Messages in this thread | | | Date | Fri, 01 Feb 2013 12:25:16 -0700 | From | Stephen Warren <> | Subject | Re: [PATCH V7] kbuild: create a rule to run the pre-processor on *.dts files |
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On 02/01/2013 10:27 AM, Stephen Warren wrote: > On 02/01/2013 09:51 AM, Rob Herring wrote: >> On 02/01/2013 03:01 AM, Srinivas KANDAGATLA wrote: >>> Hi Stephen, >>> Not sure if you have already noticed this but, >>> I did try this patch on my 3.8, and it looks like the intermediate dts >>> file replaces all instances of linux with 1 because of predefined macros >>> in gcc. >>> As a result >>> linux,stdout-path = "/soc/stm-asc2"; >>> is changed to. >>> 1,stdout-path = "/soc/stm-asc2"; >>> >>> On my version of compiler(gcc version 4.6.3) I have >>> >>> armv7-linux-gcc -E -dM - < /dev/null | grep -v _ >>> #define unix 1 >>> #define linux 1 >>> >>> Which might be true with most compiler versions aswell. >>> As we are using linux as prefix for some device tree properties it makes >>> sense to undef the linux gcc define. >>> Adding -Ulinux to cmd_dtc_cpp should fix it. >>> >>> -cmd_dtc_cpp = $(CPP) $(cpp_flags) -D__DTS__ -x assembler-with-cpp -o >>> $(dtc-tmp) $< ; \ >>> +cmd_dtc_cpp = $(CPP) $(cpp_flags) -D__DTS__ -Ulinux -x >>> assembler-with-cpp -o $(dtc-tmp) $< ; \ >>> $(objtree)/scripts/dtc/dtc -O dtb -o $@ -b 0 $(DTC_FLAGS) $(dtc-tmp) >> >> That's a hackish solution that seems fragile as well. Is there no way to >> turn off all built-in defines? > > I'm pretty sure there is; I'll go find it.
Hmmm. I can't actually find one.
> But we do want to keep some of the built-in defines. for example, -x > assembler-with-cpp turns on __ASSEMBLY__ or similar, which headers can > use to determine whether to only set up #defines, or also C-oriented > stuff like types/prototypes. So, at least that one would need to be > explicitly re-defined.
I grep'd through the kernel's include/ and there are quite a few hits for some of the pre-define macros such as __linux__, __GNUC__, __STRICT_ANSI__, __KERNEL__, __arm__ (and presumably other arch macros), etc. I'd guess that an explicit blacklisting of -Dlinux and -Dunix might be the most manageable path. Thoughts?
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