* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-tip:
x86, fpu: fix CONFIG_PREEMPT=y corruption of application's FPU stack
suspend-vs-iommu: prevent suspend if we could not resume
x86: section mismatch fix
x86: fix Xorg crash with xf86MapVidMem error
x86: fix pointer type warning in arch/x86/mm/init_64.c:early_memtest
x86: fix bad pmd ffff810000207xxx(9090909090909090)
x86: ioremap fix failing nesting check
x86: fix broken math-emu with lazy allocation of fpu area
x86: enable preemption in delay
x86: disable preemption in native_smp_prepare_cpus
x86: fix APIC warning on 32bit v2
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>
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>
RSK7203 is supportable through the generic machvec, so we add a defconfig
for those bits. This gets updated with more complete board support later.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/blackfin-2.6:
8250 Serial Driver: revert extra IRQ flag definition patch
Blackfin arch: update anomaly headers from toolchain trunk
Blackfin arch: Remove bad and usless code
Blackfin arch: Fix bug - set corret SSEL and IRQ to enable AD7877 on BF527
Blackfin arch: Fix typo. it should be _outsw_8
Blackfin arch: Cleanup no functional changes
4k stacks on nommu ends up blowing up with all sorts of interesting
slab corruption. Disable this by default unless BROKEN is also
enabled.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This patch fixes the following build error caused by
commit a1dc4b59fa
(sh: intc_sh5 depends on cayman board for IRQ priority table.):
<-- snip -->
...
CC arch/sh/kernel/cpu/irq/intc-sh5.o
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/kernel/cpu/irq/intc-sh5.c: In function 'plat_irq_setup':
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/sh/kernel/cpu/irq/intc-sh5.c:257: error: expected declaration or statement at end of input
make[4]: *** [arch/sh/kernel/cpu/irq/intc-sh5.o] Error 1
<-- snip -->
Reported-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
