1 files changed, 92 insertions, 43 deletions

diff --git a/tools/objtool/elf.c b/tools/objtool/elf.c
index 743c2e9d0f56..8676c7598728 100644
--- a/tools/objtool/elf.c
+++ b/tools/objtool/elf.c
@@ -9,6 +9,7 @@
 
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/mman.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -27,21 +28,27 @@ static inline u32 str_hash(const char *str)
 	return jhash(str, strlen(str), 0);
 }
 
-static inline int elf_hash_bits(void)
-{
-	return vmlinux ? ELF_HASH_BITS : 16;
-}
+#define __elf_table(name)	(elf->name##_hash)
+#define __elf_bits(name)	(elf->name##_bits)
 
-#define elf_hash_add(hashtable, node, key) \
-	hlist_add_head(node, &hashtable[hash_min(key, elf_hash_bits())])
+#define elf_hash_add(name, node, key) \
+	hlist_add_head(node, &__elf_table(name)[hash_min(key, __elf_bits(name))])
 
-static void elf_hash_init(struct hlist_head *table)
-{
-	__hash_init(table, 1U << elf_hash_bits());
-}
+#define elf_hash_for_each_possible(name, obj, member, key) \
+	hlist_for_each_entry(obj, &__elf_table(name)[hash_min(key, __elf_bits(name))], member)
 
-#define elf_hash_for_each_possible(name, obj, member, key)			\
-	hlist_for_each_entry(obj, &name[hash_min(key, elf_hash_bits())], member)
+#define elf_alloc_hash(name, size) \
+({ \
+	__elf_bits(name) = max(10, ilog2(size)); \
+	__elf_table(name) = mmap(NULL, sizeof(struct hlist_head) << __elf_bits(name), \
+				 PROT_READ|PROT_WRITE, \
+				 MAP_PRIVATE|MAP_ANON, -1, 0); \
+	if (__elf_table(name) == (void *)-1L) { \
+		WARN("mmap fail " #name); \
+		__elf_table(name) = NULL; \
+	} \
+	__elf_table(name); \
+})
 
 static bool symbol_to_offset(struct rb_node *a, const struct rb_node *b)
 {
@@ -80,9 +87,10 @@ struct section *find_section_by_name(const struct elf *elf, const char *name)
 {
 	struct section *sec;
 
-	elf_hash_for_each_possible(elf->section_name_hash, sec, name_hash, str_hash(name))
+	elf_hash_for_each_possible(section_name, sec, name_hash, str_hash(name)) {
 		if (!strcmp(sec->name, name))
 			return sec;
+	}
 
 	return NULL;
 }
@@ -92,9 +100,10 @@ static struct section *find_section_by_index(struct elf *elf,
 {
 	struct section *sec;
 
-	elf_hash_for_each_possible(elf->section_hash, sec, hash, idx)
+	elf_hash_for_each_possible(section, sec, hash, idx) {
 		if (sec->idx == idx)
 			return sec;
+	}
 
 	return NULL;
 }
@@ -103,9 +112,10 @@ static struct symbol *find_symbol_by_index(struct elf *elf, unsigned int idx)
 {
 	struct symbol *sym;
 
-	elf_hash_for_each_possible(elf->symbol_hash, sym, hash, idx)
+	elf_hash_for_each_possible(symbol, sym, hash, idx) {
 		if (sym->idx == idx)
 			return sym;
+	}
 
 	return NULL;
 }
@@ -170,9 +180,10 @@ struct symbol *find_symbol_by_name(const struct elf *elf, const char *name)
 {
 	struct symbol *sym;
 
-	elf_hash_for_each_possible(elf->symbol_name_hash, sym, name_hash, str_hash(name))
+	elf_hash_for_each_possible(symbol_name, sym, name_hash, str_hash(name)) {
 		if (!strcmp(sym->name, name))
 			return sym;
+	}
 
 	return NULL;
 }
@@ -189,8 +200,8 @@ struct reloc *find_reloc_by_dest_range(const struct elf *elf, struct section *se
 	sec = sec->reloc;
 
 	for_offset_range(o, offset, offset + len) {
-		elf_hash_for_each_possible(elf->reloc_hash, reloc, hash,
-				       sec_offset_hash(sec, o)) {
+		elf_hash_for_each_possible(reloc, reloc, hash,
+					   sec_offset_hash(sec, o)) {
 			if (reloc->sec != sec)
 				continue;
 
@@ -228,6 +239,10 @@ static int read_sections(struct elf *elf)
 		return -1;
 	}
 
+	if (!elf_alloc_hash(section, sections_nr) ||
+	    !elf_alloc_hash(section_name, sections_nr))
+		return -1;
+
 	for (i = 0; i < sections_nr; i++) {
 		sec = malloc(sizeof(*sec));
 		if (!sec) {
@@ -273,13 +288,18 @@ static int read_sections(struct elf *elf)
 		}
 		sec->len = sec->sh.sh_size;
 
+		if (sec->sh.sh_flags & SHF_EXECINSTR)
+			elf->text_size += sec->len;
+
 		list_add_tail(&sec->list, &elf->sections);
-		elf_hash_add(elf->section_hash, &sec->hash, sec->idx);
-		elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));
+		elf_hash_add(section, &sec->hash, sec->idx);
+		elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
 	}
 
-	if (stats)
+	if (stats) {
 		printf("nr_sections: %lu\n", (unsigned long)sections_nr);
+		printf("section_bits: %d\n", elf->section_bits);
+	}
 
 	/* sanity check, one more call to elf_nextscn() should return NULL */
 	if (elf_nextscn(elf->elf, s)) {
@@ -308,8 +328,8 @@ static void elf_add_symbol(struct elf *elf, struct symbol *sym)
 	else
 		entry = &sym->sec->symbol_list;
 	list_add(&sym->list, entry);
-	elf_hash_add(elf->symbol_hash, &sym->hash, sym->idx);
-	elf_hash_add(elf->symbol_name_hash, &sym->name_hash, str_hash(sym->name));
+	elf_hash_add(symbol, &sym->hash, sym->idx);
+	elf_hash_add(symbol_name, &sym->name_hash, str_hash(sym->name));
 
 	/*
 	 * Don't store empty STT_NOTYPE symbols in the rbtree.  They
@@ -329,19 +349,25 @@ static int read_symbols(struct elf *elf)
 	Elf32_Word shndx;
 
 	symtab = find_section_by_name(elf, ".symtab");
-	if (!symtab) {
+	if (symtab) {
+		symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
+		if (symtab_shndx)
+			shndx_data = symtab_shndx->data;
+
+		symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;
+	} else {
 		/*
 		 * A missing symbol table is actually possible if it's an empty
-		 * .o file.  This can happen for thunk_64.o.
+		 * .o file. This can happen for thunk_64.o. Make sure to at
+		 * least allocate the symbol hash tables so we can do symbol
+		 * lookups without crashing.
 		 */
-		return 0;
+		symbols_nr = 0;
 	}
 
-	symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
-	if (symtab_shndx)
-		shndx_data = symtab_shndx->data;
-
-	symbols_nr = symtab->sh.sh_size / symtab->sh.sh_entsize;
+	if (!elf_alloc_hash(symbol, symbols_nr) ||
+	    !elf_alloc_hash(symbol_name, symbols_nr))
+		return -1;
 
 	for (i = 0; i < symbols_nr; i++) {
 		sym = malloc(sizeof(*sym));
@@ -389,8 +415,10 @@ static int read_symbols(struct elf *elf)
 		elf_add_symbol(elf, sym);
 	}
 
-	if (stats)
+	if (stats) {
 		printf("nr_symbols: %lu\n", (unsigned long)symbols_nr);
+		printf("symbol_bits: %d\n", elf->symbol_bits);
+	}
 
 	/* Create parent/child links for any cold subfunctions */
 	list_for_each_entry(sec, &elf->sections, list) {
@@ -479,7 +507,7 @@ int elf_add_reloc(struct elf *elf, struct section *sec, unsigned long offset,
 	reloc->addend = addend;
 
 	list_add_tail(&reloc->list, &sec->reloc->reloc_list);
-	elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));
+	elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));
 
 	sec->reloc->changed = true;
 
@@ -556,6 +584,9 @@ static int read_relocs(struct elf *elf)
 	unsigned int symndx;
 	unsigned long nr_reloc, max_reloc = 0, tot_reloc = 0;
 
+	if (!elf_alloc_hash(reloc, elf->text_size / 16))
+		return -1;
+
 	list_for_each_entry(sec, &elf->sections, list) {
 		if ((sec->sh.sh_type != SHT_RELA) &&
 		    (sec->sh.sh_type != SHT_REL))
@@ -600,7 +631,7 @@ static int read_relocs(struct elf *elf)
 			}
 
 			list_add_tail(&reloc->list, &sec->reloc_list);
-			elf_hash_add(elf->reloc_hash, &reloc->hash, reloc_hash(reloc));
+			elf_hash_add(reloc, &reloc->hash, reloc_hash(reloc));
 
 			nr_reloc++;
 		}
@@ -611,6 +642,7 @@ static int read_relocs(struct elf *elf)
 	if (stats) {
 		printf("max_reloc: %lu\n", max_reloc);
 		printf("tot_reloc: %lu\n", tot_reloc);
+		printf("reloc_bits: %d\n", elf->reloc_bits);
 	}
 
 	return 0;
@@ -632,12 +664,6 @@ struct elf *elf_open_read(const char *name, int flags)
 
 	INIT_LIST_HEAD(&elf->sections);
 
-	elf_hash_init(elf->symbol_hash);
-	elf_hash_init(elf->symbol_name_hash);
-	elf_hash_init(elf->section_hash);
-	elf_hash_init(elf->section_name_hash);
-	elf_hash_init(elf->reloc_hash);
-
 	elf->fd = open(name, flags);
 	if (elf->fd == -1) {
 		fprintf(stderr, "objtool: Can't open '%s': %s\n",
@@ -717,7 +743,7 @@ static int elf_add_string(struct elf *elf, struct section *strtab, char *str)
 
 struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)
 {
-	struct section *symtab;
+	struct section *symtab, *symtab_shndx;
 	struct symbol *sym;
 	Elf_Data *data;
 	Elf_Scn *s;
@@ -769,6 +795,29 @@ struct symbol *elf_create_undef_symbol(struct elf *elf, const char *name)
 	symtab->len += data->d_size;
 	symtab->changed = true;
 
+	symtab_shndx = find_section_by_name(elf, ".symtab_shndx");
+	if (symtab_shndx) {
+		s = elf_getscn(elf->elf, symtab_shndx->idx);
+		if (!s) {
+			WARN_ELF("elf_getscn");
+			return NULL;
+		}
+
+		data = elf_newdata(s);
+		if (!data) {
+			WARN_ELF("elf_newdata");
+			return NULL;
+		}
+
+		data->d_buf = &sym->sym.st_size; /* conveniently 0 */
+		data->d_size = sizeof(Elf32_Word);
+		data->d_align = 4;
+		data->d_type = ELF_T_WORD;
+
+		symtab_shndx->len += 4;
+		symtab_shndx->changed = true;
+	}
+
 	sym->sec = find_section_by_index(elf, 0);
 
 	elf_add_symbol(elf, sym);
@@ -851,8 +900,8 @@ struct section *elf_create_section(struct elf *elf, const char *name,
 		return NULL;
 
 	list_add_tail(&sec->list, &elf->sections);
-	elf_hash_add(elf->section_hash, &sec->hash, sec->idx);
-	elf_hash_add(elf->section_name_hash, &sec->name_hash, str_hash(sec->name));
+	elf_hash_add(section, &sec->hash, sec->idx);
+	elf_hash_add(section_name, &sec->name_hash, str_hash(sec->name));
 
 	elf->changed = true;