Commit Graph

7 Commits

Author SHA1 Message Date
Bernhard Kaindl
2b1f6278d7 [PATCH] x86: Save the MTRRs of the BSP before booting an AP
Applied fix by Andew Morton:
http://lkml.org/lkml/2007/4/8/88 - Fix `make headers_check'.

AMD and Intel x86 CPU manuals state that it is the responsibility of
system software to initialize and maintain MTRR consistency across
all processors in Multi-Processing Environments.

Quote from page 188 of the AMD64 System Programming manual (Volume 2):

7.6.5 MTRRs in Multi-Processing Environments

"In multi-processing environments, the MTRRs located in all processors must
characterize memory in the same way. Generally, this means that identical
values are written to the MTRRs used by the processors." (short omission here)
"Failure to do so may result in coherency violations or loss of atomicity.
Processor implementations do not check the MTRR settings in other processors
to ensure consistency. It is the responsibility of system software to
initialize and maintain MTRR consistency across all processors."

Current Linux MTRR code already implements the above in the case that the
BIOS does not properly initialize MTRRs on the secondary processors,
but the case where the fixed-range MTRRs of the boot processor are changed
after Linux started to boot, before the initialsation of a secondary
processor, is not handled yet.

In this case, secondary processors are currently initialized by Linux
with MTRRs which the boot processor had very early, when mtrr_bp_init()
did run, but not with the MTRRs which the boot processor uses at the
time when that secondary processors is actually booted,
causing differing MTRR contents on the secondary processors.

Such situation happens on Acer Ferrari 1000 and 5000 notebooks where the
BIOS enables and sets AMD-specific IORR bits in the fixed-range MTRRs
of the boot processor when it transitions the system into ACPI mode.
The SMI handler of the BIOS does this in SMM, entered while Linux ACPI
code runs acpi_enable().

Other occasions where the SMI handler of the BIOS may change bits in
the MTRRs could occur as well. To initialize newly booted secodary
processors with the fixed-range MTRRs which the boot processor uses
at that time, this patch saves the fixed-range MTRRs of the boot
processor before new secondary processors are started. When the
secondary processors run their Linux initialisation code, their
fixed-range MTRRs will be updated with the saved fixed-range MTRRs.

If CONFIG_MTRR is not set, we define mtrr_save_state
as an empty statement because there is nothing to do.

Possible TODOs:

*) CPU-hotplugging outside of SMP suspend/resume is not yet tested
   with this patch.

*) If, even in this case, an AP never runs i386/do_boot_cpu or x86_64/cpu_up,
   then the calls to mtrr_save_state() could be replaced by calls to
   mtrr_save_fixed_ranges(NULL) and  mtrr_save_state() would not be
   needed.

   That would need either verification of the CPU-hotplug code or
   at least a test on a >2 CPU machine.

*) The MTRRs of other running processors are not yet checked at this
   time but it might be interesting to syncronize the MTTRs of all
   processors before booting. That would be an incremental patch,
   but of rather low priority since there is no machine known so
   far which would require this.

AK: moved prototypes on x86-64 around to fix warnings

Signed-off-by: Bernhard Kaindl <bk@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
2007-05-02 19:27:17 +02:00
Bernhard Kaindl
2b3b4835c9 [PATCH] x86: Adds mtrr_save_fixed_ranges() for use in two later patches.
In this current implementation which is used in other patches,
mtrr_save_fixed_ranges() accepts a dummy void pointer because
in the current implementation of one of these patches, this
function may be called from smp_call_function_single() which
requires that this function takes a void pointer argument.

This function calls get_fixed_ranges(), passing mtrr_state.fixed_ranges
which is the element of the static struct which stores our current
backup of the fixed-range MTRR values which all CPUs shall be
using.

Because  mtrr_save_fixed_ranges calls get_fixed_ranges after
kernel initialisation time, __init needs to be removed from
the declaration of get_fixed_ranges().

If CONFIG_MTRR is not set, we define mtrr_save_fixed_ranges
as an empty statement because there is nothing to do.

AK: Moved prototypes for x86-64 around to fix warnings

Signed-off-by: Bernhard Kaindl <bk@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <ak@suse.de>
Cc: Dave Jones <davej@codemonkey.org.uk>
2007-05-02 19:27:17 +02:00
Andi Kleen
856f44ff4a [PATCH] x86-64: Move mtrr prototypes from proto.h to mtrr.h
Signed-off-by: Andi Kleen <ak@suse.de>
2007-05-02 19:27:17 +02:00
David Woodhouse
2c23d62abb Move inclusion of <linux/compat.h> out of user scope in asm-x86_64/mtrr.h
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-05-21 22:51:13 +01:00
David Woodhouse
62c4f0a2d5 Don't include linux/config.h from anywhere else in include/
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-26 12:56:16 +01:00
Brian Gerst
c531178157 [PATCH] Clean up mtrr compat ioctl code
Handle 32-bit mtrr ioctls in the mtrr driver instead of the ia32
compatability layer.

Signed-off-by: Brian Gerst <bgerst@didntduck.org>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-30 17:37:13 -08:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00