linux-kernel - Re: [PATCH RFC 07/19] perf tools: Workaround missing maps for x86

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]

Message-ID: <20180510204700.GF4311@kernel.org>
Date:   Thu, 10 May 2018 17:47:00 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     "Hunter, Adrian" <adrian.hunter@...el.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, Andi Kleen <ak@...ux.intel.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>, Jiri Olsa <jolsa@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [PATCH RFC 07/19] perf tools: Workaround missing maps for x86_64
 KPTI entry trampolines

Em Thu, May 10, 2018 at 05:19:22PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Thu, May 10, 2018 at 05:15:42PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Thu, May 10, 2018 at 07:08:37PM +0000, Hunter, Adrian escreveu:
> > > Let me know if you want me to post the workaround patches separately,
> > > otherwise I will wait a bit before sending the patches again.

> > I'll see if I went thru all of the patches already...
 
> So I looked at the patches posted and one comment is about the terse
> commit logs for some of the kcore_copy patches, for instance:
 
> --------------------
>  In preparation to add more program headers, get rid of kernel_map and
> modules_map.
> --------------------
 
> Can't this be made a bit more verbose? Lemme re-read the patch...

So you had just one pointers to the kernel map and a module_maps, and
then this is replaced by kcore_copy__map() that instead of populating
those fields that are being removed:

-       struct phdr_data kernel_map;
-       struct phdr_data modules_map;

Will allocate and add "struct phdr_data" instances to the
kcore_copy_info->phdrs list, so I propose, to follow convention used
elsewhere in tools/perf/ that you rename kcore_copy__map() to

  kcore_copy_info__addnew(kci, fields)

I would do it as:

struct phdr_data *phdr_data__new(fields)
{
	return  zalloc() + init fields;
}

struct phdr_data *kcore_copy_info__addnew(kci, fields)
{
	struct phdr_data *pd = phdr_data__new(fields);

	if (pd)
		list_add(&pd->list, &kci->phdrs)
}

Also please rename pd->list to pd->node, to clarify that it is a node in
some list, not a list.

The commit log list then could reflect that somehow, with something
around:

----------------------

Move ->kernel_map and ->modules_map to newly allocated entries in the
->phdrs list.

----------------------

wdyt?

- Arnaldo