In both cases, I went with the 32-bit behaviour.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Most users by far do not care about the exact return value (they only
really care about whether the copy succeeded in its entirety or not),
but a few special core routines actually care deeply about exactly how
many bytes were copied from user space.
And the unrolled versions of the x86-64 user copy routines would
sometimes report that it had copied more bytes than it actually had.
Very few uses actually have partial copies to begin with, but to make
this bug even harder to trigger, most x86 CPU's use the "rep string"
instructions for normal user copies, and that version didn't have this
issue.
To make it even harder to hit, the one user of this that really cared
about the return value (and used the uncached version of the copy that
doesn't use the "rep string" instructions) was the generic write
routine, which pre-populated its source, once more hiding the problem by
avoiding the exception case that triggers the bug.
In other words, very special thanks to Bron Gondwana who not only
triggered this, but created a test-program to show it, and bisected the
behavior down to commit 08291429cf ("mm:
fix pagecache write deadlocks") which changed the access pattern just
enough that you can now trigger it with 'writev()' with multiple
iovec's.
That commit itself was not the cause of the bug, it just allowed all the
stars to align just right that you could trigger the problem.
[ Side note: this is just the minimal fix to make the copy routines
(with __copy_from_user_inatomic_nocache as the particular version that
was involved in showing this) have the right return values.
We really should improve on the exceptional case further - to make the
copy do a byte-accurate copy up to the exact page limit that causes it
to fail. As it is, the callers have to do extra work to handle the
limit case gracefully. ]
Reported-by: Bron Gondwana <brong@fastmail.fm>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(which didn't have this problem), and since
most users that do the carethis was very hard to trigger, but
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
PCI: fixup write combine comment in pci_mmap_resource
x86: PAT export resource_wc in pci sysfs
x86, pci-dma.c: don't always add __GFP_NORETRY to gfp
suspend-vs-iommu: prevent suspend if we could not resume
x86: pci-dma.c: use __GFP_NO_OOM instead of __GFP_NORETRY
pci, x86: add workaround for bug in ASUS A7V600 BIOS (rev 1005)
PCI: use dev_to_node in pci_call_probe
PCI: Correct last two HP entries in the bfsort whitelist
Recently (around 2.6.25) I've noticed that RTC no longer works for me. It
turned out this is because I use pnpacpi=off kernel option to work around
the parport_pc bugs. I always did so, but RTC used to work fine in the
past, and now it have regressed.
The patch fixes the problem by creating the platform device for the RTC
when PNP is disabled. This may also help running the PNP-enabled kernel
on an older PCs.
Signed-off-by: Stas Sergeev <stsp@aknet.ru>
Cc: David Brownell <david-b@pacbell.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Adam Belay <ambx1@neo.rr.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changed the call to find_e820_area_size to pass u64 instead of unsigned long.
Signed-off-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Alessandro Suardi reported:
> Recently upgraded my FC6 desktop to Fedora 9; with the
> latest nautilus RPM updates my VNC session went nuts
> with nautilus pegging the CPU for everything that breathed.
>
> I now reverted to an earlier nautilus package, but during
> the peak CPU period my kernel spat this:
>
> [314185.623294] ------------[ cut here ]------------
> [314185.623414] WARNING: at kernel/lockdep.c:2658 check_flags+0x4c/0x128()
> [314185.623514] Modules linked in: iptable_filter ip_tables x_tables
> sunrpc ipv6 fuse snd_via82xx snd_ac97_codec ac97_bus snd_mpu401_uart
> snd_rawmidi via686a hwmon parport_pc sg parport uhci_hcd ehci_hcd
> [314185.623924] Pid: 12314, comm: nautilus Not tainted 2.6.26-rc5-git2 #4
> [314185.624021] [<c0115b95>] warn_on_slowpath+0x41/0x7b
> [314185.624021] [<c010de70>] ? do_page_fault+0x2c1/0x5fd
> [314185.624021] [<c0128396>] ? up_read+0x16/0x28
> [314185.624021] [<c010de70>] ? do_page_fault+0x2c1/0x5fd
> [314185.624021] [<c012fa33>] ? __lock_acquire+0xbb4/0xbc3
> [314185.624021] [<c012d0a0>] check_flags+0x4c/0x128
> [314185.624021] [<c012fa73>] lock_acquire+0x31/0x7d
> [314185.624021] [<c0128cf6>] __atomic_notifier_call_chain+0x30/0x80
> [314185.624021] [<c0128cc6>] ? __atomic_notifier_call_chain+0x0/0x80
> [314185.624021] [<c0128d52>] atomic_notifier_call_chain+0xc/0xe
> [314185.624021] [<c0128d81>] notify_die+0x2d/0x2f
> [314185.624021] [<c01043b0>] do_int3+0x1f/0x4d
> [314185.624021] [<c02f2d3b>] int3+0x27/0x2c
> [314185.624021] =======================
> [314185.624021] ---[ end trace 1923f65a2d7bb246 ]---
> [314185.624021] possible reason: unannotated irqs-off.
> [314185.624021] irq event stamp: 488879
> [314185.624021] hardirqs last enabled at (488879): [<c0102d67>]
> restore_nocheck+0x12/0x15
> [314185.624021] hardirqs last disabled at (488878): [<c0102dca>]
> work_resched+0x19/0x30
> [314185.624021] softirqs last enabled at (488876): [<c011a1ba>]
> __do_softirq+0xa6/0xac
> [314185.624021] softirqs last disabled at (488865): [<c010476e>]
> do_softirq+0x57/0xa6
>
> I didn't seem to find it with some googling, so here it is.
>
> I was incidentally ltracing that process to try and find out
> what was gulping down that much CPU (sorry, no idea
> whether ltrace and the WARNING happened at the same
> time or which came first) and:
Yeah, this is extremely likely to be the source of the warning.
The warning should be harmless, however.
> Box is my trusty noname K7-800, 512MB RAM; if there's
> anything else useful I might be able to provide, just ask.
It would be interesting to see where the int3 comes from. Too bad,
lockdep doesn't provide the register dump. The stacktrace also doesn't
go further than the int3(), I wonder if this int3 came from userspace?
The ltrace readme says "software breakpoints, like gdb", so I guess
this is the case. Yep, seems like it.
This looks relevant:
| commit fb1dac909d
| Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
| Date: Wed Jan 16 09:51:59 2008 +0100
|
| lockdep: more hardirq annotations for notify_die()
I'm attaching a similarly-looking patch for this case (DO_VM86_ERROR),
though I suspect it might be missing for the other cases
(DO_ERROR/DO_ERROR_INFO) as well.
Reported-by: Alessandro Suardi <alessandro.suardi@gmail.com>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix an incompatible pointer type warning on x86_64 compilations.
early_memtest() is passing a u64* to find_e820_area_size() which is expecting
an unsigned long. Change t_start and t_size to unsigned long as those are
also 64-bit types on x88_64.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On Mon, May 19, 2008 at 04:10:02PM -0700, Linus Torvalds wrote:
> It also causes these warnings on 32-bit PAE:
>
> AS arch/x86/kernel/head_32.o
> arch/x86/kernel/head_32.S: Assembler messages:
> arch/x86/kernel/head_32.S:225: Warning: left operand is a bignum; integer 0 assumed
> arch/x86/kernel/head_32.S:609: Warning: left operand is a bignum; integer 0 assumed
>
> and I do not see why (the end result seems to be identical).
Fix head_32.S gcc bignum warnings when CONFIG_PAE=y.
arch/x86/kernel/head_32.S: Assembler messages:
arch/x86/kernel/head_32.S:225: Warning: left operand is a bignum; integer 0 assumed
arch/x86/kernel/head_32.S:609: Warning: left operand is a bignum; integer 0 assumed
The assembler was stumbling over the 64-bit constant 0x100000000 in the
KPMDS #define.
Testing: a cmp(1) on head_32.o before and after shows the binary is unchanged.
Signed-off-by: Joe Korty <joe.korty@ccur.com
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Gabriel C <nix.or.die@googlemail.com>
Cc: Keith Packard <keithp@keithp.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: "Siddha Suresh B" <suresh.b.siddha@intel.com>
Cc: bugme-daemon@bugzilla.kernel.org
Cc: airlied@linux.ie
Cc: "Barnes Jesse" <jesse.barnes@intel.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Page faults in kernel address space between PAGE_OFFSET up to
VMALLOC_START should not try to map as vmalloc.
Fix rarely endless page faults inside mount_block_root for root
filesystem at boot time.
All 32bit kernels up to 2.6.25 can fail into this hole.
I can not present this under native linux kernel. I see, that the 64bit
has fixed the problem. I copied the same lines into 32bit part.
Recorded debugs are from coLinux kernel 2.6.22.18 (virtualisation):
http://www.henrynestler.com/colinux/testing/pfn-check-0.7.3/20080410-antinx/bug16-recursive-page-fault-endless.txt
The physicaly memory was trimmed down to 192MB to better catch the bug.
More memory gets the bug more rarely.
Details, how every x86 32bit system can fail:
Start from "mount_block_root",
http://lxr.linux.no/linux/init/do_mounts.c#L297
There the variable "fs_names" got one memory page with 4096 bytes.
Variable "p" walks through the existing file system types. The first
string is no problem.
But, with the second loop in mount_block_root the offset of "p" is not
at beginning of page, the offset is for example +9, if "reiserfs" is the
first in list.
Than calls do_mount_root, and lands in sys_mount.
Remember: Variable "type_page" contains now "fs_type+9" and not contains
a full page.
The sys_mount copies 4096 bytes with function "exact_copy_from_user()":
http://lxr.linux.no/linux/fs/namespace.c#L1540
Mostly exist pages after the buffer "fs_names+4096+9" and the page fault
handler was not called. No problem.
In the case, if the page after "fs_names+4096" is not mapped, the page
fault handler was called from http://lxr.linux.no/linux/fs/namespace.c#L1320
The do_page_fault gots an address 0xc03b4000.
It's kernel address, address >= TASK_SIZE, but not from vmalloc! It's
from "__getname()" alias "kmem_cache_alloc".
The "error_code" is 0. "vmalloc_fault" will be call:
http://lxr.linux.no/linux/arch/i386/mm/fault.c#L332
"vmalloc_fault" tryed to find the physical page for a non existing
virtual memory area. The macro "pte_present" in vmalloc_fault()
got a next page fault for 0xc0000ed0 at:
http://lxr.linux.no/linux/arch/i386/mm/fault.c#L282
No PTE exist for such virtual address. The page fault handler was trying
to sync the physical page for the PTE lockup.
This called vmalloc_fault() again for address 0xc000000, and that also
was not existing. The endless began...
In normal case the cpu would still loop with disabled interrrupts. Under
coLinux this was catched by a stack overflow inside printk debugs.
Signed-off-by: Henry Nestler <henry.nestler@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* 'core/iter-div' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
always_inline timespec_add_ns
add an inlined version of iter_div_u64_rem
common implementation of iterative div/mod
We have a few instances of the open-coded iterative div/mod loop, used
when we don't expcet the dividend to be much bigger than the divisor.
Unfortunately modern gcc's have the tendency to strength "reduce" this
into a full mod operation, which isn't necessarily any faster, and
even if it were, doesn't exist if gcc implements it in libgcc.
The workaround is to put a dummy asm statement in the loop to prevent
gcc from performing the transformation.
This patch creates a single implementation of this loop, and uses it
to replace the open-coded versions I know about.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Christian Kujau <lists@nerdbynature.de>
Cc: Robert Hancock <hancockr@shaw.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is a SLIT sanity checking patch. It moves slit_valid() function to
generic ACPI code and does sanity checking for both x86 and ia64. It sets up
node_distance with LOCAL_DISTANCE and REMOTE_DISTANCE when hitting invalid
SLIT table on ia64. It also cleans up unused variable localities in
acpi_parse_slit() on x86.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
* 'kvm-updates-2.6.26' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
KVM: MMU: Fix is_empty_shadow_page() check
KVM: MMU: Fix printk() format string
KVM: IOAPIC: only set remote_irr if interrupt was injected
KVM: MMU: reschedule during shadow teardown
KVM: VMX: Clear CR4.VMXE in hardware_disable
KVM: migrate PIT timer
KVM: ppc: Report bad GFNs
KVM: ppc: Use a read lock around MMU operations, and release it on error
KVM: ppc: Remove unmatched kunmap() call
KVM: ppc: add lwzx/stwz emulation
KVM: ppc: Remove duplicate function
KVM: s390: Fix race condition in kvm_s390_handle_wait
KVM: s390: Send program check on access error
KVM: s390: fix interrupt delivery
KVM: s390: handle machine checks when guest is running
KVM: s390: fix locking order problem in enable_sie
KVM: s390: use yield instead of schedule to implement diag 0x44
KVM: x86 emulator: fix hypercall return value on AMD
KVM: ia64: fix zero extending for mmio ld1/2/4 emulation in KVM
Currently arch/x86/kernel/pci-dma.c always adds __GFP_NORETRY
to the allocation flags, because it wants to be reasonably
sure not to deadlock when calling alloc_pages().
But really that should only be done in two cases:
- when allocating memory in the lower 16 MB DMA zone.
If there's no free memory there, waiting or OOM killing is of no use
- when optimistically trying an allocation in the DMA32 zone
when dma_mask < DMA_32BIT_MASK hoping that the allocation
happens to fall within the limits of the dma_mask
Also blindly adding __GFP_NORETRY to the the gfp variable might
not be a good idea since we then also use it when calling
dma_ops->alloc_coherent(). Clearing it might also not be a
good idea, dma_alloc_coherent()'s caller might have set it
on purpose. The gfp variable should not be clobbered.
[ mingo@elte.hu: converted to delta patch ontop of previous version. ]
Signed-off-by: Miquel van Smoorenburg <miquels@cistron.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
x86/PCI: add workaround for bug in ASUS A7V600 BIOS (rev 1005)
PCI/x86: fix up PCI stuff so that PCI_GOANY supports OLPC
Shadows for large guests can take a long time to tear down, so reschedule
occasionally to avoid softlockup warnings.
Signed-off-by: Avi Kivity <avi@qumranet.com>
Clear CR4.VMXE in hardware_disable. There's no reason to leave it set
after doing a VMXOFF.
VMware Workstation 6.5 checks CR4.VMXE as a proxy for whether the CPU is
in VMX mode, so leaving VMXE set means we'll refuse to power on. With this
change the user can power on after unloading the kvm-intel module. I
tested on kvm-67 and kvm-69.
Signed-off-by: Eli Collins <ecollins@vmware.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Migrate the PIT timer to the physical CPU which vcpu0 is scheduled on,
similarly to what is done for the LAPIC timers, otherwise PIT interrupts
will be delayed until an unrelated event causes an exit.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
The hypercall instructions on Intel and AMD are different. KVM allows the
guest to choose one or the other (the default is Intel), and if the guest
chooses incorrectly, KVM will patch it at runtime to select the correct
instruction. This allows live migration between Intel and AMD machines.
This patching occurs in the x86 emulator. The current code also executes
the hypercall. Unfortunately, the tail end of the x86 emulator code also
executes, overwriting the return value of the hypercall with the original
contents of rax (which happens to be the hypercall number).
Fix not by executing the hypercall in the emulator context; instead let the
guest reissue the patched instruction and execute the hypercall via the
normal path.
Signed-off-by: Avi Kivity <avi@qumranet.com>
This BIOS claims the VIA 8237 south bridge to be compatible with VIA 586,
which it is not.
Without this patch, I get the following warning while booting,
among others,
| PCI: Using IRQ router VIA [1106/3227] at 0000:00:11.0
| ------------[ cut here ]------------
| WARNING: at arch/x86/pci/irq.c:265 pirq_via586_get+0x4a/0x60()
| Modules linked in:
| Pid: 1, comm: swapper Not tainted 2.6.26-rc4-00015-g1ec7d99 #1
| [<c0119fd4>] warn_on_slowpath+0x54/0x70
| [<c02246e0>] ? vt_console_print+0x210/0x2b0
| [<c02244d0>] ? vt_console_print+0x0/0x2b0
| [<c011a413>] ? __call_console_drivers+0x43/0x60
| [<c011a482>] ? _call_console_drivers+0x52/0x80
| [<c011aa89>] ? release_console_sem+0x1c9/0x200
| [<c0291d21>] ? raw_pci_read+0x41/0x70
| [<c0291e8f>] ? pci_read+0x2f/0x40
| [<c029151a>] pirq_via586_get+0x4a/0x60
| [<c02914d0>] ? pirq_via586_get+0x0/0x60
| [<c029178d>] pcibios_lookup_irq+0x15d/0x430
| [<c03b895a>] pcibios_irq_init+0x17a/0x3e0
| [<c03a66f0>] ? kernel_init+0x0/0x250
| [<c03a6763>] kernel_init+0x73/0x250
| [<c03b87e0>] ? pcibios_irq_init+0x0/0x3e0
| [<c0114d00>] ? schedule_tail+0x10/0x40
| [<c0102dee>] ? ret_from_fork+0x6/0x1c
| [<c03a66f0>] ? kernel_init+0x0/0x250
| [<c03a66f0>] ? kernel_init+0x0/0x250
| [<c010324b>] kernel_thread_helper+0x7/0x1c
| =======================
| ---[ end trace 4eaa2a86a8e2da22 ]---
and IRQ trouble later,
| irq 10: nobody cared (try booting with the "irqpoll" option)
Now that's an VIA 8237 chip, so pirq_via586_get shouldn't be called
at all; adding this workaround to via_router_probe() fixes the
problem for me.
Amazingly I have a 2.6.23.8 kernel that somehow works fine ... I'll
never understand why.
Signed-off-by: Bertram Felgenhauer <int-e@gmx.de>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Previously, one would have to specifically choose CONFIG_OLPC and
CONFIG_PCI_GOOLPC in order to enable PCI_OLPC. That doesn't really work
for distro kernels, so this patch allows one to choose CONFIG_OLPC and
CONFIG_PCI_GOANY in order to build in OLPC support in a generic kernel (as
requested by Robert Millan).
This also moves GOOLPC before GOANY in the menuconfig list.
Finally, make pci_access_init return early if we detect OLPC hardware.
There's no need to continue probing stuff, and pci_pcbios_init
specifically trashes our settings (we didn't run into that before because
PCI_GOANY wasn't supported).
Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Here is an attempt to translate the prompt and help text into something
which is legible and, as a bonus, correct.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Jürgen Mell reported an FPU state corruption bug under CONFIG_PREEMPT,
and bisected it to commit v2.6.19-1363-gacc2076, "i386: add sleazy FPU
optimization".
Add tsk_used_math() checks to prevent calling math_state_restore()
which can sleep in the case of !tsk_used_math(). This prevents
making a blocking call in __switch_to().
Apparently "fpu_counter > 5" check is not enough, as in some signal handling
and fork/exec scenarios, fpu_counter > 5 and !tsk_used_math() is possible.
It's a side effect though. This is the failing scenario:
process 'A' in save_i387_ia32() just after clear_used_math()
Got an interrupt and pre-empted out.
At the next context switch to process 'A' again, kernel tries to restore
the math state proactively and sees a fpu_counter > 0 and !tsk_used_math()
This results in init_fpu() during the __switch_to()'s math_state_restore()
And resulting in fpu corruption which will be saved/restored
(save_i387_fxsave and restore_i387_fxsave) during the remaining
part of the signal handling after the context switch.
Bisected-by: Jürgen Mell <j.mell@t-online.de>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Jürgen Mell <j.mell@t-online.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
iommu/gart support misses suspend/resume code, which can do bad stuff,
including memory corruption on resume. Prevent system suspend in case we
would be unable to resume.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Tested-by: Patrick <ragamuffin@datacomm.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix this:
WARNING: vmlinux.o(.text+0x114bb): Section mismatch in reference from
the function nopat() to the function .cpuinit.text:pat_disable()
The function nopat() references
the function __cpuinit pat_disable().
This is often because nopat lacks a __cpuinit
annotation or the annotation of pat_disable is wrong.
Reported-by: "Fabio Comolli" <fabio.comolli@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Clarify the usage of mtrr_lookup() in PAT code, and to make PAT code
resilient to mtrr lookup problems.
Specifically, pat_x_mtrr_type() is restructured to highlight, under what
conditions we look for mtrr hint. pat_x_mtrr_type() uses a default type
when there are any errors in mtrr lookup (still maintaining the pat
consistency). And, reserve_memtype() highlights its usage ot mtrr_lookup
for request type of '-1' and also defaults in a sane way on any mtrr
lookup failure.
pat.c looks at mtrr type of a range to get a hint on what mapping type
to request when user/API: (1) hasn't specified any type (/dev/mem
mapping) and we do not want to take performance hit by always mapping
UC_MINUS. This will be the case for /dev/mem mappings used to map BIOS
area or ACPI region which are WB'able. In this case, as long as MTRR is
not WB, PAT will request UC_MINUS for such mappings.
(2) user/API requests WB mapping while in reality MTRR may have UC or
WC. In this case, PAT can map as WB (without checking MTRR) and still
effective type will be UC or WC. But, a subsequent request to map same
region as UC or WC may fail, as the region will get trackked as WB in
PAT list. Looking at MTRR hint helps us to track based on effective type
rather than what user requested. Again, here mtrr_lookup is only used as
hint and we fallback to WB mapping (as requested by user) as default.
In both cases, after using the mtrr hint, we still go through the
memtype list to make sure there are no inconsistencies among multiple
users.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Tested-by: Rufus & Azrael <rufus-azrael@numericable.fr>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Changed the call to find_e820_area_size to pass u64 instead of unsigned long.
Signed-off-by: Kevin Winchester <kjwinchester@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
OGAWA Hirofumi and Fede have reported rare pmd_ERROR messages:
mm/memory.c:127: bad pmd ffff810000207xxx(9090909090909090).
Initialization's cleanup_highmap was leaving alignment filler
behind in the pmd for MODULES_VADDR: when vmalloc's guard page
would occupy a new page table, it's not allocated, and then
module unload's vfree hits the bad 9090 pmd entry left over.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Mika Kukkonen noticed that the nesting check in early_iounmap() is not
actually done.
Reported-by: Mika Kukkonen <mikukkon@srv1-m700-lanp.koti>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: torvalds@linux-foundation.org
Cc: arjan@linux.intel.com
Cc: mikukkon@iki.fi
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fix the math emulation that got broken with the recent lazy allocation of FPU
area. init_fpu() need to be added for the math-emulation path aswell
for the FPU area allocation.
math emulation enabled kernel booted fine with this, in the presence
of "no387 nofxsr" boot param.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: hpa@zytor.com
Cc: mingo@elte.hu
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
The RT team has been searching for a nasty latency. This latency shows
up out of the blue and has been seen to be as big as 5ms!
Using ftrace I found the cause of the latency.
pcscd-2995 3dNh1 52360300us : irq_exit (smp_apic_timer_interrupt)
pcscd-2995 3dN.2 52360301us : idle_cpu (irq_exit)
pcscd-2995 3dN.2 52360301us : rcu_irq_exit (irq_exit)
pcscd-2995 3dN.1 52360771us : smp_apic_timer_interrupt (apic_timer_interrupt
)
pcscd-2995 3dN.1 52360771us : exit_idle (smp_apic_timer_interrupt)
Here's an example of a 400 us latency. pcscd took a timer interrupt and
returned with "need resched" enabled, but did not reschedule until after
the next interrupt came in at 52360771us 400us later!
At first I thought we somehow missed a preemption check in entry.S. But
I also noticed that this always seemed to happen during a __delay call.
pcscd-2995 3dN.2 52360836us : rcu_irq_exit (irq_exit)
pcscd-2995 3.N.. 52361265us : preempt_schedule (__delay)
Looking at the x86 delay, I found my problem.
In git commit 35d5d08a08, Andrew Morton
placed preempt_disable around the entire delay due to TSC's not working
nicely on SMP. Unfortunately for those that care about latencies this
is devastating! Especially when we have callers to mdelay(8).
Here I enable preemption during the loop and account for anytime the task
migrates to a new CPU. The delay asked for may be extended a bit by
the migration, but delay only guarantees that it will delay for that minimum
time. Delaying longer should not be an issue.
[
Thanks to Thomas Gleixner for spotting that cpu wasn't updated,
and to place the rep_nop between preempt_enabled/disable.
]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: akpm@osdl.org
Cc: Clark Williams <clark.williams@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Luis Claudio R. Goncalves" <lclaudio@uudg.org>
Cc: Gregory Haskins <ghaskins@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andi Kleen <andi-suse@firstfloor.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
for http://bugzilla.kernel.org/show_bug.cgi?id=10613
BIOS bug, APIC version is 0 for CPU#0! fixing up to 0x10. (tell your hw vendor)
v2: fix 64 bit compilation
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Gabriel C <nix.or.die@googlemail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
iommu/gart support misses suspend/resume code, which can do bad stuff,
including memory corruption on resume. Prevent system suspend in case we
would be unable to resume.
Signed-off-by: Pavel Machek <pavel@suse.cz>
Tested-by: Patrick <ragamuffin@datacomm.ch>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On Wed, 2008-05-28 at 04:47 +0200, Andi Kleen wrote:
> > So... why not just remove the setting of __GFP_NORETRY? Why is it
> > wrong to oom-kill things in this case?
>
> When the 16MB zone overflows (which can be common in some workloads)
> calling the OOM killer is pretty useless because it has barely any
> real user data [only exception would be the "only 16MB" case Alan
> mentioned]. Killing random processes in this case is bad.
>
> I think for 16MB __GFP_NORETRY is ok because there should be
> nothing freeable in there so looping is useless. Only exception would be the
> "only 16MB total" case again but I'm not sure 2.6 supports that at all
> on x86.
>
> On the other hand d_a_c() does more allocations than just 16MB, especially
> on 64bit and the other zones need different strategies.
Okay, so how about this then ?
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This BIOS claims the VIA 8237 south bridge to be compatible with VIA 586,
which it is not.
Without this patch, I get the following warning while booting,
among others,
| PCI: Using IRQ router VIA [1106/3227] at 0000:00:11.0
| ------------[ cut here ]------------
| WARNING: at arch/x86/pci/irq.c:265 pirq_via586_get+0x4a/0x60()
| Modules linked in:
| Pid: 1, comm: swapper Not tainted 2.6.26-rc4-00015-g1ec7d99 #1
| [<c0119fd4>] warn_on_slowpath+0x54/0x70
| [<c02246e0>] ? vt_console_print+0x210/0x2b0
| [<c02244d0>] ? vt_console_print+0x0/0x2b0
| [<c011a413>] ? __call_console_drivers+0x43/0x60
| [<c011a482>] ? _call_console_drivers+0x52/0x80
| [<c011aa89>] ? release_console_sem+0x1c9/0x200
| [<c0291d21>] ? raw_pci_read+0x41/0x70
| [<c0291e8f>] ? pci_read+0x2f/0x40
| [<c029151a>] pirq_via586_get+0x4a/0x60
| [<c02914d0>] ? pirq_via586_get+0x0/0x60
| [<c029178d>] pcibios_lookup_irq+0x15d/0x430
| [<c03b895a>] pcibios_irq_init+0x17a/0x3e0
| [<c03a66f0>] ? kernel_init+0x0/0x250
| [<c03a6763>] kernel_init+0x73/0x250
| [<c03b87e0>] ? pcibios_irq_init+0x0/0x3e0
| [<c0114d00>] ? schedule_tail+0x10/0x40
| [<c0102dee>] ? ret_from_fork+0x6/0x1c
| [<c03a66f0>] ? kernel_init+0x0/0x250
| [<c03a66f0>] ? kernel_init+0x0/0x250
| [<c010324b>] kernel_thread_helper+0x7/0x1c
| =======================
| ---[ end trace 4eaa2a86a8e2da22 ]---
and IRQ trouble later,
| irq 10: nobody cared (try booting with the "irqpoll" option)
Now that's an VIA 8237 chip, so pirq_via586_get shouldn't be called
at all; adding this workaround to via_router_probe() fixes the
problem for me.
Amazingly I have a 2.6.23.8 kernel that somehow works fine ... I'll
never understand why.
Signed-off-by: Bertram Felgenhauer <int-e@gmx.de>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
init/Kconfig contains a list of configs that are searched
for if 'make *config' are used with no .config present.
Extend this list to look at the config identified by
ARCH_DEFCONFIG.
With this change we now try the defconfig targets last.
This fixes a regression reported
by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
x86: prevent PGE flush from interruption/preemption
x86: use explicit copy in vdso_gettimeofday()
namespacecheck: automated fixes
x86/xen: fix arbitrary_virt_to_machine()
x86: don't read maxlvt before checking if APIC is mapped
x86: disable TSC for sched_clock() when calibration failed
x86: distangle user disabled TSC from unstable
x86: fix setup of cyc2ns in tsc_64.c
