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From: Kees Cook <keescook@chromium.org>
To: Borislav Petkov <bp@alien8.de>
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 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA
Date: Thu, 10 Oct 2019 09:47:26 -0700	[thread overview]
Message-ID: <201910100947.AC066B160@keescook> (raw)
In-Reply-To: <20191010152516.GG7658@zn.tnic>

On Thu, Oct 10, 2019 at 05:25:16PM +0200, Borislav Petkov wrote:
> On Thu, Sep 26, 2019 at 10:55:47AM -0700, Kees Cook wrote:
> > Many architectures have an EXCEPTION_TABLE that needs only to be
> > read-only. As such, it should live in RO_DATA. This creates a macro to
> > identify this case for the architectures that can move EXCEPTION_TABLE
> > into RO_DATA.
> > 
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> >  include/asm-generic/vmlinux.lds.h | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> > index d57a28786bb8..35a6cba39d9f 100644
> > --- a/include/asm-generic/vmlinux.lds.h
> > +++ b/include/asm-generic/vmlinux.lds.h
> > @@ -69,6 +69,17 @@
> >  #define NOTES_HEADERS_RESTORE
> >  #endif
> >  
> > +/*
> > + * Some architectures have non-executable read-only exception tables.
> > + * They can be added to the RO_DATA segment by specifying their desired
> > + * alignment.
> > + */
> > +#ifdef RO_DATA_EXCEPTION_TABLE_ALIGN
> > +#define RO_DATA_EXCEPTION_TABLE	EXCEPTION_TABLE(RO_DATA_EXCEPTION_TABLE_ALIGN)
> > +#else
> > +#define RO_DATA_EXCEPTION_TABLE
> > +#endif
> > +
> >  /* Align . to a 8 byte boundary equals to maximum function alignment. */
> >  #define ALIGN_FUNCTION()  . = ALIGN(8)
> >  
> > @@ -508,6 +519,7 @@
> >  		__stop___modver = .;					\
> >  	}								\
> >  									\
> > +	RO_DATA_EXCEPTION_TABLE						\
> >  	NOTES								\
> >  									\
> >  	. = ALIGN((align));						\
> > -- 
> 
> I think you can drop the "DATA" from the names as it is kinda clear
> where the exception table lands:
> 
> RO_EXCEPTION_TABLE_ALIGN
> RO_EXCEPTION_TABLE
> 
> The "read-only" part is the important one.

Excellent point; I was not loving the how long the name was either. :)

-- 
Kees Cook

  reply	other threads:[~2019-10-10 16:47 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
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 [this message]
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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