module: replace module_layout with module_memory

module_layout manages different types of memory (text, data, rodata, etc.)
in one allocation, which is problematic for some reasons:

1. It is hard to enable CONFIG_STRICT_MODULE_RWX.
2. It is hard to use huge pages in modules (and not break strict rwx).
3. Many archs uses module_layout for arch-specific data, but it is not
   obvious how these data are used (are they RO, RX, or RW?)

Improve the scenario by replacing 2 (or 3) module_layout per module with
up to 7 module_memory per module:

        MOD_TEXT,
        MOD_DATA,
        MOD_RODATA,
        MOD_RO_AFTER_INIT,
        MOD_INIT_TEXT,
        MOD_INIT_DATA,
        MOD_INIT_RODATA,

and allocating them separately. This adds slightly more entries to
mod_tree (from up to 3 entries per module, to up to 7 entries per
module). However, this at most adds a small constant overhead to
__module_address(), which is expected to be fast.

Various archs use module_layout for different data. These data are put
into different module_memory based on their location in module_layout.
IOW, data that used to go with text is allocated with MOD_MEM_TYPE_TEXT;
data that used to go with data is allocated with MOD_MEM_TYPE_DATA, etc.

module_memory simplifies quite some of the module code. For example,
ARCH_WANTS_MODULES_DATA_IN_VMALLOC is a lot cleaner, as it just uses a
different allocator for the data. kernel/module/strict_rwx.c is also
much cleaner with module_memory.

Signed-off-by: Song Liu <song@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

1 files changed, 63 insertions, 26 deletions

diff --git a/include/linux/module.h b/include/linux/module.h
index 4435ad9439abba..c0593a96e158fc 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -320,17 +320,47 @@ struct mod_tree_node {
 	struct latch_tree_node node;
 };
 
-struct module_layout {
-	/* The actual code + data. */
+enum mod_mem_type {
+	MOD_TEXT = 0,
+	MOD_DATA,
+	MOD_RODATA,
+	MOD_RO_AFTER_INIT,
+	MOD_INIT_TEXT,
+	MOD_INIT_DATA,
+	MOD_INIT_RODATA,
+
+	MOD_MEM_NUM_TYPES,
+	MOD_INVALID = -1,
+};
+
+#define mod_mem_type_is_init(type)	\
+	((type) == MOD_INIT_TEXT ||	\
+	 (type) == MOD_INIT_DATA ||	\
+	 (type) == MOD_INIT_RODATA)
+
+#define mod_mem_type_is_core(type) (!mod_mem_type_is_init(type))
+
+#define mod_mem_type_is_text(type)	\
+	 ((type) == MOD_TEXT ||		\
+	  (type) == MOD_INIT_TEXT)
+
+#define mod_mem_type_is_data(type) (!mod_mem_type_is_text(type))
+
+#define mod_mem_type_is_core_data(type)	\
+	(mod_mem_type_is_core(type) &&	\
+	 mod_mem_type_is_data(type))
+
+#define for_each_mod_mem_type(type)			\
+	for (enum mod_mem_type (type) = 0;		\
+	     (type) < MOD_MEM_NUM_TYPES; (type)++)
+
+#define for_class_mod_mem_type(type, class)		\
+	for_each_mod_mem_type(type)			\
+		if (mod_mem_type_is_##class(type))
+
+struct module_memory {
 	void *base;
-	/* Total size. */
 	unsigned int size;
-	/* The size of the executable code.  */
-	unsigned int text_size;
-	/* Size of RO section of the module (text+rodata) */
-	unsigned int ro_size;
-	/* Size of RO after init section */
-	unsigned int ro_after_init_size;
 
 #ifdef CONFIG_MODULES_TREE_LOOKUP
 	struct mod_tree_node mtn;
@@ -339,9 +369,9 @@ struct module_layout {
 
 #ifdef CONFIG_MODULES_TREE_LOOKUP
 /* Only touch one cacheline for common rbtree-for-core-layout case. */
-#define __module_layout_align ____cacheline_aligned
+#define __module_memory_align ____cacheline_aligned
 #else
-#define __module_layout_align
+#define __module_memory_align
 #endif
 
 struct mod_kallsyms {
@@ -426,12 +456,7 @@ struct module {
 	/* Startup function. */
 	int (*init)(void);
 
-	/* Core layout: rbtree is accessed frequently, so keep together. */
-	struct module_layout core_layout __module_layout_align;
-	struct module_layout init_layout;
-#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
-	struct module_layout data_layout;
-#endif
+	struct module_memory mem[MOD_MEM_NUM_TYPES] __module_memory_align;
 
 	/* Arch-specific module values */
 	struct mod_arch_specific arch;
@@ -581,23 +606,35 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr);
 bool is_module_percpu_address(unsigned long addr);
 bool is_module_text_address(unsigned long addr);
 
+static inline bool within_module_mem_type(unsigned long addr,
+					  const struct module *mod,
+					  enum mod_mem_type type)
+{
+	unsigned long base, size;
+
+	base = (unsigned long)mod->mem[type].base;
+	size = mod->mem[type].size;
+	return addr - base < size;
+}
+
 static inline bool within_module_core(unsigned long addr,
 				      const struct module *mod)
 {
-#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
-	if ((unsigned long)mod->data_layout.base <= addr &&
-	    addr < (unsigned long)mod->data_layout.base + mod->data_layout.size)
-		return true;
-#endif
-	return (unsigned long)mod->core_layout.base <= addr &&
-	       addr < (unsigned long)mod->core_layout.base + mod->core_layout.size;
+	for_class_mod_mem_type(type, core) {
+		if (within_module_mem_type(addr, mod, type))
+			return true;
+	}
+	return false;
 }
 
 static inline bool within_module_init(unsigned long addr,
 				      const struct module *mod)
 {
-	return (unsigned long)mod->init_layout.base <= addr &&
-	       addr < (unsigned long)mod->init_layout.base + mod->init_layout.size;
+	for_class_mod_mem_type(type, init) {
+		if (within_module_mem_type(addr, mod, type))
+			return true;
+	}
+	return false;
 }
 
 static inline bool within_module(unsigned long addr, const struct module *mod)