Date:   Wed, 8 Feb 2023 17:48:26 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Song Liu <song@...nel.org>,
        "linux-modules@...r.kernel.org" <linux-modules@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "hch@....de" <hch@....de>,
        "kernel-team@...a.com" <kernel-team@...a.com>,
        Luis Chamberlain <mcgrof@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Guenter Roeck <linux@...ck-us.net>
Subject: Re: [PATCH v10] module: replace module_layout with module_memory



Le 07/02/2023 à 01:28, Song Liu a écrit :
> 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@...nel.org>
> Cc: Luis Chamberlain <mcgrof@...nel.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Guenter Roeck <linux@...ck-us.net>
> Cc: Christophe Leroy <christophe.leroy@...roup.eu>
> 
> ---
> This is the preparation work for the type aware module_alloc() discussed
> in [1]. While this work is not covered much in the discussion, it is a
> critical step of the effort.
> 
> As this part grows pretty big (~1000 lines, + and -), I would like get
> some feedback on it, so that I know it is on the right track.
> 
> Please share your comments. Thanks!
> 
> Test coverage: Tested on x86_64.
> v9 passed build tests by kernel test bot in [2].
> 
> [1] https://lore.kernel.org/linux-mm/20221107223921.3451913-1-song@kernel.org/T/#u
> [2] https://lore.kernel.org/linux-raid/63df0daa.eKYOEelTitBUzF+e%25lkp@intel.com/T/#u
> 
> Changes v1 => v2:
> 1. Add data_addr_[min|max] for CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
>     case.
> 
> Changes v2 => v3:
> 1. Fix and remove the last use of INIT_OFFSET_MASK.
> 2. Add more information in the commit log. (Luis Chamberlain)
> 3. Rebase and fix issues in x86/calltrunks.
> 4. Minor cleanup.
> 
> Changes v3 => v4:
> 1. Shorten enum/variable names, so that the code are easier to read.
>     (Christophe Leroy)
> 2. Remove an used variable. (Guenter Roeck, Christophe Leroy)
> 
> Changes v4 => v5:
> 1. Simplify some code some code. (Peter Zijlstra, Christophe Leroy)
> 2. Remove module_check_misalignment(), which is not useful any more.
> 
> Changes v5 => v6:
> 1. Improve mod_mem_type_is_* and for_*mod_mem_type marcos.
>     (Peter Zijlstra).
> 
> Changes v6 => v7:
> 1. Use --ignore-space-at-eol instead of -b.
> 
> Changes v7 => v8:
> 1. Address feedback from Peter.
> 
> Changes v8 => v9:
> 1. Fix a compile error for powerpc. (Christophe Leroy)
> 
> Changes v9 => v10:
> 1. Clean-up, style improvements, more comments. (Thomas Gleixner)
> ---
>   arch/alpha/kernel/module.c      |   2 +-
>   arch/arc/kernel/unwind.c        |   9 +-
>   arch/arm/kernel/module-plts.c   |   9 +-
>   arch/arm64/kernel/module-plts.c |  13 +-
>   arch/ia64/kernel/module.c       |  24 +-
>   arch/mips/kernel/vpe.c          |  11 +-
>   arch/parisc/kernel/module.c     |  51 ++--
>   arch/powerpc/kernel/module_32.c |   7 +-
>   arch/s390/kernel/module.c       |  26 +-
>   arch/x86/kernel/callthunks.c    |   4 +-
>   arch/x86/kernel/module.c        |   4 +-
>   include/linux/module.h          |  89 +++++--
>   kernel/module/internal.h        |  40 ++--
>   kernel/module/kallsyms.c        |  58 +++--
>   kernel/module/kdb.c             |  17 +-
>   kernel/module/main.c            | 404 +++++++++++++++++---------------
>   kernel/module/procfs.c          |  16 +-
>   kernel/module/strict_rwx.c      |  99 ++------
>   kernel/module/tree_lookup.c     |  39 ++-
>   19 files changed, 457 insertions(+), 465 deletions(-)
> 
> diff --git a/arch/alpha/kernel/module.c b/arch/alpha/kernel/module.c
> index 5b60c248de9e..9109213abc09 100644
> --- a/arch/alpha/kernel/module.c
> +++ b/arch/alpha/kernel/module.c
> @@ -148,7 +148,7 @@ apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab,
>   
>   	/* The small sections were sorted to the end of the segment.
>   	   The following should definitely cover them.  */
> -	gp = (u64)me->core_layout.base + me->core_layout.size - 0x8000;
> +	gp = (u64)me->mem[MOD_DATA].base + me->mem[MOD_DATA].size - 0x8000;
>   	got = sechdrs[me->arch.gotsecindex].sh_addr;
>   
>   	for (i = 0; i < n; i++) {
> diff --git a/arch/arc/kernel/unwind.c b/arch/arc/kernel/unwind.c
> index 200270a94558..933451f4494f 100644
> --- a/arch/arc/kernel/unwind.c
> +++ b/arch/arc/kernel/unwind.c
> @@ -369,6 +369,8 @@ void *unwind_add_table(struct module *module, const void *table_start,
>   		       unsigned long table_size)
>   {
>   	struct unwind_table *table;
> +	struct module_memory *mod_mem_core_text;
> +	struct module_memory *mod_mem_init_text;

This function is small (35 lines) so no need to have so big names for 
local functions, see 
https://docs.kernel.org/process/coding-style.html#naming

	struct module_memory *core_text;
	struct module_memory *init_text;

>   
>   	if (table_size <= 0)
>   		return NULL;
> @@ -377,9 +379,12 @@ void *unwind_add_table(struct module *module, const void *table_start,
>   	if (!table)
>   		return NULL;
>   
> +	mod_mem_core_text = &module->mem[MOD_TEXT];
> +	mod_mem_init_text = &module->mem[MOD_INIT_TEXT];
> +
>   	init_unwind_table(table, module->name,
> -			  module->core_layout.base, module->core_layout.size,
> -			  module->init_layout.base, module->init_layout.size,
> +			  mod_mem_core_text->base, mod_mem_core_text->size,
> +			  mod_mem_init_text->base, mod_mem_init_text->size,
>   			  table_start, table_size,
>   			  NULL, 0);

Shorter naming allows you to reduce the number of lines of the above 
function call:

	init_unwind_table(table, module->name, core_text->base, core_text->size,
			  init_text->base, init_text->size, table_start, table_size, NULL, 0);


> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index d3be89de706d..b9617d7e8db2 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -80,12 +80,6 @@ struct mod_tree_root mod_tree __cacheline_aligned = {
>   	.addr_min = -1UL,
>   };
>   
> -#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
> -struct mod_tree_root mod_data_tree __cacheline_aligned = {
> -	.addr_min = -1UL,
> -};
> -#endif
> -
>   struct symsearch {
>   	const struct kernel_symbol *start, *stop;
>   	const s32 *crcs;
> @@ -93,14 +87,24 @@ struct symsearch {
>   };
>   
>   /*
> - * Bounds of module text, for speeding up __module_address.
> + * Bounds of module memory, for speeding up __module_address.
>    * Protected by module_mutex.
>    */
> -static void __mod_update_bounds(void *base, unsigned int size, struct mod_tree_root *tree)
> +static void __mod_update_bounds(enum mod_mem_type type __maybe_unused, void *base,
> +				unsigned int size, struct mod_tree_root *tree)
>   {
>   	unsigned long min = (unsigned long)base;
>   	unsigned long max = min + size;
>   
> +#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC

A #ifdef shouldn't be required. You can use IS_ENABLED() instead:



> +	if (mod_mem_type_is_core_data(type)) {

	if (IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC) &&
	    mod_mem_type_is_core_data(type))

> +		if (min < tree->data_addr_min)
> +			tree->data_addr_min = min;
> +		if (max > tree->data_addr_max)
> +			tree->data_addr_max = max;
> +		return;
> +	}
> +#endif
>   	if (min < tree->addr_min)
>   		tree->addr_min = min;
>   	if (max > tree->addr_max)
> @@ -109,12 +113,12 @@ static void __mod_update_bounds(void *base, unsigned int size, struct mod_tree_r
>   
>   static void mod_update_bounds(struct module *mod)
>   {
> -	__mod_update_bounds(mod->core_layout.base, mod->core_layout.size, &mod_tree);
> -	if (mod->init_layout.size)
> -		__mod_update_bounds(mod->init_layout.base, mod->init_layout.size, &mod_tree);
> -#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
> -	__mod_update_bounds(mod->data_layout.base, mod->data_layout.size, &mod_data_tree);
> -#endif
> +	for_each_mod_mem_type(type) {
> +		struct module_memory *mod_mem = &mod->mem[type];
> +
> +		if (mod_mem->size)
> +			__mod_update_bounds(type, mod_mem->base, mod_mem->size, &mod_tree);
> +	}
>   }
>   
>   /* Block module loading/unloading? */
> @@ -923,12 +927,27 @@ static ssize_t store_uevent(struct module_attribute *mattr,
>   struct module_attribute module_uevent =
>   	__ATTR(uevent, 0200, NULL, store_uevent);
>   
> +#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC

It should be possible to have only one show_coresize() function, with 
IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC) ; see 
https://docs.kernel.org/process/coding-style.html#conditional-compilation


> +
>   static ssize_t show_coresize(struct module_attribute *mattr,
>   			     struct module_kobject *mk, char *buffer)
>   {
> -	return sprintf(buffer, "%u\n", mk->mod->core_layout.size);
> +	return sprintf(buffer, "%u\n", mk->mod->mem[MOD_TEXT].size);
>   }
>   
> +#else
> +
> +static ssize_t show_coresize(struct module_attribute *mattr,
> +			     struct module_kobject *mk, char *buffer)
> +{
> +	unsigned int size = 0;
> +
> +	for_class_mod_mem_type(type, core)
> +		size += mk->mod->mem[type].size;
> +	return sprintf(buffer, "%u\n", size);
> +}
> +#endif
> +
>   static struct module_attribute modinfo_coresize =
>   	__ATTR(coresize, 0444, show_coresize, NULL);
>   
> @@ -936,7 +955,11 @@ static struct module_attribute modinfo_coresize =
>   static ssize_t show_datasize(struct module_attribute *mattr,
>   			     struct module_kobject *mk, char *buffer)
>   {
> -	return sprintf(buffer, "%u\n", mk->mod->data_layout.size);
> +	unsigned int size = 0;
> +
> +	for_class_mod_mem_type(type, core_data)
> +		size += mk->mod->mem[type].size;
> +	return sprintf(buffer, "%u\n", size);
>   }
>   
>   static struct module_attribute modinfo_datasize =
> @@ -946,7 +969,11 @@ static struct module_attribute modinfo_datasize =
>   static ssize_t show_initsize(struct module_attribute *mattr,
>   			     struct module_kobject *mk, char *buffer)
>   {
> -	return sprintf(buffer, "%u\n", mk->mod->init_layout.size);
> +	unsigned int size = 0;
> +
> +	for_class_mod_mem_type(type, init)
> +		size += mk->mod->mem[type].size;
> +	return sprintf(buffer, "%u\n", size);
>   }
>   
>   static struct module_attribute modinfo_initsize =
> @@ -1143,6 +1170,65 @@ void __weak module_arch_freeing_init(struct module *mod)
>   {
>   }
>   
> +#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC

Same, could simply be

	return IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC) &&
	       mod_mem_type_is_core_data(type);

> +static bool mod_mem_use_vmalloc(enum mod_mem_type type)
> +{
> +	return mod_mem_type_is_core_data(type);
> +}
> +#else
> +static bool mod_mem_use_vmalloc(enum mod_mem_type type)
> +{
> +	return false;
> +}
> +#endif
> +
> +static void *module_memory_alloc(unsigned int size, enum mod_mem_type type)
> +{
> +	if (mod_mem_use_vmalloc(type))
> +		return vzalloc(size);
> +	return module_alloc(size);
> +}
> +
> +static void module_memory_free(void *ptr, enum mod_mem_type type)
> +{
> +	if (mod_mem_use_vmalloc(type))
> +		vfree(ptr);
> +	else
> +		module_memfree(ptr);
> +}
> +
> +static void free_mod_mem(struct module *mod)
> +{
> +	/* free the memory in the right order to avoid use-after-free */

Instead of 'right order', explain what the right order is.
As far as I understand it is only to free MOD_DATA last. Everything else 
doesn't matter.

> +	static enum mod_mem_type mod_mem_free_order[MOD_MEM_NUM_TYPES] = {
> +		/* first free init sections */
> +		MOD_INIT_TEXT,
> +		MOD_INIT_DATA,
> +		MOD_INIT_RODATA,
> +
> +		/* then core sections, except rw data */
> +		MOD_TEXT,
> +		MOD_RODATA,
> +		MOD_RO_AFTER_INIT,
> +
> +		/* last, rw data */
> +		MOD_DATA,
> +	};
> +	int i;
> +
> +	BUILD_BUG_ON(ARRAY_SIZE(mod_mem_free_order) != MOD_MEM_NUM_TYPES);
> +
> +	for (i = 0; i < MOD_MEM_NUM_TYPES; i++) {
> +		enum mod_mem_type type = mod_mem_free_order[i];
> +		struct module_memory *mod_mem = &mod->mem[type];
> +
> +		/* Free lock-classes; relies on the preceding sync_rcu(). */
> +		lockdep_free_key_range(mod_mem->base, mod_mem->size);
> +		if (mod_mem->size)
> +			module_memory_free(mod_mem->base, type);
> +	}
> +}
> +
>   /* Free a module, remove from lists, etc. */
>   static void free_module(struct module *mod)
>   {

> @@ -1428,84 +1504,63 @@ static void layout_sections(struct module *mod, struct load_info *info)
>   		{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
>   		{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
>   	};
> -	unsigned int m, i;
> -
> -	for (i = 0; i < info->hdr->e_shnum; i++)
> -		info->sechdrs[i].sh_entsize = ~0UL;
> +	static const int core_m_to_mem_type[] = {
> +		MOD_TEXT,
> +		MOD_RODATA,
> +		MOD_RO_AFTER_INIT,
> +		MOD_DATA,
> +		MOD_INVALID,	/* This is needed to match the masks array */
> +	};
> +	static const int init_m_to_mem_type[] = {
> +		MOD_INIT_TEXT,
> +		MOD_INIT_RODATA,
> +		MOD_INVALID,
> +		MOD_INIT_DATA,
> +		MOD_INVALID,	/* This is needed to match the masks array */
> +	};
>   
> -	pr_debug("Core section allocation order:\n");
>   	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
> +		enum mod_mem_type type = is_init ? init_m_to_mem_type[m] : core_m_to_mem_type[m];
> +
>   		for (i = 0; i < info->hdr->e_shnum; ++i) {
>   			Elf_Shdr *s = &info->sechdrs[i];
>   			const char *sname = info->secstrings + s->sh_name;
> -			unsigned int *sizep;
>   
>   			if ((s->sh_flags & masks[m][0]) != masks[m][0]
>   			    || (s->sh_flags & masks[m][1])
>   			    || s->sh_entsize != ~0UL
> -			    || module_init_layout_section(sname))
> +			    || is_init != module_init_layout_section(sname))
>   				continue;
> -			sizep = m ? &mod->data_layout.size : &mod->core_layout.size;
> -			s->sh_entsize = module_get_offset(mod, sizep, s, i);
> -			pr_debug("\t%s\n", sname);
> -		}
> -		switch (m) {
> -		case 0: /* executable */
> -			mod->core_layout.size = strict_align(mod->core_layout.size);

Where is the strict alignment done now ?

> -			mod->core_layout.text_size = mod->core_layout.size;
> -			break;
> -		case 1: /* RO: text and ro-data */
> -			mod->data_layout.size = strict_align(mod->data_layout.size);
> -			mod->data_layout.ro_size = mod->data_layout.size;
> -			break;
> -		case 2: /* RO after init */
> -			mod->data_layout.size = strict_align(mod->data_layout.size);
> -			mod->data_layout.ro_after_init_size = mod->data_layout.size;
> -			break;
> -		case 4: /* whole core */
> -			mod->data_layout.size = strict_align(mod->data_layout.size);
> -			break;
> -		}
> -	}
>   
> -	pr_debug("Init section allocation order:\n");
> -	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
> -		for (i = 0; i < info->hdr->e_shnum; ++i) {
> -			Elf_Shdr *s = &info->sechdrs[i];
> -			const char *sname = info->secstrings + s->sh_name;
> -
> -			if ((s->sh_flags & masks[m][0]) != masks[m][0]
> -			    || (s->sh_flags & masks[m][1])
> -			    || s->sh_entsize != ~0UL
> -			    || !module_init_layout_section(sname))
> +			if (WARN_ON_ONCE(type == MOD_INVALID))
>   				continue;
> -			s->sh_entsize = (module_get_offset(mod, &mod->init_layout.size, s, i)
> -					 | INIT_OFFSET_MASK);
> +
> +			s->sh_entsize = module_get_offset_and_type(mod, type, s, i);
>   			pr_debug("\t%s\n", sname);
>   		}
> -		switch (m) {
> -		case 0: /* executable */
> -			mod->init_layout.size = strict_align(mod->init_layout.size);
> -			mod->init_layout.text_size = mod->init_layout.size;
> -			break;
> -		case 1: /* RO: text and ro-data */
> -			mod->init_layout.size = strict_align(mod->init_layout.size);
> -			mod->init_layout.ro_size = mod->init_layout.size;
> -			break;
> -		case 2:
> -			/*
> -			 * RO after init doesn't apply to init_layout (only
> -			 * core_layout), so it just takes the value of ro_size.
> -			 */
> -			mod->init_layout.ro_after_init_size = mod->init_layout.ro_size;
> -			break;
> -		case 4: /* whole init */
> -			mod->init_layout.size = strict_align(mod->init_layout.size);
> -			break;
> -		}
>   	}
>   }
>   
> +/*
> + * Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
> + * might -- code, read-only data, read-write data, small data.  Tally
> + * sizes, and place the offsets into sh_entsize fields: high bit means it
> + * belongs in init.
> + */
> +static void layout_sections(struct module *mod, struct load_info *info)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < info->hdr->e_shnum; i++)
> +		info->sechdrs[i].sh_entsize = ~0UL;
> +
> +	pr_debug("Core section allocation order:\n");
> +	__layout_sections(mod, info, false);
> +
> +	pr_debug("Init section allocation order:\n");
> +	__layout_sections(mod, info, true);
> +}
> +
>   static void set_license(struct module *mod, const char *license)
>   {
>   	if (!license)
> @@ -2122,72 +2177,42 @@ static int move_module(struct module *mod, struct load_info *info)
>   {
>   	int i;
>   	void *ptr;
> +	enum mod_mem_type t;
>   
> -	/* Do the allocs. */
> -	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
> -	 * leak.
> -	 */
> -	kmemleak_not_leak(ptr);
> -	if (!ptr)
> -		return -ENOMEM;
> -
> -	memset(ptr, 0, mod->core_layout.size);
> -	mod->core_layout.base = ptr;
> +	for_each_mod_mem_type(type) {
> +		if (!mod->mem[type].size) {
> +			mod->mem[type].base = NULL;
> +			continue;
> +		}
> +		mod->mem[type].size = PAGE_ALIGN(mod->mem[type].size);
> +		ptr = module_memory_alloc(mod->mem[type].size, type);
>   
> -	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
> -		 * scanned as it contains data and code that will be freed
> -		 * after the module is initialized.
> +		 * which is inside the block. Just mark it as not being a
> +		 * leak.
>   		 */
>   		kmemleak_ignore(ptr);
>   		if (!ptr) {
> -			module_memfree(mod->core_layout.base);
> -			return -ENOMEM;
> +			t = type;
> +			goto out_enomem;
>   		}
> -		memset(ptr, 0, mod->init_layout.size);
> -		mod->init_layout.base = ptr;
> -	} else
> -		mod->init_layout.base = NULL;
> -
> -#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
> -	/* Do the allocs. */
> -	ptr = vzalloc(mod->data_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
> -	 * leak.
> -	 */
> -	kmemleak_not_leak(ptr);
> -	if (!ptr) {
> -		module_memfree(mod->core_layout.base);
> -		module_memfree(mod->init_layout.base);
> -		return -ENOMEM;
> +		memset(ptr, 0, mod->mem[type].size);
> +		mod->mem[type].base = ptr;
>   	}
>   
> -	mod->data_layout.base = ptr;
> -#endif
>   	/* Transfer each section which specifies SHF_ALLOC */
>   	pr_debug("final section addresses:\n");
>   	for (i = 0; i < info->hdr->e_shnum; i++) {
>   		void *dest;
>   		Elf_Shdr *shdr = &info->sechdrs[i];
> +		enum mod_mem_type type = shdr->sh_entsize >> SH_ENTSIZE_TYPE_SHIFT;
>   
>   		if (!(shdr->sh_flags & SHF_ALLOC))
>   			continue;
>   
> -		if (shdr->sh_entsize & INIT_OFFSET_MASK)
> -			dest = mod->init_layout.base
> -				+ (shdr->sh_entsize & ~INIT_OFFSET_MASK);
> -		else if (!(shdr->sh_flags & SHF_EXECINSTR))
> -			dest = mod->data_layout.base + shdr->sh_entsize;
> -		else
> -			dest = mod->core_layout.base + shdr->sh_entsize;
> +		dest = mod->mem[type].base +
> +			(shdr->sh_entsize & SH_ENTSIZE_OFFSET_MASK);

Can't that fit on a single line ?

>   
>   		if (shdr->sh_type != SHT_NOBITS)
>   			memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);

> @@ -3060,20 +3091,21 @@ bool is_module_address(unsigned long addr)
>   struct module *__module_address(unsigned long addr)
>   {
>   	struct module *mod;
> -	struct mod_tree_root *tree;
>   
>   	if (addr >= mod_tree.addr_min && addr <= mod_tree.addr_max)
> -		tree = &mod_tree;
> +		goto lookup;
> +
>   #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC

Can we try to avoid that #ifdef ?
I know that means getting data_addr_min and data_addr_max alwyas 
existing, maybe through an unnamed union or a macro or a static inline 
helper ?

> -	else if (addr >= mod_data_tree.addr_min && addr <= mod_data_tree.addr_max)
> -		tree = &mod_data_tree;
> +	if (addr >= mod_tree.data_addr_min && addr <= mod_tree.data_addr_max)
> +		goto lookup;
>   #endif
> -	else
> -		return NULL;
>   
> +	return NULL;
> +
> +lookup:
>   	module_assert_mutex_or_preempt();
>   
> -	mod = mod_find(addr, tree);
> +	mod = mod_find(addr, &mod_tree);
>   	if (mod) {
>   		BUG_ON(!within_module(addr, mod));
>   		if (mod->state == MODULE_STATE_UNFORMED)

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