Messages in this thread | | | Date | Tue, 25 Sep 2012 22:37:13 +0200 | Subject | Re: [PATCH/resend/bypass] um: Preinclude include/linux/kern_levels.h | From | Geert Uytterhoeven <> |
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On Tue, Sep 25, 2012 at 9:43 PM, Al Viro <viro@zeniv.linux.org.uk> wrote: > On Tue, Sep 25, 2012 at 12:20:55PM -0700, Linus Torvalds wrote: >> IOW, this part of the patch: >> >> - c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS) -include user.h >> $(CFLAGS_$(basetarget).o) >> + c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS) -include >> $(srctree)/include/linux/kern_levels.h -include user.h >> $(CFLAGS_$(basetarget).o) >> >> just makes me go want to puke. The user.h file already has other >> #include's in it, so I really don't see why you create this insane >> special case. >> >> And why does UM have those "UM_KERN_XYZ" defines in the first place? >> Why isn't it just using KERN_XYZ directly? Is it because kern_levels.h >> didn't use to exist, so it was some kind of "let's create our own that >> we can hide in our special headers". > > Because user.h is included *without* kernel headers in include path.
Indeed.
> It's for the stuff that is compiled with host libc headers. Keep in > mind that UML talks to libc like normal architecture would talk to > hardware. IOW, analogs of asm glue are in (host) userland C. And > they need libc headers instead of the kernel ones. That's what that > USER_OBJ thing is about. Kernel-side constants, etc. are delivered > to that sucker using the same mechanism we normally use to give them > to assembler - asm-offsets.c. And here, of course, slapping ifndef > __ASSEMBLER__ around the tricky bits will not work - the header itself > is just fine, but getting kernel headers in the search path really > isn't. > > I agree that proposed solution is ugly. What we can do is copy > the damn header into include/generated and #include <generated/kern_levels.h> > from user.h. And kill UM_KERN_... stuff. Objections?
My first submission had "We may convert all UM_KERN_* users to KERN_* and drop the extra defines?" as a suggestion, but so far I haven't found time to implement that...
Still, no one came up with a better patch, and this is a regression.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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