Currently it is possible for userspace to see the result of
gettimeofday() going backwards by 1 microsecond, assuming that
userspace is using the gettimeofday() in the VDSO. The VDSO
gettimeofday() algorithm computes the time in "xsecs", which are
units of 2^-20 seconds, or approximately 0.954 microseconds,
using the algorithm
now = (timebase - tb_orig_stamp) * tb_to_xs + stamp_xsec
and then converts the time in xsecs to seconds and microseconds.
The kernel updates the tb_orig_stamp and stamp_xsec values every
tick in update_vsyscall(). If the length of the tick is not an
integer number of xsecs, then some precision is lost in converting
the current time to xsecs. For example, with CONFIG_HZ=1000, the
tick is 1ms long, which is 1048.576 xsecs. That means that
stamp_xsec will advance by either 1048 or 1049 on each tick.
With the right conditions, it is possible for userspace to get
(timebase - tb_orig_stamp) * tb_to_xs being 1049 if the kernel is
slightly late in updating the vdso_datapage, and then for stamp_xsec
to advance by 1048 when the kernel does update it, and for userspace
to then see (timebase - tb_orig_stamp) * tb_to_xs being zero due to
integer truncation. The result is that time appears to go backwards
by 1 microsecond.
To fix this we change the VDSO gettimeofday to use a new field in the
VDSO datapage which stores the nanoseconds part of the time as a
fractional number of seconds in a 0.32 binary fraction format.
(Or put another way, as a 32-bit number in units of 0.23283 ns.)
This is convenient because we can use the mulhwu instruction to
convert it to either microseconds or nanoseconds.
Since it turns out that computing the time of day using this new field
is simpler than either using stamp_xsec (as gettimeofday does) or
stamp_xtime.tv_nsec (as clock_gettime does), this converts both
gettimeofday and clock_gettime to use the new field. The existing
__do_get_tspec function is converted to use the new field and take
a parameter in r7 that indicates the desired resolution, 1,000,000
for microseconds or 1,000,000,000 for nanoseconds. The __do_get_xsec
function is then unused and is deleted.
The new algorithm is
now = ((timebase - tb_orig_stamp) << 12) * tb_to_xs
+ (stamp_xtime_seconds << 32) + stamp_sec_fraction
with 'now' in units of 2^-32 seconds. That is then converted to
seconds and either microseconds or nanoseconds with
seconds = now >> 32
partseconds = ((now & 0xffffffff) * resolution) >> 32
The 32-bit VDSO code also makes a further simplification: it ignores
the bottom 32 bits of the tb_to_xs value, which is a 0.64 format binary
fraction. Doing so gets rid of 4 multiply instructions. Assuming
a timebase frequency of 1GHz or less and an update interval of no
more than 10ms, the upper 32 bits of tb_to_xs will be at least
4503599, so the error from ignoring the low 32 bits will be at most
2.2ns, which is more than an order of magnitude less than the time
taken to do gettimeofday or clock_gettime on our fastest processors,
so there is no possibility of seeing inconsistent values due to this.
This also moves update_gtod() down next to its only caller, and makes
update_vsyscall use the time passed in via the wall_time argument rather
than accessing xtime directly. At present, wall_time always points to
xtime, but that could change in future.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband:
IPoIB: Fix world-writable child interface control sysfs attributes
IB/qib: Clean up properly if qib_init() fails
IB/qib: Completion queue callback needs to be single threaded
IB/qib: Update 7322 serdes tables
IB/qib: Clear 6120 hardware error register
IB/qib: Clear eager buffer memory for each new process
IB/qib: Mask hardware error during link reset
IB/qib: Don't mark VL15 bufs as WC to avoid a rare 7322 chip problem
RDMA/cxgb4: Derive smac_idx from port viid
RDMA/cxgb4: Avoid false GTS CIDX_INC overflows
RDMA/cxgb4: Don't call abort_connection() for active connect failures
RDMA/cxgb4: Use the DMA state API instead of the pci equivalents
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
writeback: simplify the write back thread queue
writeback: split writeback_inodes_wb
writeback: remove writeback_inodes_wbc
fs-writeback: fix kernel-doc warnings
splice: check f_mode for seekable file
splice: direct_splice_actor() should not use pos in sd
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc:
powerpc: Fix userspace build of ptrace.h
powerpc: Fix default_machine_crash_shutdown #ifdef botch
powerpc: Fix logic error in fixup_irqs
powerpc/iseries: Fix possible null pointer dereference in iSeries_pcibios_fixup_resources
powerpc: Linux cannot run with 0 cores
powerpc: Fix feature-fixup tests for gcc 4.5
powerpc: Disable SPARSE_IRQ by default
powerpc: Fix compile errors in prom_init_check for gcc 4.5
powerpc: Fix module building for gcc 4.5 and 64 bit
powerpc/perf_event: Fix for power_pmu_disable()
Build of ptrace.h failed for assembly because it
pulls in stdint.h.
Use exportable types (__u32, __u64) to avoid the dependency
on stdint.h.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Andrey Volkov <avolkov@varma-el.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
crash_kexec_wait_realmode() is defined only if CONFIG_PPC_STD_MMU_64
and CONFIG_SMP, but is called if CONFIG_PPC_STD_MMU_64 even if !CONFIG_SMP.
Fix the conditional compilation around the invocation.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When SPARSE_IRQ is set, irq_to_desc() can
return NULL. While the code here has a
check for NULL, it's not really correct.
Fix it by separating the check for it.
This fixes CPU hot unplug for me.
Reported-by: Alastair Bridgewater <alastair.bridgewater@gmail.com>
Cc: stable@kernel.org [2.6.32+]
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
I don't know if this is a right fix for the problem
since of_get_property can return NULL.
Since iseries_device_information is used only for informational purpose,
we can skip this function without valid HvSubBusNumber number.
Signed-off-by: Denis Kirjanov <dkirjanov@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
If we configure with CONFIG_SMP=n or set NR_CPUS less than the number of
SMT threads we will set the max cores property to 0 in the
ibm,client-architecture-support structure. On new versions of firmware that
understand this property it obliges and terminates our partition.
Use DIV_ROUND_UP so we handle not only the CONFIG_SMP=n case but also the
case where NR_CPUS isn't a multiple of the number of SMT threads.
Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The feature-fixup test declare some extern void variables and then take
their addresses. Fix this by declaring them as extern u8 instead.
Fixes these warnings (treated as errors):
CC arch/powerpc/lib/feature-fixups.o
cc1: warnings being treated as errors
arch/powerpc/lib/feature-fixups.c: In function 'test_cpu_macros':
arch/powerpc/lib/feature-fixups.c:293:23: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:294:9: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:297:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:297:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c: In function 'test_fw_macros':
arch/powerpc/lib/feature-fixups.c:306:23: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:307:9: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:310:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:310:2: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c: In function 'test_lwsync_macros':
arch/powerpc/lib/feature-fixups.c:321:23: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:322:9: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:326:3: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:326:3: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:329:3: error: taking address of expression of type 'void'
arch/powerpc/lib/feature-fixups.c:329:3: error: taking address of expression of type 'void'
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The SPARSE_IRQ considerably adds overhead to critical path of IRQ
handling. However it doesn't benefit much in space for most systems with
limited IRQ_NR. Should be disabled unless really necessary.
Signed-off-by: Li Yang <leoli@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Just whitelist these extra compiler generated symbols.
Fixes these errors:
Error: External symbol '_restgpr0_14' referenced from prom_init.c
Error: External symbol '_restgpr0_20' referenced from prom_init.c
Error: External symbol '_restgpr0_22' referenced from prom_init.c
Error: External symbol '_restgpr0_24' referenced from prom_init.c
Error: External symbol '_restgpr0_25' referenced from prom_init.c
Error: External symbol '_restgpr0_26' referenced from prom_init.c
Error: External symbol '_restgpr0_27' referenced from prom_init.c
Error: External symbol '_restgpr0_28' referenced from prom_init.c
Error: External symbol '_restgpr0_29' referenced from prom_init.c
Error: External symbol '_restgpr0_31' referenced from prom_init.c
Error: External symbol '_savegpr0_14' referenced from prom_init.c
Error: External symbol '_savegpr0_20' referenced from prom_init.c
Error: External symbol '_savegpr0_22' referenced from prom_init.c
Error: External symbol '_savegpr0_24' referenced from prom_init.c
Error: External symbol '_savegpr0_25' referenced from prom_init.c
Error: External symbol '_savegpr0_26' referenced from prom_init.c
Error: External symbol '_savegpr0_27' referenced from prom_init.c
Error: External symbol '_savegpr0_28' referenced from prom_init.c
Error: External symbol '_savegpr0_29' referenced from prom_init.c
Error: External symbol '_savegpr0_31' referenced from prom_init.c
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Gcc 4.5 is now generating out of line register save and restore
in the function prefix and postfix when we use -Os.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When power_pmu_disable() removes the given event from a particular index into
cpuhw->event[], it shuffles down higher event[] entries. But, this array is
paired with cpuhw->events[] and cpuhw->flags[] so should shuffle them
similarly.
If these arrays get out of sync, code such as power_check_constraints() will
fail. This caused a bug where events were temporarily disabled and then failed
to be re-enabled; subsequent code tried to write_pmc() with its (disabled) idx
of 0, causing a message "oops trying to write PMC0". This triggers this bug on
POWER7, running a miss-heavy test:
perf record -e L1-dcache-load-misses -e L1-dcache-store-misses ./misstest
Signed-off-by: Matt Evans <matt@ozlabs.org>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (35 commits)
NET: SB1250: Initialize .owner
vxge: show startup message with KERN_INFO
ll_temac: Fix missing iounmaps
bridge: Clear IPCB before possible entry into IP stack
bridge br_multicast: BUG: unable to handle kernel NULL pointer dereference
net: Fix definition of netif_vdbg() when VERBOSE_DEBUG is defined
net/ne: fix memory leak in ne_drv_probe()
xfrm: fix xfrm by MARK logic
virtio_net: fix oom handling on tx
virtio_net: do not reschedule rx refill forever
s2io: resolve statistics issues
linux/net.h: fix kernel-doc warnings
net: decreasing real_num_tx_queues needs to flush qdisc
sched: qdisc_reset_all_tx is calling qdisc_reset without qdisc_lock
qlge: fix a eeh handler to not add a pending timer
qlge: Replacing add_timer() to mod_timer()
usbnet: Set parent device early for netdev_printk()
net: Revert "rndis_host: Poll status channel before control channel"
netfilter: ip6t_REJECT: fix a dst leak in ipv6 REJECT
drivers: bluetooth: bluecard_cs.c: Fixed include error, changed to linux/io.h
...
The original KERN_CRIT will mess up terminals.
CC: Sreenivasa Honnur <Sreenivasa.Honnur@neterion.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The bridge protocol lives dangerously by having incestuous relations
with the IP stack. In this instance an abomination has been created
where a bogus IPCB area from a bridged packet leads to a crash in
the IP stack because it's interpreted as IP options.
This patch papers over the problem by clearing the IPCB area in that
particular spot. To fix this properly we'd also need to parse any
IP options if present but I'm way too lazy for that.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Cheers,
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm: correctly update connector DPMS status in drm_fb_helper
drm/radeon/kms: fix shared ddc handling
drm/ttm: Allocate the page pool manager in the heap.
We don't currently update the DPMS status of the connector (both in the
connector itself and the connector's DPMS property) in the fb helper
code. This means that if the kernel FB core has blanked the screen,
sysfs will still show a DPMS status of "on". It also means that when X
starts, it will try to light up the connectors, but the drm_crtc_helper
code will ignore the DPMS change since according to the connector, the
DPMS status is already on.
Fixes https://bugs.freedesktop.org/show_bug.cgi?id=28436 (the annoying
"my screen was blanked when I started X and now it won't light up" bug).
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Connectors with a shared ddc line can be connected to different
encoders.
Reported by Pasi Kärkkäinen <pasik@iki.fi> on dri-devel
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
Repeated ttm_page_alloc_init/fini fails noisily because the pool
manager kobj isn't zeroed out between uses (we could do just that but
statically allocated kobjects are generally considered a bad thing).
Move it to kzalloc'ed memory.
Note that this patch drops the refcounting behavior of the pool
allocator init/fini functions: it would have led to a race condition
in its current form, and anyway it was never exploited.
This fixes a regression with reloading kms modules at runtime, since
page allocator was introduced.
Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This patch introduces 3 VFS accessors: 'sb_mark_dirty()',
'sb_mark_clean()', and 'sb_is_dirty()'. They simply
set 'sb->s_dirt' or test 'sb->s_dirt'. The plan is to make
every FS use these accessors later instead of manipulating
the 'sb->s_dirt' flag directly.
Ultimately, this change is a preparation for the periodic
superblock synchronization optimization which is about
preventing the "sync_supers" kernel thread from waking up
even if there is nothing to synchronize.
This patch does not do any functional change, just adds
accessor functions.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rbtree: Undo augmented trees performance damage and regression
x86, Calgary: Limit the max PHB number to 256
* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus: (22 commits)
MIPS: Return after handling coprocessor 2 exception
MIPS: BCM47xx: Add NVRAM support devices
MIPS: Loongson: Define rtc device on MC146818-equipped systems
MIPS: MT: Fix FPU affinity.
MIPS: Oprofile: Fixup of loongson2_exit()
MIPS: Alchemy: sleepcode without compile-time cputype dependencies
MIPS: Tracing: Cleanup of address space checking
MIPS: Tracing: Cleanup of function graph tracer
MIPS: Tracing: Reduce the overhead of dynamic Function Tracer
MIPS: Tracing: Cleanup of instructions used
MIPS: Tracing: Fix 32-bit support with -mmcount-ra-address
MIPS: Tracing: Fix argument passing of the 32bit support with gcc 4.5
MIPS: Tracing: Cleanup comments
MIPS: Tracing: Cleanup the arguments passing of prepare_ftrace_return
MIPS: Tracing: Merge adjacent #ifdefs with same condition.
MIPS: AR7, BCM63xx: fix gpio_to_irq() return value
MIPS: Restore signalling NaN behaviour for abs.[sd]
MIPS: Loongson: CS5536: Fix ISA support
MIPS: Loongson: Add a missing break statement in CS5536 IDE code
MIPS: Loongson: CS5536: Add missing RDMSRs for IDE and USB
...
Commit 0a564b2 broke LOCALVERSION for O=... builds. Ouch.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-and-tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Peter Anvin <hpa@zytor.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sumeet Lahorani <sumeet.lahorani@oracle.com> reported that the IPoIB
child entries are world-writable; however we don't want ordinary users
to be able to create and destroy child interfaces, so fix them to be
writable only by root.
Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
If qib_init() fails, the driver fails to free memory, unregister
device files, and unregister with the PCIe framework. The driver will
unload without error but a subsequent driver load will cause the
system to panic. This was found by changing the 7220 code to load the
serdes microcode separately and not installing the microcode file.
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Workqueues aren't exactly equivalent to tasklets since the callback
function may be called from multiple CPUs before the callback returns.
This causes completion notification callbacks to have MT bugs since
they weren't expecting this behavior. The fix is to use a single
threaded work queue.
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
The hardware error register needs to be cleared or another interrupt
will be generated, thus causing an infinite loop. This is a
regression introduced when removing debug output.
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
The eager buffers are not being cleared before being mmapped into a
new user address space. This is a potential security risk and should
be fixed. Note that the eager header queue is already being cleared.
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
The HCA checks for certain hardware errors which can be falsely
triggered when the IB link is reset. The fix is to mask them rather
than report them.
Signed-off-by: Ralph Campbell <ralph.campbell@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Don't set write combining via PAT on the VL15 buffers to avoid a rare
problem with unaligned writes from interrupt-flushed store buffers.
Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
The T4 IQ hw design assumes CIDX_INC credits will be returned on a
regular basis and always before the CIDX counter crosses over the PIDX
counter. For RDMA CQs, however, returning CIDX_INC credits is only
needed and desired when and if the CQ is armed for notification. This
can lead to a GTS write returning credits that causes the HW to reject
the credit update because it causes CIDX to pass PIDX. Once this
happens, the CIDX/PIDX counters get out of whack and an application
can miss a notification and get stuck blocked awaiting a notification.
To avoid this, we allocate the HW IQ 2x times the requested size.
This seems to avoid the false overflow failures. If we see more
issues with this, then we'll have to add code in the poll path to
return credits periodically like when the amount reaches 1/2 the queue
depth). I would like to avoid this as it adds a PCI write transaction
for applications that never arm the CQ (like most MPIs).
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This replace the PCI DMA state API (include/linux/pci-dma.h) with the
DMA equivalents since the PCI DMA state API will be obsolete.
No functional change.
For further information about the background:
http://marc.info/?l=linux-netdev&m=127037540020276&w=2
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
First remove items from work_list as soon as we start working on them. This
means we don't have to track any pending or visited state and can get
rid of all the RCU magic freeing the work items - we can simply free
them once the operation has finished. Second use a real completion for
tracking synchronous requests - if the caller sets the completion pointer
we complete it, otherwise use it as a boolean indicator that we can free
the work item directly. Third unify struct wb_writeback_args and struct
bdi_work into a single data structure, wb_writeback_work. Previous we
set all parameters into a struct wb_writeback_args, copied it into
struct bdi_work, copied it again on the stack to use it there. Instead
of just allocate one structure dynamically or on the stack and use it
all the way through the stack.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
The case where we have a superblock doesn't require a loop here as we scan
over all inodes in writeback_sb_inodes. Split it out into a separate helper
to make the code simpler. This also allows to get rid of the sb member in
struct writeback_control, which was rather out of place there.
Also update the comments in writeback_sb_inodes that explain the handling
of inodes from wrong superblocks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This was just an odd wrapper around writeback_inodes_wb. Removing this
also allows to get rid of the bdi member of struct writeback_control
which was rather out of place there.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
