linux-kernel - Re: [PATCH] Remove initialization of page_table in one_page_table

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 14 Jul 2009 03:18:39 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Zhaolei <zhaolei@...fujitsu.com>
cc:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Remove initialization of page_table in
 one_page_table_init()

On Tue, 14 Jul 2009, Zhaolei wrote:

> diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
> index 3cd7711..55da09b 100644
> --- a/arch/x86/mm/init_32.c
> +++ b/arch/x86/mm/init_32.c
> @@ -108,13 +108,13 @@ static pmd_t * __init one_md_table_init(pgd_t *pgd)
> static pte_t * __init one_page_table_init(pmd_t *pmd)
> {
>     if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
> -        pte_t *page_table = NULL;
> +        pte_t *page_table;
> 
>         if (after_bootmem) {
> #if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
>             page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
> -#endif
>             if (!page_table)
> +#endif
>                 page_table =
>                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
>         } else

Nack, gcc will already optimize the branch out for configs without 
CONFIG_DEBUG_PAGEALLOC and CONFIG_KMEMCHECK.  The only thing this change 
does is make the code less readable.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/