From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (bilbo.ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zwd2v6XrszDrnh for ; Wed, 7 Mar 2018 00:31:19 +1100 (AEDT) In-Reply-To: <20180301010249.GA18370@beast> To: Kees Cook From: Michael Ellerman Cc: linux-kernel@vger.kernel.org, Paul Mackerras , linuxppc-dev@lists.ozlabs.org Subject: Re: powerpc: Keep const vars out of writable .sdata Message-Id: <3zwd2v0v8nz9shN@ozlabs.org> Date: Wed, 7 Mar 2018 00:31:17 +1100 (AEDT) List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2018-03-01 at 01:02:49 UTC, Kees Cook wrote: > From: Segher Boessenkool > > Newer gcc will support "-mno-readonly-in-sdata"[1], which makes sure that > the optimization on PPC32 for variables getting moved into the .sdata > section will not apply to const variables (which must be in .rodata). > > This was originally noticed in mm/rodata_test.c when rodata_test_data > was not static: > > c0695034 g O .data 00000004 rodata_test_data > > After this patch with an updated compiler, this is correctly in .rodata. > > [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82411 > > Reported-by: Christophe Leroy > Signed-off-by: Segher Boessenkool > Signed-off-by: Kees Cook Applied to powerpc next, thanks. https://git.kernel.org/powerpc/c/51d42f0f5fd6c74144d19bf6a66352 cheers