Hi Nick, thanks for reporting this.
On 9/24/19 7:06 PM, Nick Desaulniers wrote: > Hi Vincenzo, > We also are having issues building the cross vDSO with Clang: > https://github.com/ClangBuiltLinux/linux/issues/595 > The initial implementation of vdso32 does not have support for Clang. I was planning to add it with a second patch set but it seems requiring more work. > It seems that `LINUXINCLUDE` in arch/arm64/kernel/vdso32/Makefile is including > arm64 headers in the arm part of the vdso32 build, which causes Clang to error > on the arm64 inline asm constraints being used in arm64. > > I think if the issue Will described is fixed, it will be simpler for us to fix > the rest to get it to build w/ Clang. > > https://github.com/ClangBuiltLinux/linux/issues/595#issuecomment-509874891 > is the basis of such a patch. > I agree with you this issue needs to be solved once and for all, but I feel that the solution is not straight forward. Next week I will post a fix to the problem Will raised and then will start investigating a more long term solution. > Clang ships with all backends on by default, and uses a `-target <triple>` to > cross compile; so the idea of passing two cross compiler binaries for a compat > vDSO build doesn't really apply to Clang. > My idea was to derivate the triple for clang from the compat cross compiler name removing the final dash. I have in my Makefile something on the lines: CLANG_TRIPLE ?= $(CONFIG_CROSS_COMPILE_COMPAT_VDSO:"%-"=%) ... COMPATCC := $(CC) --target=$(notdir $CLANG_TRIPLE) -- Regards, Vincenzo
