From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH 14/29] vmlinux.lds.h: Allow EXCEPTION_TABLE to live in RO_DATA Date: Thu, 10 Oct 2019 17:25:16 +0200 Message-ID: <20191010152516.GG7658@zn.tnic> References: <20190926175602.33098-1-keescook@chromium.org> <20190926175602.33098-15-keescook@chromium.org> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1570721124; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=oFtLtIT92PEjPANVccNt8bv5ZEw6stfT1hPzmyy05AU=; b=XvDnIWbOWnxP5VFZO9ko7ahJhTcRm/Xsrm8HgemYJGsHSBOE6Uta44f3AIYcSZ6OfEGl/a AEH1A9BDC9JA4n3PgugNym5/q4Nt+C+NeHY9F4IhvYggxoRn7C5NPgZWNAKd44J4GzphzU Yg/gusTeVLuPtqp+cJTKXO0tNksVAHs= Content-Disposition: inline In-Reply-To: <20190926175602.33098-15-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Kees Cook Cc: Thomas Gleixner , Rick Edgecombe , Ingo Molnar , "H. Peter Anvin" , Dave Hansen , Andy Lutomirski , Arnd Bergmann , 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 , Michal Simek , linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org, x86@kernel.org, linux-kernel@vger.kernel.org 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 > --- > 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. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette