Messages in this thread | | | Date | Fri, 28 Jan 2022 15:26:26 -0800 | Subject | Re: [PATCH v2] kbuild: Add environment variables for userprogs flags | From | Elliot Berman <> |
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On 1/28/2022 2:49 PM, Nick Desaulniers wrote: > On Fri, Jan 28, 2022 at 2:45 PM Fangrui Song <maskray@google.com> wrote: >> >> On 2022-01-28, Elliot Berman wrote: >>> Allow additional arguments be passed to userprogs compilation. >>> Reproducible clang builds need to provide a sysroot and gcc path to >>> ensure same toolchain is used across hosts. KCFLAGS is not currently >>> used for any user programs compilation, so add new USERCFLAGS and >>> USERLDFLAGS which serves similar purpose as HOSTCFLAGS/HOSTLDFLAGS. >>> >>> Specifically, I'm trying to force CC_CAN_LINK to consistently fail in >>> an environment where a user sysroot is not specifically available. >>> Currently, Clang might automatically detect GCC installation on hosts >>> which have it installed to a default location in /. With addition of >>> these environment variables, you can specify flags such as: >>> >>> $ make USERCFLAGS=--sysroot=/dev/null USERLDFLAGS=-Wl,--sysroot=/dev/null >>> >>> to force sysroot detection to fail. >> >> -Wl,--sysroot=/dev/null => --sysroot >> >> As I mentioned in >> https://lore.kernel.org/all/20220128031549.w5a4bilxbkppagfu@google.com/ >> -Wl,--sysroot=/dev/null does not suppress search paths like -L/lib . > > In that case, Elliot, can you please test whether USERLDFLAGS is > necessary to be specified AT ALL? Maybe we can drop that addition from > this patch if so?
USERLDFLAGS as --sysroot=/dev/null isn't necessary and not needed for the Android kernel usecase. I've included here since we have HOSTLDFLAGS and LDFLAGS for host programs and kernel respectively.
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