linux-kernel - Re: [PATCH 09/28] nios2: Page table management

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, 22 Apr 2014 16:09:46 +0800
From:	Ley Foon Tan <lftan@...era.com>
To:	Pavel Machek <pavel@...x.de>
Cc:	linux-arch@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-doc@...r.kernel.org, cltang@...esourcery.com
Subject: Re: [PATCH 09/28] nios2: Page table management

Hi

On Sun, Apr 20, 2014 at 12:05 AM, Pavel Machek <pavel@...x.de> wrote:

>> +static void pgd_init(pgd_t *pgd)
>> +{
>> +     unsigned long *p = (unsigned long *) pgd;
>> +     int i;
>> +
>> +     for (i = 0; i < USER_PTRS_PER_PGD; i += 8) {
>> +             p[i + 0] = (unsigned long) invalid_pte_table;
>> +             p[i + 1] = (unsigned long) invalid_pte_table;
>> +             p[i + 2] = (unsigned long) invalid_pte_table;
>> +             p[i + 3] = (unsigned long) invalid_pte_table;
>> +             p[i + 4] = (unsigned long) invalid_pte_table;
>> +             p[i + 5] = (unsigned long) invalid_pte_table;
>> +             p[i + 6] = (unsigned long) invalid_pte_table;
>> +             p[i + 7] = (unsigned long) invalid_pte_table;
>> +     }
>
> Umm. Manual loop unrolling. Does it really improve performance? Is the
> code hot enough to warrant the uglyness?
We can use the memset here because invalid_pte_table is full 32 bit value.
BTW, arch for score and mips have the similar implementation as well.

Regards
--
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/