Re: [PATCH] Check compiler version, SMP and PREEMPT.

[Keith Owens <kaos@ocs.com.au>]

On Mon, 13 Jan 2003 16:13:19 +1100, 
Rusty Russell <rusty@rustcorp.com.au> wrote:
>Linus, please apply if you agree.
>
>Tridge reported getting burned by gcc 3.2 compiled (Debian) XFree
>modules not working on his gcc 2.95-compiled kernel.  Interestingly,
>(as Tridge points out) modversions probably would not have caught the
>change in spinlock size, since the ioctl takes a void*, not a
>structure pointer...
>
>Simple bitmask, allows extension later, and prevents this kind of
>thing (maybe a warning is more appropriate: this refuses to load it).

Worse than that.  There is a long list of critical config options which
should :-

(a) Force a complete rebuild if any are changed and
(b) Refuse to load a module with different critical config options.

To make things more complicated, that list is arch dependent.

>From kbuild 2.5 (which handled this problem months ago)

define_string CONFIG_KBUILD_CRITICAL "CONFIG_SMP CONFIG_KBUILD_GCC_VERSION"
define_string CONFIG_KBUILD_CRITICAL_ARCH_X86 "CONFIG_M386 CONFIG_M486 \
       CONFIG_M586 CONFIG_M586TSC CONFIG_M586MMX CONFIG_M686 \
       CONFIG_MPENTIUMIII CONFIG_MPENTIUM4 \
       CONFIG_MK6 CONFIG_MK7 \
       CONFIG_MCRUSOE \
       CONFIG_MWINCHIPC6 CONFIG_MWINCHIP2 CONFIG_MWINCHIP3D \
       CONFIG_MCYRIXIII"