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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id fu5sm5201126pjb.11.2020.11.20.16.08.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 20 Nov 2020 16:08:44 -0800 (PST) Date: Fri, 20 Nov 2020 16:08:43 -0800 From: Kees Cook To: Masahiro Yamada Cc: Nathan Chancellor , Michal Marek , Russell King , Catalin Marinas , Will Deacon , Michael Ellerman , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Nick Desaulniers , Arvind Sankar , linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, clang-built-linux@googlegroups.com Subject: Re: [PATCH v2 1/2] kbuild: Hoist '--orphan-handling' into Kconfig Message-ID: <202011201607.75FA476@keescook> References: <20201113195553.1487659-1-natechancellor@gmail.com> <20201119204656.3261686-1-natechancellor@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201119204656.3261686-1-natechancellor@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 19, 2020 at 01:46:56PM -0700, Nathan Chancellor wrote: > Currently, '--orphan-handling=warn' is spread out across four different > architectures in their respective Makefiles, which makes it a little > unruly to deal with in case it needs to be disabled for a specific > linker version (in this case, ld.lld 10.0.1). > > To make it easier to control this, hoist this warning into Kconfig and > the main Makefile so that disabling it is simpler, as the warning will > only be enabled in a couple places (main Makefile and a couple of > compressed boot folders that blow away LDFLAGS_vmlinx) and making it > conditional is easier due to Kconfig syntax. One small additional > benefit of this is saving a call to ld-option on incremental builds > because we will have already evaluated it for CONFIG_LD_ORPHAN_WARN. > > To keep the list of supported architectures the same, introduce > CONFIG_ARCH_WANT_LD_ORPHAN_WARN, which an architecture can select to > gain this automatically after all of the sections are specified and size > asserted. A special thanks to Kees Cook for the help text on this > config. > > Link: https://github.com/ClangBuiltLinux/linux/issues/1187 > Acked-by: Kees Cook > Acked-by: Michael Ellerman (powerpc) > Reviewed-by: Nick Desaulniers > Tested-by: Nick Desaulniers > Signed-off-by: Nathan Chancellor Masahiro, do you want to take these to get them to Linus for v5.10? I can send them if you'd prefer. -Kees -- Kees Cook