public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
From: Florian Weimer <fw@deneb.enyo.de>
To: wangboshi <wangboshi@huawei.com>
Cc: <libc-alpha@sourceware.org>
Subject: Re: [RFC][PATCH] AArch64: use movz/movk instead of literal pools in start.S
Date: Thu, 07 Sep 2017 11:43:00 -0000	[thread overview]
Message-ID: <877exalool.fsf@mid.deneb.enyo.de> (raw)
In-Reply-To: <e65025af-5168-c999-bfc1-7ac614314836@huawei.com> (wangboshi@huawei.com's message of "Thu, 7 Sep 2017 15:33:34 +0800")

> eXecute-Only Memory (XOM) is a protection mechanism against some ROP
> attacks. XOM sets the code as executable and unreadable, so the
> access to any data, like literal pools, in the code section causes
> the fault with XOM. The compiler can disable literal pools for C
> source files, but not for assembly files, so I use movz/movk instead
> of literal pools in start.S for XOM.

Isn't the main goal of XOM to make it more difficult for the
legitimate device owner to view running machine code?

| Execute-only memory allows you to protect your intellectual property
| by preventing executable code being read by users. For example, you
| can place firmware in execute-only memory and load user code and
| drivers separately. Placing the firmware in execute-only memory
| prevents users from trivially reading the code.

<http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471m/chr1368698326509.html>

I don't think it's in the interests of the GNU projet to support such
a thing.

  reply	other threads:[~2017-09-07 11:43 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-07  7:34 wangboshi
2017-09-07 11:43 ` Florian Weimer [this message]
2017-09-11  8:58   ` Szabolcs Nagy
2017-09-11  9:09 ` Andrew Pinski
2017-09-11  9:24   ` Szabolcs Nagy
2017-09-12  8:54   ` Boshi Wang
2017-09-11  9:11 ` Szabolcs Nagy
     [not found]   ` <336560e5-c9de-08bc-c850-28994cac2c33@huawei.com>
2017-09-14  8:35     ` Szabolcs Nagy
2017-09-15  1:16       ` Boshi Wang
2017-09-18 17:21         ` Szabolcs Nagy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=877exalool.fsf@mid.deneb.enyo.de \
    --to=fw@deneb.enyo.de \
    --cc=libc-alpha@sourceware.org \
    --cc=wangboshi@huawei.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).