linux-kernel - Re: [PATCH 1/7] modules: Refactor within_module_core() and within_module

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Message-ID: <YfG+zVl8aV+UszoE@kernel.org>
Date:   Wed, 26 Jan 2022 23:36:13 +0200
From:   Mike Rapoport <rppt@...nel.org>
To:     Christophe Leroy <christophe.leroy@...roup.eu>
Cc:     Luis Chamberlain <mcgrof@...nel.org>, Jessica Yu <jeyu@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        "kgdb-bugreport@...ts.sourceforge.net" 
        <kgdb-bugreport@...ts.sourceforge.net>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>
Subject: Re: [PATCH 1/7] modules: Refactor within_module_core() and
 within_module_init()

On Mon, Jan 24, 2022 at 09:22:15AM +0000, Christophe Leroy wrote:
> within_module_core() and within_module_init() are doing the exact same
> test, one on core_layout, the second on init_layout.
> 
> In preparation of increasing the complexity of that verification,
> refactor it into a single function called within_module_layout().
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> ---
>  include/linux/module.h | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/include/linux/module.h b/include/linux/module.h
> index c9f1200b2312..33b4db8f5ca5 100644
> --- a/include/linux/module.h
> +++ b/include/linux/module.h
> @@ -565,18 +565,27 @@ 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_range(unsigned long addr, void *base, unsigned int size)
> +{
> +	return addr >= (unsigned long)base && addr < (unsigned long)base + size;
> +}

There's also 'within' at least in arch/x86/mm/pat/set_memory.c and surely
tons of open-coded "address within" code.

Should it live in, say, include/linux/range.h?

> +
> +static inline bool within_module_layout(unsigned long addr,
> +					const struct module_layout *layout)
> +{
> +	return within_range(addr, layout->base, layout->size);
> +}
> +
>  static inline bool within_module_core(unsigned long addr,
>  				      const struct module *mod)
>  {
> -	return (unsigned long)mod->core_layout.base <= addr &&
> -	       addr < (unsigned long)mod->core_layout.base + mod->core_layout.size;
> +	return within_module_layout(addr, &mod->core_layout);
>  }
>  
>  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;
> +	return within_module_layout(addr, &mod->init_layout);
>  }
>  
>  static inline bool within_module(unsigned long addr, const struct module *mod)
> -- 
> 2.33.1
> 

-- 
Sincerely yours,
Mike.