linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Joe Lawrence <joe.lawrence@redhat.com>
To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kbuild@vger.kernel.org
Subject: Re: [RFC PATCH v6 03/12] livepatch: Add klp-convert tool
Date: Wed, 16 Feb 2022 11:46:58 -0500	[thread overview]
Message-ID: <Yg0qgtSFNQx5Mo1i@redhat.com> (raw)
In-Reply-To: <20220216163940.228309-4-joe.lawrence@redhat.com>

On Wed, Feb 16, 2022 at 11:39:31AM -0500, Joe Lawrence wrote:
> 
>  [ ... snip ... ]
> 
> +/*
> + * Checks if rela conversion is supported in given section
> + */
> +static bool supported_section(struct section *sec, char *object_name)
> +{
> +#if 0
> +	/*
> +	 * klp-relocations forbidden in sections that otherwise would
> +	 * match in allowed_prefixes[]
> +	 */
> +	static const char * const not_allowed[] = {
> +		".rela.data.rel.ro",
> +		".rela.data.rel.ro.local",
> +		".rela.data..ro_after_init",
> +		NULL
> +	};
> +#endif
> +
> +	/* klp-relocations allowed in sections only for vmlinux */
> +	static const char * const allowed_vmlinux[] = {
> +		".rela__jump_table",
> +		NULL
> +	};
> +
> +	/* klp-relocations allowed in sections with prefixes */
> +	static const char * const allowed_prefixes[] = {
> +		".rela.data",
> +		".rela.rodata",	// supported ???
> +		".rela.sdata",
> +		".rela.text",
> +		".rela.toc",
> +		NULL
> +	};
> +
> +	const char * const *name;
> +
> +#if 0
> +	for (name = not_allowed; *name; name++)
> +		if (strcmp(sec->name, *name) == 0)
> +			return false;
> +#endif

I wasn't sure if relocations in .rela.<read-only> sections should be
supported or not, particularly in the late relocation use case.  For
most, I think they can be easily avoided by the livepatch author
changing the storage class for the C pointer that is relocated.  On the
other hand, this may be disruptive to automated tools like
kpatch-build... or maybe there is no issue at all for late relocating
.rela.<read-only>?

-- Joe


  reply	other threads:[~2022-02-16 16:47 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-16 16:39 [RFC PATCH v6 00/12] livepatch: klp-convert tool Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 01/12] livepatch: Create and include UAPI headers Joe Lawrence
2022-04-14  8:50   ` Petr Mladek
2022-02-16 16:39 ` [RFC PATCH v6 02/12] kbuild: Support for symbols.klp creation Joe Lawrence
2022-04-14  9:35   ` Petr Mladek
2022-04-14 17:59     ` Nicolas Schier
2022-04-18 18:12       ` Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 03/12] livepatch: Add klp-convert tool Joe Lawrence
2022-02-16 16:46   ` Joe Lawrence [this message]
2022-02-16 16:56   ` Joe Lawrence
2022-04-14 15:03   ` elf API: was: " Petr Mladek
2022-04-18 18:01     ` Joe Lawrence
2023-02-06 18:16   ` Marcos Paulo de Souza
2022-02-16 16:39 ` [RFC PATCH v6 04/12] livepatch: Add klp-convert annotation helpers Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 05/12] modpost: Integrate klp-convert Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 06/12] livepatch: Add sample livepatch module Joe Lawrence
2023-02-07 12:52   ` Marcos Paulo de Souza
2022-02-16 16:39 ` [RFC PATCH v6 07/12] documentation: Update on livepatch elf format Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 08/12] livepatch/selftests: add klp-convert Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 09/12] livepatch/selftests: test multiple sections Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 10/12] livepatch/selftests: add __asm__ symbol renaming examples Joe Lawrence
2022-02-16 17:03   ` Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 11/12] livepatch/selftests: add data relocations test Joe Lawrence
2022-02-16 17:12   ` Joe Lawrence
2022-02-16 16:39 ` [RFC PATCH v6 12/12] livepatch/selftests: add static keys test Joe Lawrence
2022-02-16 17:17 ` [RFC PATCH v6 00/12] livepatch: klp-convert tool Joe Lawrence
2023-02-07 12:57 ` Marcos Paulo de Souza
2023-02-07 15:54   ` Joe Lawrence

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=Yg0qgtSFNQx5Mo1i@redhat.com \
    --to=joe.lawrence@redhat.com \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=live-patching@vger.kernel.org \
    /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 NNTP newsgroup(s).