module: use a structure to encapsulate layout.

Makes it easier to handle init vs core cleanly, though the change is
fairly invasive across random architectures.

It simplifies the rbtree code immediately, however, while keeping the
core data together in the same cachline (now iff the rbtree code is
enabled).

Acked-by: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 92 insertions, 107 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 14b2249..a0a3d6d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -108,13 +108,6 @@ static LIST_HEAD(modules);
  * Use a latched RB-tree for __module_address(); this allows us to use
  * RCU-sched lookups of the address from any context.
  *
- * Because modules have two address ranges: init and core, we need two
- * latch_tree_nodes entries. Therefore we need the back-pointer from
- * mod_tree_node.
- *
- * Because init ranges are short lived we mark them unlikely and have placed
- * them outside the critical cacheline in struct module.
- *
  * This is conditional on PERF_EVENTS || TRACING because those can really hit
  * __module_address() hard by doing a lot of stack unwinding; potentially from
  * NMI context.
@@ -122,24 +115,16 @@ static LIST_HEAD(modules);
 
 static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
 {
-	struct mod_tree_node *mtn = container_of(n, struct mod_tree_node, node);
-	struct module *mod = mtn->mod;
+	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
 
-	if (unlikely(mtn == &mod->mtn_init))
-		return (unsigned long)mod->module_init;
-
-	return (unsigned long)mod->module_core;
+	return (unsigned long)layout->base;
 }
 
 static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
 {
-	struct mod_tree_node *mtn = container_of(n, struct mod_tree_node, node);
-	struct module *mod = mtn->mod;
-
-	if (unlikely(mtn == &mod->mtn_init))
-		return (unsigned long)mod->init_size;
+	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
 
-	return (unsigned long)mod->core_size;
+	return (unsigned long)layout->size;
 }
 
 static __always_inline bool
@@ -197,23 +182,23 @@ static void __mod_tree_remove(struct mod_tree_node *node)
  */
 static void mod_tree_insert(struct module *mod)
 {
-	mod->mtn_core.mod = mod;
-	mod->mtn_init.mod = mod;
+	mod->core_layout.mtn.mod = mod;
+	mod->init_layout.mtn.mod = mod;
 
-	__mod_tree_insert(&mod->mtn_core);
-	if (mod->init_size)
-		__mod_tree_insert(&mod->mtn_init);
+	__mod_tree_insert(&mod->core_layout.mtn);
+	if (mod->init_layout.size)
+		__mod_tree_insert(&mod->init_layout.mtn);
 }
 
 static void mod_tree_remove_init(struct module *mod)
 {
-	if (mod->init_size)
-		__mod_tree_remove(&mod->mtn_init);
+	if (mod->init_layout.size)
+		__mod_tree_remove(&mod->init_layout.mtn);
 }
 
 static void mod_tree_remove(struct module *mod)
 {
-	__mod_tree_remove(&mod->mtn_core);
+	__mod_tree_remove(&mod->core_layout.mtn);
 	mod_tree_remove_init(mod);
 }
 
@@ -267,9 +252,9 @@ static void __mod_update_bounds(void *base, unsigned int size)
 
 static void mod_update_bounds(struct module *mod)
 {
-	__mod_update_bounds(mod->module_core, mod->core_size);
-	if (mod->init_size)
-		__mod_update_bounds(mod->module_init, mod->init_size);
+	__mod_update_bounds(mod->core_layout.base, mod->core_layout.size);
+	if (mod->init_layout.size)
+		__mod_update_bounds(mod->init_layout.base, mod->init_layout.size);
 }
 
 #ifdef CONFIG_KGDB_KDB
@@ -1214,7 +1199,7 @@ struct module_attribute module_uevent =
 static ssize_t show_coresize(struct module_attribute *mattr,
 			     struct module_kobject *mk, char *buffer)
 {
-	return sprintf(buffer, "%u\n", mk->mod->core_size);
+	return sprintf(buffer, "%u\n", mk->mod->core_layout.size);
 }
 
 static struct module_attribute modinfo_coresize =
@@ -1223,7 +1208,7 @@ static struct module_attribute modinfo_coresize =
 static ssize_t show_initsize(struct module_attribute *mattr,
 			     struct module_kobject *mk, char *buffer)
 {
-	return sprintf(buffer, "%u\n", mk->mod->init_size);
+	return sprintf(buffer, "%u\n", mk->mod->init_layout.size);
 }
 
 static struct module_attribute modinfo_initsize =
@@ -1917,29 +1902,29 @@ static void set_section_ro_nx(void *base,
 
 static void set_module_core_ro_nx(struct module *mod)
 {
-	set_section_ro_nx(mod->module_core, mod->core_text_size,
-			  mod->core_ro_size, mod->core_size,
+	set_section_ro_nx(mod->core_layout.base, mod->core_layout.text_size,
+			  mod->core_layout.ro_size, mod->core_layout.size,
 			  set_memory_ro, set_memory_nx);
 }
 
 static void unset_module_core_ro_nx(struct module *mod)
 {
-	set_section_ro_nx(mod->module_core, mod->core_text_size,
-			  mod->core_ro_size, mod->core_size,
+	set_section_ro_nx(mod->core_layout.base, mod->core_layout.text_size,
+			  mod->core_layout.ro_size, mod->core_layout.size,
 			  set_memory_rw, set_memory_x);
 }
 
 static void set_module_init_ro_nx(struct module *mod)
 {
-	set_section_ro_nx(mod->module_init, mod->init_text_size,
-			  mod->init_ro_size, mod->init_size,
+	set_section_ro_nx(mod->init_layout.base, mod->init_layout.text_size,
+			  mod->init_layout.ro_size, mod->init_layout.size,
 			  set_memory_ro, set_memory_nx);
 }
 
 static void unset_module_init_ro_nx(struct module *mod)
 {
-	set_section_ro_nx(mod->module_init, mod->init_text_size,
-			  mod->init_ro_size, mod->init_size,
+	set_section_ro_nx(mod->init_layout.base, mod->init_layout.text_size,
+			  mod->init_layout.ro_size, mod->init_layout.size,
 			  set_memory_rw, set_memory_x);
 }
 
@@ -1952,14 +1937,14 @@ void set_all_modules_text_rw(void)
 	list_for_each_entry_rcu(mod, &modules, list) {
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
-		if ((mod->module_core) && (mod->core_text_size)) {
-			set_page_attributes(mod->module_core,
-						mod->module_core + mod->core_text_size,
+		if ((mod->core_layout.base) && (mod->core_layout.text_size)) {
+			set_page_attributes(mod->core_layout.base,
+						mod->core_layout.base + mod->core_layout.text_size,
 						set_memory_rw);
 		}
-		if ((mod->module_init) && (mod->init_text_size)) {
-			set_page_attributes(mod->module_init,
-						mod->module_init + mod->init_text_size,
+		if ((mod->init_layout.base) && (mod->init_layout.text_size)) {
+			set_page_attributes(mod->init_layout.base,
+						mod->init_layout.base + mod->init_layout.text_size,
 						set_memory_rw);
 		}
 	}
@@ -1975,14 +1960,14 @@ void set_all_modules_text_ro(void)
 	list_for_each_entry_rcu(mod, &modules, list) {
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
-		if ((mod->module_core) && (mod->core_text_size)) {
-			set_page_attributes(mod->module_core,
-						mod->module_core + mod->core_text_size,
+		if ((mod->core_layout.base) && (mod->core_layout.text_size)) {
+			set_page_attributes(mod->core_layout.base,
+						mod->core_layout.base + mod->core_layout.text_size,
 						set_memory_ro);
 		}
-		if ((mod->module_init) && (mod->init_text_size)) {
-			set_page_attributes(mod->module_init,
-						mod->module_init + mod->init_text_size,
+		if ((mod->init_layout.base) && (mod->init_layout.text_size)) {
+			set_page_attributes(mod->init_layout.base,
+						mod->init_layout.base + mod->init_layout.text_size,
 						set_memory_ro);
 		}
 	}
@@ -2047,16 +2032,16 @@ static void free_module(struct module *mod)
 	/* This may be NULL, but that's OK */
 	unset_module_init_ro_nx(mod);
 	module_arch_freeing_init(mod);
-	module_memfree(mod->module_init);
+	module_memfree(mod->init_layout.base);
 	kfree(mod->args);
 	percpu_modfree(mod);
 
 	/* Free lock-classes; relies on the preceding sync_rcu(). */
-	lockdep_free_key_range(mod->module_core, mod->core_size);
+	lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
 
 	/* Finally, free the core (containing the module structure) */
 	unset_module_core_ro_nx(mod);
-	module_memfree(mod->module_core);
+	module_memfree(mod->core_layout.base);
 
 #ifdef CONFIG_MPU
 	update_protections(current->mm);
@@ -2259,20 +2244,20 @@ static void layout_sections(struct module *mod, struct load_info *info)
 			    || s->sh_entsize != ~0UL
 			    || strstarts(sname, ".init"))
 				continue;
-			s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
+			s->sh_entsize = get_offset(mod, &mod->core_layout.size, s, i);
 			pr_debug("\t%s\n", sname);
 		}
 		switch (m) {
 		case 0: /* executable */
-			mod->core_size = debug_align(mod->core_size);
-			mod->core_text_size = mod->core_size;
+			mod->core_layout.size = debug_align(mod->core_layout.size);
+			mod->core_layout.text_size = mod->core_layout.size;
 			break;
 		case 1: /* RO: text and ro-data */
-			mod->core_size = debug_align(mod->core_size);
-			mod->core_ro_size = mod->core_size;
+			mod->core_layout.size = debug_align(mod->core_layout.size);
+			mod->core_layout.ro_size = mod->core_layout.size;
 			break;
 		case 3: /* whole core */
-			mod->core_size = debug_align(mod->core_size);
+			mod->core_layout.size = debug_align(mod->core_layout.size);
 			break;
 		}
 	}
@@ -2288,21 +2273,21 @@ static void layout_sections(struct module *mod, struct load_info *info)
 			    || s->sh_entsize != ~0UL
 			    || !strstarts(sname, ".init"))
 				continue;
-			s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
+			s->sh_entsize = (get_offset(mod, &mod->init_layout.size, s, i)
 					 | INIT_OFFSET_MASK);
 			pr_debug("\t%s\n", sname);
 		}
 		switch (m) {
 		case 0: /* executable */
-			mod->init_size = debug_align(mod->init_size);
-			mod->init_text_size = mod->init_size;
+			mod->init_layout.size = debug_align(mod->init_layout.size);
+			mod->init_layout.text_size = mod->init_layout.size;
 			break;
 		case 1: /* RO: text and ro-data */
-			mod->init_size = debug_align(mod->init_size);
-			mod->init_ro_size = mod->init_size;
+			mod->init_layout.size = debug_align(mod->init_layout.size);
+			mod->init_layout.ro_size = mod->init_layout.size;
 			break;
 		case 3: /* whole init */
-			mod->init_size = debug_align(mod->init_size);
+			mod->init_layout.size = debug_align(mod->init_layout.size);
 			break;
 		}
 	}
@@ -2477,7 +2462,7 @@ static void layout_symtab(struct module *mod, struct load_info *info)
 
 	/* Put symbol section at end of init part of module. */
 	symsect->sh_flags |= SHF_ALLOC;
-	symsect->sh_entsize = get_offset(mod, &mod->init_size, symsect,
+	symsect->sh_entsize = get_offset(mod, &mod->init_layout.size, symsect,
 					 info->index.sym) | INIT_OFFSET_MASK;
 	pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
 
@@ -2494,16 +2479,16 @@ static void layout_symtab(struct module *mod, struct load_info *info)
 	}
 
 	/* Append room for core symbols at end of core part. */
-	info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1);
-	info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym);
-	mod->core_size += strtab_size;
-	mod->core_size = debug_align(mod->core_size);
+	info->symoffs = ALIGN(mod->core_layout.size, symsect->sh_addralign ?: 1);
+	info->stroffs = mod->core_layout.size = info->symoffs + ndst * sizeof(Elf_Sym);
+	mod->core_layout.size += strtab_size;
+	mod->core_layout.size = debug_align(mod->core_layout.size);
 
 	/* Put string table section at end of init part of module. */
 	strsect->sh_flags |= SHF_ALLOC;
-	strsect->sh_entsize = get_offset(mod, &mod->init_size, strsect,
+	strsect->sh_entsize = get_offset(mod, &mod->init_layout.size, strsect,
 					 info->index.str) | INIT_OFFSET_MASK;
-	mod->init_size = debug_align(mod->init_size);
+	mod->init_layout.size = debug_align(mod->init_layout.size);
 	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
 }
 
@@ -2524,8 +2509,8 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
 	for (i = 0; i < mod->num_symtab; i++)
 		mod->symtab[i].st_info = elf_type(&mod->symtab[i], info);
 
-	mod->core_symtab = dst = mod->module_core + info->symoffs;
-	mod->core_strtab = s = mod->module_core + info->stroffs;
+	mod->core_symtab = dst = mod->core_layout.base + info->symoffs;
+	mod->core_strtab = s = mod->core_layout.base + info->stroffs;
 	src = mod->symtab;
 	for (ndst = i = 0; i < mod->num_symtab; i++) {
 		if (i == 0 ||
@@ -2975,7 +2960,7 @@ static int move_module(struct module *mod, struct load_info *info)
 	void *ptr;
 
 	/* Do the allocs. */
-	ptr = module_alloc(mod->core_size);
+	ptr = module_alloc(mod->core_layout.size);
 	/*
 	 * The pointer to this block is stored in the module structure
 	 * which is inside the block. Just mark it as not being a
@@ -2985,11 +2970,11 @@ static int move_module(struct module *mod, struct load_info *info)
 	if (!ptr)
 		return -ENOMEM;
 
-	memset(ptr, 0, mod->core_size);
-	mod->module_core = ptr;
+	memset(ptr, 0, mod->core_layout.size);
+	mod->core_layout.base = ptr;
 
-	if (mod->init_size) {
-		ptr = module_alloc(mod->init_size);
+	if (mod->init_layout.size) {
+		ptr = module_alloc(mod->init_layout.size);
 		/*
 		 * The pointer to this block is stored in the module structure
 		 * which is inside the block. This block doesn't need to be
@@ -2998,13 +2983,13 @@ static int move_module(struct module *mod, struct load_info *info)
 		 */
 		kmemleak_ignore(ptr);
 		if (!ptr) {
-			module_memfree(mod->module_core);
+			module_memfree(mod->core_layout.base);
 			return -ENOMEM;
 		}
-		memset(ptr, 0, mod->init_size);
-		mod->module_init = ptr;
+		memset(ptr, 0, mod->init_layout.size);
+		mod->init_layout.base = ptr;
 	} else
-		mod->module_init = NULL;
+		mod->init_layout.base = NULL;
 
 	/* Transfer each section which specifies SHF_ALLOC */
 	pr_debug("final section addresses:\n");
@@ -3016,10 +3001,10 @@ static int move_module(struct module *mod, struct load_info *info)
 			continue;
 
 		if (shdr->sh_entsize & INIT_OFFSET_MASK)
-			dest = mod->module_init
+			dest = mod->init_layout.base
 				+ (shdr->sh_entsize & ~INIT_OFFSET_MASK);
 		else
-			dest = mod->module_core + shdr->sh_entsize;
+			dest = mod->core_layout.base + shdr->sh_entsize;
 
 		if (shdr->sh_type != SHT_NOBITS)
 			memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
@@ -3081,12 +3066,12 @@ static void flush_module_icache(const struct module *mod)
 	 * Do it before processing of module parameters, so the module
 	 * can provide parameter accessor functions of its own.
 	 */
-	if (mod->module_init)
-		flush_icache_range((unsigned long)mod->module_init,
-				   (unsigned long)mod->module_init
-				   + mod->init_size);
-	flush_icache_range((unsigned long)mod->module_core,
-			   (unsigned long)mod->module_core + mod->core_size);
+	if (mod->init_layout.base)
+		flush_icache_range((unsigned long)mod->init_layout.base,
+				   (unsigned long)mod->init_layout.base
+				   + mod->init_layout.size);
+	flush_icache_range((unsigned long)mod->core_layout.base,
+			   (unsigned long)mod->core_layout.base + mod->core_layout.size);
 
 	set_fs(old_fs);
 }
@@ -3144,8 +3129,8 @@ static void module_deallocate(struct module *mod, struct load_info *info)
 {
 	percpu_modfree(mod);
 	module_arch_freeing_init(mod);
-	module_memfree(mod->module_init);
-	module_memfree(mod->module_core);
+	module_memfree(mod->init_layout.base);
+	module_memfree(mod->core_layout.base);
 }
 
 int __weak module_finalize(const Elf_Ehdr *hdr,
@@ -3232,7 +3217,7 @@ static noinline int do_init_module(struct module *mod)
 		ret = -ENOMEM;
 		goto fail;
 	}
-	freeinit->module_init = mod->module_init;
+	freeinit->module_init = mod->init_layout.base;
 
 	/*
 	 * We want to find out whether @mod uses async during init.  Clear
@@ -3292,10 +3277,10 @@ static noinline int do_init_module(struct module *mod)
 	mod_tree_remove_init(mod);
 	unset_module_init_ro_nx(mod);
 	module_arch_freeing_init(mod);
-	mod->module_init = NULL;
-	mod->init_size = 0;
-	mod->init_ro_size = 0;
-	mod->init_text_size = 0;
+	mod->init_layout.base = NULL;
+	mod->init_layout.size = 0;
+	mod->init_layout.ro_size = 0;
+	mod->init_layout.text_size = 0;
 	/*
 	 * We want to free module_init, but be aware that kallsyms may be
 	 * walking this with preempt disabled.  In all the failure paths, we
@@ -3575,7 +3560,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	mutex_unlock(&module_mutex);
  free_module:
 	/* Free lock-classes; relies on the preceding sync_rcu() */
-	lockdep_free_key_range(mod->module_core, mod->core_size);
+	lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
 
 	module_deallocate(mod, info);
  free_copy:
@@ -3653,9 +3638,9 @@ static const char *get_ksymbol(struct module *mod,
 
 	/* At worse, next value is at end of module */
 	if (within_module_init(addr, mod))
-		nextval = (unsigned long)mod->module_init+mod->init_text_size;
+		nextval = (unsigned long)mod->init_layout.base+mod->init_layout.text_size;
 	else
-		nextval = (unsigned long)mod->module_core+mod->core_text_size;
+		nextval = (unsigned long)mod->core_layout.base+mod->core_layout.text_size;
 
 	/* Scan for closest preceding symbol, and next symbol. (ELF
 	   starts real symbols at 1). */
@@ -3902,7 +3887,7 @@ static int m_show(struct seq_file *m, void *p)
 		return 0;
 
 	seq_printf(m, "%s %u",
-		   mod->name, mod->init_size + mod->core_size);
+		   mod->name, mod->init_layout.size + mod->core_layout.size);
 	print_unload_info(m, mod);
 
 	/* Informative for users. */
@@ -3911,7 +3896,7 @@ static int m_show(struct seq_file *m, void *p)
 		   mod->state == MODULE_STATE_COMING ? "Loading" :
 		   "Live");
 	/* Used by oprofile and other similar tools. */
-	seq_printf(m, " 0x%pK", mod->module_core);
+	seq_printf(m, " 0x%pK", mod->core_layout.base);
 
 	/* Taints info */
 	if (mod->taints)
@@ -4054,8 +4039,8 @@ struct module *__module_text_address(unsigned long addr)
 	struct module *mod = __module_address(addr);
 	if (mod) {
 		/* Make sure it's within the text section. */
-		if (!within(addr, mod->module_init, mod->init_text_size)
-		    && !within(addr, mod->module_core, mod->core_text_size))
+		if (!within(addr, mod->init_layout.base, mod->init_layout.text_size)
+		    && !within(addr, mod->core_layout.base, mod->core_layout.text_size))
 			mod = NULL;
 	}
 	return mod;