The EFI RTC functions are only available on 32 bit. commit 7bd867df
(x86: Move get/set_wallclock to x86_platform_ops) removed the 32bit
dependency which leads to boot crashes on 64bit EFI systems.
Add the dependency back.
Solves: http://bugzilla.kernel.org/show_bug.cgi?id=14466
Tested-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Feng Tang <feng.tang@intel.com>
LKML-Reference: <20091020125402.028d66d5@feng-desktop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Restoring %ebp after the call to audit_syscall_exit() is not
only unnecessary (because the register didn't get clobbered),
but in the sysenter case wasn't even doing the right thing: It
loaded %ebp from a location below the top of stack (RBP <
ARGOFFSET), i.e. arbitrary kernel data got passed back to user
mode in the register.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <stable@kernel.org>
LKML-Reference: <4AE5CC4D020000780001BD13@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Non-PAE 32-bit dump kernels may wrap an address around 4G and
poke unwanted space. ptes there are 32-bit long, and since
pfn << PAGE_SIZE may exceed this limit, high pfn bits are
cropped and wrong address mapped by kmap_atomic_pfn in
copy_oldmem_page.
Don't allow this behavior in non-PAE kdump kernels by checking
pfns passed into copy_oldmem_page. In the case of failure,
userspace process gets EFAULT.
[v2]
- fix comments
- move ifdefs inside the function
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Paul Mundt <lethal@linux-sh.org>
LKML-Reference: <1256551903-30567-1-git-send-email-jirislaby@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit 79e1dd05d1 "x86: Provide an alternative() based
cmpxchg64()" broke lguest, even on systems which have cmpxchg8b
support. The emulation code gets used until alternatives get
run, but it contains native instructions, not their paravirt
alternatives.
The simplest fix is to turn this code off except for 386 and 486
builds.
Reported-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: lguest@ozlabs.org
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <200910261426.05769.rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
STACKPROTECTOR_ALL has a really high overhead (runtime and stack
footprint) and is not really worth it protection wise (the
normal STACKPROTECTOR is in effect for all functions with
buffers already), so lets just remove the option entirely.
Reported-by: Dave Jones <davej@redhat.com>
Reported-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Eric Sandeen <sandeen@redhat.com>
LKML-Reference: <20091023073101.3dce4ebb@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When sending a NMI_VECTOR IPI using the UV_HUB_IPI_INT register,
we need to ensure the delivery mode field of that register has
NMI delivery selected.
This makes those IPIs true NMIs, instead of flat IPIs. It
matters to reboot sequences and KGDB, both of which use NMI
IPIs.
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Jack Steiner <steiner@sgi.com>
Cc: Martin Hicks <mort@sgi.com>
Cc: <stable@kernel.org>
LKML-Reference: <20091020193620.877322000@alcatraz.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Create an inline function to extract the pnode from a global
physical address and then convert the broadcast assist unit to
use the newly created uv_gpa_to_pnode function.
The open-coded code was wrong as well - it might explain a
few of our unexplained bau hangs.
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Cliff Whickman <cpw@sgi.com>
Cc: linux-mm@kvack.org
Cc: Jack Steiner <steiner@sgi.com>
LKML-Reference: <20091016112920.GZ8903@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The MCE initialization code explicitly says it doesn't handle
asymmetric configurations where different CPUs support different
numbers of MCE banks, and it prints a big warning in that case.
Therefore, printing the "mce: CPU supports <x> MCE banks"
message into the kernel log for every CPU is pure redundancy
that clutters the log significantly for systems with lots of
CPUs.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
LKML-Reference: <adaeip473qt.fsf@cisco.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
A few parts of the uv_hub_info structure are initialized
incorrectly.
- n_val is being loaded with m_val.
- gpa_mask is initialized with a bytes instead of an unsigned long.
- Handle the case where none of the alias registers are used.
Lastly I converted the bau over to using the uv_hub_info->m_val
which is the correct value.
Without this patch, booting a large configuration hits a
problem where the upper bits of the gnode affect the pnode
and the bau will not operate.
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Jack Steiner <steiner@sgi.com>
Cc: Cliff Whickman <cpw@sgi.com>
Cc: stable@kernel.org
LKML-Reference: <20091015224946.396355000@alcatraz.americas.sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Older binutils breaks if ASSERT() is used without a sink
for the output.
For example 2.14.90.0.6 is known to be broken, the link
fails with:
LD .tmp_vmlinux1
ld:arch/x86/kernel/vmlinux.lds:678: parse error
Document this quirk in all three files that use it.
See: http://marc.info/?l=linux-kbuild&m=124930110427870&w=2
See[2]: d2ba8b2 ("x86: Fix assert syntax in vmlinux.lds.S")
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
LKML-Reference: <4AD6523D.5030909@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This reverts commit e9a63a4e55.
This breaks older binutils, where sink-less asserts are broken.
See this commit for further details:
d2ba8b2: x86: Fix assert syntax in vmlinux.lds.S
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4AD6523D.5030909@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86/paravirt: Use normal calling sequences for irq enable/disable
x86: fix kernel panic on 32 bits when profiling
x86: Fix Suspend to RAM freeze on Acer Aspire 1511Lmi laptop
x86, vmi: Mark VMI deprecated and schedule it for removal
The linker scripts grew some use of weirdly wrong linker script syntax.
It happens to work, but it's not what the syntax is documented to be.
Clean it up to use the official syntax.
Signed-off-by: Roland McGrath <roland@redhat.com>
CC: Ian Lance Taylor <iant@google.com>
In 'cdd6c482c9ff9c55475ee7392ec8f672eddb7be6', we renamed
Performance Counters -> Performance Events.
The name showed up in /proc/interrupts also needs a change. I use
PMI (Performance monitoring interrupt) here, since it is the
official name used in Intel's documents.
Signed-off-by: Li Hong <lihong.hi@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091014105039.GA22670@uhli>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.infradead.org/~dwmw2/iommu-2.6.32:
x86: Move pci_iommu_init to rootfs_initcall()
Run pci_apply_final_quirks() sooner.
Mark pci_apply_final_quirks() __init rather than __devinit
Rename pci_init() to pci_apply_final_quirks(), move it to quirks.c
intel-iommu: Yet another BIOS workaround: Isoch DMAR unit with no TLB space
intel-iommu: Decode (and ignore) RHSA entries
intel-iommu: Make "Unknown DMAR structure" message more informative
Bastian Blank reported a boot crash with stackprotector enabled,
and debugged it back to edx register corruption.
For historical reasons irq enable/disable/save/restore had special
calling sequences to make them more efficient. With the more
recent introduction of higher-level and more general optimisations
this is no longer necessary so we can just use the normal PVOP_
macros.
This fixes some residual bugs in the old implementations which left
edx liable to inadvertent clobbering. Also, fix some bugs in
__PVOP_VCALLEESAVE which were revealed by actual use.
Reported-by: Bastian Blank <bastian@waldi.eu.org>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Cc: Xen-devel <xen-devel@lists.xensource.com>
LKML-Reference: <4AD3BC9B.7040501@goop.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Latest kernel has a kernel panic in booting on i386 machine when
profile=2 setting in cmdline. It is due to 'sp' being incorrect in
profile_pc().
BUG: unable to handle kernel NULL pointer dereference at 00000246
IP: [<c01288b6>] profile_pc+0x2a/0x48
*pde = 00000000
Oops: 0000 [#1] SMP
This differs from the original version by Alex Shi in that we use the
kernel_stack_pointer() inline already defined in <asm/ptrace.h> for
this purpose, instead of #ifdef.
Originally-by: Alex Shi <alex.shi@intel.com>
Cc: "Chen, Tim C" <tim.c.chen@intel.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Move the trampoline and accessors back out of .cpuinit.* for the
case of 64-bits+ACPI_SLEEP.
This solves s2ram hangs reported in:
http://bugzilla.kernel.org/show_bug.cgi?id=14279
Reported-and-bisected-by: Christian Casteyde <casteyde.christian@free.fr>
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: <bugzilla-daemon@bugzilla.kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We want this to happen after the PCI quirks, which are now running at
the very end of the fs_initcalls.
This works around the BIOS problems which were originally addressed by
commit db8be50c43 ('USB: Work around BIOS
bugs by quiescing USB controllers earlier'), which was reverted in
commit d93a8f829f.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
As reported in
http://bugzilla.kernel.org/show_bug.cgi?id=13940
on some system when acpi are enabled, acpi clears some BAR for some
devices without reason, and kernel will need to allocate devices for
them. It then apparently hits some undocumented resource conflict,
resulting in non-working devices.
Try to increase alignment to get more safe range for unassigned devices.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After m68k's task_thread_info() doesn't refer to current,
it's possible to remove sched.h from interrupt.h and not break m68k!
Many thanks to Heiko Carstens for allowing this.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
This reverts commit 9bcbdd9c58.
The real bug producing LatencyTop latencies has been fixed in:
f5dc375: sched: Update the clock of runqueue select_task_rq() selected
And the commit being reverted here triggers local timer processing
from every device IRQ. If device IRQs come in at a high frequency,
this could cause a performance regression.
The commit being reverted here purely 'fixed' the reported latency
as a side effect, because CPUs were being moved out of idle more
often.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Frans Pop <elendil@planet.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091008064041.67219b13@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add text in feature-removal.txt indicating that VMI will be removed in
the 2.6.37 timeframe.
Signed-off-by: Alok N Kataria <akataria@vmware.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
LKML-Reference: <1254193238.13456.48.camel@ank32.eng.vmware.com>
[ removed a bogus Kconfig change, marked (DEPRECATED) in Kconfig ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that range timers and deferred timers are common, I found a
problem with these using the "perf timechart" tool. Frans Pop also
reported high scheduler latencies via LatencyTop, when using
iwlagn.
It turns out that on x86, these two 'opportunistic' timers only get
checked when another "real" timer happens. These opportunistic
timers have the objective to save power by hitchhiking on other
wakeups, as to avoid CPU wakeups by themselves as much as possible.
The change in this patch runs this check not only at timer
interrupts, but at all (device) interrupts. The effect is that:
1) the deferred timers/range timers get delayed less
2) the range timers cause less wakeups by themselves because
the percentage of hitchhiking on existing wakeup events goes up.
I've verified the working of the patch using "perf timechart", the
original exposed bug is gone with this patch. Frans also reported
success - the latencies are now down in the expected ~10 msec
range.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Tested-by: Frans Pop <elendil@planet.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091008064041.67219b13@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'kvm-updates/2.6.32' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: add support for change_pte mmu notifiers
KVM: MMU: add SPTE_HOST_WRITEABLE flag to the shadow ptes
KVM: MMU: dont hold pagecount reference for mapped sptes pages
KVM: Prevent overflow in KVM_GET_SUPPORTED_CPUID
KVM: VMX: flush TLB with INVEPT on cpu migration
KVM: fix LAPIC timer period overflow
KVM: s390: fix memsize >= 4G
KVM: SVM: Handle tsc in svm_get_msr/svm_set_msr correctly
KVM: SVM: Fix tsc offset adjustment when running nested
this is needed for kvm if it want ksm to directly map pages into its
shadow page tables.
[marcelo: cast pfn assignment to u64]
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
this flag notify that the host physical page we are pointing to from
the spte is write protected, and therefore we cant change its access
to be write unless we run get_user_pages(write = 1).
(this is needed for change_pte support in kvm)
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
When using mmu notifiers, we are allowed to remove the page count
reference tooken by get_user_pages to a specific page that is mapped
inside the shadow page tables.
This is needed so we can balance the pagecount against mapcount
checking.
(Right now kvm increase the pagecount and does not increase the
mapcount when mapping page into shadow page table entry,
so when comparing pagecount against mapcount, you have no
reliable result.)
Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The number of entries is multiplied by the entry size, which can
overflow on 32-bit hosts. Bound the entry count instead.
Reported-by: David Wagner <daw@cs.berkeley.edu>
Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
It is possible that stale EPTP-tagged mappings are used, if a
vcpu migrates to a different pcpu.
Set KVM_REQ_TLB_FLUSH in vmx_vcpu_load, when switching pcpus, which
will invalidate both VPID and EPT mappings on the next vm-entry.
Cc: stable@kernel.org
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
When running nested we need to touch the l1 guests
tsc_offset. Otherwise changes will be lost or a wrong value
be read.
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
When svm_vcpu_load is called while the vcpu is running in
guest mode the tsc adjustment made there is lost on the next
emulated #vmexit. This causes the tsc running backwards in
the guest. This patch fixes the issue by also adjusting the
tsc_offset in the emulated hsave area so that it will not
get lost.
Cc: stable@kernel.org
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
The current bound checks for copy_from_user in the MTRR driver are
not as obvious as they could be, and gcc agrees with that.
This patch simplifies the boundary checks to the point that gcc can
now prove to itself that the copy_from_user() is never going past
its bounds.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20090926205150.30797709@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make decoding of MCEs happen only on AMD hardware by registering a
non-default callback only on CPU families which support it.
While looking at the interaction of decode_mce() with the other MCE
code i also noticed a few other things and made the following
cleanups/fixes:
- Fixed the mce_decode() weak alias - a weak alias is really not
good here, it should be a proper callback. A weak alias will be
overriden if a piece of code is built into the kernel - not
good, obviously.
- The patch initializes the callback on AMD family 10h and 11h.
- Added the more correct fallback printk of:
No support for human readable MCE decoding on this CPU type.
Transcribe the message and run it through 'mcelog --ascii' to decode.
On CPUs that dont have a decoder.
- Made the surrounding code more readable.
Note that the callback allows us to have a default fallback -
without having to check the CPU versions during the printout
itself. When an EDAC module registers itself, it can install the
decode-print function.
(there's no unregister needed as this is core code.)
version -v2 by Borislav Petkov:
- add K8 to the set of supported CPUs
- always build in edac_mce_amd since we use an early_initcall now
- fix checkpatch warnings
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
LKML-Reference: <20091001141432.GA11410@aftab>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Just like ip_fast_csum, the assembly snippet in csum_ipv6_magic needs a
memory clobber, as it is only passed the address of the buffer, not a
memory reference to the buffer itself.
This caused failures in Hurd's pfinetv4 when we tried to compile it with
gcc-4.3 (bogus checksums).
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While 32-bit processes can't directly access R8...R15, they can
gain access to these registers by temporarily switching themselves
into 64-bit mode.
Therefore, registers not preserved anyway by called C functions
(i.e. R8...R11) must be cleared prior to returning to user mode.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: <stable@kernel.org>
LKML-Reference: <4AC34D73020000780001744A@vpn.id2.novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove unused CONFIG FAST_CMPXCHG_LOCAL from Kconfig.
Reported-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Robert P. J. Day" <rpjday@crashcourse.ca>
Cc: linux-mm@kvack.org
LKML-Reference: <1253981501.4568.61.camel@ht.satnam>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Commit c953094 ("early_printk: Allow more than one early console")
introduced a regression in the parsing of the earlyprintk= kernel
arguments.
If you specify "earlyprintk=serial,ttyS0,115200" as a kernel
argument, the "serial,ttyS" should be parsed as a single argument
and not as "serial" and then "ttyS".
Also update the documentation to reflect you can specify the ttyS
directly without the "serial" argument.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
LKML-Reference: <4ABB7D5E.6000301@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Conditionaly compile cmpxchg8b_emu.o and EXPORT_SYMBOL(cmpxchg8b_emu).
This reduces the kernel size a bit.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <4AC43E7E.1000600@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Just like ip_fast_csum, the assembly snippet in csum_ipv6_magic needs a
memory clobber, as it is only passed the address of the buffer, not a
memory reference to the buffer itself.
This caused failures in Hurd's pfinetv4 when we tried to compile it with
gcc-4.3 (bogus checksums).
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Try to avoid the 'alternates()' code when we can statically
determine that cmpxchg8b is fine. We already have that
CONFIG_x86_CMPXCHG64 (enabled by PAE support), and we could easily
also enable it for some of the CPU cases.
Note, this patch only adds CMPXCHG8B for the obvious Intel CPU's,
not for others. (There was something really messy about cmpxchg8b
and clone CPU's, so if you enable it on other CPUs later, do it
carefully.)
If we avoid that asm-alternative thing when we can assume the
instruction exists, we'll generate less support crud, and we'll
avoid the whole issue with that extra 'nop' for padding instruction
sizes etc.
LKML-Reference: <alpine.LFD.2.01.0909301743150.6996@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
