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From: Borislav Petkov <bp@alien8.de>
To: Kees Cook <keescook@chromium.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Rick Edgecombe <rick.p.edgecombe@intel.com>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
	linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org,
	linux-s390@vger.kernel.org, linux-c6x-dev@linux-c6x.org,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	Michal Simek <monstr@monstr.eu>,
	linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 07/29] x86: Restore "text" Program Header with dummy section
Date: Thu, 10 Oct 2019 12:33:05 +0200	[thread overview]
Message-ID: <20191010103305.GD7658@zn.tnic> (raw)
In-Reply-To: <20190926175602.33098-8-keescook@chromium.org>

On Thu, Sep 26, 2019 at 10:55:40AM -0700, Kees Cook wrote:
> Instead of depending on markings in the section following NOTES to
> restore the associated Program Header, use a dummy section, as done
> in other architectures.

This is very laconic and after some staring at ld.info, I think you mean
this:

"   If you place a section in one or more segments using ':PHDR', then
the linker will place all subsequent allocatable sections which do not
specify ':PHDR' in the same segments."

but I could be way off. Yes, no?

IOW, please write in the commit messages first what the problem is
you're addressing.

> This is preparation for moving NOTES into the
> RO_DATA macro.
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
>  arch/x86/kernel/vmlinux.lds.S | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
> index e2feacf921a0..788e78978030 100644
> --- a/arch/x86/kernel/vmlinux.lds.S
> +++ b/arch/x86/kernel/vmlinux.lds.S
> @@ -147,8 +147,9 @@ SECTIONS
>  	} :text = 0x9090
>  
>  	NOTES :text :note
> +	.dummy : { *(.dummy) } :text
>  
> -	EXCEPTION_TABLE(16) :text = 0x9090
> +	EXCEPTION_TABLE(16)

This is killing the filler byte but I have a suspicion that'll change
eventually to INT3... :)

-- 
Regards/Gruss,
    Boris.

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

  reply	other threads:[~2019-10-10 10:33 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-26 17:55 [PATCH 00/29] vmlinux.lds.h: Refactor EXCEPTION_TABLE and NOTES Kees Cook
2019-09-26 17:55 ` [PATCH 01/29] powerpc: Rename "notes" PT_NOTE to "note" Kees Cook
2019-09-26 17:55 ` [PATCH 02/29] powerpc: Remove PT_NOTE workaround Kees Cook
2019-09-26 17:55 ` [PATCH 03/29] powerpc: Rename PT_LOAD identifier "kernel" to "text" Kees Cook
2019-09-26 17:55 ` [PATCH 04/29] alpha: " Kees Cook
2019-09-26 17:55 ` [PATCH 05/29] ia64: Rename PT_LOAD identifier "code" " Kees Cook
2019-09-26 17:55 ` [PATCH 06/29] s390: Move RO_DATA into "text" PT_LOAD Program Header Kees Cook
2019-09-26 17:55 ` [PATCH 07/29] x86: Restore "text" Program Header with dummy section Kees Cook
2019-10-10 10:33   ` Borislav Petkov [this message]
2019-10-10 16:46     ` Kees Cook
2019-09-26 17:55 ` [PATCH 08/29] vmlinux.lds.h: Provide EMIT_PT_NOTE to indicate export of .notes Kees Cook
2019-10-10 10:40   ` Borislav Petkov
2019-09-26 17:55 ` [PATCH 09/29] vmlinux.lds.h: Move Program Header restoration into NOTES macro Kees Cook
2019-09-26 17:55 ` [PATCH 10/29] vmlinux.lds.h: Move NOTES into RO_DATA Kees Cook
2019-09-26 17:55 ` [PATCH 11/29] vmlinux.lds.h: Replace RODATA with RO_DATA Kees Cook
2019-09-26 17:55 ` [PATCH 12/29] vmlinux.lds.h: Replace RO_DATA_SECTION " Kees Cook
2019-09-26 17:55 ` [PATCH 13/29] vmlinux.lds.h: Replace RW_DATA_SECTION with RW_DATA Kees Cook
2019-09-26 17:55 ` [PATCH 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA Kees Cook
2019-10-01  9:05   ` Will Deacon
2019-10-10 15:25   ` Borislav Petkov
2019-10-10 16:47     ` Kees Cook
2019-09-26 17:55 ` [PATCH 15/29] x86: Actually use _etext for end of text segment Kees Cook
2019-09-26 17:55 ` [PATCH 16/29] x86: Move EXCEPTION_TABLE to RO_DATA segment Kees Cook
2019-09-26 17:55 ` [PATCH 17/29] alpha: " Kees Cook
2019-09-26 17:55 ` [PATCH 18/29] arm64: " Kees Cook
2019-10-01  9:03   ` Will Deacon
2019-10-01 15:48     ` Kees Cook
2019-09-26 17:55 ` [PATCH 19/29] c6x: " Kees Cook
2019-09-26 17:55 ` [PATCH 20/29] h8300: " Kees Cook
2019-09-26 17:55 ` [PATCH 21/29] ia64: " Kees Cook
2019-09-26 17:55 ` [PATCH 22/29] microblaze: " Kees Cook
2019-09-26 17:55 ` [PATCH 23/29] parisc: " Kees Cook
2019-09-26 17:55 ` [PATCH 24/29] powerpc: " Kees Cook
2019-09-26 17:55 ` [PATCH 25/29] xtensa: " Kees Cook
2019-09-26 17:55 ` [PATCH 26/29] x86/mm: Remove redundant &s on addresses Kees Cook
2019-09-26 17:56 ` [PATCH 27/29] x86/mm: Report which part of kernel image is freed Kees Cook
2019-09-26 17:56 ` [PATCH 28/29] x86/mm: Report actual image regions in /proc/iomem Kees Cook
2019-10-10 18:00   ` Borislav Petkov
2019-09-26 17:56 ` [PATCH 29/29] x86: Use INT3 instead of NOP for linker fill bytes Kees Cook
2019-10-10 18:03 ` [PATCH 00/29] vmlinux.lds.h: Refactor EXCEPTION_TABLE and NOTES Borislav Petkov
2019-10-10 23:57   ` Kees Cook
2019-10-11  1:38     ` hpa

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