linux/arch/x86
Jeremy Fitzhardinge f97b895495 x86/paravirt: revert exports to restore old behaviour
Subdividing the paravirt_ops structure caused a regression in certain
non-GPL modules which try to use mmu_ops and cpu_ops.  This restores the
old behaviour, and makes it consistent with the non-CONFIG_PARAVIRT case.

Takashi Iwai <tiwai@suse.de> adds:
> I took at this problem (as I have an nvidia card on one of my
> workstations), and found out that the following suffer from
> EXPORT_SYMBOL_GPL changes:
>
> * local_disable_irq(), local_irq_save*(), etc.
> * MSR-related macros like rdmsr(), wrmsr(), read_cr0(), etc.
>   wbinvd(), too.
> * pmd_val(), pgd_val(), etc are all involved with pv_mm_ops.
>   pmd_large() and pmd_bad() is also indirectly involved.
>   __flush_tlb() and friends suffer, too.

Christoph Hellwig objects to this patch on the grounds that modules
shouldn't be using these operations anyway.  I don't think this is a
particularly good reason to reject the patch, for several reasons:

1. These operations are still available to modules when not using
   CONFIG_PARAVIRT, since they are implicitly exported as inline
   functions via the kernel headers.  Exporting the same functionality as
   GPL-only symbols just adds a gratuitious difference between
   CONFIG_PARAVIRT and non-CONFIG_PARAVIRT configurations.  If we really
   think these operations are not for module use (or non-GPL module use),
   then we should solve the problem in a general way.

2. It's a regression from previous kernels, which would work these
   modules even with CONFIG_PARAVIRT enabled.

3. The operations in question seem pretty reasonable for modules to
   use.  The control registers/MSRs can be accessed directly anyway, so there's
   no benefit in preventing modules from using standard interfaces.  And it seems
   reasonable to allow a graphics driver to create its own mappings if it wants.

Therefore, I think this patch should go in for 2.6.24.  If people
really think that these operations should not be available to modules,
then we can address that separately.

Signed-off-by: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com>
Cc: Tobias Powalowski <t.powa@gmx.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-29 09:24:55 -08:00
..
boot x86: do not use $(ARCH) when not needed 2007-11-12 21:02:20 +01:00
configs x86 gart: rename CONFIG_IOMMU to CONFIG_GART_IOMMU 2007-10-30 00:22:22 +01:00
crypto x86: merge arch/x86/crypto Makefiles 2007-10-23 22:37:23 +02:00
ia32 x86 - 32-bit ptrace emulation mishandles 6th arg 2007-11-10 04:30:36 +01:00
kernel x86/paravirt: revert exports to restore old behaviour 2007-11-29 09:24:55 -08:00
lguest lguest: prevent VISWS or VOYAGER randconfigs 2007-11-29 09:24:55 -08:00
lib x86: disable preemption in delay_tsc() 2007-11-14 18:45:44 -08:00
mach-default spelling fixes: arch/i386/ 2007-10-20 01:13:56 +02:00
mach-es7000 i386: es7000 minor cleanups 2007-10-17 20:16:15 +02:00
mach-generic spelling fixes: arch/i386/ 2007-10-20 01:13:56 +02:00
mach-visws [x86] remove uses of magic macros for boot_params access 2007-10-16 17:38:31 -07:00
mach-voyager x86: fix smp init sections 2007-11-17 16:27:00 +01:00
math-emu kbuild: fix up CFLAGS usage 2007-10-14 21:49:42 +02:00
mm memory hotplug x86_64: fix section mismatch in init_memory_mapping() 2007-11-29 09:24:54 -08:00
oprofile x86: add instrumentation menu 2007-10-23 22:37:22 +02:00
pci Merge git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86 2007-11-26 19:41:28 -08:00
power
vdso x86: ignore the sys_getcpu() tcache parameter 2007-11-17 16:27:00 +01:00
video
xen xen: mask _PAGE_PCD from ptes 2007-11-29 09:24:52 -08:00
Kconfig x86: simplify "make ARCH=x86" and fix kconfig all.config 2007-11-17 17:21:54 +01:00
Kconfig.cpu x86: arch/x86/Kconfig.cpu unification 2007-11-12 21:02:19 +01:00
Kconfig.debug remove the dead X86_REMOTE_DEBUG option 2007-10-30 00:22:22 +01:00
Makefile x86: correctly set UTS_MACHINE for "make ARCH=x86" 2007-11-26 17:38:53 -08:00
Makefile_32 x86: do not use $(ARCH) when not needed 2007-11-12 21:02:20 +01:00
Makefile_32.cpu x86: move i386 and x86_64 Makefiles to arch/x86 2007-10-25 22:27:34 +02:00
Makefile_64 x86: do not use $(ARCH) when not needed 2007-11-12 21:02:20 +01:00