Re: [PATCH 01/14] exceptions: fork exception table content from module.h into extable.h

[Rusty Russell]

Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> writes:
> For historical reasons (i.e. pre-git) the exception table stuff was
> buried in the middle of the module.h file.  I noticed this while
> doing an audit for needless includes of module.h and found core
> kernel files (both arch specific and arch independent) were just
> including module.h for this.

I'm going to include this first patch now; it's trivial, and allows the
rest of the changes to proceed at the archs' leisure.

I have another patch series which had to be tweaked, so I'm deferring
the push to Linus for a couple of days stewing in linux-next anyway.

Thanks,
Rusty.

> The converse is also true, in that conventional drivers, be they
> for filesystems or actual hardware peripherals or similar, do not
> normally care about the exception tables.
>
> Here we fork the exception table content out of module.h into a
> new file called extable.h -- and temporarily include it into the
> module.h itself.
>
> Then we will work our way across the arch independent and arch
> specific files needing just exception table content, and move
> them off module.h and onto extable.h
>
> Once that is done, we can remove the extable.h from module.h
> and in doing it like this, we avoid introducing build failures
> into the git history.
>
> The gain here is that module.h gets a bit smaller, across all
> modular drivers that we build for allmodconfig.  Also the core
> files that only need exception table stuff don't have an include
> of module.h that brings in lots of extra stuff and just looks
> generally out of place.
>
> Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> ---
>  include/linux/extable.h | 30 ++++++++++++++++++++++++++++++
>  include/linux/module.h  | 27 ++-------------------------
>  2 files changed, 32 insertions(+), 25 deletions(-)
>  create mode 100644 include/linux/extable.h
>
> diff --git a/include/linux/extable.h b/include/linux/extable.h
> new file mode 100644
> index 000000000000..2c71dccd1bc3
> --- /dev/null
> +++ b/include/linux/extable.h
> @@ -0,0 +1,30 @@
> +#ifndef _LINUX_EXTABLE_H
> +#define _LINUX_EXTABLE_H
> +
> +struct module;
> +struct exception_table_entry;
> +
> +const struct exception_table_entry *
> +search_extable(const struct exception_table_entry *first,
> +	       const struct exception_table_entry *last,
> +	       unsigned long value);
> +void sort_extable(struct exception_table_entry *start,
> +		  struct exception_table_entry *finish);
> +void sort_main_extable(void);
> +void trim_init_extable(struct module *m);
> +
> +/* Given an address, look for it in the exception tables */
> +const struct exception_table_entry *search_exception_tables(unsigned long add);
> +
> +#ifdef CONFIG_MODULES
> +/* For extable.c to search modules' exception tables. */
> +const struct exception_table_entry *search_module_extables(unsigned long addr);
> +#else
> +static inline const struct exception_table_entry *
> +search_module_extables(unsigned long addr)
> +{
> +	return NULL;
> +}
> +#endif /*CONFIG_MODULES*/
> +
> +#endif /* _LINUX_EXTABLE_H */
> diff --git a/include/linux/module.h b/include/linux/module.h
> index f777164c238b..f95ed243a4de 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -18,6 +18,7 @@
>  #include <linux/moduleparam.h>
>  #include <linux/jump_label.h>
>  #include <linux/export.h>
> +#include <linux/extable.h>	/* only as arch move module.h -> extable.h */
>  #include <linux/rbtree_latch.h>
>  
>  #include <linux/percpu.h>
> @@ -37,6 +38,7 @@ struct modversion_info {
>  };
>  
>  struct module;
> +struct exception_table_entry;
>  
>  struct module_kobject {
>  	struct kobject kobj;
> @@ -155,18 +157,6 @@ extern void cleanup_module(void);
>  #define __INITRODATA_OR_MODULE __INITRODATA
>  #endif /*CONFIG_MODULES*/
>  
> -/* Archs provide a method of finding the correct exception table. */
> -struct exception_table_entry;
> -
> -const struct exception_table_entry *
> -search_extable(const struct exception_table_entry *first,
> -	       const struct exception_table_entry *last,
> -	       unsigned long value);
> -void sort_extable(struct exception_table_entry *start,
> -		  struct exception_table_entry *finish);
> -void sort_main_extable(void);
> -void trim_init_extable(struct module *m);
> -
>  /* Generic info of form tag = "info" */
>  #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
>  
> @@ -268,9 +258,6 @@ extern const typeof(name) __mod_##type##__##name##_device_table		\
>   * files require multiple MODULE_FIRMWARE() specifiers */
>  #define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
>  
> -/* Given an address, look for it in the exception tables */
> -const struct exception_table_entry *search_exception_tables(unsigned long add);
> -
>  struct notifier_block;
>  
>  #ifdef CONFIG_MODULES
> @@ -630,9 +617,6 @@ const char *module_address_lookup(unsigned long addr,
>  int lookup_module_symbol_name(unsigned long addr, char *symname);
>  int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
>  
> -/* For extable.c to search modules' exception tables. */
> -const struct exception_table_entry *search_module_extables(unsigned long addr);
> -
>  int register_module_notifier(struct notifier_block *nb);
>  int unregister_module_notifier(struct notifier_block *nb);
>  
> @@ -657,13 +641,6 @@ static inline bool is_livepatch_module(struct module *mod)
>  
>  #else /* !CONFIG_MODULES... */
>  
> -/* Given an address, look for it in the exception tables. */
> -static inline const struct exception_table_entry *
> -search_module_extables(unsigned long addr)
> -{
> -	return NULL;
> -}
> -
>  static inline struct module *__module_address(unsigned long addr)
>  {
>  	return NULL;
> -- 
> 2.8.4