Messages in this thread | | | Subject | Re: [PATCH v0 1/5] x86_64: march=native support | From | "H. Peter Anvin" <> | Date | Thu, 7 Dec 2017 15:32:38 -0800 |
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One more thing: you HAVE to make arch/x86/include/asm/required-features.h aware of any features that the kernel unconditionally depend on.
Again, using the gcc cpp macros that reflect what bits gcc itself broadcast. However, this is perhaps where CONFIG flags become important, since required-features.h has to be able to be compiled in the bootcode environment, which is different from the normal kernel compiler environment.
We could, however, automagically generate a reflection of these as a header file:
echo '#ifndef __LINUX_CC_DEFINES__' echo '#define __LINUX_CC_DEFINES__' $(CC) $(c_flags) -x c -E -Wp,-dM /dev/null | sort | \ sed -nr -e 's/^#define __([^[:space]]+)__$/#define __KERNEL_CC_\1/p' echo '#endif
-hpa
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