[SPARC64]: Eliminate race condition reading Hummingbird STICK register
Ensure a consistent value is read from the STICK register by ensuring
that both high and low are read without high changing due to a roll
over of the low register.
Various Debian/SPARC users (myself include) have noticed problems with
Hummingbird based systems. The symptoms are that the system time is
seen to jump forward 3 days, 6 hours, 11 minutes give or take a few
seconds. In many cases the system then hangs some time afterwards.
I've spotted a race condition in the code to read the STICK register.
I could not work out why 3d, 6h, 11m is important but guess that it is
due to the 2^32 jump of STICK (forwards on one read and then the next
read will seem to be backwards) during a timer interrupt. I'm guessing
that a change of -2^32 will get converted to a large unsigned
increment after the arithmetic manipulation between STICK,
nanoseconds, jiffies etc.
I did a test where I modified __hbird_read_stick to artificially
inject rollover faults forcefully every few seconds. With this I saw
the clock jump over 6 times in 12 hours compared to once every month
or so.
Signed-off-by: Richard Mortimer <richm@oldelvet.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Don't clobber register %l0 while checking TI_SYS_NOERROR value in
syscall return path. This bug was introduced by:
db7d9a4eb7
Problem narrowed down by Luis F. Ortiz and Richard Mortimer.
I tried using %l2 as suggested by Luis and that works for me.
Looking at the code I wonder if it makes sense to simplify the code
a little bit. The following works for me but I'm not sure how to
exercise the "NOERROR" codepath.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Commit 3e9e7c1d0b (ppc32: cleanup AMCC PPC40x
eval boards to support U-Boot) broke the kernel for ML300 / EP405.
It still compiles as there's a weak definition of the function in
misc-embedded.c, but the kernel crashes as the bd_t fixup isn't performed.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Sonny has noticed hotplug CPU on ppc64 is broken in 2.6.15-*. One of the
problems is that htab_initialize_secondary is called when a cpu is being
brought up, but it is marked __init.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, we do not pass the correct start_pfn to e820_hole_size, to
calculate holes. Following patch fixes that.
The bug results in incorrect number of node_present_pages for each pgdat
and causes ugly output in /sys and probably VM inbalances.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Sighed-off-by: Shair Fultheim <shai@scalex86.org>
Sighed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix UML compilation when SKAS mode is disabled. Indeed, we were compiling
SKAS-only object files, which failed due to some SKAS-only headers being
excluded from the search path.
Thanks to the bug report from Pekka J Enberg.
Acked-by: Pekka J Enberg <penberg (at) cs ! helsinki ! fi>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Today, when compiling UML, I got warnings for two used unexported symbols:
readdir64 and truncate64. Indeed, my glibc headers are aliasing readdir to
readdir64 and truncate to truncate64 (and so on).
I'm then adding additional exports. Since I've no idea if the symbols where
always provided in the supported glibc's, I've added weak definitions too.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Don't use printk() where "current_thread_info()" is crap.
Until when we switch to running on init_stack, current_thread_info() evaluates
to crap. Printk uses "current" at times (in detail, ¤t is evaluated with
CONFIG_DEBUG_SPINLOCK to check the spinlock owner task).
And this leads to random segmentation faults.
Exactly, what happens is that ¤t = *(current_thread_info()), i.e. round
down $esp and dereference the value. I.e. access the stack below $esp, which
causes SIGSEGV on a VM_GROWSDOWN vma (see arch/i386/mm/fault.c).
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It's definition is wrong (-1 means "no limit" not 999),
only the Sparc SunOS/Solaris compat code uses it, so
let's just kill it off completely from limits.h and
all referencing code.
Noticed by Ulrich Drepper.
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduce a Kconfig symbol SPARC that is defined on both the sparc and
sparc64 architectures.
This symbol makes some dependencies more readable.
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
It turns out that commit f9bd170a87
broke the cascade from XICS to i8259 on pSeries machines; specifically
we ended up not ever doing the EOI on the XICS for the cascade. The
result was that interrupts from the serial ports (and presumably any
other devices using ISA interrupts) didn't get through. This fixes
it and also simplifies the code, by doing the EOI on the XICS in the
xics_get_irq routine after reading and acking the interrupt on the
i8259.
Signed-off-by: Paul Mackerras <paulus@samba.org>
It was a stupid workaround for the "static inline" vs.
"extern inline" issues of long ago, and it is what causes
schedule() to be inlined like crazy into kernel/sched.c
when -Os is specified.
MIPS and S390 should probably do the same.
Now CC_OPTIMIZE_FOR_SIZE can be safely used on sparc64
once more.
Signed-off-by: David S. Miller <davem@davemloft.net>
Now needs to include the type 1 functions ("direct") too.
Reported by Pavel Roskin <proski@gnu.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Since we don't restore the volatile registers in the syscall exit
path, we need to make sure we don't leak any potentially interesting
values from the kernel to userspace. This was already the case for
all except r11. This makes it use r11 for an MSR value, so r11 will
have an (uninteresting) MSR value in it on return to userspace.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Patch from Nicolas Pitre
Strictly speaking, the NPTL kernel helpers are required for pre ARMv6
only. They are available on ARMv6+ as well for obvious compatibility
reasons. However there are cases where extra memory barriers are needed
when using an SMP ARMv6 machine but not on pre-ARMv6.
This patch adds a memory barrier kernel helper that glibc can use as
needed for pre-ARMv6 binaries to be forward compatible with an SMP
kernel on ARMv6, as well as the necessary dmb instructions to the
cmpxchg helper.
Signed-off-by: Nicolas Pitre <nico@cam.org>
Acked-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
With Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
UML skas0 stub has been miscompiling for many people (incidentally not
the authors), depending on the used GCC versions.
I think (and testing on some GCC versions shows) this patch avoids the
fundamental issue which is behind this, namely gcc using the stack when
we have just replaced it, behind gcc's back. The remapping and storage
of the return value is hidden in a blob of asm, hopefully giving gcc no
room for creativity.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
So you may have seen the miniconfig stuff wander by, which means that my
build script exits if there's a .config error, and we have this:
fs/Kconfig:1749:warning: 'select' used by config symbol 'CIFS_UPCALL'
refer to undefined symbol 'CONNECTOR'
This makes it shut up.
Signed-off-by: Rob Landley <rob@landley.net>
[ Verified it makes sense. ]
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
With Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
The current UML build assumes that on x86-64 systems, /lib is a symlink
to /lib64, but in some distributions (like PLD and CentOS) they are
separate directories, so the 64 bit library loader isn't found. This
patch inserts /lib64 at the start of the rpath on x86-64 UML builds.
Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Duplicated code - the patch adding it was probably applied twice without
enough care.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Rather than providing more wrappers for 6-arg syscalls, arrange for
them to be supported as standard. This just means that we always
store the 6th argument on the stack, rather than in the wrappers.
This means we eliminate the wrappers for:
* sys_futex
* sys_arm_fadvise64_64
* sys_mbind
* sys_ipc
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
DMA_MODE_{READ,WRITE} are declared in asm-powerpc/dma.h and their
declarations there match the definitions. Old declarations in
ppc4xx_dma.h are not right anymore (wrong type, to start with).
Killed them, added include of asm/dma.h where needed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use correct address when referencing mmconfig aperture while checking
for broken MCFG. This was a typo when porting the code from 64bit to
32bit. It caused oopses at boot on some ThinkPads.
Should definitely go into 2.6.15.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
sparc64, i386 and x86_64 have support for a special data section dedicated
to rarely updated data that is frequently read. The section was created to
avoid false sharing of those rarely read data with frequently written kernel
data.
This patch creates such a data section for ia64 and will group rarely written
data into this section.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Change the NR_CPUS default for ia64/sn up to 1024.
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: John Hesterberg <jh@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
I see why the problem exists only on SN. SN uses a different hardware
mechanism to purge TLB entries across nodes.
It looks like there is a bug in the SN TLB flushing code. During context switch,
kernel threads inherit the mm of the task that was previously running on the
cpu. This confuses the code in sn2_global_tlb_purge().
The result is a missed TLB purge for the task that owns the "borrowed" mm.
(I hit the problem running heavy stress where kswapd was purging code pages of
a user task that woke kswapd. The user task took a SIGILL fault trying to
execute code in the page that had been ripped out from underneath it).
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Use raw_smp_processor_id() instead of get_cpu() as we don't need the
extra features of get_cpu().
Signed-off-by: Jes Sorensen <jes@trained-monkey.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
The udelay() inline for ia64 uses the ITC. If CONFIG_PREEMPT is enabled
and the platform has unsynchronized ITCs and the calling task migrates
to another CPU while doing the udelay loop, then the effective delay may
be too short or very, very long.
This patch disables preemption around 100 usec chunks of the overall
desired udelay time. This minimizes preemption-holdoffs.
udelay() is now too big to be inline, move it out of line and export it.
Signed-off-by: John Hawkes <hawkes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Patch from Daniel Jacobowitz
Handle new EABI relocations when loading kernel modules. This is
necessary for CONFIG_AEABI kernels, and also for some broken
(since fixed) old ABI toolchains.
Signed-off-by: Daniel Jacobowitz <dan@codesourcery.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Andi Kleen