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commit 9993bc635d01a6ee7f6b833b4ee65ce7c06350b1 upstream.
When a machine boots up, the TSC generally gets reset. However,
when kexec is used to boot into a kernel, the TSC value would be
carried over from the previous kernel. The computation of
cycns_offset in set_cyc2ns_scale is prone to an overflow, if the
machine has been up more than 208 days prior to the kexec. The
overflow happens when we multiply *scale, even though there is
enough room to store the final answer.
We fix this issue by decomposing tsc_now into the quotient and
remainder of division by CYC2NS_SCALE_FACTOR and then performing
the multiplication separately on the two components.
Refactor code to share the calculation with the previous
fix in __cycles_2_ns().
Signed-off-by: Salman Qazi <sqazi@google.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Cc: john stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/20120310004027.19291.88460.stgit@dungbeetle.mtv.corp.google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 273fb194e86b795b08a724c7646d0f694949070b
[73d63d038ee9f769f5e5b46792d227fe20e442c5 upstream]
It causes problems, so needs to be reverted from 3.2-stable for now.
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Jon Dufresne <jon@jondufresne.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: <yinghai@kernel.org>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Teck Choon Giam <giamteckchoon@gmail.com>
Cc: Ben Guthro <ben@guthro.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit a97f4f5e524bcd09a85ef0b8821a14d35e69335f upstream.
Carlos was getting
WARNING: at drivers/pci/pci.c:118 pci_ioremap_bar+0x24/0x52()
when probing his sound card, and sound did not work. After adding
pci=use_crs to the kernel command line, no more trouble.
Ok, we can add a quirk. dmidecode output reveals that this is an MSI
MS-7253, for which we already have a quirk, but the short-sighted
author tied the quirk to a single BIOS version, making it not kick in
on Carlos's machine with BIOS V1.2. If a later BIOS update makes it
no longer necessary to look at the _CRS info it will still be
harmless, so let's stop trying to guess which versions have and don't
have accurate _CRS tables.
Addresses https://bugtrack.alsa-project.org/alsa-bug/view.php?id=5533
Also see <https://bugzilla.kernel.org/show_bug.cgi?id=42619>.
Reported-by: Carlos Luna <caralu74@gmail.com>
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 8411371709610c826bf65684f886bfdfb5780ca1 upstream.
In the spirit of commit 29cf7a30f8a0 ("x86/PCI: use host bridge _CRS
info on ASUS M2V-MX SE"), this DMI quirk turns on "pci_use_crs" by
default on a board that needs it.
This fixes boot failures and oopses introduced in 3e3da00c01d0
("x86/pci: AMD one chain system to use pci read out res"). The quirk
is quite targetted (to a specific board and BIOS version) for two
reasons:
(1) to emphasize that this method of tackling the problem one quirk
at a time is a little insane
(2) to give BIOS vendors an opportunity to use simpler tables and
allow us to return to generic behavior (whatever that happens to
be) with a later BIOS update
In other words, I am not at all happy with having quirks like this.
But it is even worse for the kernel not to work out of the box on
these machines, so...
Reference: https://bugzilla.kernel.org/show_bug.cgi?id=42619
Reported-by: Svante Signell <svante.signell@telia.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[no upstream commit match, as this is a fix for a mis-applied patch in the
previous 3.2-stable release. - gregkh]
Commit 83e4194 "ARM: tegra: select required CPU and L2 errata options"
contained two chunks; one was errata for Tegra20 (correctly applied)
and the second errata for Tegra30. The latter was accidentally applied
to the wrong config option; Tegra30 support wasn't added until v3.3,
and so the second chunk should have just been dropped. This patch does
so.
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 3751d3e85cf693e10e2c47c03c8caa65e171099b upstream.
There has long been a limitation using software breakpoints with a
kernel compiled with CONFIG_DEBUG_RODATA going back to 2.6.26. For
this particular patch, it will apply cleanly and has been tested all
the way back to 2.6.36.
The kprobes code uses the text_poke() function which accommodates
writing a breakpoint into a read-only page. The x86 kgdb code can
solve the problem similarly by overriding the default breakpoint
set/remove routines and using text_poke() directly.
The x86 kgdb code will first attempt to use the traditional
probe_kernel_write(), and next try using a the text_poke() function.
The break point install method is tracked such that the correct break
point removal routine will get called later on.
Cc: x86@kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Inspried-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6cfeba53911d6d2f17ebbd1246893557d5ff5aeb upstream.
On multi-platform kernels, the Mac platform devices should be registered
when running on Mac only. Else it may crash later.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 1d24fb3684f347226747c6b11ea426b7b992694e ]
When K >= 0xFFFF0000, AND needs the two least significant bytes of K as
its operand, but EMIT2() gives it the least significant byte of K and
0x2. EMIT() should be used here to replace EMIT2().
Signed-off-by: Feiran Zhuang <zhuangfeiran@ict.ac.cn>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Disable stuff which is known to have issues on RT
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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We can't deal with the cpumask allocations which happen in atomic
context (see arch/x86/kernel/apic/io_apic.c) on RT right now.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Restrict the preempt disabled regions to the actual floating point
operations and enable preemption for the administrative actions.
This is necessary on RT to avoid that kfree and other operations are
called with preemption disabled.
Reported-and-tested-by: Carsten Emde <cbe@osadl.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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In fact, with migrate_disable() existing one could play games with
kmap_atomic. You could save/restore the kmap_atomic slots on context
switch (if there are any in use of course), this should be esp easy now
that we have a kmap_atomic stack.
Something like the below.. it wants replacing all the preempt_disable()
stuff with pagefault_disable() && migrate_disable() of course, but then
you can flip kmaps around like below.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
[dvhart@linux.intel.com: build fix]
Link: http://lkml.kernel.org/r/1311842631.5890.208.camel@twins
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Normally the x86-64 trap handlers for debug/int 3/stack fault run
on a special interrupt stack to make them more robust
when dealing with kernel code.
The PREEMPT_RT kernel can sleep in locks even while allocating
GFP_ATOMIC memory. When one of these trap handlers needs to send
real time signals for ptrace it allocates memory and could then
try to to schedule. But it is not allowed to schedule on a
IST stack. This can cause warnings and hangs.
This patch disables the IST stacks for these handlers for PREEMPT_RT
kernel. Instead let them run on the normal process stack.
The kernel only really needs the ISTs here to make kernel debuggers more
robust in case someone sets a break point somewhere where the stack is
invalid. But there are no kernel debuggers in the standard kernel
that do this.
It also means kprobes cannot be set in situations with invalid stack;
but that sounds like a reasonable restriction.
The stack fault change could minimally impact oops quality, but not very
much because stack faults are fairly rare.
A better solution would be to use similar logic as the NMI "paranoid"
path: check if signal is for user space, if yes go back to entry.S, switch stack,
call sync_regs, then do the signal sending etc.
But this patch is much simpler and should work too with minimal impact.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Simplifies the separation of anon_rw_semaphores and rw_semaphores for
-rt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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CPU bringup calls into the random pool to initialize the stack
canary. During boot that works nicely even on RT as the might sleep
checks are disabled. During CPU hotplug the might sleep checks
trigger. Making the locks in random raw is a major PITA, so avoid the
call on RT is the only sensible solution. This is basically the same
randomness which we get during boot where the random pool has no
entropy and we rely on the TSC randomnness.
Reported-by: Carsten Emde <carsten.emde@osadl.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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mce_timer is started in atomic contexts of cpu bringup. This results
in might_sleep() warnings on RT. Convert mce_timer to a hrtimer to
avoid this.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Without this patch, ARM can not use SPLIT_PTLOCK_CPUS if
PREEMPT_RT_FULL=y because vectors_user_mapping() creates a
VM_ALWAYSDUMP mapping of the vector page (address 0xffff0000), but no
ptl->lock has been allocated for the page. An attempt to coredump
that page will result in a kernel NULL pointer dereference when
follow_page() attempts to lock the page.
The call tree to the NULL pointer dereference is:
do_notify_resume()
get_signal_to_deliver()
do_coredump()
elf_core_dump()
get_dump_page()
__get_user_pages()
follow_page()
pte_offset_map_lock() <----- a #define
...
rt_spin_lock()
The underlying problem is exposed by mm-shrink-the-page-frame-to-rt-size.patch.
Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Cc: Frank <Frank_Rowand@sonyusa.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/4E87C535.2030907@am.sony.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Use the local_irq_*_nort() variants.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Preemption must be disabled before enabling interrupts in do_trap
on x86_64 because the stack in use for int3 and debug is a per CPU
stack set by th IST. But 32bit does not have an IST and the stack
still belongs to the current task and there is no problem in scheduling
out the task.
Keep preemption enabled on X86_32 when enabling interrupts for
do_trap().
The name of the function is changed from preempt_conditional_sti/cli()
to conditional_sti/cli_ist(), to annotate that this function is used
when the stack is on the IST.
Cc: stable-rt@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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With threaded interrupts we might see an interrupt in progress on
migration. Do not unmask it when this is the case.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The machine might survive that problem and be at least in a state
which allows us to get more information about the problem.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Wrap the test for pagefault_disabled() into a helper, this allows us
to remove the need for current->pagefault_disabled on !-rt kernels.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-3yy517m8zsi9fpsf14xfaqkw@git.kernel.org
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Necessary for decoupling pagefault disable from preempt count.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Setup and remove the interrupt handler in clock event mode selection.
This avoids calling the (shared) interrupt handler when the device is
not used.
Signed-off-by: Benedikt Spranger <b.spranger@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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On x86_64 we must disable preemption before we enable interrupts
for stack faults, int3 and debugging, because the current task is using
a per CPU debug stack defined by the IST. If we schedule out, another task
can come in and use the same stack and cause the stack to be corrupted
and crash the kernel on return.
When CONFIG_PREEMPT_RT_FULL is enabled, spin_locks become mutexes, and
one of these is the spin lock used in signal handling.
Some of the debug code (int3) causes do_trap() to send a signal.
This function calls a spin lock that has been converted to a mutex
and has the possibility to sleep. If this happens, the above issues with
the corrupted stack is possible.
Instead of calling the signal right away, for PREEMPT_RT and x86_64,
the signal information is stored on the stacks task_struct and
TIF_NOTIFY_RESUME is set. Then on exit of the trap, the signal resume
code will send the signal when preemption is enabled.
[ rostedt: Switched from #ifdef CONFIG_PREEMPT_RT_FULL to
ARCH_RT_DELAYS_SIGNAL_SEND and added comments to the code. ]
Cc: stable-rt@vger.kernel.org
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Coccinelle based conversion.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The arm boot_lock is used by the secondary processor startup code. The locking
task is the idle thread, which has idle->sched_class == &idle_sched_class.
idle_sched_class->enqueue_task == NULL, so if the idle task blocks on the
lock, the attempt to wake it when the lock becomes available will fail:
try_to_wake_up()
...
activate_task()
enqueue_task()
p->sched_class->enqueue_task(rq, p, flags)
Fix by converting boot_lock to a raw spin lock.
Signed-off-by: Frank Rowand <frank.rowand@am.sony.com>
Link: http://lkml.kernel.org/r/4E77B952.3010606@am.sony.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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All timer interrupts and the perf interrupt are marked NO_THREAD, so
its safe to allow forced interrupt threading.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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PMU interrupt must not be threaded. Remove IRQF_DISABLED while at it
as we run all handlers with interrupts disabled anyway.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The update of the vdso data happens under xtime_lock, so adding a
nested lock is pointless. Just use a seqcount to sync the readers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
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The update of the vdso data happens under xtime_lock, so adding a
nested lock is pointless. Just use a seqcount to sync the readers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Changing the sequence count in update_vsyscall_tz() is completely
pointless.
The vdso code copies the data unprotected. There is no point to change
this as sys_tz is nowhere protected at all. See sys_gettimeofday().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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All interrupts which must be non threaded are marked
IRQF_NO_THREAD. So it's safe to allow force threaded handlers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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IPI handlers cannot be threaded. Remove the obsolete IRQF_DISABLED
flag (see commit e58aa3d2) while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cascade handlers must run in hard interrupt context.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Cascade interrupt must run in hard interrupt context.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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