linux-kernel - Re: [PATCH v5 02/13] module: Simple refactor in preparation for split

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Message-ID: <f40fd2b2-2038-a53b-23ec-8f63941a2103@csgroup.eu>
Date:   Thu, 10 Feb 2022 11:18:58 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Aaron Tomlin <atomlin@...hat.com>,
        "mcgrof@...nel.org" <mcgrof@...nel.org>
CC:     "cl@...ux.com" <cl@...ux.com>,
        "pmladek@...e.com" <pmladek@...e.com>,
        "mbenes@...e.cz" <mbenes@...e.cz>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "jeyu@...nel.org" <jeyu@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-modules@...r.kernel.org" <linux-modules@...r.kernel.org>,
        "live-patching@...r.kernel.org" <live-patching@...r.kernel.org>,
        "atomlin@...mlin.com" <atomlin@...mlin.com>,
        "ghalat@...hat.com" <ghalat@...hat.com>,
        "allen.lkml@...il.com" <allen.lkml@...il.com>,
        "void@...ifault.com" <void@...ifault.com>,
        "joe@...ches.com" <joe@...ches.com>,
        "msuchanek@...e.de" <msuchanek@...e.de>,
        "oleksandr@...alenko.name" <oleksandr@...alenko.name>
Subject: Re: [PATCH v5 02/13] module: Simple refactor in preparation for split



Le 09/02/2022 à 18:03, Aaron Tomlin a écrit :
> No functional change.
> 
> This patch makes it possible to move non-essential code
> out of core module code.
> 
> Signed-off-by: Aaron Tomlin <atomlin@...hat.com>
> ---
>   kernel/module/internal.h | 22 ++++++++++++++++++++++
>   kernel/module/main.c     | 23 ++---------------------
>   2 files changed, 24 insertions(+), 21 deletions(-)
> 
> diff --git a/kernel/module/internal.h b/kernel/module/internal.h
> index c49896368f7f..1a4b33ce9f5f 100644
> --- a/kernel/module/internal.h
> +++ b/kernel/module/internal.h
> @@ -7,6 +7,28 @@
>   
>   #include <linux/elf.h>
>   #include <asm/module.h>
> +#include <linux/mutex.h>
> +
> +#ifndef ARCH_SHF_SMALL
> +#define ARCH_SHF_SMALL 0
> +#endif
> +
> +/* If this is set, the section belongs in the init part of the module */
> +#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
> +/* Maximum number of characters written by module_flags() */
> +#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
> +#define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4))

This is used only in sysfs.c, why move it to internal.h ?


> +
> +extern struct mutex module_mutex;
> +extern struct list_head modules;
> +
> +/* Provided by the linker */
> +extern const struct kernel_symbol __start___ksymtab[];
> +extern const struct kernel_symbol __stop___ksymtab[];
> +extern const struct kernel_symbol __start___ksymtab_gpl[];
> +extern const struct kernel_symbol __stop___ksymtab_gpl[];
> +extern const s32 __start___kcrctab[];
> +extern const s32 __start___kcrctab_gpl[];
>   
>   struct load_info {
>   	const char *name;
> diff --git a/kernel/module/main.c b/kernel/module/main.c
> index 34a2b0cf3c3e..750e3ad28679 100644
> --- a/kernel/module/main.c
> +++ b/kernel/module/main.c
> @@ -63,10 +63,6 @@
>   #define CREATE_TRACE_POINTS
>   #include <trace/events/module.h>
>   
> -#ifndef ARCH_SHF_SMALL
> -#define ARCH_SHF_SMALL 0
> -#endif
> -
>   /*
>    * Modules' sections will be aligned on page boundaries
>    * to ensure complete separation of code and data, but
> @@ -78,9 +74,6 @@
>   # define debug_align(X) (X)
>   #endif
>   
> -/* If this is set, the section belongs in the init part of the module */
> -#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
> -
>   /*
>    * Mutex protects:
>    * 1) List of modules (also safely readable with preempt_disable),
> @@ -88,8 +81,8 @@
>    * 3) module_addr_min/module_addr_max.
>    * (delete and add uses RCU list operations).
>    */
> -static DEFINE_MUTEX(module_mutex);
> -static LIST_HEAD(modules);
> +DEFINE_MUTEX(module_mutex);
> +LIST_HEAD(modules);
>   
>   /* Work queue for freeing init sections in success case */
>   static void do_free_init(struct work_struct *w);
> @@ -408,14 +401,6 @@ static __maybe_unused void *any_section_objs(const struct load_info *info,
>   	return (void *)info->sechdrs[sec].sh_addr;
>   }
>   
> -/* Provided by the linker */
> -extern const struct kernel_symbol __start___ksymtab[];
> -extern const struct kernel_symbol __stop___ksymtab[];
> -extern const struct kernel_symbol __start___ksymtab_gpl[];
> -extern const struct kernel_symbol __stop___ksymtab_gpl[];
> -extern const s32 __start___kcrctab[];
> -extern const s32 __start___kcrctab_gpl[];
> -
>   #ifndef CONFIG_MODVERSIONS
>   #define symversion(base, idx) NULL
>   #else
> @@ -1490,7 +1475,6 @@ struct module_sect_attrs {
>   	struct module_sect_attr attrs[];
>   };
>   
> -#define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4))

This is used only in sysfs.c, why move it to internal.h ?

>   static ssize_t module_sect_read(struct file *file, struct kobject *kobj,
>   				struct bin_attribute *battr,
>   				char *buf, loff_t pos, size_t count)
> @@ -4542,9 +4526,6 @@ static void cfi_cleanup(struct module *mod)
>   #endif
>   }
>   
> -/* Maximum number of characters written by module_flags() */
> -#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
> -
>   /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
>   static char *module_flags(struct module *mod, char *buf)
>   {