Messages in this thread | | | Date | Thu, 26 Sep 2019 16:51:47 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH] arm64: Allow disabling of the compat vDSO |
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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 <catalin.marinas@arm.com> 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. > > > > > > 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*'
-- Catalin
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