On Thu, Sep 26, 2019 at 8:51 AM Catalin Marinas <[email protected]> wrote: > > On Thu, Sep 26, 2019 at 08:47:18AM +0100, Catalin Marinas wrote: > > On Thu, Sep 26, 2019 at 01:06:50AM +0100, Vincenzo Frascino wrote: > > > On 9/25/19 6:08 PM, Catalin Marinas wrote: > > > > On Wed, Sep 25, 2019 at 09:53:16AM -0700, Nick Desaulniers wrote: > > > >> On Wed, Sep 25, 2019 at 6:09 AM Catalin Marinas > > > >> <[email protected]> wrote: > > > >>> - clean up the headers includes; vDSO should not include kernel-only > > > >>> headers that may even contain code patched at run-time > > > >> > > > >> This is a big one; Clang validates the inline asm constraints for > > > >> extended inline assembly, GCC does not for dead code. So Clang chokes > > > >> on the inclusion of arm64 headers using extended inline assembly when > > > >> being compiled for arm-linux-gnueabi.
This case is very much real (not sure if Vincenzo was asking me or Catalin), see report at the bottom of this comment: https://github.com/ClangBuiltLinux/linux/issues/595#issuecomment-509874891 > > > > > > > > Whether clang or gcc, I'd like this fixed anyway. At some point we may > > > > inadvertently rely on some code which is patched at boot time for the > > > > kernel code but not for the vDSO. > > > > > > Do we have any code of this kind in header files? > > > > > > The vDSO library uses only a subset of the headers (mainly Macros) hence > > > all the > > > unused symbols should be compiled out. Is your concern only theoretical > > > or do > > > you have an example on where this could be happening? > > > > At the moment it's rather theoretical. > > Actually, it's not. The moment the compat vdso Makefile needs the line > below, we are doing it wrong: > > VDSO_CFLAGS += -D__uint128_t='void*' *yikes* -- Thanks, ~Nick Desaulniers
