSN_CALL_DYNAMIC, every (tail) call to such a symbol
+ * will be added to the .retpoline_sites section.
+ */
+__weak bool arch_is_retpoline(struct symbol *sym)
+{
+	return false;
+}
+
+/*
+ * Symbols that replace INSN_RETURN, every (tail) call to such a symbol
+ * will be added to the .return_sites section.
+ */
+__weak bool arch_is_rethunk(struct symbol *sym)
+{
+	return false;
+}
+
+/*
+ * Symbols that are embedded inside other instructions, because sometimes crazy
+ * code exists. These are mostly ignored for validation purposes.
+ */
+__weak bool arch_is_embedded_insn(struct symbol *sym)
+{
+	return false;
+}
+
+static struct reloc *insn_reloc(struct objtool_file *file, struct instruction *insn)
+{
+	struct reloc *reloc;
+
+	if (insn->no_reloc)
+		return NULL;
+
+	if (!file)
+		return NULL;
+
+	reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+					 insn->offset, insn->len);
+	if (!reloc) {
+		insn->no_reloc = 1;
+		return NULL;
+	}
+
+	return reloc;
+}
+
+static void remove_insn_ops(struct instruction *insn)
+{
+	struct stack_op *op, *next;
+
+	for (op = insn->stack_ops; op; op = next) {
+		next = op->next;
+		free(op);
+	}
+	insn->stack_ops = NULL;
+}
+
+static void annotate_call_site(struct objtool_file *file,
+			       struct instruction *insn, bool sibling)
+{
+	struct reloc *reloc = insn_reloc(file, insn);
+	struct symbol *sym = insn_call_dest(insn);
+
+	if (!sym)
+		sym = reloc->sym;
+
+	/*
+	 * Alternative replacement code is just template code which is
+	 * sometimes copied to the original instruction. For now, don't
+	 * annotate it. (In the future we might consider annotating the
+	 * original instruction if/when it ever makes sense to do so.)
+	 */
+	if (!strcmp(insn->sec->name, ".altinstr_replacement"))
+		return;
+
+	if (sym->static_call_tramp) {
+		list_add_tail(&insn->call_node, &file->static_call_list);
+		return;
+	}
+
+	if (sym->retpoline_thunk) {
+		list_add_tail(&insn->call_node, &file->retpoline_call_list);
+		return;
+	}
+
+	/*
+	 * Many compilers cannot disable KCOV or sanitizer calls with a function
+	 * attribute so they need a little help, NOP out any such calls from
+	 * noinstr text.
+	 */
+	if (opts.hack_noinstr && insn->sec->noinstr && sym->profiling_func) {
+		if (reloc)
+			set_reloc_type(file->elf, reloc, R_NONE);
+
+		elf_write_insn(file->elf, insn->sec,
+			       insn->offset, insn->len,
+			       sibling ? arch_ret_insn(insn->len)
+			               : arch_nop_insn(insn->len));
+
+		insn->type = sibling ? INSN_RETURN : INSN_NOP;
+
+		if (sibling) {
+			/*
+			 * We've replaced the tail-call JMP insn by two new
+			 * insn: RET; INT3, except we only have a single struct
+			 * insn here. Mark it retpoline_safe to avoid the SLS
+			 * warning, instead of adding another insn.
+			 */
+			insn->retpoline_safe = true;
+		}
+
+		return;
+	}
+
+	if (opts.mcount && sym->fentry) {
+		if (sibling)
+			WARN_INSN(insn, "tail call to __fentry__ !?!?");
+		if (opts.mnop) {
+			if (reloc)
+				set_reloc_type(file->elf, reloc, R_NONE);
+
+			elf_write_insn(file->elf, insn->sec,
+				       insn->offset, insn->len,
+				       arch_nop_insn(insn->len));
+
+			insn->type = INSN_NOP;
+		}
+
+		list_add_tail(&insn->call_node, &file->mcount_loc_list);
+		return;
+	}
+
+	if (insn->type == INSN_CALL && !insn->sec->init)
+		list_add_tail(&insn->call_node, &file->call_list);
+
+	if (!sibling && dead_end_function(file, sym))
+		insn->dead_end = true;
+}
+
+static void add_call_dest(struct objtool_file *file, struct instruction *insn,
+			  struct symbol *dest, bool sibling)
+{
+	insn->_call_dest = dest;
+	if (!dest)
+		return;
+
+	/*
+	 * Whatever stack impact regular CALLs have, should be undone
+	 * by the RETURN of the called function.
+	 *
+	 * Annotated intra-function calls retain the stack_ops but
+	 * are converted to JUMP, see read_intra_function_calls().
+	 */
+	remove_insn_ops(insn);
+
+	annotate_call_site(file, insn, sibling);
+}
+
+static void add_retpoline_call(struct objtool_file *file, struct instruction *insn)
+{
+	/*
+	 * Retpoline calls/jumps are really dynamic calls/jumps in disguise,
+	 * so convert them accordingly.
+	 */
+	switch (insn->type) {
+	case INSN_CALL:
+		insn->type = INSN_CALL_DYNAMIC;
+		break;
+	case INSN_JUMP_UNCONDITIONAL:
+		insn->type = INSN_JUMP_DYNAMIC;
+		break;
+	case INSN_JUMP_CONDITIONAL:
+		insn->type = INSN_JUMP_DYNAMIC_CONDITIONAL;
+		break;
+	default:
+		return;
+	}
+
+	insn->retpoline_safe = true;
+
+	/*
+	 * Whatever stack impact regular CALLs have, should be undone
+	 * by the RETURN of the called function.
+	 *
+	 * Annotated intra-function calls retain the stack_ops but
+	 * are converted to JUMP, see read_intra_function_calls().
+	 */
+	remove_insn_ops(insn);
+
+	annotate_call_site(file, insn, false);
+}
+
+static void add_return_call(struct objtool_file *file, struct instruction *insn, bool add)
+{
+	/*
+	 * Return thunk tail calls are really just returns in disguise,
+	 * so convert them accordingly.
+	 */
+	insn->type = INSN_RETURN;
+	insn->retpoline_safe = true;
+
+	if (add)
+		list_add_tail(&insn->call_node, &file->return_thunk_list);
+}
+
+static bool is_first_func_insn(struct objtool_file *file,
+			       struct instruction *insn, struct symbol *sym)
+{
+	if (insn->offset == sym->offset)
+		return true;
+
+	/* Allow direct CALL/JMP past ENDBR */
+	if (opts.ibt) {
+		struct instruction *prev = prev_insn_same_sym(file, insn);
+
+		if (prev && prev->type == INSN_ENDBR &&
+		    insn->offset == sym->offset + prev->len)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * A sibling call is a tail-call to another symbol -- to differentiate from a
+ * recursive tail-call which is to the same symbol.
+ */
+static bool jump_is_sibling_call(struct objtool_file *file,
+				 struct instruction *from, struct instruction *to)
+{
+	struct symbol *fs = from->sym;
+	struct symbol *ts = to->sym;
+
+	/* Not a sibling call if from/to a symbol hole */
+	if (!fs || !ts)
+		return false;
+
+	/* Not a sibling call if not targeting the start of a symbol. */
+	if (!is_first_func_insn(file, to, ts))
+		return false;
+
+	/* Disallow sibling calls into STT_NOTYPE */
+	if (ts->type == STT_NOTYPE)
+		return false;
+
+	/* Must not be self to be a sibling */
+	return fs->pfunc != ts->pfunc;
+}
+
+/*
+ * Find the destination instructions for all jumps.
+ */
+static int add_jump_destinations(struct objtool_file *file)
+{
+	struct instruction *insn, *jump_dest;
+	struct reloc *reloc;
+	struct section *dest_sec;
+	unsigned long dest_off;
+
+	for_each_insn(file, insn) {
+		if (insn->jump_dest) {
+			/*
+			 * handle_group_alt() may have previously set
+			 * 'jump_dest' for some alternatives.
+			 */
+			continue;
+		}
+		if (!is_static_jump(insn))
+			continue;
+
+		reloc = insn_reloc(file, insn);
+		if (!reloc) {
+			dest_sec = insn->sec;
+			dest_off = arch_jump_destination(insn);
+		} else if (reloc->sym->type == STT_SECTION) {
+			dest_sec = reloc->sym->sec;
+			dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
+		} else if (reloc->sym->retpoline_thunk) {
+			add_retpoline_call(file, insn);
+			continue;
+		} else if (reloc->sym->return_thunk) {
+			add_return_call(file, insn, true);
+			continue;
+		} else if (insn_func(insn)) {
+			/*
+			 * External sibling call or internal sibling call with
+			 * STT_FUNC reloc.
+			 */
+			add_call_dest(file, insn, reloc->sym, true);
+			continue;
+		} else if (reloc->sym->sec->idx) {
+			dest_sec = reloc->sym->sec;
+			dest_off = reloc->sym->sym.st_value +
+				   arch_dest_reloc_offset(reloc_addend(reloc));
+		} else {
+			/* non-func asm code jumping to another file */
+			continue;
+		}
+
+		jump_dest = find_insn(file, dest_sec, dest_off);
+		if (!jump_dest) {
+			struct symbol *sym = find_symbol_by_offset(dest_sec, dest_off);
+
+			/*
+			 * This is a special case for retbleed_untrain_ret().
+			 * It jumps to __x86_return_thunk(), but objtool
+			 * can't find the thunk's starting RET
+			 * instruction, because the RET is also in the
+			 * middle of another instruction.  Objtool only
+			 * knows about the outer instruction.
+			 */
+			if (sym && sym->embedded_insn) {
+				add_return_call(file, insn, false);
+				continue;
+			}
+
+			WARN_INSN(insn, "can't find jump dest instruction at %s+0x%lx",
+				  dest_sec->name, dest_off);
+			return -1;
+		}
+
+		/*
+		 * Cross-function jump.
+		 */
+		if (insn_func(insn) && insn_func(jump_dest) &&
+		    insn_func(insn) != insn_func(jump_dest)) {
+
+			/*
+			 * For GCC 8+, create parent/child links for any cold
+			 * subfunctions.  This is _mostly_ redundant with a
+			 * similar initialization in read_symbols().
+			 *
+			 * If a function has aliases, we want the *first* such
+			 * function in the symbol table to be the subfunction's
+			 * parent.  In that case we overwrite the
+			 * initialization done in read_symbols().
+			 *
+			 * However this code can't completely replace the
+			 * read_symbols() code because this doesn't detect the
+			 * case where the parent function's only reference to a
+			 * subfunction is through a jump table.
+			 */
+			if (!strstr(insn_func(insn)->name, ".cold") &&
+			    strstr(insn_func(jump_dest)->name, ".cold")) {
+				insn_func(insn)->cfunc = insn_func(jump_dest);
+				insn_func(jump_dest)->pfunc = insn_func(insn);
+			}
+		}
+
+		if (jump_is_sibling_call(file, insn, jump_dest)) {
+			/*
+			 * Internal sibling call without reloc or with
+			 * STT_SECTION reloc.
+			 */
+			add_call_dest(file, insn, insn_func(jump_dest), true);
+			continue;
+		}
+
+		insn->jump_dest = jump_dest;
+	}
+
+	return 0;
+}
+
+static struct symbol *find_call_destination(struct section *sec, unsigned long offset)
+{
+	struct symbol *call_dest;
+
+	call_dest = find_func_by_offset(sec, offset);
+	if (!call_dest)
+		call_dest = find_symbol_by_offset(sec, offset);
+
+	return call_dest;
+}
+
+/*
+ * Find the destination instructions for all calls.
+ */
+static int add_call_destinations(struct objtool_file *file)
+{
+	struct instruction *insn;
+	unsigned long dest_off;
+	struct symbol *dest;
+	struct reloc *reloc;
+
+	for_each_insn(file, insn) {
+		if (insn->type != INSN_CALL)
+			continue;
+
+		reloc = insn_reloc(file, insn);
+		if (!reloc) {
+			dest_off = arch_jump_destination(insn);
+			dest = find_call_destination(insn->sec, dest_off);
+
+			add_call_dest(file, insn, dest, false);
+
+			if (insn->ignore)
+				continue;
+
+			if (!insn_call_dest(insn)) {
+				WARN_INSN(insn, "unannotated intra-function call");
+				return -1;
+			}
+
+			if (insn_func(insn) && insn_call_dest(insn)->type != STT_FUNC) {
+				WARN_INSN(insn, "unsupported call to non-function");
+				return -1;
+			}
+
+		} else if (reloc->sym->type == STT_SECTION) {
+			dest_off = arch_dest_reloc_offset(reloc_addend(reloc));
+			dest = find_call_destination(reloc->sym->sec, dest_off);
+			if (!dest) {
+				WARN_INSN(insn, "can't find call dest symbol at %s+0x%lx",
+					  reloc->sym->sec->name, dest_off);
+				return -1;
+			}
+
+			add_call_dest(file, insn, dest, false);
+
+		} else if (reloc->sym->retpoline_thunk) {
+			add_retpoline_call(file, insn);
+
+		} else
+			add_call_dest(file, insn, reloc->sym, false);
+	}
+
+	return 0;
+}
+
+/*
+ * The .alternatives section requires some extra special care over and above
+ * other special sections because alternatives are patched in place.
+ */
+static int handle_group_alt(struct objtool_file *file,
+			    struct special_alt *special_alt,
+			    struct instruction *orig_insn,
+			    struct instruction **new_insn)
+{
+	struct instruction *last_new_insn = NULL, *insn, *nop = NULL;
+	struct alt_group *orig_alt_group, *new_alt_group;
+	unsigned long dest_off;
+
+	orig_alt_group = orig_insn->alt_group;
+	if (!orig_alt_group) {
+		struct instruction *last_orig_insn = NULL;
+
+		orig_alt_group = malloc(sizeof(*orig_alt_group));
+		if (!orig_alt_group) {
+			WARN("malloc failed");
+			return -1;
+		}
+		orig_alt_group->cfi = calloc(special_alt->orig_len,
+					     sizeof(struct cfi_state *));
+		if (!orig_alt_group->cfi) {
+			WARN("calloc failed");
+			return -1;
+		}
+
+		insn = orig_insn;
+		sec_for_each_insn_from(file, insn) {
+			if (insn->offset >= special_alt->orig_off + special_alt->orig_len)
+				break;
+
+			insn->alt_group = orig_alt_group;
+			last_orig_insn = insn;
+		}
+		orig_alt_group->orig_group = NULL;
+		orig_alt_group->first_insn = orig_insn;
+		orig_alt_group->last_insn = last_orig_insn;
+		orig_alt_group->nop = NULL;
+	} else {
+		if (orig_alt_group->last_insn->offset + orig_alt_group->last_insn->len -
+		    orig_alt_group->first_insn->offset != special_alt->orig_len) {
+			WARN_INSN(orig_insn, "weirdly overlapping alternative! %ld != %d",
+				  orig_alt_group->last_insn->offset +
+				  orig_alt_group->last_insn->len -
+				  orig_alt_group->first_insn->offset,
+				  special_alt->orig_len);
+			return -1;
+		}
+	}
+
+	new_alt_group = malloc(sizeof(*new_alt_group));
+	if (!new_alt_group) {
+		WARN("malloc failed");
+		return -1;
+	}
+
+	if (special_alt->new_len < special_alt->orig_len) {
+		/*
+		 * Insert a fake nop at the end to make the replacement
+		 * alt_group the same size as the original.  This is needed to
+		 * allow propagate_alt_cfi() to do its magic.  When the last
+		 * instruction affects the stack, the instruction after it (the
+		 * nop) will propagate the new state to the shared CFI array.
+		 */
+		nop = malloc(sizeof(*nop));
+		if (!nop) {
+			WARN("malloc failed");
+			return -1;
+		}
+		memset(nop, 0, sizeof(*nop));
+
+		nop->sec = special_alt->new_sec;
+		nop->offset = special_alt->new_off + special_alt->new_len;
+		nop->len = special_alt->orig_len - special_alt->new_len;
+		nop->type = INSN_NOP;
+		nop->sym = orig_insn->sym;
+		nop->alt_group = new_alt_group;
+		nop->ignore = orig_insn->ignore_alts;
+	}
+
+	if (!special_alt->new_len) {
+		*new_insn = nop;
+		goto end;
+	}
+
+	insn = *new_insn;
+	sec_for_each_insn_from(file, insn) {
+		struct reloc *alt_reloc;
+
+		if (insn->offset >= special_alt->new_off + special_alt->new_len)
+			break;
+
+		last_new_insn = insn;
+
+		insn->ignore = orig_insn->ignore_alts;
+		insn->sym = orig_insn->sym;
+		insn->alt_group = new_alt_group;
+
+		/*
+		 * Since alternative replacement code is copy/pasted by the
+		 * kernel after applying relocations, generally such code can't
+		 * have relative-address relocation references to outside the
+		 * .altinstr_replacement section, unless the arch's
+		 * alternatives code can adjust the relative offsets
+		 * accordingly.
+		 */
+		alt_reloc = insn_reloc(file, insn);
+		if (alt_reloc && arch_pc_relative_reloc(alt_reloc) &&
+		    !arch_support_alt_relocation(special_alt, insn, alt_reloc)) {
+
+			WARN_INSN(insn, "unsupported relocation in alternatives section");
+			return -1;
+		}
+
+		if (!is_static_jump(insn))
+			continue;
+
+		if (!insn->immediate)
+			continue;
+
+		dest_off = arch_jump_destination(insn);
+		if (dest_off == special_alt->new_off + special_alt->new_len) {
+			insn->jump_dest = next_insn_same_sec(file, orig_alt_group->last_insn);
+			if (!insn->jump_dest) {
+				WARN_INSN(insn, "can't find alternative jump destination");
+				return -1;
+			}
+		}
+	}
+
+	if (!last_new_insn) {
+		WARN_FUNC("can't find last new alternative instruction",
+			  special_alt->new_sec, special_alt->new_off);
+		return -1;
+	}
+
+end:
+	new_alt_group->orig_group = orig_alt_group;
+	new_alt_group->first_insn = *new_insn;
+	new_alt_group->last_insn = last_new_insn;
+	new_alt_group->nop = nop;
+	new_alt_group->cfi = orig_alt_group->cfi;
+	return 0;
+}
+
+/*
+ * A jump table entry can either convert a nop to a jump or a jump to a nop.
+ * If the original instruction is a jump, make the alt entry an effective nop
+ * by just skipping the original instruction.
+ */
+static int handle_jump_alt(struct objtool_file *file,
+			   struct special_alt *special_alt,
+			   struct instruction *orig_insn,
+			   struct instruction **new_insn)
+{
+	if (orig_insn->type != INSN_JUMP_UNCONDITIONAL &&
+	    orig_insn->type != INSN_NOP) {
+
+		WARN_INSN(orig_insn, "unsupported instruction at jump label");
+		return -1;
+	}
+
+	if (opts.hack_jump_label && special_alt->key_addend & 2) {
+		struct reloc *reloc = insn_reloc(file, orig_insn);
+
+		if (reloc)
+			set_reloc_type(file->elf, reloc, R_NONE);
+		elf_write_insn(file->elf, orig_insn->sec,
+			       orig_insn->offset, orig_insn->len,
+			       arch_nop_insn(orig_insn->len));
+		orig_insn->type = INSN_NOP;
+	}
+
+	if (orig_insn->type == INSN_NOP) {
+		if (orig_insn->len == 2)
+			file->jl_nop_short++;
+		else
+			file->jl_nop_long++;
+
+		return 0;
+	}
+
+	if (orig_insn->len == 2)
+		file->jl_short++;
+	else
+		file->jl_long++;
+
+	*new_insn = next_insn_same_sec(file, orig_insn);
+	return 0;
+}
+
+/*
+ * Read all the special sections which have alternate instructions which can be
+ * patched in or redirected to at runtime.  Each instruction having alternate
+ * instruction(s) has them added to its insn->alts list, which will be
+ * traversed in validate_branch().
+ */
+static int add_special_section_alts(struct objtool_file *file)
+{
+	struct list_head special_alts;
+	struct instruction *orig_insn, *new_insn;
+	struct special_alt *special_alt, *tmp;
+	struct alternative *alt;
+	int ret;
+
+	ret = special_get_alts(file->elf, &special_alts);
+	if (ret)
+		return ret;
+
+	list_for_each_entry_safe(special_alt, tmp, &special_alts, list) {
+
+		orig_insn = find_insn(file, special_alt->orig_sec,
+				      special_alt->orig_off);
+		if (!orig_insn) {
+			WARN_FUNC("special: can't find orig instruction",
+				  special_alt->orig_sec, special_alt->orig_off);
+			ret = -1;
+			goto out;
+		}
+
+		new_insn = NULL;
+		if (!special_alt->group || special_alt->new_len) {
+			new_insn = find_insn(file, special_alt->new_sec,
+					     special_alt->new_off);
+			if (!new_insn) {
+				WARN_FUNC("special: can't find new instruction",
+					  special_alt->new_sec,
+					  special_alt->new_off);
+				ret = -1;
+				goto out;
+			}
+		}
+
+		if (special_alt->group) {
+			if (!special_alt->orig_len) {
+				WARN_INSN(orig_insn, "empty alternative entry");
+				continue;
+			}
+
+			ret = handle_group_alt(file, special_alt, orig_insn,
+					       &new_insn);
+			if (ret)
+				goto out;
+		} else if (special_alt->jump_or_nop) {
+			ret = handle_jump_alt(file, special_alt, orig_insn,
+					      &new_insn);
+			if (ret)
+				goto out;
+		}
+
+		alt = malloc(sizeof(*alt));
+		if (!alt) {
+			WARN("malloc failed");
+			ret = -1;
+			goto out;
+		}
+
+		alt->insn = new_insn;
+		alt->skip_orig = special_alt->skip_orig;
+		orig_insn->ignore_alts |= special_alt->skip_alt;
+		alt->next = orig_insn->alts;
+		orig_insn->alts = alt;
+
+		list_del(&special_alt->list);
+		free(special_alt);
+	}
+
+	if (opts.stats) {
+		printf("jl\\\tNOP\tJMP\n");
+		printf("short:\t%ld\t%ld\n", file->jl_nop_short, file->jl_short);
+		printf("long:\t%ld\t%ld\n", file->jl_nop_long, file->jl_long);
+	}
+
+out:
+	return ret;
+}
+
+static int add_jump_table(struct objtool_file *file, struct instruction *insn,
+			  struct reloc *next_table)
+{
+	struct symbol *pfunc = insn_func(insn)->pfunc;
+	struct reloc *table = insn_jump_table(insn);
+	struct instruction *dest_insn;
+	unsigned int prev_offset = 0;
+	struct reloc *reloc = table;
+	struct alternative *alt;
+
+	/*
+	 * Each @reloc is a switch table relocation which points to the target
+	 * instruction.
+	 */
+	for_each_reloc_from(table->sec, reloc) {
+
+		/* Check for the end of the table: */
+		if (reloc != table && reloc == next_table)
+			break;
+
+		/* Make sure the table entries are consecutive: */
+		if (prev_offset && reloc_offset(reloc) != prev_offset + 8)
+			break;
+
+		/* Detect function pointers from contiguous objects: */
+		if (reloc->sym->sec == pfunc->sec &&
+		    reloc_addend(reloc) == pfunc->offset)
+			break;
+
+		dest_insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!dest_insn)
+			break;
+
+		/* Make sure the destination is in the same function: */
+		if (!insn_func(dest_insn) || insn_func(dest_insn)->pfunc != pfunc)
+			break;
+
+		alt = malloc(sizeof(*alt));
+		if (!alt) {
+			WARN("malloc failed");
+			return -1;
+		}
+
+		alt->insn = dest_insn;
+		alt->next = insn->alts;
+		insn->alts = alt;
+		prev_offset = reloc_offset(reloc);
+	}
+
+	if (!prev_offset) {
+		WARN_INSN(insn, "can't find switch jump table");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * find_jump_table() - Given a dynamic jump, find the switch jump table
+ * associated with it.
+ */
+static struct reloc *find_jump_table(struct objtool_file *file,
+				      struct symbol *func,
+				      struct instruction *insn)
+{
+	struct reloc *table_reloc;
+	struct instruction *dest_insn, *orig_insn = insn;
+
+	/*
+	 * Backward search using the @first_jump_src links, these help avoid
+	 * much of the 'in between' code. Which avoids us getting confused by
+	 * it.
+	 */
+	for (;
+	     insn && insn_func(insn) && insn_func(insn)->pfunc == func;
+	     insn = insn->first_jump_src ?: prev_insn_same_sym(file, insn)) {
+
+		if (insn != orig_insn && insn->type == INSN_JUMP_DYNAMIC)
+			break;
+
+		/* allow small jumps within the range */
+		if (insn->type == INSN_JUMP_UNCONDITIONAL &&
+		    insn->jump_dest &&
+		    (insn->jump_dest->offset <= insn->offset ||
+		     insn->jump_dest->offset > orig_insn->offset))
+		    break;
+
+		table_reloc = arch_find_switch_table(file, insn);
+		if (!table_reloc)
+			continue;
+		dest_insn = find_insn(file, table_reloc->sym->sec, reloc_addend(table_reloc));
+		if (!dest_insn || !insn_func(dest_insn) || insn_func(dest_insn)->pfunc != func)
+			continue;
+
+		return table_reloc;
+	}
+
+	return NULL;
+}
+
+/*
+ * First pass: Mark the head of each jump table so that in the next pass,
+ * we know when a given jump table ends and the next one starts.
+ */
+static void mark_func_jump_tables(struct objtool_file *file,
+				    struct symbol *func)
+{
+	struct instruction *insn, *last = NULL;
+	struct reloc *reloc;
+
+	func_for_each_insn(file, func, insn) {
+		if (!last)
+			last = insn;
+
+		/*
+		 * Store back-pointers for unconditional forward jumps such
+		 * that find_jump_table() can back-track using those and
+		 * avoid some potentially confusing code.
+		 */
+		if (insn->type == INSN_JUMP_UNCONDITIONAL && insn->jump_dest &&
+		    insn->offset > last->offset &&
+		    insn->jump_dest->offset > insn->offset &&
+		    !insn->jump_dest->first_jump_src) {
+
+			insn->jump_dest->first_jump_src = insn;
+			last = insn->jump_dest;
+		}
+
+		if (insn->type != INSN_JUMP_DYNAMIC)
+			continue;
+
+		reloc = find_jump_table(file, func, insn);
+		if (reloc)
+			insn->_jump_table = reloc;
+	}
+}
+
+static int add_func_jump_tables(struct objtool_file *file,
+				  struct symbol *func)
+{
+	struct instruction *insn, *insn_t1 = NULL, *insn_t2;
+	int ret = 0;
+
+	func_for_each_insn(file, func, insn) {
+		if (!insn_jump_table(insn))
+			continue;
+
+		if (!insn_t1) {
+			insn_t1 = insn;
+			continue;
+		}
+
+		insn_t2 = insn;
+
+		ret = add_jump_table(file, insn_t1, insn_jump_table(insn_t2));
+		if (ret)
+			return ret;
+
+		insn_t1 = insn_t2;
+	}
+
+	if (insn_t1)
+		ret = add_jump_table(file, insn_t1, NULL);
+
+	return ret;
+}
+
+/*
+ * For some switch statements, gcc generates a jump table in the .rodata
+ * section which contains a list of addresses within the function to jump to.
+ * This finds these jump tables and adds them to the insn->alts lists.
+ */
+static int add_jump_table_alts(struct objtool_file *file)
+{
+	struct symbol *func;
+	int ret;
+
+	if (!file->rodata)
+		return 0;
+
+	for_each_sym(file, func) {
+		if (func->type != STT_FUNC)
+			continue;
+
+		mark_func_jump_tables(file, func);
+		ret = add_func_jump_tables(file, func);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void set_func_state(struct cfi_state *state)
+{
+	state->cfa = initial_func_cfi.cfa;
+	memcpy(&state->regs, &initial_func_cfi.regs,
+	       CFI_NUM_REGS * sizeof(struct cfi_reg));
+	state->stack_size = initial_func_cfi.cfa.offset;
+	state->type = UNWIND_HINT_TYPE_CALL;
+}
+
+static int read_unwind_hints(struct objtool_file *file)
+{
+	struct cfi_state cfi = init_cfi;
+	struct section *sec;
+	struct unwind_hint *hint;
+	struct instruction *insn;
+	struct reloc *reloc;
+	int i;
+
+	sec = find_section_by_name(file->elf, ".discard.unwind_hints");
+	if (!sec)
+		return 0;
+
+	if (!sec->rsec) {
+		WARN("missing .rela.discard.unwind_hints section");
+		return -1;
+	}
+
+	if (sec->sh.sh_size % sizeof(struct unwind_hint)) {
+		WARN("struct unwind_hint size mismatch");
+		return -1;
+	}
+
+	file->hints = true;
+
+	for (i = 0; i < sec->sh.sh_size / sizeof(struct unwind_hint); i++) {
+		hint = (struct unwind_hint *)sec->data->d_buf + i;
+
+		reloc = find_reloc_by_dest(file->elf, sec, i * sizeof(*hint));
+		if (!reloc) {
+			WARN("can't find reloc for unwind_hints[%d]", i);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("can't find insn for unwind_hints[%d]", i);
+			return -1;
+		}
+
+		insn->hint = true;
+
+		if (hint->type == UNWIND_HINT_TYPE_UNDEFINED) {
+			insn->cfi = &force_undefined_cfi;
+			continue;
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_SAVE) {
+			insn->hint = false;
+			insn->save = true;
+			continue;
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_RESTORE) {
+			insn->restore = true;
+			continue;
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_REGS_PARTIAL) {
+			struct symbol *sym = find_symbol_by_offset(insn->sec, insn->offset);
+
+			if (sym && sym->bind == STB_GLOBAL) {
+				if (opts.ibt && insn->type != INSN_ENDBR && !insn->noendbr) {
+					WARN_INSN(insn, "UNWIND_HINT_IRET_REGS without ENDBR");
+				}
+			}
+		}
+
+		if (hint->type == UNWIND_HINT_TYPE_FUNC) {
+			insn->cfi = &func_cfi;
+			continue;
+		}
+
+		if (insn->cfi)
+			cfi = *(insn->cfi);
+
+		if (arch_decode_hint_reg(hint->sp_reg, &cfi.cfa.base)) {
+			WARN_INSN(insn, "unsupported unwind_hint sp base reg %d", hint->sp_reg);
+			return -1;
+		}
+
+		cfi.cfa.offset = bswap_if_needed(file->elf, hint->sp_offset);
+		cfi.type = hint->type;
+		cfi.signal = hint->signal;
+
+		insn->cfi = cfi_hash_find_or_add(&cfi);
+	}
+
+	return 0;
+}
+
+static int read_noendbr_hints(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *rsec;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.noendbr");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		insn = find_insn(file, reloc->sym->sec,
+				 reloc->sym->offset + reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.noendbr entry");
+			return -1;
+		}
+
+		insn->noendbr = 1;
+	}
+
+	return 0;
+}
+
+static int read_retpoline_hints(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct instruction *insn;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.retpoline_safe");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.retpoline_safe entry");
+			return -1;
+		}
+
+		if (insn->type != INSN_JUMP_DYNAMIC &&
+		    insn->type != INSN_CALL_DYNAMIC &&
+		    insn->type != INSN_RETURN &&
+		    insn->type != INSN_NOP) {
+			WARN_INSN(insn, "retpoline_safe hint not an indirect jump/call/ret/nop");
+			return -1;
+		}
+
+		insn->retpoline_safe = true;
+	}
+
+	return 0;
+}
+
+static int read_instr_hints(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct instruction *insn;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.instr_end");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.instr_end entry");
+			return -1;
+		}
+
+		insn->instr--;
+	}
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.instr_begin");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.instr_begin entry");
+			return -1;
+		}
+
+		insn->instr++;
+	}
+
+	return 0;
+}
+
+static int read_validate_unret_hints(struct objtool_file *file)
+{
+	struct section *rsec;
+	struct instruction *insn;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.validate_unret");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s", rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.instr_end entry");
+			return -1;
+		}
+		insn->unret = 1;
+	}
+
+	return 0;
+}
+
+
+static int read_intra_function_calls(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct section *rsec;
+	struct reloc *reloc;
+
+	rsec = find_section_by_name(file->elf, ".rela.discard.intra_function_calls");
+	if (!rsec)
+		return 0;
+
+	for_each_reloc(rsec, reloc) {
+		unsigned long dest_off;
+
+		if (reloc->sym->type != STT_SECTION) {
+			WARN("unexpected relocation symbol type in %s",
+			     rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (!insn) {
+			WARN("bad .discard.intra_function_call entry");
+			return -1;
+		}
+
+		if (insn->type != INSN_CALL) {
+			WARN_INSN(insn, "intra_function_call not a direct call");
+			return -1;
+		}
+
+		/*
+		 * Treat intra-function CALLs as JMPs, but with a stack_op.
+		 * See add_call_destinations(), which strips stack_ops from
+		 * normal CALLs.
+		 */
+		insn->type = INSN_JUMP_UNCONDITIONAL;
+
+		dest_off = arch_jump_destination(insn);
+		insn->jump_dest = find_insn(file, insn->sec, dest_off);
+		if (!insn->jump_dest) {
+			WARN_INSN(insn, "can't find call dest at %s+0x%lx",
+				  insn->sec->name, dest_off);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Return true if name matches an instrumentation function, where calls to that
+ * function from noinstr code can safely be removed, but compilers won't do so.
+ */
+static bool is_profiling_func(const char *name)
+{
+	/*
+	 * Many compilers cannot disable KCOV with a function attribute.
+	 */
+	if (!strncmp(name, "__sanitizer_cov_", 16))
+		return true;
+
+	/*
+	 * Some compilers currently do not remove __tsan_func_entry/exit nor
+	 * __tsan_atomic_signal_fence (used for barrier instrumentation) with
+	 * the __no_sanitize_thread attribute, remove them. Once the kernel's
+	 * minimum Clang version is 14.0, this can be removed.
+	 */
+	if (!strncmp(name, "__tsan_func_", 12) ||
+	    !strcmp(name, "__tsan_atomic_signal_fence"))
+		return true;
+
+	return false;
+}
+
+static int classify_symbols(struct objtool_file *file)
+{
+	struct symbol *func;
+
+	for_each_sym(file, func) {
+		if (func->bind != STB_GLOBAL)
+			continue;
+
+		if (!strncmp(func->name, STATIC_CALL_TRAMP_PREFIX_STR,
+			     strlen(STATIC_CALL_TRAMP_PREFIX_STR)))
+			func->static_call_tramp = true;
+
+		if (arch_is_retpoline(func))
+			func->retpoline_thunk = true;
+
+		if (arch_is_rethunk(func))
+			func->return_thunk = true;
+
+		if (arch_is_embedded_insn(func))
+			func->embedded_insn = true;
+
+		if (arch_ftrace_match(func->name))
+			func->fentry = true;
+
+		if (is_profiling_func(func->name))
+			func->profiling_func = true;
+	}
+
+	return 0;
+}
+
+static void mark_rodata(struct objtool_file *file)
+{
+	struct section *sec;
+	bool found = false;
+
+	/*
+	 * Search for the following rodata sections, each of which can
+	 * potentially contain jump tables:
+	 *
+	 * - .rodata: can contain GCC switch tables
+	 * - .rodata.<func>: same, if -fdata-sections is being used
+	 * - .rodata..c_jump_table: contains C annotated jump tables
+	 *
+	 * .rodata.str1.* sections are ignored; they don't contain jump tables.
+	 */
+	for_each_sec(file, sec) {
+		if (!strncmp(sec->name, ".rodata", 7) &&
+		    !strstr(sec->name, ".str1.")) {
+			sec->rodata = true;
+			found = true;
+		}
+	}
+
+	file->rodata = found;
+}
+
+static int decode_sections(struct objtool_file *file)
+{
+	int ret;
+
+	mark_rodata(file);
+
+	ret = init_pv_ops(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before add_{jump_call}_destination.
+	 */
+	ret = classify_symbols(file);
+	if (ret)
+		return ret;
+
+	ret = decode_instructions(file);
+	if (ret)
+		return ret;
+
+	add_ignores(file);
+	add_uaccess_safe(file);
+
+	ret = add_ignore_alternatives(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before read_unwind_hints() since that needs insn->noendbr.
+	 */
+	ret = read_noendbr_hints(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before add_jump_destinations(), which depends on 'func'
+	 * being set for alternatives, to enable proper sibling call detection.
+	 */
+	if (opts.stackval || opts.orc || opts.uaccess || opts.noinstr) {
+		ret = add_special_section_alts(file);
+		if (ret)
+			return ret;
+	}
+
+	ret = add_jump_destinations(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be before add_call_destination(); it changes INSN_CALL to
+	 * INSN_JUMP.
+	 */
+	ret = read_intra_function_calls(file);
+	if (ret)
+		return ret;
+
+	ret = add_call_destinations(file);
+	if (ret)
+		return ret;
+
+	/*
+	 * Must be after add_call_destinations() such that it can override
+	 * dead_end_function() marks.
+	 */
+	ret = add_dead_ends(file);
+	if (ret)
+		return ret;
+
+	ret = add_jump_table_alts(file);
+	if (ret)
+		return ret;
+
+	ret = read_unwind_hints(file);
+	if (ret)
+		return ret;
+
+	ret = read_retpoline_hints(file);
+	if (ret)
+		return ret;
+
+	ret = read_instr_hints(file);
+	if (ret)
+		return ret;
+
+	ret = read_validate_unret_hints(file);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static bool is_special_call(struct instruction *insn)
+{
+	if (insn->type == INSN_CALL) {
+		struct symbol *dest = insn_call_dest(insn);
+
+		if (!dest)
+			return false;
+
+		if (dest->fentry || dest->embedded_insn)
+			return true;
+	}
+
+	return false;
+}
+
+static bool has_modified_stack_frame(struct instruction *insn, struct insn_state *state)
+{
+	struct cfi_state *cfi = &state->cfi;
+	int i;
+
+	if (cfi->cfa.base != initial_func_cfi.cfa.base || cfi->drap)
+		return true;
+
+	if (cfi->cfa.offset != initial_func_cfi.cfa.offset)
+		return true;
+
+	if (cfi->stack_size != initial_func_cfi.cfa.offset)
+		return true;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		if (cfi->regs[i].base != initial_func_cfi.regs[i].base ||
+		    cfi->regs[i].offset != initial_func_cfi.regs[i].offset)
+			return true;
+	}
+
+	return false;
+}
+
+static bool check_reg_frame_pos(const struct cfi_reg *reg,
+				int expected_offset)
+{
+	return reg->base == CFI_CFA &&
+	       reg->offset == expected_offset;
+}
+
+static bool has_valid_stack_frame(struct insn_state *state)
+{
+	struct cfi_state *cfi = &state->cfi;
+
+	if (cfi->cfa.base == CFI_BP &&
+	    check_reg_frame_pos(&cfi->regs[CFI_BP], -cfi->cfa.offset) &&
+	    check_reg_frame_pos(&cfi->regs[CFI_RA], -cfi->cfa.offset + 8))
+		return true;
+
+	if (cfi->drap && cfi->regs[CFI_BP].base == CFI_BP)
+		return true;
+
+	return false;
+}
+
+static int update_cfi_state_regs(struct instruction *insn,
+				  struct cfi_state *cfi,
+				  struct stack_op *op)
+{
+	struct cfi_reg *cfa = &cfi->cfa;
+
+	if (cfa->base != CFI_SP && cfa->base != CFI_SP_INDIRECT)
+		return 0;
+
+	/* push */
+	if (op->dest.type == OP_DEST_PUSH || op->dest.type == OP_DEST_PUSHF)
+		cfa->offset += 8;
+
+	/* pop */
+	if (op->src.type == OP_SRC_POP || op->src.type == OP_SRC_POPF)
+		cfa->offset -= 8;
+
+	/* add immediate to sp */
+	if (op->dest.type == OP_DEST_REG && op->src.type == OP_SRC_ADD &&
+	    op->dest.reg == CFI_SP && op->src.reg == CFI_SP)
+		cfa->offset -= op->src.offset;
+
+	return 0;
+}
+
+static void save_reg(struct cfi_state *cfi, unsigned char reg, int base, int offset)
+{
+	if (arch_callee_saved_reg(reg) &&
+	    cfi->regs[reg].base == CFI_UNDEFINED) {
+		cfi->regs[reg].base = base;
+		cfi->regs[reg].offset = offset;
+	}
+}
+
+static void restore_reg(struct cfi_state *cfi, unsigned char reg)
+{
+	cfi->regs[reg].base = initial_func_cfi.regs[reg].base;
+	cfi->regs[reg].offset = initial_func_cfi.regs[reg].offset;
+}
+
+/*
+ * A note about DRAP stack alignment:
+ *
+ * GCC has the concept of a DRAP register, which is used to help keep track of
+ * the stack pointer when aligning the stack.  r10 or r13 is used as the DRAP
+ * register.  The typical DRAP pattern is:
+ *
+ *   4c 8d 54 24 08		lea    0x8(%rsp),%r10
+ *   48 83 e4 c0		and    $0xffffffffffffffc0,%rsp
+ *   41 ff 72 f8		pushq  -0x8(%r10)
+ *   55				push   %rbp
+ *   48 89 e5			mov    %rsp,%rbp
+ *				(more pushes)
+ *   41 52			push   %r10
+ *				...
+ *   41 5a			pop    %r10
+ *				(more pops)
+ *   5d				pop    %rbp
+ *   49 8d 62 f8		lea    -0x8(%r10),%rsp
+ *   c3				retq
+ *
+ * There are some variations in the epilogues, like:
+ *
+ *   5b				pop    %rbx
+ *   41 5a			pop    %r10
+ *   41 5c			pop    %r12
+ *   41 5d			pop    %r13
+ *   41 5e			pop    %r14
+ *   c9				leaveq
+ *   49 8d 62 f8		lea    -0x8(%r10),%rsp
+ *   c3				retq
+ *
+ * and:
+ *
+ *   4c 8b 55 e8		mov    -0x18(%rbp),%r10
+ *   48 8b 5d e0		mov    -0x20(%rbp),%rbx
+ *   4c 8b 65 f0		mov    -0x10(%rbp),%r12
+ *   4c 8b 6d f8		mov    -0x8(%rbp),%r13
+ *   c9				leaveq
+ *   49 8d 62 f8		lea    -0x8(%r10),%rsp
+ *   c3				retq
+ *
+ * Sometimes r13 is used as the DRAP register, in which case it's saved and
+ * restored beforehand:
+ *
+ *   41 55			push   %r13
+ *   4c 8d 6c 24 10		lea    0x10(%rsp),%r13
+ *   48 83 e4 f0		and    $0xfffffffffffffff0,%rsp
+ *				...
+ *   49 8d 65 f0		lea    -0x10(%r13),%rsp
+ *   41 5d			pop    %r13
+ *   c3				retq
+ */
+static int update_cfi_state(struct instruction *insn,
+			    struct instruction *next_insn,
+			    struct cfi_state *cfi, struct stack_op *op)
+{
+	struct cfi_reg *cfa = &cfi->cfa;
+	struct cfi_reg *regs = cfi->regs;
+
+	/* ignore UNWIND_HINT_UNDEFINED regions */
+	if (cfi->force_undefined)
+		return 0;
+
+	/* stack operations don't make sense with an undefined CFA */
+	if (cfa->base == CFI_UNDEFINED) {
+		if (insn_func(insn)) {
+			WARN_INSN(insn, "undefined stack state");
+			return -1;
+		}
+		return 0;
+	}
+
+	if (cfi->type == UNWIND_HINT_TYPE_REGS ||
+	    cfi->type == UNWIND_HINT_TYPE_REGS_PARTIAL)
+		return update_cfi_state_regs(insn, cfi, op);
+
+	switch (op->dest.type) {
+
+	case OP_DEST_REG:
+		switch (op->src.type) {
+
+		case OP_SRC_REG:
+			if (op->src.reg == CFI_SP && op->dest.reg == CFI_BP &&
+			    cfa->base == CFI_SP &&
+			    check_reg_frame_pos(&regs[CFI_BP], -cfa->offset)) {
+
+				/* mov %rsp, %rbp */
+				cfa->base = op->dest.reg;
+				cfi->bp_scratch = false;
+			}
+
+			else if (op->src.reg == CFI_SP &&
+				 op->dest.reg == CFI_BP && cfi->drap) {
+
+				/* drap: mov %rsp, %rbp */
+				regs[CFI_BP].base = CFI_BP;
+				regs[CFI_BP].offset = -cfi->stack_size;
+				cfi->bp_scratch = false;
+			}
+
+			else if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
+
+				/*
+				 * mov %rsp, %reg
+				 *
+				 * This is needed for the rare case where GCC
+				 * does:
+				 *
+				 *   mov    %rsp, %rax
+				 *   ...
+				 *   mov    %rax, %rsp
+				 */
+				cfi->vals[op->dest.reg].base = CFI_CFA;
+				cfi->vals[op->dest.reg].offset = -cfi->stack_size;
+			}
+
+			else if (op->src.reg == CFI_BP && op->dest.reg == CFI_SP &&
+				 (cfa->base == CFI_BP || cfa->base == cfi->drap_reg)) {
+
+				/*
+				 * mov %rbp, %rsp
+				 *
+				 * Restore the original stack pointer (Clang).
+				 */
+				cfi->stack_size = -cfi->regs[CFI_BP].offset;
+			}
+
+			else if (op->dest.reg == cfa->base) {
+
+				/* mov %reg, %rsp */
+				if (cfa->base == CFI_SP &&
+				    cfi->vals[op->src.reg].base == CFI_CFA) {
+
+					/*
+					 * This is needed for the rare case
+					 * where GCC does something dumb like:
+					 *
+					 *   lea    0x8(%rsp), %rcx
+					 *   ...
+					 *   mov    %rcx, %rsp
+					 */
+					cfa->offset = -cfi->vals[op->src.reg].offset;
+					cfi->stack_size = cfa->offset;
+
+				} else if (cfa->base == CFI_SP &&
+					   cfi->vals[op->src.reg].base == CFI_SP_INDIRECT &&
+					   cfi->vals[op->src.reg].offset == cfa->offset) {
+
+					/*
+					 * Stack swizzle:
+					 *
+					 * 1: mov %rsp, (%[tos])
+					 * 2: mov %[tos], %rsp
+					 *    ...
+					 * 3: pop %rsp
+					 *
+					 * Where:
+					 *
+					 * 1 - places a pointer to the previous
+					 *     stack at the Top-of-Stack of the
+					 *     new stack.
+					 *
+					 * 2 - switches to the new stack.
+					 *
+					 * 3 - pops the Top-of-Stack to restore
+					 *     the original stack.
+					 *
+					 * Note: we set base to SP_INDIRECT
+					 * here and preserve offset. Therefore
+					 * when the unwinder reaches ToS it
+					 * will dereference SP and then add the
+					 * offset to find the next frame, IOW:
+					 * (%rsp) + offset.
+					 */
+					cfa->base = CFI_SP_INDIRECT;
+
+				} else {
+					cfa->base = CFI_UNDEFINED;
+					cfa->offset = 0;
+				}
+			}
+
+			else if (op->dest.reg == CFI_SP &&
+				 cfi->vals[op->src.reg].base == CFI_SP_INDIRECT &&
+				 cfi->vals[op->src.reg].offset == cfa->offset) {
+
+				/*
+				 * The same stack swizzle case 2) as above. But
+				 * because we can't change cfa->base, case 3)
+				 * will become a regular POP. Pretend we're a
+				 * PUSH so things don't go unbalanced.
+				 */
+				cfi->stack_size += 8;
+			}
+
+
+			break;
+
+		case OP_SRC_ADD:
+			if (op->dest.reg == CFI_SP && op->src.reg == CFI_SP) {
+
+				/* add imm, %rsp */
+				cfi->stack_size -= op->src.offset;
+				if (cfa->base == CFI_SP)
+					cfa->offset -= op->src.offset;
+				break;
+			}
+
+			if (op->dest.reg == CFI_SP && op->src.reg == CFI_BP) {
+
+				/* lea disp(%rbp), %rsp */
+				cfi->stack_size = -(op->src.offset + regs[CFI_BP].offset);
+				break;
+			}
+
+			if (op->src.reg == CFI_SP && cfa->base == CFI_SP) {
+
+				/* drap: lea disp(%rsp), %drap */
+				cfi->drap_reg = op->dest.reg;
+
+				/*
+				 * lea disp(%rsp), %reg
+				 *
+				 * This is needed for the rare case where GCC
+				 * does something dumb like:
+				 *
+				 *   lea    0x8(%rsp), %rcx
+				 *   ...
+				 *   mov    %rcx, %rsp
+				 */
+				cfi->vals[op->dest.reg].base = CFI_CFA;
+				cfi->vals[op->dest.reg].offset = \
+					-cfi->stack_size + op->src.offset;
+
+				break;
+			}
+
+			if (cfi->drap && op->dest.reg == CFI_SP &&
+			    op->src.reg == cfi->drap_reg) {
+
+				 /* drap: lea disp(%drap), %rsp */
+				cfa->base = CFI_SP;
+				cfa->offset = cfi->stack_size = -op->src.offset;
+				cfi->drap_reg = CFI_UNDEFINED;
+				cfi->drap = false;
+				break;
+			}
+
+			if (op->dest.reg == cfi->cfa.base && !(next_insn && next_insn->hint)) {
+				WARN_INSN(insn, "unsupported stack register modification");
+				return -1;
+			}
+
+			break;
+
+		case OP_SRC_AND:
+			if (op->dest.reg != CFI_SP ||
+			    (cfi->drap_reg != CFI_UNDEFINED && cfa->base != CFI_SP) ||
+			    (cfi->drap_reg == CFI_UNDEFINED && cfa->base != CFI_BP)) {
+				WARN_INSN(insn, "unsupported stack pointer realignment");
+				return -1;
+			}
+
+			if (cfi->drap_reg != CFI_UNDEFINED) {
+				/* drap: and imm, %rsp */
+				cfa->base = cfi->drap_reg;
+				cfa->offset = cfi->stack_size = 0;
+				cfi->drap = true;
+			}
+
+			/*
+			 * Older versions of GCC (4.8ish) realign the stack
+			 * without DRAP, with a frame pointer.
+			 */
+
+			break;
+
+		case OP_SRC_POP:
+		case OP_SRC_POPF:
+			if (op->dest.reg == CFI_SP && cfa->base == CFI_SP_INDIRECT) {
+
+				/* pop %rsp; # restore from a stack swizzle */
+				cfa->base = CFI_SP;
+				break;
+			}
+
+			if (!cfi->drap && op->dest.reg == cfa->base) {
+
+				/* pop %rbp */
+				cfa->base = CFI_SP;
+			}
+
+			if (cfi->drap && cfa->base == CFI_BP_INDIRECT &&
+			    op->dest.reg == cfi->drap_reg &&
+			    cfi->drap_offset == -cfi->stack_size) {
+
+				/* drap: pop %drap */
+				cfa->base = cfi->drap_reg;
+				cfa->offset = 0;
+				cfi->drap_offset = -1;
+
+			} else if (cfi->stack_size == -regs[op->dest.reg].offset) {
+
+				/* pop %reg */
+				restore_reg(cfi, op->dest.reg);
+			}
+
+			cfi->stack_size -= 8;
+			if (cfa->base == CFI_SP)
+				cfa->offset -= 8;
+
+			break;
+
+		case OP_SRC_REG_INDIRECT:
+			if (!cfi->drap && op->dest.reg == cfa->base &&
+			    op->dest.reg == CFI_BP) {
+
+				/* mov disp(%rsp), %rbp */
+				cfa->base = CFI_SP;
+				cfa->offset = cfi->stack_size;
+			}
+
+			if (cfi->drap && op->src.reg == CFI_BP &&
+			    op->src.offset == cfi->drap_offset) {
+
+				/* drap: mov disp(%rbp), %drap */
+				cfa->base = cfi->drap_reg;
+				cfa->offset = 0;
+				cfi->drap_offset = -1;
+			}
+
+			if (cfi->drap && op->src.reg == CFI_BP &&
+			    op->src.offset == regs[op->dest.reg].offset) {
+
+				/* drap: mov disp(%rbp), %reg */
+				restore_reg(cfi, op->dest.reg);
+
+			} else if (op->src.reg == cfa->base &&
+			    op->src.offset == regs[op->dest.reg].offset + cfa->offset) {
+
+				/* mov disp(%rbp), %reg */
+				/* mov disp(%rsp), %reg */
+				restore_reg(cfi, op->dest.reg);
+
+			} else if (op->src.reg == CFI_SP &&
+				   op->src.offset == regs[op->dest.reg].offset + cfi->stack_size) {
+
+				/* mov disp(%rsp), %reg */
+				restore_reg(cfi, op->dest.reg);
+			}
+
+			break;
+
+		default:
+			WARN_INSN(insn, "unknown stack-related instruction");
+			return -1;
+		}
+
+		break;
+
+	case OP_DEST_PUSH:
+	case OP_DEST_PUSHF:
+		cfi->stack_size += 8;
+		if (cfa->base == CFI_SP)
+			cfa->offset += 8;
+
+		if (op->src.type != OP_SRC_REG)
+			break;
+
+		if (cfi->drap) {
+			if (op->src.reg == cfa->base && op->src.reg == cfi->drap_reg) {
+
+				/* drap: push %drap */
+				cfa->base = CFI_BP_INDIRECT;
+				cfa->offset = -cfi->stack_size;
+
+				/* save drap so we know when to restore it */
+				cfi->drap_offset = -cfi->stack_size;
+
+			} else if (op->src.reg == CFI_BP && cfa->base == cfi->drap_reg) {
+
+				/* drap: push %rbp */
+				cfi->stack_size = 0;
+
+			} else {
+
+				/* drap: push %reg */
+				save_reg(cfi, op->src.reg, CFI_BP, -cfi->stack_size);
+			}
+
+		} else {
+
+			/* push %reg */
+			save_reg(cfi, op->src.reg, CFI_CFA, -cfi->stack_size);
+		}
+
+		/* detect when asm code uses rbp as a scratch register */
+		if (opts.stackval && insn_func(insn) && op->src.reg == CFI_BP &&
+		    cfa->base != CFI_BP)
+			cfi->bp_scratch = true;
+		break;
+
+	case OP_DEST_REG_INDIRECT:
+
+		if (cfi->drap) {
+			if (op->src.reg == cfa->base && op->src.reg == cfi->drap_reg) {
+
+				/* drap: mov %drap, disp(%rbp) */
+				cfa->base = CFI_BP_INDIRECT;
+				cfa->offset = op->dest.offset;
+
+				/* save drap offset so we know when to restore it */
+				cfi->drap_offset = op->dest.offset;
+			} else {
+
+				/* drap: mov reg, disp(%rbp) */
+				save_reg(cfi, op->src.reg, CFI_BP, op->dest.offset);
+			}
+
+		} else if (op->dest.reg == cfa->base) {
+
+			/* mov reg, disp(%rbp) */
+			/* mov reg, disp(%rsp) */
+			save_reg(cfi, op->src.reg, CFI_CFA,
+				 op->dest.offset - cfi->cfa.offset);
+
+		} else if (op->dest.reg == CFI_SP) {
+
+			/* mov reg, disp(%rsp) */
+			save_reg(cfi, op->src.reg, CFI_CFA,
+				 op->dest.offset - cfi->stack_size);
+
+		} else if (op->src.reg == CFI_SP && op->dest.offset == 0) {
+
+			/* mov %rsp, (%reg); # setup a stack swizzle. */
+			cfi->vals[op->dest.reg].base = CFI_SP_INDIRECT;
+			cfi->vals[op->dest.reg].offset = cfa->offset;
+		}
+
+		break;
+
+	case OP_DEST_MEM:
+		if (op->src.type != OP_SRC_POP && op->src.type != OP_SRC_POPF) {
+			WARN_INSN(insn, "unknown stack-related memory operation");
+			return -1;
+		}
+
+		/* pop mem */
+		cfi->stack_size -= 8;
+		if (cfa->base == CFI_SP)
+			cfa->offset -= 8;
+
+		break;
+
+	default:
+		WARN_INSN(insn, "unknown stack-related instruction");
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * The stack layouts of alternatives instructions can sometimes diverge when
+ * they have stack modifications.  That's fine as long as the potential stack
+ * layouts don't conflict at any given potential instruction boundary.
+ *
+ * Flatten the CFIs of the different alternative code streams (both original
+ * and replacement) into a single shared CFI array which can be used to detect
+ * conflicts and nicely feed a linear array of ORC entries to the unwinder.
+ */
+static int propagate_alt_cfi(struct objtool_file *file, struct instruction *insn)
+{
+	struct cfi_state **alt_cfi;
+	int group_off;
+
+	if (!insn->alt_group)
+		return 0;
+
+	if (!insn->cfi) {
+		WARN("CFI missing");
+		return -1;
+	}
+
+	alt_cfi = insn->alt_group->cfi;
+	group_off = insn->offset - insn->alt_group->first_insn->offset;
+
+	if (!alt_cfi[group_off]) {
+		alt_cfi[group_off] = insn->cfi;
+	} else {
+		if (cficmp(alt_cfi[group_off], insn->cfi)) {
+			struct alt_group *orig_group = insn->alt_group->orig_group ?: insn->alt_group;
+			struct instruction *orig = orig_group->first_insn;
+			char *where = offstr(insn->sec, insn->offset);
+			WARN_INSN(orig, "stack layout conflict in alternatives: %s", where);
+			free(where);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+static int handle_insn_ops(struct instruction *insn,
+			   struct instruction *next_insn,
+			   struct insn_state *state)
+{
+	struct stack_op *op;
+
+	for (op = insn->stack_ops; op; op = op->next) {
+
+		if (update_cfi_state(insn, next_insn, &state->cfi, op))
+			return 1;
+
+		if (!insn->alt_group)
+			continue;
+
+		if (op->dest.type == OP_DEST_PUSHF) {
+			if (!state->uaccess_stack) {
+				state->uaccess_stack = 1;
+			} else if (state->uaccess_stack >> 31) {
+				WARN_INSN(insn, "PUSHF stack exhausted");
+				return 1;
+			}
+			state->uaccess_stack <<= 1;
+			state->uaccess_stack  |= state->uaccess;
+		}
+
+		if (op->src.type == OP_SRC_POPF) {
+			if (state->uaccess_stack) {
+				state->uaccess = state->uaccess_stack & 1;
+				state->uaccess_stack >>= 1;
+				if (state->uaccess_stack == 1)
+					state->uaccess_stack = 0;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static bool insn_cfi_match(struct instruction *insn, struct cfi_state *cfi2)
+{
+	struct cfi_state *cfi1 = insn->cfi;
+	int i;
+
+	if (!cfi1) {
+		WARN("CFI missing");
+		return false;
+	}
+
+	if (memcmp(&cfi1->cfa, &cfi2->cfa, sizeof(cfi1->cfa))) {
+
+		WARN_INSN(insn, "stack state mismatch: cfa1=%d%+d cfa2=%d%+d",
+			  cfi1->cfa.base, cfi1->cfa.offset,
+			  cfi2->cfa.base, cfi2->cfa.offset);
+
+	} else if (memcmp(&cfi1->regs, &cfi2->regs, sizeof(cfi1->regs))) {
+		for (i = 0; i < CFI_NUM_REGS; i++) {
+			if (!memcmp(&cfi1->regs[i], &cfi2->regs[i],
+				    sizeof(struct cfi_reg)))
+				continue;
+
+			WARN_INSN(insn, "stack state mismatch: reg1[%d]=%d%+d reg2[%d]=%d%+d",
+				  i, cfi1->regs[i].base, cfi1->regs[i].offset,
+				  i, cfi2->regs[i].base, cfi2->regs[i].offset);
+			break;
+		}
+
+	} else if (cfi1->type != cfi2->type) {
+
+		WARN_INSN(insn, "stack state mismatch: type1=%d type2=%d",
+			  cfi1->type, cfi2->type);
+
+	} else if (cfi1->drap != cfi2->drap ||
+		   (cfi1->drap && cfi1->drap_reg != cfi2->drap_reg) ||
+		   (cfi1->drap && cfi1->drap_offset != cfi2->drap_offset)) {
+
+		WARN_INSN(insn, "stack state mismatch: drap1=%d(%d,%d) drap2=%d(%d,%d)",
+			  cfi1->drap, cfi1->drap_reg, cfi1->drap_offset,
+			  cfi2->drap, cfi2->drap_reg, cfi2->drap_offset);
+
+	} else
+		return true;
+
+	return false;
+}
+
+static inline bool func_uaccess_safe(struct symbol *func)
+{
+	if (func)
+		return func->uaccess_safe;
+
+	return false;
+}
+
+static inline const char *call_dest_name(struct instruction *insn)
+{
+	static char pvname[19];
+	struct reloc *reloc;
+	int idx;
+
+	if (insn_call_dest(insn))
+		return insn_call_dest(insn)->name;
+
+	reloc = insn_reloc(NULL, insn);
+	if (reloc && !strcmp(reloc->sym->name, "pv_ops")) {
+		idx = (reloc_addend(reloc) / sizeof(void *));
+		snprintf(pvname, sizeof(pvname), "pv_ops[%d]", idx);
+		return pvname;
+	}
+
+	return "{dynamic}";
+}
+
+static bool pv_call_dest(struct objtool_file *file, struct instruction *insn)
+{
+	struct symbol *target;
+	struct reloc *reloc;
+	int idx;
+
+	reloc = insn_reloc(file, insn);
+	if (!reloc || strcmp(reloc->sym->name, "pv_ops"))
+		return false;
+
+	idx = (arch_dest_reloc_offset(reloc_addend(reloc)) / sizeof(void *));
+
+	if (file->pv_ops[idx].clean)
+		return true;
+
+	file->pv_ops[idx].clean = true;
+
+	list_for_each_entry(target, &file->pv_ops[idx].targets, pv_target) {
+		if (!target->sec->noinstr) {
+			WARN("pv_ops[%d]: %s", idx, target->name);
+			file->pv_ops[idx].clean = false;
+		}
+	}
+
+	return file->pv_ops[idx].clean;
+}
+
+static inline bool noinstr_call_dest(struct objtool_file *file,
+				     struct instruction *insn,
+				     struct symbol *func)
+{
+	/*
+	 * We can't deal with indirect function calls at present;
+	 * assume they're instrumented.
+	 */
+	if (!func) {
+		if (file->pv_ops)
+			return pv_call_dest(file, insn);
+
+		return false;
+	}
+
+	/*
+	 * If the symbol is from a noinstr section; we good.
+	 */
+	if (func->sec->noinstr)
+		return true;
+
+	/*
+	 * If the symbol is a static_call trampoline, we can't tell.
+	 */
+	if (func->static_call_tramp)
+		return true;
+
+	/*
+	 * The __ubsan_handle_*() calls are like WARN(), they only happen when
+	 * something 'BAD' happened. At the risk of taking the machine down,
+	 * let them proceed to get the message out.
+	 */
+	if (!strncmp(func->name, "__ubsan_handle_", 15))
+		return true;
+
+	return false;
+}
+
+static int validate_call(struct objtool_file *file,
+			 struct instruction *insn,
+			 struct insn_state *state)
+{
+	if (state->noinstr && state->instr <= 0 &&
+	    !noinstr_call_dest(file, insn, insn_call_dest(insn))) {
+		WARN_INSN(insn, "call to %s() leaves .noinstr.text section", call_dest_name(insn));
+		return 1;
+	}
+
+	if (state->uaccess && !func_uaccess_safe(insn_call_dest(insn))) {
+		WARN_INSN(insn, "call to %s() with UACCESS enabled", call_dest_name(insn));
+		return 1;
+	}
+
+	if (state->df) {
+		WARN_INSN(insn, "call to %s() with DF set", call_dest_name(insn));
+		return 1;
+	}
+
+	return 0;
+}
+
+static int validate_sibling_call(struct objtool_file *file,
+				 struct instruction *insn,
+				 struct insn_state *state)
+{
+	if (insn_func(insn) && has_modified_stack_frame(insn, state)) {
+		WARN_INSN(insn, "sibling call from callable instruction with modified stack frame");
+		return 1;
+	}
+
+	return validate_call(file, insn, state);
+}
+
+static int validate_return(struct symbol *func, struct instruction *insn, struct insn_state *state)
+{
+	if (state->noinstr && state->instr > 0) {
+		WARN_INSN(insn, "return with instrumentation enabled");
+		return 1;
+	}
+
+	if (state->uaccess && !func_uaccess_safe(func)) {
+		WARN_INSN(insn, "return with UACCESS enabled");
+		return 1;
+	}
+
+	if (!state->uaccess && func_uaccess_safe(func)) {
+		WARN_INSN(insn, "return with UACCESS disabled from a UACCESS-safe function");
+		return 1;
+	}
+
+	if (state->df) {
+		WARN_INSN(insn, "return with DF set");
+		return 1;
+	}
+
+	if (func && has_modified_stack_frame(insn, state)) {
+		WARN_INSN(insn, "return with modified stack frame");
+		return 1;
+	}
+
+	if (state->cfi.bp_scratch) {
+		WARN_INSN(insn, "BP used as a scratch register");
+		return 1;
+	}
+
+	return 0;
+}
+
+static struct instruction *next_insn_to_validate(struct objtool_file *file,
+						 struct instruction *insn)
+{
+	struct alt_group *alt_group = insn->alt_group;
+
+	/*
+	 * Simulate the fact that alternatives are patched in-place.  When the
+	 * end of a replacement alt_group is reached, redirect objtool flow to
+	 * the end of the original alt_group.
+	 *
+	 * insn->alts->insn -> alt_group->first_insn
+	 *		       ...
+	 *		       alt_group->last_insn
+	 *		       [alt_group->nop]      -> next(orig_group->last_insn)
+	 */
+	if (alt_group) {
+		if (alt_group->nop) {
+			/* ->nop implies ->orig_group */
+			if (insn == alt_group->last_insn)
+				return alt_group->nop;
+			if (insn == alt_group->nop)
+				goto next_orig;
+		}
+		if (insn == alt_group->last_insn && alt_group->orig_group)
+			goto next_orig;
+	}
+
+	return next_insn_same_sec(file, insn);
+
+next_orig:
+	return next_insn_same_sec(file, alt_group->orig_group->last_insn);
+}
+
+/*
+ * Follow the branch starting at the given instruction, and recursively follow
+ * any other branches (jumps).  Meanwhile, track the frame pointer state at
+ * each instruction and validate all the rules described in
+ * tools/objtool/Documentation/objtool.txt.
+ */
+static int validate_branch(struct objtool_file *file, struct symbol *func,
+			   struct instruction *insn, struct insn_state state)
+{
+	struct alternative *alt;
+	struct instruction *next_insn, *prev_insn = NULL;
+	struct section *sec;
+	u8 visited;
+	int ret;
+
+	sec = insn->sec;
+
+	while (1) {
+		next_insn = next_insn_to_validate(file, insn);
+
+		if (func && insn_func(insn) && func != insn_func(insn)->pfunc) {
+			/* Ignore KCFI type preambles, which always fall through */
+			if (!strncmp(func->name, "__cfi_", 6) ||
+			    !strncmp(func->name, "__pfx_", 6))
+				return 0;
+
+			WARN("%s() falls through to next function %s()",
+			     func->name, insn_func(insn)->name);
+			return 1;
+		}
+
+		if (func && insn->ignore) {
+			WARN_INSN(insn, "BUG: why am I validating an ignored function?");
+			return 1;
+		}
+
+		visited = VISITED_BRANCH << state.uaccess;
+		if (insn->visited & VISITED_BRANCH_MASK) {
+			if (!insn->hint && !insn_cfi_match(insn, &state.cfi))
+				return 1;
+
+			if (insn->visited & visited)
+				return 0;
+		} else {
+			nr_insns_visited++;
+		}
+
+		if (state.noinstr)
+			state.instr += insn->instr;
+
+		if (insn->hint) {
+			if (insn->restore) {
+				struct instruction *save_insn, *i;
+
+				i = insn;
+				save_insn = NULL;
+
+				sym_for_each_insn_continue_reverse(file, func, i) {
+					if (i->save) {
+						save_insn = i;
+						break;
+					}
+				}
+
+				if (!save_insn) {
+					WARN_INSN(insn, "no corresponding CFI save for CFI restore");
+					return 1;
+				}
+
+				if (!save_insn->visited) {
+					WARN_INSN(insn, "objtool isn't smart enough to handle this CFI save/restore combo");
+					return 1;
+				}
+
+				insn->cfi = save_insn->cfi;
+				nr_cfi_reused++;
+			}
+
+			state.cfi = *insn->cfi;
+		} else {
+			/* XXX track if we actually changed state.cfi */
+
+			if (prev_insn && !cficmp(prev_insn->cfi, &state.cfi)) {
+				insn->cfi = prev_insn->cfi;
+				nr_cfi_reused++;
+			} else {
+				insn->cfi = cfi_hash_find_or_add(&state.cfi);
+			}
+		}
+
+		insn->visited |= visited;
+
+		if (propagate_alt_cfi(file, insn))
+			return 1;
+
+		if (!insn->ignore_alts && insn->alts) {
+			bool skip_orig = false;
+
+			for (alt = insn->alts; alt; alt = alt->next) {
+				if (alt->skip_orig)
+					skip_orig = true;
+
+				ret = validate_branch(file, func, alt->insn, state);
+				if (ret) {
+					BT_INSN(insn, "(alt)");
+					return ret;
+				}
+			}
+
+			if (skip_orig)
+				return 0;
+		}
+
+		if (handle_insn_ops(insn, next_insn, &state))
+			return 1;
+
+		switch (insn->type) {
+
+		case INSN_RETURN:
+			return validate_return(func, insn, &state);
+
+		case INSN_CALL:
+		case INSN_CALL_DYNAMIC:
+			ret = validate_call(file, insn, &state);
+			if (ret)
+				return ret;
+
+			if (opts.stackval && func && !is_special_call(insn) &&
+			    !has_valid_stack_frame(&state)) {
+				WARN_INSN(insn, "call without frame pointer save/setup");
+				return 1;
+			}
+
+			if (insn->dead_end)
+				return 0;
+
+			break;
+
+		case INSN_JUMP_CONDITIONAL:
+		case INSN_JUMP_UNCONDITIONAL:
+			if (is_sibling_call(insn)) {
+				ret = validate_sibling_call(file, insn, &state);
+				if (ret)
+					return ret;
+
+			} else if (insn->jump_dest) {
+				ret = validate_branch(file, func,
+						      insn->jump_dest, state);
+				if (ret) {
+					BT_INSN(insn, "(branch)");
+					return ret;
+				}
+			}
+
+			if (insn->type == INSN_JUMP_UNCONDITIONAL)
+				return 0;
+
+			break;
+
+		case INSN_JUMP_DYNAMIC:
+		case INSN_JUMP_DYNAMIC_CONDITIONAL:
+			if (is_sibling_call(insn)) {
+				ret = validate_sibling_call(file, insn, &state);
+				if (ret)
+					return ret;
+			}
+
+			if (insn->type == INSN_JUMP_DYNAMIC)
+				return 0;
+
+			break;
+
+		case INSN_CONTEXT_SWITCH:
+			if (func && (!next_insn || !next_insn->hint)) {
+				WARN_INSN(insn, "unsupported instruction in callable function");
+				return 1;
+			}
+			return 0;
+
+		case INSN_STAC:
+			if (state.uaccess) {
+				WARN_INSN(insn, "recursive UACCESS enable");
+				return 1;
+			}
+
+			state.uaccess = true;
+			break;
+
+		case INSN_CLAC:
+			if (!state.uaccess && func) {
+				WARN_INSN(insn, "redundant UACCESS disable");
+				return 1;
+			}
+
+			if (func_uaccess_safe(func) && !state.uaccess_stack) {
+				WARN_INSN(insn, "UACCESS-safe disables UACCESS");
+				return 1;
+			}
+
+			state.uaccess = false;
+			break;
+
+		case INSN_STD:
+			if (state.df) {
+				WARN_INSN(insn, "recursive STD");
+				return 1;
+			}
+
+			state.df = true;
+			break;
+
+		case INSN_CLD:
+			if (!state.df && func) {
+				WARN_INSN(insn, "redundant CLD");
+				return 1;
+			}
+
+			state.df = false;
+			break;
+
+		default:
+			break;
+		}
+
+		if (insn->dead_end)
+			return 0;
+
+		if (!next_insn) {
+			if (state.cfi.cfa.base == CFI_UNDEFINED)
+				return 0;
+			WARN("%s: unexpected end of section", sec->name);
+			return 1;
+		}
+
+		prev_insn = insn;
+		insn = next_insn;
+	}
+
+	return 0;
+}
+
+static int validate_unwind_hint(struct objtool_file *file,
+				  struct instruction *insn,
+				  struct insn_state *state)
+{
+	if (insn->hint && !insn->visited && !insn->ignore) {
+		int ret = validate_branch(file, insn_func(insn), insn, *state);
+		if (ret)
+			BT_INSN(insn, "<=== (hint)");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int validate_unwind_hints(struct objtool_file *file, struct section *sec)
+{
+	struct instruction *insn;
+	struct insn_state state;
+	int warnings = 0;
+
+	if (!file->hints)
+		return 0;
+
+	init_insn_state(file, &state, sec);
+
+	if (sec) {
+		sec_for_each_insn(file, sec, insn)
+			warnings += validate_unwind_hint(file, insn, &state);
+	} else {
+		for_each_insn(file, insn)
+			warnings += validate_unwind_hint(file, insn, &state);
+	}
+
+	return warnings;
+}
+
+/*
+ * Validate rethunk entry constraint: must untrain RET before the first RET.
+ *
+ * Follow every branch (intra-function) and ensure VALIDATE_UNRET_END comes
+ * before an actual RET instruction.
+ */
+static int validate_unret(struct objtool_file *file, struct instruction *insn)
+{
+	struct instruction *next, *dest;
+	int ret;
+
+	for (;;) {
+		next = next_insn_to_validate(file, insn);
+
+		if (insn->visited & VISITED_UNRET)
+			return 0;
+
+		insn->visited |= VISITED_UNRET;
+
+		if (!insn->ignore_alts && insn->alts) {
+			struct alternative *alt;
+			bool skip_orig = false;
+
+			for (alt = insn->alts; alt; alt = alt->next) {
+				if (alt->skip_orig)
+					skip_orig = true;
+
+				ret = validate_unret(file, alt->insn);
+				if (ret) {
+					BT_INSN(insn, "(alt)");
+					return ret;
+				}
+			}
+
+			if (skip_orig)
+				return 0;
+		}
+
+		switch (insn->type) {
+
+		case INSN_CALL_DYNAMIC:
+		case INSN_JUMP_DYNAMIC:
+		case INSN_JUMP_DYNAMIC_CONDITIONAL:
+			WARN_INSN(insn, "early indirect call");
+			return 1;
+
+		case INSN_JUMP_UNCONDITIONAL:
+		case INSN_JUMP_CONDITIONAL:
+			if (!is_sibling_call(insn)) {
+				if (!insn->jump_dest) {
+					WARN_INSN(insn, "unresolved jump target after linking?!?");
+					return -1;
+				}
+				ret = validate_unret(file, insn->jump_dest);
+				if (ret) {
+					BT_INSN(insn, "(branch%s)",
+						insn->type == INSN_JUMP_CONDITIONAL ? "-cond" : "");
+					return ret;
+				}
+
+				if (insn->type == INSN_JUMP_UNCONDITIONAL)
+					return 0;
+
+				break;
+			}
+
+			/* fallthrough */
+		case INSN_CALL:
+			dest = find_insn(file, insn_call_dest(insn)->sec,
+					 insn_call_dest(insn)->offset);
+			if (!dest) {
+				WARN("Unresolved function after linking!?: %s",
+				     insn_call_dest(insn)->name);
+				return -1;
+			}
+
+			ret = validate_unret(file, dest);
+			if (ret) {
+				BT_INSN(insn, "(call)");
+				return ret;
+			}
+			/*
+			 * If a call returns without error, it must have seen UNTRAIN_RET.
+			 * Therefore any non-error return is a success.
+			 */
+			return 0;
+
+		case INSN_RETURN:
+			WARN_INSN(insn, "RET before UNTRAIN");
+			return 1;
+
+		case INSN_NOP:
+			if (insn->retpoline_safe)
+				return 0;
+			break;
+
+		default:
+			break;
+		}
+
+		if (!next) {
+			WARN_INSN(insn, "teh end!");
+			return -1;
+		}
+		insn = next;
+	}
+
+	return 0;
+}
+
+/*
+ * Validate that all branches starting at VALIDATE_UNRET_BEGIN encounter
+ * VALIDATE_UNRET_END before RET.
+ */
+static int validate_unrets(struct objtool_file *file)
+{
+	struct instruction *insn;
+	int ret, warnings = 0;
+
+	for_each_insn(file, insn) {
+		if (!insn->unret)
+			continue;
+
+		ret = validate_unret(file, insn);
+		if (ret < 0) {
+			WARN_INSN(insn, "Failed UNRET validation");
+			return ret;
+		}
+		warnings += ret;
+	}
+
+	return warnings;
+}
+
+static int validate_retpoline(struct objtool_file *file)
+{
+	struct instruction *insn;
+	int warnings = 0;
+
+	for_each_insn(file, insn) {
+		if (insn->type != INSN_JUMP_DYNAMIC &&
+		    insn->type != INSN_CALL_DYNAMIC &&
+		    insn->type != INSN_RETURN)
+			continue;
+
+		if (insn->retpoline_safe)
+			continue;
+
+		if (insn->sec->init)
+			continue;
+
+		if (insn->type == INSN_RETURN) {
+			if (opts.rethunk) {
+				WARN_INSN(insn, "'naked' return found in RETHUNK build");
+			} else
+				continue;
+		} else {
+			WARN_INSN(insn, "indirect %s found in RETPOLINE build",
+				  insn->type == INSN_JUMP_DYNAMIC ? "jump" : "call");
+		}
+
+		warnings++;
+	}
+
+	return warnings;
+}
+
+static bool is_kasan_insn(struct instruction *insn)
+{
+	return (insn->type == INSN_CALL &&
+		!strcmp(insn_call_dest(insn)->name, "__asan_handle_no_return"));
+}
+
+static bool is_ubsan_insn(struct instruction *insn)
+{
+	return (insn->type == INSN_CALL &&
+		!strcmp(insn_call_dest(insn)->name,
+			"__ubsan_handle_builtin_unreachable"));
+}
+
+static bool ignore_unreachable_insn(struct objtool_file *file, struct instruction *insn)
+{
+	int i;
+	struct instruction *prev_insn;
+
+	if (insn->ignore || insn->type == INSN_NOP || insn->type == INSN_TRAP)
+		return true;
+
+	/*
+	 * Ignore alternative replacement instructions.  This can happen
+	 * when a whitelisted function uses one of the ALTERNATIVE macros.
+	 */
+	if (!strcmp(insn->sec->name, ".altinstr_replacement") ||
+	    !strcmp(insn->sec->name, ".altinstr_aux"))
+		return true;
+
+	/*
+	 * Whole archive runs might encounter dead code from weak symbols.
+	 * This is where the linker will have dropped the weak symbol in
+	 * favour of a regular symbol, but leaves the code in place.
+	 *
+	 * In this case we'll find a piece of code (whole function) that is not
+	 * covered by a !section symbol. Ignore them.
+	 */
+	if (opts.link && !insn_func(insn)) {
+		int size = find_symbol_hole_containing(insn->sec, insn->offset);
+		unsigned long end = insn->offset + size;
+
+		if (!size) /* not a hole */
+			return false;
+
+		if (size < 0) /* hole until the end */
+			return true;
+
+		sec_for_each_insn_continue(file, insn) {
+			/*
+			 * If we reach a visited instruction at or before the
+			 * end of the hole, ignore the unreachable.
+			 */
+			if (insn->visited)
+				return true;
+
+			if (insn->offset >= end)
+				break;
+
+			/*
+			 * If this hole jumps to a .cold function, mark it ignore too.
+			 */
+			if (insn->jump_dest && insn_func(insn->jump_dest) &&
+			    strstr(insn_func(insn->jump_dest)->name, ".cold")) {
+				struct instruction *dest = insn->jump_dest;
+				func_for_each_insn(file, insn_func(dest), dest)
+					dest->ignore = true;
+			}
+		}
+
+		return false;
+	}
+
+	if (!insn_func(insn))
+		return false;
+
+	if (insn_func(insn)->static_call_tramp)
+		return true;
+
+	/*
+	 * CONFIG_UBSAN_TRAP inserts a UD2 when it sees
+	 * __builtin_unreachable().  The BUG() macro has an unreachable() after
+	 * the UD2, which causes GCC's undefined trap logic to emit another UD2
+	 * (or occasionally a JMP to UD2).
+	 *
+	 * It may also insert a UD2 after calling a __noreturn function.
+	 */
+	prev_insn = prev_insn_same_sec(file, insn);
+	if (prev_insn->dead_end &&
+	    (insn->type == INSN_BUG ||
+	     (insn->type == INSN_JUMP_UNCONDITIONAL &&
+	      insn->jump_dest && insn->jump_dest->type == INSN_BUG)))
+		return true;
+
+	/*
+	 * Check if this (or a subsequent) instruction is related to
+	 * CONFIG_UBSAN or CONFIG_KASAN.
+	 *
+	 * End the search at 5 instructions to avoid going into the weeds.
+	 */
+	for (i = 0; i < 5; i++) {
+
+		if (is_kasan_insn(insn) || is_ubsan_insn(insn))
+			return true;
+
+		if (insn->type == INSN_JUMP_UNCONDITIONAL) {
+			if (insn->jump_dest &&
+			    insn_func(insn->jump_dest) == insn_func(insn)) {
+				insn = insn->jump_dest;
+				continue;
+			}
+
+			break;
+		}
+
+		if (insn->offset + insn->len >= insn_func(insn)->offset + insn_func(insn)->len)
+			break;
+
+		insn = next_insn_same_sec(file, insn);
+	}
+
+	return false;
+}
+
+static int add_prefix_symbol(struct objtool_file *file, struct symbol *func)
+{
+	struct instruction *insn, *prev;
+	struct cfi_state *cfi;
+
+	insn = find_insn(file, func->sec, func->offset);
+	if (!insn)
+		return -1;
+
+	for (prev = prev_insn_same_sec(file, insn);
+	     prev;
+	     prev = prev_insn_same_sec(file, prev)) {
+		u64 offset;
+
+		if (prev->type != INSN_NOP)
+			return -1;
+
+		offset = func->offset - prev->offset;
+
+		if (offset > opts.prefix)
+			return -1;
+
+		if (offset < opts.prefix)
+			continue;
+
+		elf_create_prefix_symbol(file->elf, func, opts.prefix);
+		break;
+	}
+
+	if (!prev)
+		return -1;
+
+	if (!insn->cfi) {
+		/*
+		 * This can happen if stack validation isn't enabled or the
+		 * function is annotated with STACK_FRAME_NON_STANDARD.
+		 */
+		return 0;
+	}
+
+	/* Propagate insn->cfi to the prefix code */
+	cfi = cfi_hash_find_or_add(insn->cfi);
+	for (; prev != insn; prev = next_insn_same_sec(file, prev))
+		prev->cfi = cfi;
+
+	return 0;
+}
+
+static int add_prefix_symbols(struct objtool_file *file)
+{
+	struct section *sec;
+	struct symbol *func;
+
+	for_each_sec(file, sec) {
+		if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+			continue;
+
+		sec_for_each_sym(sec, func) {
+			if (func->type != STT_FUNC)
+				continue;
+
+			add_prefix_symbol(file, func);
+		}
+	}
+
+	return 0;
+}
+
+static int validate_symbol(struct objtool_file *file, struct section *sec,
+			   struct symbol *sym, struct insn_state *state)
+{
+	struct instruction *insn;
+	int ret;
+
+	if (!sym->len) {
+		WARN("%s() is missing an ELF size annotation", sym->name);
+		return 1;
+	}
+
+	if (sym->pfunc != sym || sym->alias != sym)
+		return 0;
+
+	insn = find_insn(file, sec, sym->offset);
+	if (!insn || insn->ignore || insn->visited)
+		return 0;
+
+	state->uaccess = sym->uaccess_safe;
+
+	ret = validate_branch(file, insn_func(insn), insn, *state);
+	if (ret)
+		BT_INSN(insn, "<=== (sym)");
+	return ret;
+}
+
+static int validate_section(struct objtool_file *file, struct section *sec)
+{
+	struct insn_state state;
+	struct symbol *func;
+	int warnings = 0;
+
+	sec_for_each_sym(sec, func) {
+		if (func->type != STT_FUNC)
+			continue;
+
+		init_insn_state(file, &state, sec);
+		set_func_state(&state.cfi);
+
+		warnings += validate_symbol(file, sec, func, &state);
+	}
+
+	return warnings;
+}
+
+static int validate_noinstr_sections(struct objtool_file *file)
+{
+	struct section *sec;
+	int warnings = 0;
+
+	sec = find_section_by_name(file->elf, ".noinstr.text");
+	if (sec) {
+		warnings += validate_section(file, sec);
+		warnings += validate_unwind_hints(file, sec);
+	}
+
+	sec = find_section_by_name(file->elf, ".entry.text");
+	if (sec) {
+		warnings += validate_section(file, sec);
+		warnings += validate_unwind_hints(file, sec);
+	}
+
+	sec = find_section_by_name(file->elf, ".cpuidle.text");
+	if (sec) {
+		warnings += validate_section(file, sec);
+		warnings += validate_unwind_hints(file, sec);
+	}
+
+	return warnings;
+}
+
+static int validate_functions(struct objtool_file *file)
+{
+	struct section *sec;
+	int warnings = 0;
+
+	for_each_sec(file, sec) {
+		if (!(sec->sh.sh_flags & SHF_EXECINSTR))
+			continue;
+
+		warnings += validate_section(file, sec);
+	}
+
+	return warnings;
+}
+
+static void mark_endbr_used(struct instruction *insn)
+{
+	if (!list_empty(&insn->call_node))
+		list_del_init(&insn->call_node);
+}
+
+static bool noendbr_range(struct objtool_file *file, struct instruction *insn)
+{
+	struct symbol *sym = find_symbol_containing(insn->sec, insn->offset-1);
+	struct instruction *first;
+
+	if (!sym)
+		return false;
+
+	first = find_insn(file, sym->sec, sym->offset);
+	if (!first)
+		return false;
+
+	if (first->type != INSN_ENDBR && !first->noendbr)
+		return false;
+
+	return insn->offset == sym->offset + sym->len;
+}
+
+static int validate_ibt_insn(struct objtool_file *file, struct instruction *insn)
+{
+	struct instruction *dest;
+	struct reloc *reloc;
+	unsigned long off;
+	int warnings = 0;
+
+	/*
+	 * Looking for function pointer load relocations.  Ignore
+	 * direct/indirect branches:
+	 */
+	switch (insn->type) {
+	case INSN_CALL:
+	case INSN_CALL_DYNAMIC:
+	case INSN_JUMP_CONDITIONAL:
+	case INSN_JUMP_UNCONDITIONAL:
+	case INSN_JUMP_DYNAMIC:
+	case INSN_JUMP_DYNAMIC_CONDITIONAL:
+	case INSN_RETURN:
+	case INSN_NOP:
+		return 0;
+	default:
+		break;
+	}
+
+	for (reloc = insn_reloc(file, insn);
+	     reloc;
+	     reloc = find_reloc_by_dest_range(file->elf, insn->sec,
+					      reloc_offset(reloc) + 1,
+					      (insn->offset + insn->len) - (reloc_offset(reloc) + 1))) {
+
+		/*
+		 * static_call_update() references the trampoline, which
+		 * doesn't have (or need) ENDBR.  Skip warning in that case.
+		 */
+		if (reloc->sym->static_call_tramp)
+			continue;
+
+		off = reloc->sym->offset;
+		if (reloc_type(reloc) == R_X86_64_PC32 ||
+		    reloc_type(reloc) == R_X86_64_PLT32)
+			off += arch_dest_reloc_offset(reloc_addend(reloc));
+		else
+			off += reloc_addend(reloc);
+
+		dest = find_insn(file, reloc->sym->sec, off);
+		if (!dest)
+			continue;
+
+		if (dest->type == INSN_ENDBR) {
+			mark_endbr_used(dest);
+			continue;
+		}
+
+		if (insn_func(dest) && insn_func(insn) &&
+		    insn_func(dest)->pfunc == insn_func(insn)->pfunc) {
+			/*
+			 * Anything from->to self is either _THIS_IP_ or
+			 * IRET-to-self.
+			 *
+			 * There is no sane way to annotate _THIS_IP_ since the
+			 * compiler treats the relocation as a constant and is
+			 * happy to fold in offsets, skewing any annotation we
+			 * do, leading to vast amounts of false-positives.
+			 *
+			 * There's also compiler generated _THIS_IP_ through
+			 * KCOV and such which we have no hope of annotating.
+			 *
+			 * As such, blanket accept self-references without
+			 * issue.
+			 */
+			continue;
+		}
+
+		/*
+		 * Accept anything ANNOTATE_NOENDBR.
+		 */
+		if (dest->noendbr)
+			continue;
+
+		/*
+		 * Accept if this is the instruction after a symbol
+		 * that is (no)endbr -- typical code-range usage.
+		 */
+		if (noendbr_range(file, dest))
+			continue;
+
+		WARN_INSN(insn, "relocation to !ENDBR: %s", offstr(dest->sec, dest->offset));
+
+		warnings++;
+	}
+
+	return warnings;
+}
+
+static int validate_ibt_data_reloc(struct objtool_file *file,
+				   struct reloc *reloc)
+{
+	struct instruction *dest;
+
+	dest = find_insn(file, reloc->sym->sec,
+			 reloc->sym->offset + reloc_addend(reloc));
+	if (!dest)
+		return 0;
+
+	if (dest->type == INSN_ENDBR) {
+		mark_endbr_used(dest);
+		return 0;
+	}
+
+	if (dest->noendbr)
+		return 0;
+
+	WARN_FUNC("data relocation to !ENDBR: %s",
+		  reloc->sec->base, reloc_offset(reloc),
+		  offstr(dest->sec, dest->offset));
+
+	return 1;
+}
+
+/*
+ * Validate IBT rules and remove used ENDBR instructions from the seal list.
+ * Unused ENDBR instructions will be annotated for sealing (i.e., replaced with
+ * NOPs) later, in create_ibt_endbr_seal_sections().
+ */
+static int validate_ibt(struct objtool_file *file)
+{
+	struct section *sec;
+	struct reloc *reloc;
+	struct instruction *insn;
+	int warnings = 0;
+
+	for_each_insn(file, insn)
+		warnings += validate_ibt_insn(file, insn);
+
+	for_each_sec(file, sec) {
+
+		/* Already done by validate_ibt_insn() */
+		if (sec->sh.sh_flags & SHF_EXECINSTR)
+			continue;
+
+		if (!sec->rsec)
+			continue;
+
+		/*
+		 * These sections can reference text addresses, but not with
+		 * the intent to indirect branch to them.
+		 */
+		if ((!strncmp(sec->name, ".discard", 8) &&
+		     strcmp(sec->name, ".discard.ibt_endbr_noseal"))	||
+		    !strncmp(sec->name, ".debug", 6)			||
+		    !strcmp(sec->name, ".altinstructions")		||
+		    !strcmp(sec->name, ".ibt_endbr_seal")		||
+		    !strcmp(sec->name, ".orc_unwind_ip")		||
+		    !strcmp(sec->name, ".parainstructions")		||
+		    !strcmp(sec->name, ".retpoline_sites")		||
+		    !strcmp(sec->name, ".smp_locks")			||
+		    !strcmp(sec->name, ".static_call_sites")		||
+		    !strcmp(sec->name, "_error_injection_whitelist")	||
+		    !strcmp(sec->name, "_kprobe_blacklist")		||
+		    !strcmp(sec->name, "__bug_table")			||
+		    !strcmp(sec->name, "__ex_table")			||
+		    !strcmp(sec->name, "__jump_table")			||
+		    !strcmp(sec->name, "__mcount_loc")			||
+		    !strcmp(sec->name, ".kcfi_traps")			||
+		    strstr(sec->name, "__patchable_function_entries"))
+			continue;
+
+		for_each_reloc(sec->rsec, reloc)
+			warnings += validate_ibt_data_reloc(file, reloc);
+	}
+
+	return warnings;
+}
+
+static int validate_sls(struct objtool_file *file)
+{
+	struct instruction *insn, *next_insn;
+	int warnings = 0;
+
+	for_each_insn(file, insn) {
+		next_insn = next_insn_same_sec(file, insn);
+
+		if (insn->retpoline_safe)
+			continue;
+
+		switch (insn->type) {
+		case INSN_RETURN:
+			if (!next_insn || next_insn->type != INSN_TRAP) {
+				WARN_INSN(insn, "missing int3 after ret");
+				warnings++;
+			}
+
+			break;
+		case INSN_JUMP_DYNAMIC:
+			if (!next_insn || next_insn->type != INSN_TRAP) {
+				WARN_INSN(insn, "missing int3 after indirect jump");
+				warnings++;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+
+	return warnings;
+}
+
+static bool ignore_noreturn_call(struct instruction *insn)
+{
+	struct symbol *call_dest = insn_call_dest(insn);
+
+	/*
+	 * FIXME: hack, we need a real noreturn solution
+	 *
+	 * Problem is, exc_double_fault() may or may not return, depending on
+	 * whether CONFIG_X86_ESPFIX64 is set.  But objtool has no visibility
+	 * to the kernel config.
+	 *
+	 * Other potential ways to fix it:
+	 *
+	 *   - have compiler communicate __noreturn functions somehow
+	 *   - remove CONFIG_X86_ESPFIX64
+	 *   - read the .config file
+	 *   - add a cmdline option
+	 *   - create a generic objtool annotation format (vs a bunch of custom
+	 *     formats) and annotate it
+	 */
+	if (!strcmp(call_dest->name, "exc_double_fault")) {
+		/* prevent further unreachable warnings for the caller */
+		insn->sym->warned = 1;
+		return true;
+	}
+
+	return false;
+}
+
+static int validate_reachable_instructions(struct objtool_file *file)
+{
+	struct instruction *insn, *prev_insn;
+	struct symbol *call_dest;
+	int warnings = 0;
+
+	if (file->ignore_unreachables)
+		return 0;
+
+	for_each_insn(file, insn) {
+		if (insn->visited || ignore_unreachable_insn(file, insn))
+			continue;
+
+		prev_insn = prev_insn_same_sec(file, insn);
+		if (prev_insn && prev_insn->dead_end) {
+			call_dest = insn_call_dest(prev_insn);
+			if (call_dest && !ignore_noreturn_call(prev_insn)) {
+				WARN_INSN(insn, "%s() is missing a __noreturn annotation",
+					  call_dest->name);
+				warnings++;
+				continue;
+			}
+		}
+
+		WARN_INSN(insn, "unreachable instruction");
+		warnings++;
+	}
+
+	return warnings;
+}
+
+/* 'funcs' is a space-separated list of function names */
+static int disas_funcs(const char *funcs)
+{
+	const char *objdump_str, *cross_compile;
+	int size, ret;
+	char *cmd;
+
+	cross_compile = getenv("CROSS_COMPILE");
+
+	objdump_str = "%sobjdump -wdr %s | gawk -M -v _funcs='%s' '"
+			"BEGIN { split(_funcs, funcs); }"
+			"/^$/ { func_match = 0; }"
+			"/<.*>:/ { "
+				"f = gensub(/.*<(.*)>:/, \"\\\\1\", 1);"
+				"for (i in funcs) {"
+					"if (funcs[i] == f) {"
+						"func_match = 1;"
+						"base = strtonum(\"0x\" $1);"
+						"break;"
+					"}"
+				"}"
+			"}"
+			"{"
+				"if (func_match) {"
+					"addr = strtonum(\"0x\" $1);"
+					"printf(\"%%04x \", addr - base);"
+					"print;"
+				"}"
+			"}' 1>&2";
+
+	/* fake snprintf() to calculate the size */
+	size = snprintf(NULL, 0, objdump_str, cross_compile, objname, funcs) + 1;
+	if (size <= 0) {
+		WARN("objdump string size calculation failed");
+		return -1;
+	}
+
+	cmd = malloc(size);
+
+	/* real snprintf() */
+	snprintf(cmd, size, objdump_str, cross_compile, objname, funcs);
+	ret = system(cmd);
+	if (ret) {
+		WARN("disassembly failed: %d", ret);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int disas_warned_funcs(struct objtool_file *file)
+{
+	struct symbol *sym;
+	char *funcs = NULL, *tmp;
+
+	for_each_sym(file, sym) {
+		if (sym->warned) {
+			if (!funcs) {
+				funcs = malloc(strlen(sym->name) + 1);
+				strcpy(funcs, sym->name);
+			} else {
+				tmp = malloc(strlen(funcs) + strlen(sym->name) + 2);
+				sprintf(tmp, "%s %s", funcs, sym->name);
+				free(funcs);
+				funcs = tmp;
+			}
+		}
+	}
+
+	if (funcs)
+		disas_funcs(funcs);
+
+	return 0;
+}
+
+struct insn_chunk {
+	void *addr;
+	struct insn_chunk *next;
+};
+
+/*
+ * Reduce peak RSS usage by freeing insns memory before writing the ELF file,
+ * which can trigger more allocations for .debug_* sections whose data hasn't
+ * been read yet.
+ */
+static void free_insns(struct objtool_file *file)
+{
+	struct instruction *insn;
+	struct insn_chunk *chunks = NULL, *chunk;
+
+	for_each_insn(file, insn) {
+		if (!insn->idx) {
+			chunk = malloc(sizeof(*chunk));
+			chunk->addr = insn;
+			chunk->next = chunks;
+			chunks = chunk;
+		}
+	}
+
+	for (chunk = chunks; chunk; chunk = chunk->next)
+		free(chunk->addr);
+}
+
+int check(struct objtool_file *file)
+{
+	int ret, warnings = 0;
+
+	arch_initial_func_cfi_state(&initial_func_cfi);
+	init_cfi_state(&init_cfi);
+	init_cfi_state(&func_cfi);
+	set_func_state(&func_cfi);
+	init_cfi_state(&force_undefined_cfi);
+	force_undefined_cfi.force_undefined = true;
+
+	if (!cfi_hash_alloc(1UL << (file->elf->symbol_bits - 3)))
+		goto out;
+
+	cfi_hash_add(&init_cfi);
+	cfi_hash_add(&func_cfi);
+
+	ret = decode_sections(file);
+	if (ret < 0)
+		goto out;
+
+	warnings += ret;
+
+	if (!nr_insns)
+		goto out;
+
+	if (opts.retpoline) {
+		ret = validate_retpoline(file);
+		if (ret < 0)
+			return ret;
+		warnings += ret;
+	}
+
+	if (opts.stackval || opts.orc || opts.uaccess) {
+		ret = validate_functions(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+
+		ret = validate_unwind_hints(file, NULL);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+
+		if (!warnings) {
+			ret = validate_reachable_instructions(file);
+			if (ret < 0)
+				goto out;
+			warnings += ret;
+		}
+
+	} else if (opts.noinstr) {
+		ret = validate_noinstr_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.unret) {
+		/*
+		 * Must be after validate_branch() and friends, it plays
+		 * further games with insn->visited.
+		 */
+		ret = validate_unrets(file);
+		if (ret < 0)
+			return ret;
+		warnings += ret;
+	}
+
+	if (opts.ibt) {
+		ret = validate_ibt(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.sls) {
+		ret = validate_sls(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.static_call) {
+		ret = create_static_call_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.retpoline) {
+		ret = create_retpoline_sites_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.cfi) {
+		ret = create_cfi_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.rethunk) {
+		ret = create_return_sites_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+
+		if (opts.hack_skylake) {
+			ret = create_direct_call_sections(file);
+			if (ret < 0)
+				goto out;
+			warnings += ret;
+		}
+	}
+
+	if (opts.mcount) {
+		ret = create_mcount_loc_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.prefix) {
+		ret = add_prefix_symbols(file);
+		if (ret < 0)
+			return ret;
+		warnings += ret;
+	}
+
+	if (opts.ibt) {
+		ret = create_ibt_endbr_seal_sections(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	if (opts.orc && nr_insns) {
+		ret = orc_create(file);
+		if (ret < 0)
+			goto out;
+		warnings += ret;
+	}
+
+	free_insns(file);
+
+	if (opts.verbose)
+		disas_warned_funcs(file);
+
+	if (opts.stats) {
+		printf("nr_insns_visited: %ld\n", nr_insns_visited);
+		printf("nr_cfi: %ld\n", nr_cfi);
+		printf("nr_cfi_reused: %ld\n", nr_cfi_reused);
+		printf("nr_cfi_cache: %ld\n", nr_cfi_cache);
+	}
+
+out:
+	/*
+	 *  For now, don't fail the kernel build on fatal warnings.  These
+	 *  errors are still fairly common due to the growing matrix of
+	 *  supported toolchains and their recent pace of change.
+	 */
+	return 0;
+}