Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 25 Nov 2022 17:41:31 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Petr Pavlu <petr.pavlu@suse.com>
Cc:     tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com,
        x86@kernel.org, hpa@zytor.com, nicolas@fjasle.eu,
        masahiroy@kernel.org, kirill.shutemov@linux.intel.com,
        tony.luck@intel.com, michael.roth@amd.com, nathan@kernel.org,
        ndesaulniers@google.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86: Avoid relocation information in final vmlinux
Message-ID: <Y4DwOzkN04uYIAox@zn.tnic>
References: <20220927084632.14531-1-petr.pavlu@suse.com>
 <Y34SXeU6JEk+UGfV@zn.tnic>
 <1af5ee66-5ab1-45b2-f229-182f89dc6b94@suse.com>
 <Y35CNdPVwq11NCYN@zn.tnic>
 <765e1e78-c540-0753-7a19-7d335bcc998b@suse.com>
 <Y39lwk3itVnsADrP@zn.tnic>
 <1cc97d84-da4d-c8cc-dbcd-fcdc34c6d11c@suse.com>
 <Y3+Ql1ETyO9FP2xU@zn.tnic>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <Y3+Ql1ETyO9FP2xU@zn.tnic>
Precedence: bulk

On Thu, Nov 24, 2022 at 04:41:11PM +0100, Borislav Petkov wrote:
> This is in both cases with your patch, once with RANDOMIZE_BASE=y and
> once with RANDOMIZE_BASE=n.
> 
> IOW, your patch actually makes my vmlinux bigger by 51K.
> 
> IOW, I cannot reproduce your
> 
> | Configuration      | With relocs | Stripped relocs |
> | x86_64_defconfig   |       70 MB |           43 MB |
> 
> claim, but not with a defconfig but with my specially tailored config.
> 
> I guess the next thing I'll try is without your patch.

Ok, I tried reproducing your defconfig numbers first:

defconfig:						vmlinux
- with patch: NEED_RELOCS=y				 48053656
- with patch, NEED_RELOCS=n, 				 48000696
- without patch, NEED_RELOCS=n, 			 48000696
- without patch: NEED_RELOCS=y				 83091744

So yes, I can reproduce your observation - defconfig *with* your patch
does slim down vmlinux, because, well, it is moving the reloc sections
into a separate file. Doh.

And with my .config too:

tailored config:
- with patch: 		NEED_RELOCS=y			377718768
- without patch, 	NEED_RELOCS=y			639952576

So I guess we can try it - let's see who complains.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette