Граф коммитов

22783 Коммитов

Автор SHA1 Сообщение Дата
Ben Dooks dd1086f43d [ARM] JIVE: Add power off on shutdown support
Add pm_power_off hook to allow the Logitech Jive to shutdown
when asked to halt.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:27 +01:00
Ben Dooks d10d8a5f79 [ARM] JIVE: Add i2c device info for LIS302DL sensor
Add i2c bus definition for the LIS302DL sensor driver
which is connected on the i2c bus.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:26 +01:00
Ben Dooks fd2de272b2 [ARM] JIVE: Add board definitions for audio
Add board definitions for the audio device connected
on the Logitech Jive.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:26 +01:00
Ben Dooks c2c1708f9d [ARM] JIVE: Add LCD display setup information
Add the setup information for the LCD display
connected to the device.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:25 +01:00
Ben Dooks a2ed406515 [ARM] JIVE: Add SPI bus definitions for LCD controller
Add the definitions for the VGG2432A4 intelligent
LCD display conneected via an GPIO-based SPI bus
on the Logitech Jive.

Signed-of-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:25 +01:00
Ben Dooks 0f99263cda [ARM] JIVE: Add setup information for the S3C2412 LCD controller
Setup the video controller information for the Jive.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:25 +01:00
Ben Dooks 54c272acd1 [ARM] JIVE: Initialise the sleep configuration registers
Ensure that the S3C2412 sleep configuration registers
are approriately setup so that the device can safely
go to sleep.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:24 +01:00
Ben Dooks 9db829f485 [ARM] JIVE: Initial machine support for Logitech Jive
This is the base machine support for the Logitech Jive
machine.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:24 +01:00
Ben Dooks b999f0db94 [ARM] S3C24XX: Support for PWM timer clocks via clk_* API
Add support for the PWM timer clock routing via the
standard clk_ API.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:23 +01:00
Ben Dooks f348a2a281 [ARM] S3C24XX: Add gpiolib support
Add support for gpilib on all S3C24XX platforms.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:23 +01:00
Ben Dooks ed9137f103 [ARM] S3C24XX: s3c2410_defconfig: enable USB subset of drivers
Enable a subset of USB drivers which are useful for
using on these devices.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:22 +01:00
Ben Dooks 328dce1fa0 [ARM] S3C24XX: s3c2410_defconfig: add SCSI support
Enable SCSI support, mainly to help with adding
USB storage support later and for the imminent
changes for libata.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:22 +01:00
Ben Dooks 186eb08b8b [ARM] S3C24XX: s3c2410_defconfig: update networking options
Add the following to the networking confgiuration:

1) Packet socket support (useful for userland dhcp)
2) Add bluetooth and USB bluetooth drivers as modules
3) Add basic IPv6 support as modules.
4) Add the wireless core as modules.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:21 +01:00
Ben Dooks d947ae5721 [ARM] S3C24XX: s3c2410_defconfig: update miscellaneous options
Add some basic config filesystem, ensure errors are verbose
by default.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:21 +01:00
Ben Dooks fa941dc986 [ARM] S3C24XX: s3c2410_defconfig: update filesystem options
Enable new filesystem options, such as:

- JFFS2 summary nodes
- Ext2/3 externed options
- Standard CDROM filesystems

Also add NTFS as a module.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:20 +01:00
Ben Dooks a373473a90 [ARM] S3C24XX: s3c2410_defconfig: enable useful NLS options
Enable some useful NLS codepages to be built into
the kernel, and build the rest as modules.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:20 +01:00
Ben Dooks d951f55d6a [ARM] S3C24XX: s3c2410_defconfig: update list of used drivers
Update the drivers built, such as the SM501 and
parallel port.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:20 +01:00
Ben Dooks 0acaff300f [ARM] S3C24XX: s3c2410_defconfig: update to rc8
Update the s3c2410_defconfig to rc8

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2008-07-03 16:51:19 +01:00
Ben Dooks 9cf345e399 [ARM] S3C2410: Fix flags on DM9000 resources on BAST and VR1000
Fix the flags entries for the DM9000 IRQ entries on both the
Simtec BAST and Thorcom VR1000 board. The current entries use
the IRQF_ flags, but we should be using the IORESOURCE_IRQ_
definitions.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
PATCH FOLLOWS
KernelVersion: 2.6.26-rc5
2008-07-03 16:51:18 +01:00
Linus Torvalds bd8c540fe8 Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] Eliminate NULL test after alloc_bootmem in iosapic_alloc_rte()
  [IA64] Handle count==0 in sn2_ptc_proc_write()
  [IA64] Fix boot failure on ia64/sn2
2008-06-24 18:12:33 -07:00
Linus Torvalds 919c0d14ae Merge branch 'kvm-updates-2.6.26' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm
* 'kvm-updates-2.6.26' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm:
  KVM: Remove now unused structs from kvm_para.h
  x86: KVM guest: Use the paravirt clocksource structs and functions
  KVM: Make kvm host use the paravirt clocksource structs
  x86: Make xen use the paravirt clocksource structs and functions
  x86: Add structs and functions for paravirt clocksource
  KVM: VMX: Fix host msr corruption with preemption enabled
  KVM: ioapic: fix lost interrupt when changing a device's irq
  KVM: MMU: Fix oops on guest userspace access to guest pagetable
  KVM: MMU: large page update_pte issue with non-PAE 32-bit guests (resend)
  KVM: MMU: Fix rmap_write_protect() hugepage iteration bug
  KVM: close timer injection race window in __vcpu_run
  KVM: Fix race between timer migration and vcpu migration
2008-06-24 18:09:06 -07:00
Linus Torvalds 9bf8a943ad Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  xen: remove support for non-PAE 32-bit
2008-06-24 11:21:47 -07:00
Gerd Hoffmann f6e16d5ad4 x86: KVM guest: Use the paravirt clocksource structs and functions
This patch updates the kvm host code to use the pvclock structs
and functions, thereby making it compatible with Xen.

The patch also fixes an initialization bug: on SMP systems the
per-cpu has two different locations early at boot and after CPU
bringup.  kvmclock must take that in account when registering the
physical address within the host.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 21:02:33 +03:00
Gerd Hoffmann 50d0a0f987 KVM: Make kvm host use the paravirt clocksource structs
This patch updates the kvm host code to use the pvclock structs.
It also makes the paravirt clock compatible with Xen.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 21:02:32 +03:00
Gerd Hoffmann 1c7b67f757 x86: Make xen use the paravirt clocksource structs and functions
This patch updates the xen guest to use the pvclock structs
and helper functions.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 21:02:32 +03:00
Gerd Hoffmann 7af192c954 x86: Add structs and functions for paravirt clocksource
This patch adds structs for the paravirt clocksource ABI
used by both xen and kvm (pvclock-abi.h).

It also adds some helper functions to read system time and
wall clock time from a paravirtual clocksource (pvclock.[ch]).
They are based on the xen code.  They are enabled using
CONFIG_PARAVIRT_CLOCK.

Subsequent patches of this series will put the code in use.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 21:02:31 +03:00
Julia Lawall e2569b7e57 [IA64] Eliminate NULL test after alloc_bootmem in iosapic_alloc_rte()
As noted by Akinobu Mita alloc_bootmem and related functions never return
NULL and always return a zeroed region of memory.  Thus a NULL test or
memset after calls to these functions is unnecessary.

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2008-06-24 10:28:55 -07:00
Cliff Wickman 8097110d17 [IA64] Handle count==0 in sn2_ptc_proc_write()
The fix applied in e0c6d97c65
"security hole in sn2_ptc_proc_write" didn't take into account
the case where count==0 (which results in a buffer underrun
when adding the trailing '\0').  Thanks to Andi Kleen for
pointing this out.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2008-06-24 10:20:06 -07:00
Jes Sorensen 2826f8c0f4 [IA64] Fix boot failure on ia64/sn2
Call check_sal_cache_flush() after platform_setup() as
check_sal_cache_flush() now relies on being able to call platform
vector code.

Problem was introduced by: 3463a93def
"Update check_sal_cache_flush to use platform_send_ipi()"

Signed-off-by: Jes Sorensen <jes@sgi.com>
Tested-by: Alex Chiang: <achiang@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2008-06-24 10:16:27 -07:00
Jeremy Fitzhardinge 2849914393 xen: remove support for non-PAE 32-bit
Non-PAE operation has been deprecated in Xen for a while, and is
rarely tested or used.  xen-unstable has now officially dropped
non-PAE support.  Since Xen/pvops' non-PAE support has also been
broken for a while, we may as well completely drop it altogether.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24 17:00:55 +02:00
Avi Kivity a9b21b6229 KVM: VMX: Fix host msr corruption with preemption enabled
Switching msrs can occur either synchronously as a result of calls to
the msr management functions (usually in response to the guest touching
virtualized msrs), or asynchronously when preempting a kvm thread that has
guest state loaded.  If we're unlucky enough to have the two at the same
time, host msrs are corrupted and the machine goes kaput on the next syscall.

Most easily triggered by Windows Server 2008, as it does a lot of msr
switching during bootup.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 12:26:17 +03:00
Avi Kivity 6bf6a9532f KVM: MMU: Fix oops on guest userspace access to guest pagetable
KVM has a heuristic to unshadow guest pagetables when userspace accesses
them, on the assumption that most guests do not allow userspace to access
pagetables directly. Unfortunately, in addition to unshadowing the pagetables,
it also oopses.

This never triggers on ordinary guests since sane OSes will clear the
pagetables before assigning them to userspace, which will trigger the flood
heuristic, unshadowing the pagetables before the first userspace access. One
particular guest, though (Xenner) will run the kernel in userspace, triggering
the oops.  Since the heuristic is incorrect in this case, we can simply
remove it.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 12:20:12 +03:00
Marcelo Tosatti 3094538739 KVM: MMU: large page update_pte issue with non-PAE 32-bit guests (resend)
kvm_mmu_pte_write() does not handle 32-bit non-PAE large page backed
guests properly. It will instantiate two 2MB sptes pointing to the same
physical 2MB page when a guest large pte update is trapped.

Instead of duplicating code to handle this, disallow directory level
updates to happen through kvm_mmu_pte_write(), so the two 2MB sptes
emulating one guest 4MB pte can be correctly created by the page fault
handling path.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 12:18:18 +03:00
Marcelo Tosatti 6597ca09e6 KVM: MMU: Fix rmap_write_protect() hugepage iteration bug
rmap_next() does not work correctly after rmap_remove(), as it expects
the rmap chains not to change during iteration.  Fix (for now) by restarting
iteration from the beginning.

Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 12:17:10 +03:00
Marcelo Tosatti 06e0564566 KVM: close timer injection race window in __vcpu_run
If a timer fires after kvm_inject_pending_timer_irqs() but before
local_irq_disable() the code will enter guest mode and only inject such
timer interrupt the next time an unrelated event causes an exit.

It would be simpler if the timer->pending irq conversion could be done
with IRQ's disabled, so that the above problem cannot happen.

For now introduce a new vcpu requests bit to cancel guest entry.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 12:16:59 +03:00
Marcelo Tosatti d4acf7e7ab KVM: Fix race between timer migration and vcpu migration
A guest vcpu instance can be scheduled to a different physical CPU
between the test for KVM_REQ_MIGRATE_TIMER and local_irq_disable().

If that happens, the timer will only be migrated to the current pCPU on
the next exit, meaning that guest LAPIC timer event can be delayed until
a host interrupt is triggered.

Fix it by cancelling guest entry if any vcpu request is pending.  This
has the side effect of nicely consolidating vcpu->requests checks.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2008-06-24 12:16:52 +03:00
Linus Torvalds ee5c2ab09b Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  xen: don't drop NX bit
  xen: mask unwanted pte bits in __supported_pte_mask
  xen: Use wmb instead of rmb in xen_evtchn_do_upcall().
  x86: fix NULL pointer deref in __switch_to
2008-06-23 12:48:17 -07:00
Linus Torvalds b732d9680b Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
  [IA64] SN2: security hole in sn2_ptc_proc_write
2008-06-20 17:10:04 -07:00
Ivan Kokshaysky a744e0160a alpha: resurrect Cypress IDE quirk
Which was removed in the hope that generic legacy IDE quirk in
drivers/pci/probe.c is sufficient for Cypress IDE.
It isn't, as this controller has non-standard BAR layout:
secondary channel registers are in the BAR0-1 of the second
PCI function - not in the BAR2-3 of the same function, as the
generic quirk routine assumes.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-20 16:46:10 -07:00
Ivan Kokshaysky d559d4a24a alpha: fix compile failures with gcc-4.3 (bug #10438)
Vast majority of these build failures are gcc-4.3 warnings
about static functions and objects being referenced from
non-static (read: "extern inline") functions, in conjunction
with our -Werror.

We cannot just convert "extern inline" to "static inline",
as people keep suggesting all the time, because "extern inline"
logic is crucial for generic kernel build.
So
- just make sure that all callees of critical "extern inline"
  functions are also "extern inline";
- use "static inline", wherever it's possible.

traps.c: work around gcc-4.3 being too smart about array
bounds-checking.

TODO: add "gnu_inline" attribute to all our "extern inline"
functions to ensure desired behaviour with future compilers.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-20 16:46:10 -07:00
Ivan Kokshaysky ede426923b alpha: link failure fix
With built-in scsi disk driver, the final link fails with a following
error:
`.exit.text' referenced in section `.rodata' of drivers/built-in.o:
defined in discarded section `.exit.text' of drivers/built-in.o

This happens with -Os (CONFIG_CC_OPTIMIZE_FOR_SIZE=y) with all gcc-4
versions, and also with -O2 and gcc-4.3.

The problem is in sd.c:sd_major() being inlined into __exit function
exit_sd(), and the compiler generating a jump table in .rodata section
for the 'switch' statement in sd_major(). So we have references to
discarded section.

Fixed with a big hammer in the form of -fno-jump-tables.

Note that jump tables vs. discarded sections is a generic problem,
other architectures are just lucky not to suffer from it. But with
a slightly more complex switch/case statement it can be reproduced
on x86 as well. So maybe at some point we should consider
-fno-jump-tables as a generic compile option...

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-20 16:46:10 -07:00
Linus Torvalds b1ae8d3a00 Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, geode: add a VSA2 ID for General Software
  x86: use BOOTMEM_EXCLUSIVE on 32-bit
  x86, 32-bit: fix boot failure on TSC-less processors
  x86: fix NULL pointer deref in __switch_to
  x86: set PAE PHYSICAL_MASK_SHIFT to 44 bits.
2008-06-20 12:36:38 -07:00
Cliff Wickman e0c6d97c65 [IA64] SN2: security hole in sn2_ptc_proc_write
Security hole in sn2_ptc_proc_write

It is possible to overrun a buffer with a write to this /proc file.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2008-06-20 12:02:00 -07:00
Linus Torvalds 89f5b7da2a Reinstate ZERO_PAGE optimization in 'get_user_pages()' and fix XIP
KAMEZAWA Hiroyuki and Oleg Nesterov point out that since the commit
557ed1fa26 ("remove ZERO_PAGE") removed
the ZERO_PAGE from the VM mappings, any users of get_user_pages() will
generally now populate the VM with real empty pages needlessly.

We used to get the ZERO_PAGE when we did the "handle_mm_fault()", but
since fault handling no longer uses ZERO_PAGE for new anonymous pages,
we now need to handle that special case in follow_page() instead.

In particular, the removal of ZERO_PAGE effectively removed the core
file writing optimization where we would skip writing pages that had not
been populated at all, and increased memory pressure a lot by allocating
all those useless newly zeroed pages.

This reinstates the optimization by making the unmapped PTE case the
same as for a non-existent page table, which already did this correctly.

While at it, this also fixes the XIP case for follow_page(), where the
caller could not differentiate between the case of a page that simply
could not be used (because it had no "struct page" associated with it)
and a page that just wasn't mapped.

We do that by simply returning an error pointer for pages that could not
be turned into a "struct page *".  The error is arbitrarily picked to be
EFAULT, since that was what get_user_pages() already used for the
equivalent IO-mapped page case.

[ Also removed an impossible test for pte_offset_map_lock() failing:
  that's not how that function works ]

Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Nick Piggin <npiggin@suse.de>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-20 11:18:25 -07:00
Jeremy Fitzhardinge ebb9cfe20f xen: don't drop NX bit
Because NX is now enforced properly, we must put the hypercall page
into the .text segment so that it is executable.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Cc: the arch/x86 maintainers <x86@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-20 14:56:41 +02:00
Jeremy Fitzhardinge 05345b0f00 xen: mask unwanted pte bits in __supported_pte_mask
[ Stable: this isn't a bugfix in itself, but it's a pre-requiste
  for "xen: don't drop NX bit" ]

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Cc: the arch/x86 maintainers <x86@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-20 14:56:36 +02:00
Jordan Crouse ffe6e1da86 x86, geode: add a VSA2 ID for General Software
General Software writes their own VSA2 module for their version
of the Geode BIOS, which returns a different ID then the standard
VSA2.  This was causing the framebuffer driver to break for most
GSW boards.

Signed-off-by: Jordan Crouse <jordan.crouse@amd.com>
Cc: tglx@linutronix.de
Cc: linux-geode@lists.infradead.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-19 14:19:03 +02:00
Bernhard Walle d3942cff62 x86: use BOOTMEM_EXCLUSIVE on 32-bit
This patch uses the BOOTMEM_EXCLUSIVE for crashkernel reservation also for
i386 and prints a error message on failure.

The patch is still for 2.6.26 since it is only bug fixing. The unification
of reserve_crashkernel() between i386 and x86_64 should be done for 2.6.27.

Signed-off-by: Bernhard Walle <bwalle@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
2008-06-19 10:08:48 +02:00
Mikael Pettersson df17b1d990 x86, 32-bit: fix boot failure on TSC-less processors
Booting 2.6.26-rc6 on my 486 DX/4 fails with a "BUG: Int 6"
(invalid opcode) and a kernel halt immediately after the
kernel has been uncompressed. The BUG shows EIP pointing
to an rdtsc instruction in native_read_tsc(), invoked from
native_sched_clock().

(This error occurs so early that not even the serial console
can capture it.)

A bisection showed that this bug first occurs in 2.6.26-rc3-git7,
via commit 9ccc906c97e34fd91dc6aaf5b69b52d824386910:

>x86: distangle user disabled TSC from unstable
>
>tsc_enabled is set to 0 from the command line switch "notsc" and from
>the mark_tsc_unstable code. Seperate those functionalities and replace
>tsc_enable with tsc_disable. This makes also the native_sched_clock()
>decision when to use TSC understandable.
>
>Preparatory patch to solve the sched_clock() issue on 32 bit.
>
>Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

The core reason for this bug is that native_sched_clock() gets
called before tsc_init().

Before the commit above, tsc_32.c used a "tsc_enabled" variable
which defaulted to 0 == disabled, and which only got enabled late
in tsc_init(). Thus early calls to native_sched_clock() would skip
the TSC and use jiffies instead.

After the commit above, tsc_32.c uses a "tsc_disabled" variable
which defaults to 0, meaning that the TSC is Ok to use. Early calls
to native_sched_clock() now erroneously try to use the TSC on
!cpu_has_tsc processors, leading to invalid opcode exceptions.

My proposed fix is to initialise tsc_disabled to a "soft disabled"
state distinct from the hard disabled state set up by the "notsc"
kernel option. This fixes the native_sched_clock() problem. It also
allows tsc_init() to be simplified: instead of setting tsc_disabled = 1
on every error return, we just set tsc_disabled = 0 once when all
checks have succeeded.

I've verified that this lets my 486 boot again. I've also verified
that a Core2 machine still uses the TSC as clocksource after the patch.

Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-19 10:08:47 +02:00
Suresh Siddha 75118a82e2 x86: fix NULL pointer deref in __switch_to
Patrick McHardy reported a crash:

> > I get this oops once a day, its apparently triggered by something
> > run by cron, but the process is a different one each time.
> >
> > Kernel is -git from yesterday shortly before the -rc6 release
> > (last commit is the usb-2.6 merge, the x86 patches are missing),
> > .config is attached.
> >
> > I'll retry with current -git, but the patches that have gone in
> > since I last updated don't look related.
> >
> > [62060.043009] BUG: unable to handle kernel NULL pointer dereference at
> > 000001ff
> > [62060.043009] IP: [<c0102a9b>] __switch_to+0x2f/0x118
> > [62060.043009] *pde = 00000000
> > [62060.043009] Oops: 0002 [#1] PREEMPT

Vegard Nossum analyzed it:

> This decodes to
>
>    0:   0f ae 00                fxsave (%eax)
>
> so it's related to the floating-point context. This is the exact
> location of the crash:
>
> $ addr2line -e arch/x86/kernel/process_32.o -i ab0
> include/asm/i387.h:232
> include/asm/i387.h:262
> arch/x86/kernel/process_32.c:595
>
> ...so it looks like prev_task->thread.xstate->fxsave has become NULL.
> Or maybe it never had any other value.

Somehow (as described below) TS_USEDFPU is set but the fpu is not
allocated or freed.

Another possible FPU pre-emption issue with the sleazy FPU optimization
which was benign before but not so anymore, with the dynamic FPU allocation
patch.

New task is getting exec'd and it is prempted at the below point.

flush_thread() {
	...
	/*
	* Forget coprocessor state..
	*/
	clear_fpu(tsk);
		<----- Preemption point
	clear_used_math();
	...
}

Now when it context switches in again, as the used_math() is still set
and fpu_counter can be > 5, we will do a math_state_restore() which sets
the task's TS_USEDFPU. After it continues from the above preemption point
it does clear_used_math() and much later free_thread_xstate().

Now, at the next context switch, it is quite possible that xstate is
null, used_math() is not set and TS_USEDFPU is still set. This will
trigger unlazy_fpu() causing kernel oops.

Fix this  by clearing tsk's fpu_counter before clearing task's fpu.

Reported-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-19 10:08:45 +02:00