We should zap the low mappings, as soon as possible, so that we can catch
kernel bugs more effectively. Previously early boot had NULL mapped
and didn't trap on NULL references.
This patch introduces boot_level4_pgt, which will always have low identity
addresses mapped. Druing boot, all the processors will use this as their
level4 pgt. On BP, we will switch to init_level4_pgt as soon as we enter C
code and zap the low mappings as soon as we are done with the usage of
identity low mapped addresses. On AP's we will zap the low mappings as
soon as we jump to C code.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add a new 4GB GFP_DMA32 zone between the GFP_DMA and GFP_NORMAL zones.
As a bit of historical background: when the x86-64 port
was originally designed we had some discussion if we should
use a 16MB DMA zone like i386 or a 4GB DMA zone like IA64 or
both. Both was ruled out at this point because it was in early
2.4 when VM is still quite shakey and had bad troubles even
dealing with one DMA zone. We settled on the 16MB DMA zone mainly
because we worried about older soundcards and the floppy.
But this has always caused problems since then because
device drivers had trouble getting enough DMA able memory. These days
the VM works much better and the wide use of NUMA has proven
it can deal with many zones successfully.
So this patch adds both zones.
This helps drivers who need a lot of memory below 4GB because
their hardware is not accessing more (graphic drivers - proprietary
and free ones, video frame buffer drivers, sound drivers etc.).
Previously they could only use IOMMU+16MB GFP_DMA, which
was not enough memory.
Another common problem is that hardware who has full memory
addressing for >4GB misses it for some control structures in memory
(like transmit rings or other metadata). They tended to allocate memory
in the 16MB GFP_DMA or the IOMMU/swiotlb then using pci_alloc_consistent,
but that can tie up a lot of precious 16MB GFPDMA/IOMMU/swiotlb memory
(even on AMD systems the IOMMU tends to be quite small) especially if you have
many devices. With the new zone pci_alloc_consistent can just put
this stuff into memory below 4GB which works better.
One argument was still if the zone should be 4GB or 2GB. The main
motivation for 2GB would be an unnamed not so unpopular hardware
raid controller (mostly found in older machines from a particular four letter
company) who has a strange 2GB restriction in firmware. But
that one works ok with swiotlb/IOMMU anyways, so it doesn't really
need GFP_DMA32. I chose 4GB to be compatible with IA64 and because
it seems to be the most common restriction.
The new zone is so far added only for x86-64.
For other architectures who don't set up this
new zone nothing changes. Architectures can set a compatibility
define in Kconfig CONFIG_DMA_IS_DMA32 that will define GFP_DMA32
as GFP_DMA. Otherwise it's a nop because on 32bit architectures
it's normally not needed because GFP_NORMAL (=0) is DMA able
enough.
One problem is still that GFP_DMA means different things on different
architectures. e.g. some drivers used to have #ifdef ia64 use GFP_DMA
(trusting it to be 4GB) #elif __x86_64__ (use other hacks like
the swiotlb because 16MB is not enough) ... . This was quite
ugly and is now obsolete.
These should be now converted to use GFP_DMA32 unconditionally. I haven't done
this yet. Or best only use pci_alloc_consistent/dma_alloc_coherent
which will use GFP_DMA32 transparently.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Rather than blindly re-enabling interrupts in oops_end(), save their state
in oope_begin() and then restore that state.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The FLATMEM people added it, but there doesn't seem a good reason
because end_pfn is identical.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
get_cpu_vendor() no longer has any users in other files.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There has been some discuss about solving the SMP MTRR suspend/resume
breakage, but I didn't find a patch for it. This is an intent for it. The
basic idea is moving mtrr initializing into cpu_identify for all APs (so it
works for cpu hotplug). For BP, restore_processor_state is responsible for
restoring MTRR.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
There are unfortunately more and more multi processor Opteron systems which
don't have HPET timer support in the southbridge. This covers in particular
Nvidia and VIA chipsets. They also don't guarantee that the TSCs are
synchronized between CPUs; and especially with MP powernow the systems are
nearly unusable because the time gets very inconsistent between CPUs.
The timer code for x86-64 was originally written under the assumption that we
could fall back to the HPET timer on such systems. But this doesn't work
there.
Another alternative is to use the ACPI PM timer as primary time source. This
patch does that. The kernel only uses PM timer when there is no other choice
because it has some disadvantages.
Ported over from i386. It should be faster than the i386 version because I
dropped the "read three times" workaround, but is still considerable slower
than HPET and also does not work together with vsyscalls which have to be
disabled.
Cc: <mark.langsdorf@amd.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This will allow hotplug CPU in the future and in general cleans up a lot of
crufty code. It also should plug some races that the old hackish way
introduces. Remove one old race workaround in NMI watchdog setup that is not
needed anymore.
I removed the old total sum of bogomips reporting code. The brag value of
BogoMips has been greatly devalued in the last years on the open market.
Real CPU hotplug will need some more work, but the infrastructure for it is
there now.
One drawback: the new TSC sync algorithm is less accurate than before. The
old way of zeroing TSCs is too intrusive to do later. Instead the TSC of the
BP is duplicated now, which is less accurate.
akpm:
- sync_tsc_bp_init seems to have the sense of `init' inverted.
- SPIN_LOCK_UNLOCKED is deprecated - use DEFINE_SPINLOCK.
Cc: <rusty@rustcorp.com.au>
Cc: <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use a real VMA to map the 32bit vsyscall page
This interacts better with Hugh's upcomming VMA walk optimization
Also removes some ugly special cases.
Code roughly modelled after the ppc64 vdso version from Ben Herrenschmidt.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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!
Siddha, Suresh B