From: Calum Mackay <firstname.lastname@example.org>
To: Christoph Hellwig <email@example.com>
Cc: Calum Mackay <firstname.lastname@example.org>,
Subject: Re: [PATCH] 2.4: export the symbol "mmu_cr4_features" for XFree86 DRM kernel drivers
Date: Sat, 02 Aug 2003 12:54:25 +0100 [thread overview]
Message-ID: <3F2BA671.email@example.com> (raw)
Christoph Hellwig wrote:
> Can you explain why they need it and why they magically need it
> because of vmap() ?
Sorry, of course.
[as Mitch has already pointed out privately] e.g the XFree86 DRM radeon
Makefile includes this:
# Check for 4-argument vmap() in some 2.5.x and 2.4.x kernels
VMAP := $(shell grep -A1 'vmap.*count,$$'
$(LINUXDIR)/include/linux/vmalloc.h | grep -c prot)
EXTRA_CFLAGS += -DVMAP_4_ARGS
Christoph's vmap() backport introduced this reference in
linux/vmalloc.h, so the DRM module is now compiled with VMAP_4_ARGS defined.
The radeon kernel driver source includes (via drm_memory.h)
linux/vmalloc.h, iff VMAP_4_ARGS is defined. The latter includes (on
i386) asm/asm-i386/pgtable.h, which includes asm/asm-i386/processor.h.
processor.h defines some inline functions [set_in_cr4() &
clear_in_cr4()] which reference mmu_cr4_features.
mmu_cr4_features is currently declared in arch/i386/kernel/setup.c [and
also arch/x86_64/kernel/setup.c] but not currently exported.
[The problem is not restricted to the radeon kernel driver; I've just
used it as an example]
next prev parent reply other threads:[~2003-08-02 11:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-01 12:52 [PATCH] 2.4: export the symbol "mmu_cr4_features" for XFree86 DRM kernel drivers Calum Mackay
2003-08-01 13:14 ` Christoph Hellwig
2003-08-02 11:54 ` Calum Mackay [this message]
2003-08-02 12:34 ` Calum Mackay
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